Nanophytoremediation: An Overview of Novel and Sustainable Biological Advancement

*Silpi Sarkar, Manoj Kumar Enamala, Murthy Chavali, G.V.S. Subbaroy Sarma, Mannam Krishna Murthy, Abudukeremu Kadier, Ashokkumar Veeramuthu and K. Chandrasekhar*

## **Abstract**

Increased threat of metals simultaneous to the biota well-being and the environs is continually causing a major apprehension worldwide. The phytoremediation technique is highly advantageous involving the natural processes of plants viz., translocation, evapotranspiration, and bioaccumulation, thus degrading contaminants slowly. In particular, nanophytoremediation is a rapid green alternative as it reduces the ancillary impacts of the environment such as green gas emissions, waste generation, and natural resource consumption to the present scenario as there is a great potential of nanoparticles from plants which can be synthesized. Nanophytoremediation is a current methodology for remediation of pollutants, contaminants by using synthesized nanoparticles from plants. In this, the use of different strategies enhances the selective uptake capabilities of plants. The metal elements in excess are affecting the physiological processes in plants; thus, it is necessary to apply nanophytoremediation technology through transgenic plants. In this review paper, we focused on plant species, which can be used as metal tolerant, hyperaccumulators. Due to the insurmountable pressure of a sustainable cleaner environment, bioremediation can be concurrent with nanoparticles for efficient and effective sustainable measures.

**Keywords:** nanoparticles, phytoremediation technologies, hyperaccumulators, bioelements, contaminants, transgenic plants

## **1. Introduction**

Plants are autotrophic in nature, thus are self-sufficient in the utilization of sunshine and CO2 as energy and carbon sources. The vegetation mostly depends on its roots for water, nutrients, and minerals from groundwater and soil. The maintenance of the greener environment is mostly integrated with plants. Further, the sustainability of these plants depends on the environment, which is contaminated mostly from anthropogenic activities and pollution. In contrast, plants also absorb

**Figure 1.** *Illustration of physiological processes occurring in plants during phytoremediation.*


#### **Table 1.**

*Technologies related to phytoremediation.*

diverse compounds that are toxic in nature, thus can be considered as an efficient detoxification mechanism for the removal of contaminants. Thus, from this viewpoint, plants are employed effectively in the treatment of contaminants viz.,

**217**

**Table 2.**

*Nanophytoremediation: An Overview of Novel and Sustainable Biological Advancement*

organic contaminants, polyaromatic hydrocarbons, which are potentially viable in contaminant detoxification. Previously, the traditional remediation of metalcontaminated soil includes on-site management and subsequent disposal of wastes to another landfill site. However, this makes the site hazardous with additional risks of migration of contamination. There are various clean-up techniques for soils that can be categorized as physical, chemical, and biological. There are reports of the chemical and physical processes, which have limitations viz., great price, labor intensive, variations in properties of soil, and disturbance of the native soil microflora, whereas chemical techniques increase secondary pollution problems with large volumetric sludge which increases the cost. The biological remediation processes consist of bioventing, bioleaching, bioremediation, bioreactors, bioaugmentation, biostimulation, and land forming. In this context, the phytoremediation technology has been in existence in par with other remediation technologies as a

Phytoremediation created from Greek prefix "*phyto*" means plant and Latin suffix "*remedium*" means remedy or restore. Phytoremediation is a versatile technology to treat polluted soils, pollutants, deposits, and groundwater, in a profitable as well as environmental welcoming the usage of plants [1], thus can be referred to as natural green biotechnology **Figure 1** denotes the different phytoremediation technologies. Phytoremediation technology is suitable against several types of contaminants

> *Pelargonium graveolens*, *Hibiscus rosasinensis*, *Citrus sinensis*, *Diospyros kaki (Persimmon)*, *Emblica officinalis*, *Phyllanthium*, *Mushroom extract*, *Coriandrum*

*Ocimum* sp., *Nerium indicum*, *Brassica juncea*, *Azadirachta indica*, *Pongamia pinnata*, *Clerodendrum inerme*, *Opuntia ficus-indica*, *Gliricidia sepium*, *Desmodium triflorum*, *Carica papaya*, *Coriandrum sativum*, *Peargoneum graveolens*, *Avicennia marnia*, *Aloe vera extract*, *Capsicum annum*, *Rhizophora mucronata*, *Ceriops tagal*, *Rumex* 

*Camellia sinensis* L*.*, *Chenopodium album* L*.*, *Justicia gendarussa* L*.*, *Macrotyloma uniflorum* (Lam) Verde, *Azadirachta indica* A. Juss, *Magnolia kobus and Diospyros kaki*, *Cinnamomum zeylanicum*, *Mentha piperita* L*.*, *Mirabilis jalapa* L*.*, *Syzygiuma* 

*Cinnamomum zeylanicum* Blume, *Cinnamomum camphora* L*.*, *Gardenia jasminoides*

*DOI: http://dx.doi.org/10.5772/intechopen.93300*

novel natural ecological, biological remediation process.

**Nanoparticles Plant**

Silicon-Germanium

Ag, Ni, Co, Zn and Cu nanoparticles

Lead nanoparticles Indium oxide nanoparticles Gold/Silver bimetallic nanoparticles

*Numerous nanoparticles synthesized from the plants.*

Platinum nanoparticles

Palladium nanoparticles

(Si-Ge) nanoparticles

Au and Ag nanoparticles

[2] in the atmosphere in a variety of media, as mentioned in **Table 1**.

Freshwater diatom *Stauroneis* sp.

Ag nanoparticles *Elettaria cardamom*, *Parthenium hysterophorus*, *Euphorbia hirta,*

*hymenosepalus*, *Pterocarpus santalinus*, *Sonchus asper* Au nanoparticles *Terminalia catappa*, Banana peel, *Mucuna pruriens*, *Medicago sativa*, *Allium cepa* L*.*,

*romaticum*, *Terminalia catappa* L., and *Amaranthus spinosus*

*Brassica juncea*, *Medicago sativa*, and *Helianthus annuus*

*Diospyros kaki* and *Ocimum sanctum* L*.*,

Ellis*.*, *Soybean (Glycine max)* L*.,*

*Vitis vinifera* L*.* and *Jatropha curcas* L*. Aloe vera* (*Aloe barbadensis* Miller)*, Azadirachta indica* (Neem)

*sativum*

#### *Nanophytoremediation: An Overview of Novel and Sustainable Biological Advancement DOI: http://dx.doi.org/10.5772/intechopen.93300*

organic contaminants, polyaromatic hydrocarbons, which are potentially viable in contaminant detoxification. Previously, the traditional remediation of metalcontaminated soil includes on-site management and subsequent disposal of wastes to another landfill site. However, this makes the site hazardous with additional risks of migration of contamination. There are various clean-up techniques for soils that can be categorized as physical, chemical, and biological. There are reports of the chemical and physical processes, which have limitations viz., great price, labor intensive, variations in properties of soil, and disturbance of the native soil microflora, whereas chemical techniques increase secondary pollution problems with large volumetric sludge which increases the cost. The biological remediation processes consist of bioventing, bioleaching, bioremediation, bioreactors, bioaugmentation, biostimulation, and land forming. In this context, the phytoremediation technology has been in existence in par with other remediation technologies as a novel natural ecological, biological remediation process.

Phytoremediation created from Greek prefix "*phyto*" means plant and Latin suffix "*remedium*" means remedy or restore. Phytoremediation is a versatile technology to treat polluted soils, pollutants, deposits, and groundwater, in a profitable as well as environmental welcoming the usage of plants [1], thus can be referred to as natural green biotechnology **Figure 1** denotes the different phytoremediation technologies. Phytoremediation technology is suitable against several types of contaminants [2] in the atmosphere in a variety of media, as mentioned in **Table 1**.


#### **Table 2.**

*Numerous nanoparticles synthesized from the plants.*

*Soil Contamination - Threats and Sustainable Solutions*

**216**

**Table 1.**

Bioremediation supported

*Technologies related to phytoremediation.*

by plants

**Figure 1.**

diverse compounds that are toxic in nature, thus can be considered as an efficient detoxification mechanism for the removal of contaminants. Thus, from this viewpoint, plants are employed effectively in the treatment of contaminants viz.,

**Treatment Mechanism Medium** Phytodegradation Degradation of plant uptake organics Surface and

rhizosphere

*Illustration of physiological processes occurring in plants during phytoremediation.*

degradation.

Phytostabilization Root exudes which causes metal precipitation,

Phytoextraction Metal uptake and the presence of metal

Rhizosecretion Molecular farming methodology, which

Vegetative caps Rainwater is evapotranspiration, preventing

Rhizofiltration Roots can uptake metals Surface waters and

Enhanced microbial degradation in the

concentration directly via plant tissue with the subsequent exclusion of plants for biomass

Phytovolatilization Evapo transpires Se, Hg, and volatile organics Soils and groundwaters

secretes natural products and recombinant

contaminant leaching from a waste disposal site

thus decreases the bioavailability

Phytomining Inorganic substance extraction from mine ore Soil Removal of organics Volatile organics are left out through the plant Air

proteins from roots.

groundwater

troughs

Soils

Soil

Soil

water pumped through

Soils and groundwaters within the rhizosphere

Soils, groundwaters, and tailings in a mine

**Figure 2.**

*Publication trends for phytoremediation as per the ScienceDirect database—year-wise publications, (a) category wise and (b) journal wise.*

Phytoremediation technique has its own limitations:

a.Slow remediation time

#### b.Plant waste after phytoremediation

It is seen previously that plants [3] have a tendency to produce nanoparticles under appropriate conditions, as mentioned in **Table 2**. The deployment of contained contaminants remains equally *in situ* and *ex situ*. One of the newer techniques of *in situ* remediation, nanotechnology has been in focus with the usage of nanomaterials in various laboratory investigations and field applications, mostly in North America and Europe. But in India, nanophytoremediation is not practiced. Although nanophytoremediation can be an economically viable process, proper utilization can be ecologically useful.

Several studies report the usage of nanoparticles to have an affirmative effect on plants. Mixed TiO2 (nano) and SiO2 (nano) were presented into soybean (*Glycine max*) increasing activity of nitrate reductases, which sped the plant propagation by increasing the water absorption and fertilizer utilization (Lu et al., 2001).

**219**

*Nanophytoremediation: An Overview of Novel and Sustainable Biological Advancement*

Similarly, it was found by studies that carbon dots (CDs) promote growth in mung bean at 0–1.0 mg/mL concentration (Li et al., 2016). This result supports that nanoderivatives like carbon dots can absorb and utilize nutrients that induce a physiological response. Although there are studies on nanoparticles that can cause toxicity, it has not been yet elucidated for most nanoparticles. It is vividly important to study nanoparticles and their effect on plant growth mechanisms to prevent the ecological risk of nanoparticles and to promote sustainable development of nanotechnology in the near future, particularly in the Indian context. Thus, the different integrated approaches to producing nanoparticles and apply nanoderivatives eliminating the metal impurities from soil and water; thus, a flawless, in-depth study of nanoparticles is required, which can be applied. Nanophytoremediation study is based as an alternative remediation advanced technology in addition to the phytoremediation, the current scenario of reducing

Publications wise not many were found in the literature databases; for example,

probing ScienceDirect database, it has found none on nanophytoremediation. Since the year 1995 to date, 2018, the number of publications found to be 764. Of which highest published were found to be research articles (567) followed by review

Among journal trends, the highest number was found to be in journal: Chemosphere (99) followed by Ecotoxicology and Environmental Safety (61), Ecological Engineering (52), the lowest number published was in

Journal of Biotechnology (18) over the years 1995–2018. Publication trends for phytoremediation, as observed from the ScienceDirect Database year-wise publications: (a) category wise and (b) journal wise were shown in **Figure 2**. Nanophytotechnological remediation was published in the *J. of Environ. Protec.*

a.**Phytoextraction:** Metal concentration reduction in the soil through plants that

enhancing the microbial activity in the rhizosphere of the plant. It is a type of rhizosphere phytoremediation which is used as an inexpensive approach to

cleaned up by plants and discharge them as atmospheric volatiles through

b.**Phytostabilization:** Immobilize the utilization of soil metals via adsorption

c.**Phytostimulation:** The process where root releases certain compounds

d.**Phytovolatilization:** A technique, where the soil contaminants are

e.**Phytotransformation/phytodegradation:** Breaking down of organic

articles (78), short communications (34), and rest others.

(JEP) (2016, http://dx.doi.org/10.4236/jep.2016.75066).

Phytoremediation technologies are classified in general into:

**2. Phytoremediation classification**

can accumulate metals in the shoots.

onto roots; rhizosphere precipitation.

contaminants seized through plants via

remove soil organic pollutants.

transpiration.

*DOI: http://dx.doi.org/10.5772/intechopen.93300*

the contaminants in a safer way.

**1.1 Publications**

*Nanophytoremediation: An Overview of Novel and Sustainable Biological Advancement DOI: http://dx.doi.org/10.5772/intechopen.93300*

Similarly, it was found by studies that carbon dots (CDs) promote growth in mung bean at 0–1.0 mg/mL concentration (Li et al., 2016). This result supports that nanoderivatives like carbon dots can absorb and utilize nutrients that induce a physiological response. Although there are studies on nanoparticles that can cause toxicity, it has not been yet elucidated for most nanoparticles. It is vividly important to study nanoparticles and their effect on plant growth mechanisms to prevent the ecological risk of nanoparticles and to promote sustainable development of nanotechnology in the near future, particularly in the Indian context. Thus, the different integrated approaches to producing nanoparticles and apply nanoderivatives eliminating the metal impurities from soil and water; thus, a flawless, in-depth study of nanoparticles is required, which can be applied. Nanophytoremediation study is based as an alternative remediation advanced technology in addition to the phytoremediation, the current scenario of reducing the contaminants in a safer way.

### **1.1 Publications**

*Soil Contamination - Threats and Sustainable Solutions*

*Publication trends for phytoremediation as per the ScienceDirect database—year-wise publications,* 

It is seen previously that plants [3] have a tendency to produce nanoparticles under appropriate conditions, as mentioned in **Table 2**. The deployment of contained contaminants remains equally *in situ* and *ex situ*. One of the newer techniques of *in situ* remediation, nanotechnology has been in focus with the usage of nanomaterials in various laboratory investigations and field applications, mostly in North America and Europe. But in India, nanophytoremediation is not practiced. Although nanophytoremediation can be an economically viable process, proper

Several studies report the usage of nanoparticles to have an affirmative effect on plants. Mixed TiO2 (nano) and SiO2 (nano) were presented into soybean (*Glycine max*) increasing activity of nitrate reductases, which sped the plant propagation by increasing the water absorption and fertilizer utilization (Lu et al., 2001).

Phytoremediation technique has its own limitations:

**218**

**Figure 2.**

*(a) category wise and (b) journal wise.*

a.Slow remediation time

b.Plant waste after phytoremediation

utilization can be ecologically useful.

Publications wise not many were found in the literature databases; for example, probing ScienceDirect database, it has found none on nanophytoremediation. Since the year 1995 to date, 2018, the number of publications found to be 764. Of which highest published were found to be research articles (567) followed by review articles (78), short communications (34), and rest others.

Among journal trends, the highest number was found to be in journal: Chemosphere (99) followed by Ecotoxicology and Environmental Safety (61), Ecological Engineering (52), the lowest number published was in Journal of Biotechnology (18) over the years 1995–2018. Publication trends for phytoremediation, as observed from the ScienceDirect Database year-wise publications: (a) category wise and (b) journal wise were shown in **Figure 2**. Nanophytotechnological remediation was published in the *J. of Environ. Protec.* (JEP) (2016, http://dx.doi.org/10.4236/jep.2016.75066).

#### **2. Phytoremediation classification**

Phytoremediation technologies are classified in general into:


i.*Plant metabolic processes or*

ii.*The outcome of metabolites*, *such as enzymes*, *produced by the plant*

f. **Phytoresaturation:** Re-vegetation of the drylands by plants can prevent the spread of pollutants into the environment [4].


**221**

technology.

*Nanophytoremediation: An Overview of Novel and Sustainable Biological Advancement*

An overview of metal contaminants in several phytoremediation processes is provided in **Table 3**. In the case of contaminated water, the following processes in

a.**Rhizofiltration:** Roots were used to remove aqueous toxic metals, mainly the heavy metals like, lead (Pb) and radioactive elements [5]. The plants are employed as filters in wetlands or as a hydroponic setup [6]. Wetlands are often widely considered as sinks for pollutants, and there are countless instances where the wetlands plants are considered to remove contaminants [7] used which include metals viz., Se, perchlorate, cyanide, nitrate, and phosphate [8].

b.**Hydraulic control:** It is a process in which bulk amount of water is absorbed by the wildly growing plants preventing the increase of pollutants into the

ii.Huge surface area proportionately in contact with the water body

potential (TP) are related to plants' sensitivity for phytoremediation.

These factors say both the bioconcentration factor (BCF) and translocation

In Brake fern (*Pteris vittata*), the best phytoremediation process is established as it consists of a high root to shoot metal transduction; thus, it is observed that the BCF value is greater than one. Out of the several phytoremediation technologies, phytoextraction is the most effective, which depends upon hyperaccumulation of metals into the whole plants. For phytoextraction, a heavy metal tolerant plant that grows rapidly with high biomass yield per hectare also should possess a prolific root system. When the cultivation is over by the season's end plants are harvested, dehydrated and the enriched mass with contaminants is dumped or sent into the smelter. To be active phytoextraction, the dehydrated biomass, ash extracted from the aboveground parts of a phytoremediator crop, consists of a greater concentration of the pollutants than the contaminated soil [10]. The biomass rich product exudes as the secondary metabolic waste, which requires further treatment. The phytoextraction process can be natural and induced. The energy can be recovered from biomass burn or pyrolysis; thus, phytoextraction can be used as a cost-effective technology by giving biomass yields. *Salix* and *Populus* species are also used for phytoremediation

Pollution is an undesirable change observed, which is deteriorating our raw materials, especially land and water. An overall representation of the contamination process, which can cause microorganisms to pollute soil and surface water, is shown in (**Figure 3**). At normal concentration, soil comprises bioelements, particularly metals. These bioelements serve as micronutrients and macronutrients for the soil. They can be classified as light metals (Mg and Al) metalloids (As and Se)m and heavy metals viz., Cd, Hg, Pb, Cr, Ag, and Sn. Light metals have a greater significance to health and environment [11], whereas substantial metals are the bioelements

*DOI: http://dx.doi.org/10.5772/intechopen.93300*

phytoremediation technologies are utilized as:

unpolluted surrounding zones [4].

iii.High translocation potential [9]

**3. Bioelements and their effects on pollution**

The phytoremediation methods chosen depend upon:

i.Specifically high growth rates in the polluted sites

## **Table 3.**

*Nanophytoremediation: An Overview of Novel and Sustainable Biological Advancement DOI: http://dx.doi.org/10.5772/intechopen.93300*

An overview of metal contaminants in several phytoremediation processes is provided in **Table 3**. In the case of contaminated water, the following processes in phytoremediation technologies are utilized as:


The phytoremediation methods chosen depend upon:


iii.High translocation potential [9]

These factors say both the bioconcentration factor (BCF) and translocation potential (TP) are related to plants' sensitivity for phytoremediation.

In Brake fern (*Pteris vittata*), the best phytoremediation process is established as it consists of a high root to shoot metal transduction; thus, it is observed that the BCF value is greater than one. Out of the several phytoremediation technologies, phytoextraction is the most effective, which depends upon hyperaccumulation of metals into the whole plants. For phytoextraction, a heavy metal tolerant plant that grows rapidly with high biomass yield per hectare also should possess a prolific root system. When the cultivation is over by the season's end plants are harvested, dehydrated and the enriched mass with contaminants is dumped or sent into the smelter. To be active phytoextraction, the dehydrated biomass, ash extracted from the aboveground parts of a phytoremediator crop, consists of a greater concentration of the pollutants than the contaminated soil [10]. The biomass rich product exudes as the secondary metabolic waste, which requires further treatment. The phytoextraction process can be natural and induced. The energy can be recovered from biomass burn or pyrolysis; thus, phytoextraction can be used as a cost-effective technology by giving biomass yields. *Salix* and *Populus* species are also used for phytoremediation technology.

#### **3. Bioelements and their effects on pollution**

Pollution is an undesirable change observed, which is deteriorating our raw materials, especially land and water. An overall representation of the contamination process, which can cause microorganisms to pollute soil and surface water, is shown in (**Figure 3**). At normal concentration, soil comprises bioelements, particularly metals. These bioelements serve as micronutrients and macronutrients for the soil. They can be classified as light metals (Mg and Al) metalloids (As and Se)m and heavy metals viz., Cd, Hg, Pb, Cr, Ag, and Sn. Light metals have a greater significance to health and environment [11], whereas substantial metals are the bioelements

*Soil Contamination - Threats and Sustainable Solutions*

spread of pollutants into the environment [4].

**agents**

and stabilizing agent)

(antioxidant)

Ascorbic acid (Vit-C)

(Vit-C)

(A. Acid)

(A. Acid) L-Glutamic Acid L-Glutamine L-Arginine and L-Cysteine

myoglobin

gluconic Acid

Glyconic acid

Wood-derived sugar

ii.*The outcome of metabolites*, *such as enzymes*, *produced by the plant*

f. **Phytoresaturation:** Re-vegetation of the drylands by plants can prevent the

Starch 14.1 nm distinct, well dispersed

> 50–200 nm spherical, 24 nm diameter and hexagonal

5–30 nm

17.50 nm and spherical crystalline

(hydrodynamic size)

2–5 nm aggregates, crystalline

12.5 nm roughly spherical, crystalline

100–150 nm nanospheres, 10–25 nm diameter of

iron core

Iron oxide Tannic acid <10 nm Utilization of biomass

Fe3O4 Na-Alginate 27.20 nm spherical Urea decomposition

**Size/morphology Environmental** 

<100 nm cubic Functions in catalysis,

20–75 nm, spherical Cd removal

— Low molecular,

**applications**

Degradation of chlorinated hydrocarbons in water

Magnetic storage media

biosensors, energy storage problems, nanodevices

Contrast enhancement agent for MRI applications

Biosensors, drug delivery

biocompatible

Bioconjugated

Drug delivery, cell transplantation

biomedical field

Acts as catalysts in the conversion of woodderived syngas to liquid hydrocarbons

causes the reduction of

of drug gallic acid, anticancer activity was higher for HT29 and MCF7

metal ions

cell lines

11 nm cubic Increased thermal stability

applications

4–16 nm crystalline Removal of waste in the

nanoparticles for biological

i.*Plant metabolic processes or*

**Type of nanoparticles Biochemical** 

Fe3O4-Polymer Composite Agar (reducing

Nano-shell (Fe, Cu) Ascorbic acid

nZVI Ascorbic acid

Fe3O4 (MNPs) L-Lysine

nZVI L-Lysine

FeNPs Hemoglobin and

Fe3O4 D-glucose

Fe3O4 Glucose &

Fe core-shell structure Chitosan-gallic

*Synthesis of iron nanoparticles/derivatives.*

acid

Carbon capsulated Iron

NPs

Stabilized bimetallic Fe/Pd

nanoparticles

Superparamagnetic Iron oxide (coatings and functionalization)

**220**

**Table 3.**

**Figure 3.**

*An overall representation of the contamination process—that can cause microorganisms to pollute soil and surface water.*

(At. No., Z > 20) with a density > 5.0 g/cc and have definite metal properties such as conductivity, ductility, ligand specificity, cationic stability. Beneficial heavy metals include elements such as Cu, Cr, Zn, Mn, Fe, Co, and Ni, which are essential in smaller amounts in metabolism but may be lethal in higher concentrations. Geogenic and anthropogenic contaminations by heavy metal is shown and can cause microorganisms [12] to affect the normal molecular process as shown in (**Figure 4**). Heavy metals sieve through the soil and are terminated into the soil by geogenic and anthropogenic processes [13].

Geogenic contamination can be exemplified by extensive arsenic contamination, as seen in the ground waters of Indian state of West Bengal and Bangladesh [14]. The other contamination source includes anthropogenic activities like generating huge amounts of effluents, which is a constant threat to environmental pollution. Fertilizers incorporate phosphate compounds containing Cd, which are being used in horticulture, agriculture as well as in animal industries as a trace element nutrient. Cd, Hg, and Pb metals attack the activity of the enzyme, which contains the ▬SH group which initiates chronic diseases. These heavy metals/metalloids and organics form a grave danger to animals (including humans) and plants. Heavy metal pollution on land and water shows a severe impact on the ecosystem. In Western Europe, a large mass of approximately 14,00,000 sites affected as the reports of [15], out of which 3,00,000 are contaminated, but the projected number in Europe could be greater, as the problem was progressively occurring in the Central and East European countries. In the United States, around 600,000 contaminated brownfields with heavy metals requiring reclamation [16]. Land pollution has been a great challenge in the Asian continent as seen in China, where onesixth of arable land is with heavy metal pollution, and over 45% has been ruined either due to erosion or desertification. This becomes the consequence because of human-dominated ecological problems viz., urban ecology and agricultural ecology [17]. Thus, it is vital to eliminate these pollutants from the contaminated sites in which phytoremediation is one of the processes that include complexation, accumulation, volatilization, and degradation of pollutants both of organic and inorganic origins.

**223**

Ag<sup>+</sup>

**Figure 4.**

*the normal molecular process.*

untreated controls.

and Au3+ to Ag0

and Au0

*Nanophytoremediation: An Overview of Novel and Sustainable Biological Advancement*

*DOI: http://dx.doi.org/10.5772/intechopen.93300*

**4. Biosynthesis of nanoparticles from plants**

Nanoparticles are aggregates between 1 and 100 nm; this particular size that alters the physicochemical properties equated to other material. A variety of nanoparticles are produced by bacteria, fungi, and plants [18], which have wider applications in several sectors. Plants are more appropriate than bacteria or fungi toward the synthesis of NPs, as less incubation time is required for metal ion reduction. The procedures such as plant tissue culture (PTC) and downstream processing techniques make more promising in synthesizing metal and oxide NPs at a larger scale. The documentation of hyperaccumulator exclusive genes and their succeeding transfer to the other species of transgenic plants can improve phytoremediation capacity. The plant's remediation volume shall be greatly enhanced by genetic manipulation and other viable plant-based transforming techniques. In plants, it is seen to have an inherent ability to lessen metals through their specific metabolic pathways [19]. Stampoulis et al. [20] have examined the impact of ZnO, Cu, Si, and Ag NPs on the root elongation, seed germination, and biomass production of *Cucurbita pepo* grown as hydroponics. Accordingly, experimental findings suggested that root length is reduced by 77% when seeds are exposed to Cu nanoparticles and 64% when exposed to bulk Cu powder when equated to the

*Geogenic and anthropogenic contaminations by heavy metal is shown and can cause microorganisms to affect* 

Plant biomass was reduced by 75% when exposed to Ag NPs. Shekhawat and Arya [21] used *Brassica juncea* seedlings to produce Ag NPs *in vitro*. There are reports from of synthesized gold nanoparticles by *Terminalia catappa* leaf extract in an aqueous medium [22]. The authors [4, 23] examined metal ions

Nevertheless, Ag NPs in plants are mostly modeled as Ag not only forms NPs in plants but it also exhibits higher catalytic properties as it consists of high electrochemical reduction potential and several additional useful properties. Although the research on the production of nanoparticles is in a nascent stage in plants,

NPs in *Brassica juncea* for the reduction sites.

*Nanophytoremediation: An Overview of Novel and Sustainable Biological Advancement DOI: http://dx.doi.org/10.5772/intechopen.93300*

**Figure 4.**

*Soil Contamination - Threats and Sustainable Solutions*

(At. No., Z > 20) with a density > 5.0 g/cc and have definite metal properties such as conductivity, ductility, ligand specificity, cationic stability. Beneficial heavy metals include elements such as Cu, Cr, Zn, Mn, Fe, Co, and Ni, which are essential in smaller amounts in metabolism but may be lethal in higher concentrations. Geogenic and anthropogenic contaminations by heavy metal is shown and can cause microorganisms [12] to affect the normal molecular process as shown in (**Figure 4**). Heavy metals sieve through the soil and are terminated into the soil by geogenic and anthro-

*An overall representation of the contamination process—that can cause microorganisms to pollute soil and* 

Geogenic contamination can be exemplified by extensive arsenic contamination, as seen in the ground waters of Indian state of West Bengal and Bangladesh [14]. The other contamination source includes anthropogenic activities like generating huge amounts of effluents, which is a constant threat to environmental pollution. Fertilizers incorporate phosphate compounds containing Cd, which are being used in horticulture, agriculture as well as in animal industries as a trace element nutrient. Cd, Hg, and Pb metals attack the activity of the enzyme, which contains the ▬SH group which initiates chronic diseases. These heavy metals/metalloids and organics form a grave danger to animals (including humans) and plants. Heavy metal pollution on land and water shows a severe impact on the ecosystem. In Western Europe, a large mass of approximately 14,00,000 sites affected as the reports of [15], out of which 3,00,000 are contaminated, but the projected number in Europe could be greater, as the problem was progressively occurring in the Central and East European countries. In the United States, around 600,000 contaminated brownfields with heavy metals requiring reclamation [16]. Land pollution has been a great challenge in the Asian continent as seen in China, where onesixth of arable land is with heavy metal pollution, and over 45% has been ruined either due to erosion or desertification. This becomes the consequence because of human-dominated ecological problems viz., urban ecology and agricultural ecology [17]. Thus, it is vital to eliminate these pollutants from the contaminated sites in which phytoremediation is one of the processes that include complexation, accumulation, volatilization, and degradation of pollutants both of organic and inorganic

**222**

origins.

pogenic processes [13].

**Figure 3.**

*surface water.*

*Geogenic and anthropogenic contaminations by heavy metal is shown and can cause microorganisms to affect the normal molecular process.*

## **4. Biosynthesis of nanoparticles from plants**

Nanoparticles are aggregates between 1 and 100 nm; this particular size that alters the physicochemical properties equated to other material. A variety of nanoparticles are produced by bacteria, fungi, and plants [18], which have wider applications in several sectors. Plants are more appropriate than bacteria or fungi toward the synthesis of NPs, as less incubation time is required for metal ion reduction. The procedures such as plant tissue culture (PTC) and downstream processing techniques make more promising in synthesizing metal and oxide NPs at a larger scale. The documentation of hyperaccumulator exclusive genes and their succeeding transfer to the other species of transgenic plants can improve phytoremediation capacity. The plant's remediation volume shall be greatly enhanced by genetic manipulation and other viable plant-based transforming techniques. In plants, it is seen to have an inherent ability to lessen metals through their specific metabolic pathways [19]. Stampoulis et al. [20] have examined the impact of ZnO, Cu, Si, and Ag NPs on the root elongation, seed germination, and biomass production of *Cucurbita pepo* grown as hydroponics. Accordingly, experimental findings suggested that root length is reduced by 77% when seeds are exposed to Cu nanoparticles and 64% when exposed to bulk Cu powder when equated to the untreated controls.

Plant biomass was reduced by 75% when exposed to Ag NPs. Shekhawat and Arya [21] used *Brassica juncea* seedlings to produce Ag NPs *in vitro*. There are reports from of synthesized gold nanoparticles by *Terminalia catappa* leaf extract in an aqueous medium [22]. The authors [4, 23] examined metal ions Ag<sup>+</sup> and Au3+ to Ag0 and Au0 NPs in *Brassica juncea* for the reduction sites. Nevertheless, Ag NPs in plants are mostly modeled as Ag not only forms NPs in plants but it also exhibits higher catalytic properties as it consists of high electrochemical reduction potential and several additional useful properties. Although the research on the production of nanoparticles is in a nascent stage in plants,

more qualitative work is required to realize the physiological, biochemical, and molecular mechanistic process relative to nanoparticles.

### **4.1 Nano-iron and its derivatives**

Reactive nanoscale iron product (RNIP) and nanoscale zero-valent iron (NZVI) are mostly the elementary forms of iron (nano) technology [24]. Nano zero-valent iron because of its nano-size (1–100 nm) enables high-level remedial adaptability. NZVI, a product of nanotechnology, is used to treat a range of impurities in perilous wastewater (see **Table 3**) and represents the synthesis of iron nanoparticles [25]. As for example, NZVI was tested in the removal of As(III) seen in groundwater. NZVI can be used in permeable reactive barriers (PRBs) form to intercept plumes on the subsurface and remediate them. The sustained zero-valent iron nanoparticle "*ferragels*" swiftly dispersed and immobilize Cr(VI) and Pb(II) from aqueous solutions, reducing the Cr(VI) to Cr(III) and Pb(II) to Pb(0) while oxidizing Fe to goethite (-FeOOH) [26]. Anionic hydrophilic carbon (Fe/C) and poly (acrylic acid)-supported (Fe/PAA); Fe(0) NPs were further considered as a sensitive material for the dehalogenation of chlorinated HCs in soils and ground waters [27]. Nickel-iron NPs in the ratio 1:3 were employed in the dehalogenation of trichloroethylene (TCE) [28].

### **4.2 Single-enzymed nanoparticles**

Enzymes serve as effective biocatalysts in bioremediation. Nevertheless, less stability as a result of diminutive catalytic lifetimes of enzymes limits their effectiveness being inexpensive due to oxidation. The usage of nanotechnology provides a novel method where the enzymes are stabilized in the form of single enzyme nanoparticles (SENs). Enzymes can be devoted to the magnetic iron NPs increasing stability, longevity, and reusability. The enzyme separation from the magnetic iron NPs is usually done by the use of a magnetic field. The two different catabolic enzymes—trypsin and peroxide subjected to unvarying core-shell magnetic nanoparticles (MNPs). SEN requires the involvement of modification of enzyme surface, vinyl polymer growth from the enzyme surface. There are immobilized enzymes in biopolymers and carbon nanotubes, which can add as environmental biosensors.

## **4.3 Exopolysaccharides**

Exopolysaccharides (EPSs) are polymers of the polysaccharide of high molecular weight, secreted by microorganisms. EPSs are sustainable as it has good adsorption capacity and environmental friendly. Therefore, the usage of EPS for bioremediation in the metallic and dye-based environmental pollution attracted researchers in the past years. Polysaccharides are very rich in ▬OH groups using them as a stabilizer for the production of metal NPs, an environment friendly alternate for the chemical-reducing method [29].

EPSs are used as a reducing agent and stabilizer. They are further used for the synthesis of metal NPs viz., lentinan, carboxymethylated chitosan, glucan, carboxymethyl cellulose, and carboxylic curdlan [30]. Apart from exopolysaccharides, the Au and Ag nanoparticles also consist of good dispersible capability and uniformity. EPS produced from *A. fumigatus*, [31] *Lyngbya putealis*, *Lactobacillus plantarum* [32], and *Bacillus firmus* [33] removed heavy metals viz., Cu2+, Pb2+, Cr4+, Cd2+, and Zn2+ within the adsorption capability of 50–1120 mg/g. EPS-605 obtained from newly identified *L. plantarum-*605 was obtained from a Chinese fermented food, Fuyuan pickles. When EPS-605 was self-assembled in H2O,

**225**

*Nanophytoremediation: An Overview of Novel and Sustainable Biological Advancement*

monodispersed nanoparticles were detected that are useful for bioremediation

Dendrimers are multivalent, globular, highly branched, and monodispersed molecules with synthetic elasticity. Dendrimers have proper architecture and controlled composition, which consist of three components and have an extensive assortment of applications ranging from catalysis, electronics to drug release. With unique structural characteristics viz., nanoscopic size, spheroidal surface, vast interior with exhilarating properties which consists of low viscosity, extraordinary solubility, and reactivity. Dendrimers' first dendrimers were synthesized by Fritz Vogtle in 1978 [34] consists of three constituents—a vital core, internal branch cells or radiated symmetry, and terminal branch cell or marginal group. The void spaces in dendrimers interact with nanoparticles, which enhances the catalytic activity. The dendrimer nanocomposites were also set for treatment of water and dye removal from industrial waters to enhance the reactivity by creating more surface area with a reduced amount of toxicity. PAMAM dendrimers using group of hydroxylterminated (G4-OH) poly (amidoamine) also acts as templates in the production of Cu NPs formed by coordination of Cu ions with dendrimer interior amines and subsequent reduction forming dendrimer-encapsulated Cu NPs (Cu-DEN). Cowpea mosaic virus (CPMV), a plant virus, is adequate to endorse the templated mineralization of metal and metal oxide. CMV particles used for templated fabrication of metallic NPs by an electron less deposition metallization process. In the virus capsid, Pd ions are electrostatically bound to the virus capsid and upon reduction acts as a nucleation site to deposit metal ions from solution. Further, dendrimer-modified and plain magnetite nanoparticles (MNPs) have been widely studied in environmental decontamination. Dendrimers can enhance drug targeting

Nanomaterial-based applications in the field of environment are in multiples that provide both large and portable scale and also clean up impurities that are present in our environment. Carbon-based nanomaterials viz., nanocrystals and carbon nanotubes (CNT) have wider applications as antimicrobial agents, environmental sensors, biosensors, sorbents, depth filters, renewable energy technologies, high flux membranes, and in pollution prevention [35]. CNTs are both single walled (SWCNT) or multiwalled (MWCNT); functionalized hybrids were evaluated for the elimination of Et-C6H6 from aqueous solution and remediating pollution to avert diseases from ethylbenzene (Et-C6H6) viz., cyclodextrins (CD). Nickel ions from water were remediated using MWCNT-based materials [36]. CNT-based polymeric materials incorporating nanomaterials, Calixarenes, and Thiacalixarenes were synthesized to remove both organic (p-NO2-C6H5OH) and inorganic contaminants (Cd2+, Pb2+) from water bodies [37]. CNTs immobilized by calcium alginate (CNTs/CA) materials investigated the Cu removal efficiency (69.9% at pH 2.1) via equilibrium studies [37]. Magnetic-MWCNT

nanocomposites reported eradicating cationic dyes in aqueous solutions [38].

**4.6 Engineered polymeric nanoparticles application in bioremediation for** 

Hydrophobic contaminants, say, polycyclic aromatic hydrocarbons (PAHs), are globally persistent in the atmosphere. PAHs are hydrophobic, strongly sorbed to

*DOI: http://dx.doi.org/10.5772/intechopen.93300*

**4.4 Dendrimers**

and record heavy metal and dye adsorption.

efficacy mainly to be used in drug delivery systems [34].

**4.5 Nanocrystals and carbon nanotubes**

**removal of hydrophobic contaminants**

monodispersed nanoparticles were detected that are useful for bioremediation and record heavy metal and dye adsorption.

## **4.4 Dendrimers**

*Soil Contamination - Threats and Sustainable Solutions*

**4.1 Nano-iron and its derivatives**

trichloroethylene (TCE) [28].

**4.3 Exopolysaccharides**

chemical-reducing method [29].

**4.2 Single-enzymed nanoparticles**

molecular mechanistic process relative to nanoparticles.

more qualitative work is required to realize the physiological, biochemical, and

Reactive nanoscale iron product (RNIP) and nanoscale zero-valent iron (NZVI) are mostly the elementary forms of iron (nano) technology [24]. Nano zero-valent iron because of its nano-size (1–100 nm) enables high-level remedial adaptability. NZVI, a product of nanotechnology, is used to treat a range of impurities in perilous wastewater (see **Table 3**) and represents the synthesis of iron nanoparticles [25]. As for example, NZVI was tested in the removal of As(III) seen in groundwater. NZVI can be used in permeable reactive barriers (PRBs) form to intercept plumes on the subsurface and remediate them. The sustained zero-valent iron nanoparticle "*ferragels*" swiftly dispersed and immobilize Cr(VI) and Pb(II) from aqueous solutions, reducing the Cr(VI) to Cr(III) and Pb(II) to Pb(0) while oxidizing Fe to goethite (-FeOOH) [26]. Anionic hydrophilic carbon (Fe/C) and poly (acrylic acid)-supported (Fe/PAA); Fe(0) NPs were further considered as a sensitive material for the dehalogenation of chlorinated HCs in soils and ground waters [27]. Nickel-iron NPs in the ratio 1:3 were employed in the dehalogenation of

Enzymes serve as effective biocatalysts in bioremediation. Nevertheless, less stability as a result of diminutive catalytic lifetimes of enzymes limits their effectiveness being inexpensive due to oxidation. The usage of nanotechnology provides a novel method where the enzymes are stabilized in the form of single enzyme nanoparticles (SENs). Enzymes can be devoted to the magnetic iron NPs increasing stability, longevity, and reusability. The enzyme separation from the magnetic iron NPs is usually done by the use of a magnetic field. The two different catabolic enzymes—trypsin and peroxide subjected to unvarying core-shell magnetic nanoparticles (MNPs). SEN requires the involvement of modification of enzyme surface, vinyl polymer growth from the enzyme surface. There are immobilized enzymes in biopolymers

Exopolysaccharides (EPSs) are polymers of the polysaccharide of high molecular weight, secreted by microorganisms. EPSs are sustainable as it has good adsorption capacity and environmental friendly. Therefore, the usage of EPS for bioremediation in the metallic and dye-based environmental pollution attracted researchers in the past years. Polysaccharides are very rich in ▬OH groups using them as a stabilizer for the production of metal NPs, an environment friendly alternate for the

EPSs are used as a reducing agent and stabilizer. They are further used for the synthesis of metal NPs viz., lentinan, carboxymethylated chitosan, glucan, carboxymethyl cellulose, and carboxylic curdlan [30]. Apart from exopolysaccharides, the Au and Ag nanoparticles also consist of good dispersible capability and uniformity. EPS produced from *A. fumigatus*, [31] *Lyngbya putealis*, *Lactobacillus plantarum* [32], and *Bacillus firmus* [33] removed heavy metals viz., Cu2+, Pb2+, Cr4+, Cd2+, and Zn2+ within the adsorption capability of 50–1120 mg/g. EPS-605 obtained from newly identified *L. plantarum-*605 was obtained from a Chinese fermented food, Fuyuan pickles. When EPS-605 was self-assembled in H2O,

and carbon nanotubes, which can add as environmental biosensors.

**224**

Dendrimers are multivalent, globular, highly branched, and monodispersed molecules with synthetic elasticity. Dendrimers have proper architecture and controlled composition, which consist of three components and have an extensive assortment of applications ranging from catalysis, electronics to drug release. With unique structural characteristics viz., nanoscopic size, spheroidal surface, vast interior with exhilarating properties which consists of low viscosity, extraordinary solubility, and reactivity. Dendrimers' first dendrimers were synthesized by Fritz Vogtle in 1978 [34] consists of three constituents—a vital core, internal branch cells or radiated symmetry, and terminal branch cell or marginal group. The void spaces in dendrimers interact with nanoparticles, which enhances the catalytic activity. The dendrimer nanocomposites were also set for treatment of water and dye removal from industrial waters to enhance the reactivity by creating more surface area with a reduced amount of toxicity. PAMAM dendrimers using group of hydroxylterminated (G4-OH) poly (amidoamine) also acts as templates in the production of Cu NPs formed by coordination of Cu ions with dendrimer interior amines and subsequent reduction forming dendrimer-encapsulated Cu NPs (Cu-DEN).

Cowpea mosaic virus (CPMV), a plant virus, is adequate to endorse the templated mineralization of metal and metal oxide. CMV particles used for templated fabrication of metallic NPs by an electron less deposition metallization process. In the virus capsid, Pd ions are electrostatically bound to the virus capsid and upon reduction acts as a nucleation site to deposit metal ions from solution. Further, dendrimer-modified and plain magnetite nanoparticles (MNPs) have been widely studied in environmental decontamination. Dendrimers can enhance drug targeting efficacy mainly to be used in drug delivery systems [34].

## **4.5 Nanocrystals and carbon nanotubes**

Nanomaterial-based applications in the field of environment are in multiples that provide both large and portable scale and also clean up impurities that are present in our environment. Carbon-based nanomaterials viz., nanocrystals and carbon nanotubes (CNT) have wider applications as antimicrobial agents, environmental sensors, biosensors, sorbents, depth filters, renewable energy technologies, high flux membranes, and in pollution prevention [35]. CNTs are both single walled (SWCNT) or multiwalled (MWCNT); functionalized hybrids were evaluated for the elimination of Et-C6H6 from aqueous solution and remediating pollution to avert diseases from ethylbenzene (Et-C6H6) viz., cyclodextrins (CD). Nickel ions from water were remediated using MWCNT-based materials [36]. CNT-based polymeric materials incorporating nanomaterials, Calixarenes, and Thiacalixarenes were synthesized to remove both organic (p-NO2-C6H5OH) and inorganic contaminants (Cd2+, Pb2+) from water bodies [37]. CNTs immobilized by calcium alginate (CNTs/CA) materials investigated the Cu removal efficiency (69.9% at pH 2.1) via equilibrium studies [37]. Magnetic-MWCNT nanocomposites reported eradicating cationic dyes in aqueous solutions [38].

## **4.6 Engineered polymeric nanoparticles application in bioremediation for removal of hydrophobic contaminants**

Hydrophobic contaminants, say, polycyclic aromatic hydrocarbons (PAHs), are globally persistent in the atmosphere. PAHs are hydrophobic, strongly sorbed to

the soil; thus, sorption limits the bioavailability of these pollutants on the surface. Sequestration in nonaqueous phase liquids (NAPLs) shrinks the mobility and bioavailability of hydrophobic contaminants [39]. Though surfactant micelles have shown an increased rate of PAHs and hydrocarbon solubilization in contrast also causes biodegradation.

Synthesis of nonionic amphiphilic polyurethane (APU) NPs from a mixture of polyethylene glycol (PEG) altered polyurethane acrylate (PMUA), and polyurethane acrylate precursor chains solubilize PAHs from the contaminated soil. Unlike surfactant micelles, PMUA NPs are cross-linked, so not easily breakable when it comes in contact with soil interacting with liposomes of microorganisms but have excellent properties to improve desorption and the agility of phenanthrene (PHEN) in aquifer sand [40].

#### **4.7 Polymeric nanoparticles used in soil remediation**

Research based on nanoparticles usage in soils and groundwater remediation processes increased greatly with promising results. Using nanotechnologies, polluted soils remediation becomes an emerging area with an enormous impending to advance the performance over traditional remediation technologies in a large way [41, 42]. Effective application for soil contaminants contexts, predominantly, for heavy metals, other inorganic and organic contaminants, and emerging contaminants, such as pharmaceutical, cosmetic, personal care products.

Polynuclear aromatic hydrocarbons (PAHs) that absorb intensely to soil are very challenging to eliminate. In such cases, amphiphilic polyurethane (APU) nanoparticles are used in soil remediation which is polluted with PAHs. Desired properties of APU particles can be achieved by engineering, and experimental results have shown that these designed particles make sure hydrophobic interior regions that confer a high affinity for PHEN and hydrophilic surfaces that encourage soil particle mobility. APU NPs (17–97 nm) are prepared of polyurethane acrylate (PA) and ionomer (UAA) or PEG, modified urethane acrylate (PMUA) precursor chains which are emulsified and crosslinked in water. APU particles are stable, independent to their concentration in the aqueous phase, and have interiors regions exhibiting hydrophobic property enhances PAH desorption. APU particles contrived to give the anticipated properties. APU particles affinity toward pollutants like PHEN is precisely managed by varying hydrophobic segment size required for the chain propagation. Mobility of soil APU suspensions is controlled by the charge density or the size of the water-soluble chains [40].

#### **4.8 Biogenic uraninite nanoparticles**

There is evidence of the widespread prevalence of uranium in India's groundwater. A variety of sources and studies have indicated the link between exposures to uranium in drinking waters which causes chronic kidney diseases. Although the main source is geogenic but still anthropogenic factors play their part in the decline in groundwater table and nitrate pollution promote uranium mobilization. The term *Uraninite* defines compositionally complex, nonstoichiometric, cation-substituted forms of UO2, which are found in nature. Biogenic uraninite being nanoscale biogeological material is significant due to usage in bioremediation strategies. Uraninite is utmost preferred product in situ stimulated subsurface uranium U(VI) and has its solubilization much lesser compared to other uranium species.

Uraninite nanoparticles have its properties viz., solubility and dissolution kinetics, which are crucial for microbial bioremediation which mitigates subsurface uranium contamination through uranium reduction. Uraninite exhibits structural chemistry, thus derives its properties from its open fluorite structure. Biogenic

**227**

*Nanophytoremediation: An Overview of Novel and Sustainable Biological Advancement*

uraninite forms by reduction of U(VI) to U(IV) considered as the first stage. After the reduction process, the second step formation requires the precipitation of the mineral. In situ U(VI) reduction has been observed and reported at a large number of contaminated U.S. Department of Energy (DoE) nuclear legacy sites and has shown potential results. The success in uranium bioremediation should be maintained strictly in anaerobic conditions. The surface chemistry of nanoparticulate uraninite is important for the construction of geochemical models of uranium behavior, which follows the bioremediation. This may be challenging for research in

Soil contamination manifested by trace elements, organic, and inorganic compounds is an extensive problem occurring worldwide. Common techniques in soil remediation include waste disposals, incinerations, leaching of soil thermal desorption, and vapor abstraction, but all these types of actions may be responsible for secondary pollution, which ultimately affects soil properties. Plants are the major factors to keep our environment clean and green by remediation of soil and water. The soil organic and inorganic contaminants are removed by phytoremediation. Ryegrass, oat plant, tall fescue, sunflower, and green gram grow in diverse contaminated conditions useful for phytoremediation. Certain plants known as hyperaccumulators are good in phytoremediation in particularly toward heavy metal removal.

**Table 4** defines the hyperaccumulator plants of various families, which are used to accumulate specific metals at different concentrations. Phytoextraction seems to be a feasible alternate to the traditionally conventional practice used in the decontamination of soils with heavy metals [45]. In phytoextraction, methodology plants absorb pollutants from soil. Metals that are deposited as ions in the plant's roots, stems, leaves, and inflorescences are burnt to recover metals, and the subsequent biomass is removed to dispose of safely. The build-up of heavy metals is connected to the total concentration of the metals and suggestively segregated as macro

Water pollution is dangerous, and one of the ecological risk factors suggests the need to cultivate water plants that absorb trace elements. Usually, there is a quick dilution of the contaminants in water; thus, investigating the plant tissues provides combined evidence about the quality and components of water and the method of phytoremediation [46]. The various nanomaterials that can be synthesized through several methods have been represented in **Table 5**. Further, it is observed that species viz., duckweed (*Lemna gibba*), water spinach (*Ipomoea aquatica*), and fern (*Azolla pinnata*) are prominent to phytoremediate metals [47]. like boron, chromium, and manganese, respectively [48–50]. Aquatic macrophytes such as water hyacinths are used extensively in phytoremediation of water contaminated with dyes [51]. Hasan et al. [52] stated the efficacy of water hyacinth in sorption of Zn(II) and Cd(II) from the water. The species from Lemnaceae family, eliminate dyes such as acid blue (azo dye, AB92) undergoes a transformation to form dissimilar transitional compounds [53]. Aquatic plants viz., *Azolla pinnata* (water-fern) and *Hydrilla verticillata* (water-thyme) are used for elimination of fly ash and uranium, respectively [54, 55]. *Micranthemum umbrosum* observed [56] removal of As and Cd by phytofilteration method. *Oenothera picensis* plant was quite extensively

Some hyperaccumulator families represent their metal content [44].

*DOI: http://dx.doi.org/10.5772/intechopen.93300*

nano-bio geosciences in the future [43].

**5. Soil trace element biomonitoring plants**

nutrients and micronutrients and soil acidity.

**5.1 Vascular plants**

*Nanophytoremediation: An Overview of Novel and Sustainable Biological Advancement DOI: http://dx.doi.org/10.5772/intechopen.93300*

uraninite forms by reduction of U(VI) to U(IV) considered as the first stage. After the reduction process, the second step formation requires the precipitation of the mineral. In situ U(VI) reduction has been observed and reported at a large number of contaminated U.S. Department of Energy (DoE) nuclear legacy sites and has shown potential results. The success in uranium bioremediation should be maintained strictly in anaerobic conditions. The surface chemistry of nanoparticulate uraninite is important for the construction of geochemical models of uranium behavior, which follows the bioremediation. This may be challenging for research in nano-bio geosciences in the future [43].

## **5. Soil trace element biomonitoring plants**

Soil contamination manifested by trace elements, organic, and inorganic compounds is an extensive problem occurring worldwide. Common techniques in soil remediation include waste disposals, incinerations, leaching of soil thermal desorption, and vapor abstraction, but all these types of actions may be responsible for secondary pollution, which ultimately affects soil properties. Plants are the major factors to keep our environment clean and green by remediation of soil and water. The soil organic and inorganic contaminants are removed by phytoremediation. Ryegrass, oat plant, tall fescue, sunflower, and green gram grow in diverse contaminated conditions useful for phytoremediation. Certain plants known as hyperaccumulators are good in phytoremediation in particularly toward heavy metal removal. Some hyperaccumulator families represent their metal content [44].

**Table 4** defines the hyperaccumulator plants of various families, which are used to accumulate specific metals at different concentrations. Phytoextraction seems to be a feasible alternate to the traditionally conventional practice used in the decontamination of soils with heavy metals [45]. In phytoextraction, methodology plants absorb pollutants from soil. Metals that are deposited as ions in the plant's roots, stems, leaves, and inflorescences are burnt to recover metals, and the subsequent biomass is removed to dispose of safely. The build-up of heavy metals is connected to the total concentration of the metals and suggestively segregated as macro nutrients and micronutrients and soil acidity.

#### **5.1 Vascular plants**

*Soil Contamination - Threats and Sustainable Solutions*

**4.7 Polymeric nanoparticles used in soil remediation**

pharmaceutical, cosmetic, personal care products.

**4.8 Biogenic uraninite nanoparticles**

causes biodegradation.

in aquifer sand [40].

the soil; thus, sorption limits the bioavailability of these pollutants on the surface. Sequestration in nonaqueous phase liquids (NAPLs) shrinks the mobility and bioavailability of hydrophobic contaminants [39]. Though surfactant micelles have shown an increased rate of PAHs and hydrocarbon solubilization in contrast also

Synthesis of nonionic amphiphilic polyurethane (APU) NPs from a mixture of polyethylene glycol (PEG) altered polyurethane acrylate (PMUA), and polyurethane acrylate precursor chains solubilize PAHs from the contaminated soil. Unlike surfactant micelles, PMUA NPs are cross-linked, so not easily breakable when it comes in contact with soil interacting with liposomes of microorganisms but have excellent properties to improve desorption and the agility of phenanthrene (PHEN)

Research based on nanoparticles usage in soils and groundwater remediation processes increased greatly with promising results. Using nanotechnologies, polluted soils remediation becomes an emerging area with an enormous impending to advance the performance over traditional remediation technologies in a large way [41, 42]. Effective application for soil contaminants contexts, predominantly, for heavy metals, other inorganic and organic contaminants, and emerging contaminants, such as

Polynuclear aromatic hydrocarbons (PAHs) that absorb intensely to soil are very challenging to eliminate. In such cases, amphiphilic polyurethane (APU) nanoparticles are used in soil remediation which is polluted with PAHs. Desired properties of APU particles can be achieved by engineering, and experimental results have shown that these designed particles make sure hydrophobic interior regions that confer a high affinity for PHEN and hydrophilic surfaces that encourage soil particle mobility. APU NPs (17–97 nm) are prepared of polyurethane acrylate (PA) and ionomer (UAA) or PEG, modified urethane acrylate (PMUA) precursor chains which are emulsified and crosslinked in water. APU particles are stable, independent to their concentration in the aqueous phase, and have interiors regions exhibiting hydrophobic property enhances PAH desorption. APU particles contrived to give the anticipated properties. APU particles affinity toward pollutants like PHEN is precisely managed by varying hydrophobic segment size required for the chain propagation. Mobility of soil APU suspensions

is controlled by the charge density or the size of the water-soluble chains [40].

solubilization much lesser compared to other uranium species.

There is evidence of the widespread prevalence of uranium in India's groundwater. A variety of sources and studies have indicated the link between exposures to uranium in drinking waters which causes chronic kidney diseases. Although the main source is geogenic but still anthropogenic factors play their part in the decline in groundwater table and nitrate pollution promote uranium mobilization. The term *Uraninite* defines compositionally complex, nonstoichiometric, cation-substituted forms of UO2, which are found in nature. Biogenic uraninite being nanoscale biogeological material is significant due to usage in bioremediation strategies. Uraninite is utmost preferred product in situ stimulated subsurface uranium U(VI) and has its

Uraninite nanoparticles have its properties viz., solubility and dissolution kinetics, which are crucial for microbial bioremediation which mitigates subsurface uranium contamination through uranium reduction. Uraninite exhibits structural chemistry, thus derives its properties from its open fluorite structure. Biogenic

**226**

Water pollution is dangerous, and one of the ecological risk factors suggests the need to cultivate water plants that absorb trace elements. Usually, there is a quick dilution of the contaminants in water; thus, investigating the plant tissues provides combined evidence about the quality and components of water and the method of phytoremediation [46]. The various nanomaterials that can be synthesized through several methods have been represented in **Table 5**. Further, it is observed that species viz., duckweed (*Lemna gibba*), water spinach (*Ipomoea aquatica*), and fern (*Azolla pinnata*) are prominent to phytoremediate metals [47]. like boron, chromium, and manganese, respectively [48–50]. Aquatic macrophytes such as water hyacinths are used extensively in phytoremediation of water contaminated with dyes [51]. Hasan et al. [52] stated the efficacy of water hyacinth in sorption of Zn(II) and Cd(II) from the water. The species from Lemnaceae family, eliminate dyes such as acid blue (azo dye, AB92) undergoes a transformation to form dissimilar transitional compounds [53]. Aquatic plants viz., *Azolla pinnata* (water-fern) and *Hydrilla verticillata* (water-thyme) are used for elimination of fly ash and uranium, respectively [54, 55]. *Micranthemum umbrosum* observed [56] removal of As and Cd by phytofilteration method. *Oenothera picensis* plant was quite extensively


#### **Table 4.**

*Hyperaccumulator plants for varied metals.*


**229**

*Nanophytoremediation: An Overview of Novel and Sustainable Biological Advancement*

considered toward phytoextraction of copper [57]. Algae such as charaphytes viz., *Chara aculeolata* and *Nitella opaca* were used to remove Pb, Cd, and Zn [58]. *Cystoseira indica* (brown algae) after its chemical treatment become greatly effective against chromium. Metal uptake is seen in algae species such as *Spirulina* used for chemisorptions of metals with few heavy metals like chromium and copper [59]. *Ranunculus peltatus*, *Ranunculus trichophyllus*, *Lemna minor*, *Azolla caroliniana* viz., serve as an arsenic indicator [60]. *Ulothrix cylindricum* (green algae) has biosorption capacity of 65.6 mg/g, forming an inexpensive method for biosorption of As(III) [61]. Aquatic macrophytes grow quickly, and due to their high biomass production, the greater capacity in accumulating heavy metals widely used for

A macrophyte grows in or near the water body and is emergent, submerged or floating. Aquatic plants have adjusted to living in aquatic environments (hydrophytes or macrophytes) to differentiate from algae and other microphytes. Water hyacinth (*Eichhornia crassipes*), Sensitive Plant (*Neptunia aquatica*), Lucky 4-Leaf Clover (*Marsilea mutica*) water lettuce (*Pistia stratiotes*), Moneywort (*Bacopa monnieri*), Mosaic Flower (*Ludwigia sedioides*), Water poppy (*Hydrocleys nymphoides*), and duckweed (*Lemna minor*) are a few of the aquatic macrophytes widely intended for heavy metal phytoremediation [62]. *Pistia stratiotes* have relatively high growth rate thus ideally chosen in phytoremediation study as it is proposed to accumulate As [63]. Water lettuce is observed to be a probable plant for phytoremediation for manganese contaminated waters [62]. In the elimination of Pb, Cd, Cr from the water, *Lemna minor*, a native of Europe, North America, Asia, and Africa is naturalized for its advantage to grow in several climatic conditions and also a potential accumulator of Cd to remediate the aquatic environment. *Eichhornia crassipes* was used for the tertiary treatment of wastewater phytoremediation as it has broader leaves and fibrous root system which assists in the absorption of heavy metals [64]. There has been experimentation on water hyacinth (*Eichhornia crassipes*), two algal species (*Chlorodesmis sp.* and *Cladophora sp.*) found in As-contaminated water bodies are used to determine the arsenic tolerance capability. Cladophora species are found to be appropriate for co-treatment of sewage and As-contaminated brine in algal ponds. *Typha latifolia* and *Eichhornia crassipes* are freshwater plants used to clean up the effluents that usually contain high concentrations of Co, Cd, and As. *Eleocharis acicularis* commonly known as dwarf hair grass and needle spike rush acts as hyperaccumulators as it uptakes several metals Fe, Pb, Mn, Cr, and Zn from drainages and mines [65, 66]. *Myriophyllum aquaticum* consists of enzymes that play a vital part in the transformation of organic compound contamination and is effective in the phytoremediation of an aquatic environment [9]. *Ludwigia palustris* (marsh seedbox; creeping primrose) and *Mentha aquatica (*water mint) effectively remove Cu, Fe, Hg, and Zn. Among the freshwater vascular plants, the most effica-

*DOI: http://dx.doi.org/10.5772/intechopen.93300*

wastewater treatment compared to soil-grown plants.

cious plants are *E. crassipes* and *L. minor.*

**6. Hyperaccumulator plants for different metals**

Bioconcentration factor and factor of translocation are multiplied to get the phytoextraction efficiency. It is observed that accumulated metal concentration in soil modifies its biological properties. Different plant species vary with regard to uptake of heavy metal. The hyperaccumulation of heavy metals mainly rest on several factors viz., plant species, soil circumstances (pH, temperature, humidity, soil organic content, and cation capacity), and types of heavy metals. The uptake of metals is determined by the metal type and metal chemical speciation and habitat characteristics of the plant [67]. Hence, the plant selection became significant for

#### **Table 5.**

*Synthesis of diverse nanomaterials.*

#### *Nanophytoremediation: An Overview of Novel and Sustainable Biological Advancement DOI: http://dx.doi.org/10.5772/intechopen.93300*

considered toward phytoextraction of copper [57]. Algae such as charaphytes viz., *Chara aculeolata* and *Nitella opaca* were used to remove Pb, Cd, and Zn [58].

*Cystoseira indica* (brown algae) after its chemical treatment become greatly effective against chromium. Metal uptake is seen in algae species such as *Spirulina* used for chemisorptions of metals with few heavy metals like chromium and copper [59]. *Ranunculus peltatus*, *Ranunculus trichophyllus*, *Lemna minor*, *Azolla caroliniana* viz., serve as an arsenic indicator [60]. *Ulothrix cylindricum* (green algae) has biosorption capacity of 65.6 mg/g, forming an inexpensive method for biosorption of As(III) [61]. Aquatic macrophytes grow quickly, and due to their high biomass production, the greater capacity in accumulating heavy metals widely used for wastewater treatment compared to soil-grown plants.

A macrophyte grows in or near the water body and is emergent, submerged or floating. Aquatic plants have adjusted to living in aquatic environments (hydrophytes or macrophytes) to differentiate from algae and other microphytes. Water hyacinth (*Eichhornia crassipes*), Sensitive Plant (*Neptunia aquatica*), Lucky 4-Leaf Clover (*Marsilea mutica*) water lettuce (*Pistia stratiotes*), Moneywort (*Bacopa monnieri*), Mosaic Flower (*Ludwigia sedioides*), Water poppy (*Hydrocleys nymphoides*), and duckweed (*Lemna minor*) are a few of the aquatic macrophytes widely intended for heavy metal phytoremediation [62]. *Pistia stratiotes* have relatively high growth rate thus ideally chosen in phytoremediation study as it is proposed to accumulate As [63]. Water lettuce is observed to be a probable plant for phytoremediation for manganese contaminated waters [62]. In the elimination of Pb, Cd, Cr from the water, *Lemna minor*, a native of Europe, North America, Asia, and Africa is naturalized for its advantage to grow in several climatic conditions and also a potential accumulator of Cd to remediate the aquatic environment. *Eichhornia crassipes* was used for the tertiary treatment of wastewater phytoremediation as it has broader leaves and fibrous root system which assists in the absorption of heavy metals [64]. There has been experimentation on water hyacinth (*Eichhornia crassipes*), two algal species (*Chlorodesmis sp.* and *Cladophora sp.*) found in As-contaminated water bodies are used to determine the arsenic tolerance capability. Cladophora species are found to be appropriate for co-treatment of sewage and As-contaminated brine in algal ponds. *Typha latifolia* and *Eichhornia crassipes* are freshwater plants used to clean up the effluents that usually contain high concentrations of Co, Cd, and As. *Eleocharis acicularis* commonly known as dwarf hair grass and needle spike rush acts as hyperaccumulators as it uptakes several metals Fe, Pb, Mn, Cr, and Zn from drainages and mines [65, 66]. *Myriophyllum aquaticum* consists of enzymes that play a vital part in the transformation of organic compound contamination and is effective in the phytoremediation of an aquatic environment [9]. *Ludwigia palustris* (marsh seedbox; creeping primrose) and *Mentha aquatica (*water mint) effectively remove Cu, Fe, Hg, and Zn. Among the freshwater vascular plants, the most efficacious plants are *E. crassipes* and *L. minor.*

## **6. Hyperaccumulator plants for different metals**

Bioconcentration factor and factor of translocation are multiplied to get the phytoextraction efficiency. It is observed that accumulated metal concentration in soil modifies its biological properties. Different plant species vary with regard to uptake of heavy metal. The hyperaccumulation of heavy metals mainly rest on several factors viz., plant species, soil circumstances (pH, temperature, humidity, soil organic content, and cation capacity), and types of heavy metals. The uptake of metals is determined by the metal type and metal chemical speciation and habitat characteristics of the plant [67]. Hence, the plant selection became significant for

*Soil Contamination - Threats and Sustainable Solutions*

**Cadmium**

**Zinc**

**Nickel**

**Copper**

**Lead**

**Cobalt**

*Hyperaccumulator plants for varied metals.*

Nanoparticles biosynthesis from metals (NPs)

Metal oxide Nanoparticles

**Nanomaterials The methodology used** 

Nanomaterials from polymers Electrochemical

**Table 4.**

**Metals Plant species Accumulated metal concentration (mg/kg)**

*Thlaspi caerulescens* Brassicaceae 2130

*Thlaspi caerulescens* Brassicaceae 43,710 *Thlaspi rotundifolium* Brassicaceae 18,500 *Dichapetalum gelonioides* Brassicaceae 30,000

*Thlaspi Sps.* Brassicaceae 2000-2031,000 *Allyssium Sps.* Brassicaceae 1280–29,400 *Berkheya codii* Asteraceae 11,600 *Pentacalia Sps.* Asteraceae 16,600 *Psychotria coronata* Rubiaceae 25,540

*Ipomoea alpina* Convolvulaceae 12,300

*Minuartia verna* Caryophyllaceae 20,000 *Agrostis tenuis* Poaceae 13,490 *Vetiveria zizanioides* Cyperaceae >1500

*Crotalaria cobalticola* Fabaceae 30,100 *Haumaniastrum robertii* Lamiaceae 10,232

**in the synthesis**

Electrochemical Thermochemical

deposition Laser ablation

Polymerization

Reverse micelles solvo-thermal

Sol-gel method Electrochemical deposition

Bionanomaterials Biological Plasmids, nanoparticles from protein

Nanomaterials from carbon Arc-discharge Cylindrical nanotubes (SWNT, MWNT) Fullerenes Chemical vapor

**Examples**

Photochemical Cu, Au, CoNi, CdTe, CdSe, ZnS, Rh, Pt, Ir, Pd, Co, Ag, Au, Cu, Fe & Ni Biochemical

dendrimers

viruses

ZnO, Fe2O3, Fe3O4, MgO

Hydrothermal BaCO3, BaSO4, TiO2,

Nanowires of PPy, PANI, Poly (3–4 ethylene dioxy thiophane, PAMAM,

**228**

**Table 5.**

*Synthesis of diverse nanomaterials.*

the remediation of the containment location. The accumulation efficacy of heavy metals in any plant species is calculated via a bioconcentration factor [68]. The willow plant consists of the highest biomass, thus identified itself as an appropriate plant for soil remediation [69]. In a prior experiment, plant species of Brassicaceae family, such as *Brassica juncea* L*.*, *Brassica napus* L*.*, and *Brassica rapa* L*.* are able to accumulate Zn and Cd moderately. In *Brassica juncea*, the nuts showed the bioaccumulation ability toward Cu [70]. *Pistia stratiotes* L. (water lettuce) has the potential to remove Cd from surface water [71]. Canola (*Brassica napus* L*.*) is very effective with respect to Cu, Cd, Pb, and Zn in comparison to *B. juncea* L*.* (Indian mustard). Application of Ethylene diamine tetra acetic acid (EDTA) increases heavy metal availability, thus making the plant uptake showing the prominence of organic chelates in increasing metal solubility/availability, thus applicable to enhancing the efficiency of phytoremediation technique.

**Table 6** represents the advantages and limitations of phytoremediation technologies. In Brassicaceae family, plants are used for biofumigation. *Helianthus annuus* (Sunflower) has the capability for soil remediation contaminated by Pb. Soybean plants characteristically synthesize homophytochelatins alternative to phytochelatins when heavy metals are exposed. For the soybean seeds and young seedlings, Cr metal is found to be extremely toxic at higher concentrations [72]. Crops are affected as it is seen that soil contamination by heavy metals causes a considerable loss in seed production of soybean canopies [73]. Agricultural soils accumulate toxic metals in edible portions of crops which grow in contaminated soils that described in crops viz., rice, soybean, maize, and vegetables.


**231**

warranted [78].

in their shoot system.

*Nanophytoremediation: An Overview of Novel and Sustainable Biological Advancement*

of metals are unknown in developing seeds, to embryos and cotyledons.

Similarly, few experiments have focused on the detoxification of metals by phytochelatins (PC) and metallothioneins (MT). Similarly, Shanker et al. [75] have studied extensively about the chromium toxicity in plants which predominantly hinge on valence states of chromium ions. Cr has toxic effects on plant development which includes modifications in the germination process, development of roots, leaves, and stems which ultimately affects entire dry mass production and yield. Chromium too has harmful effects on the plant's physiological processes such as photosynthesis, water channeling, and mineral nutrition. Shukla et al. [76] inspected the effects of cadmium in wheat (*Triticum aestivum* L.) plant. Gupta and Gupta [77] reported in their publication that nutrient toxicities in crops due to manganese and boron are more compared with other nutrients. The foremost toxicity symptoms in crops include burning, chlorosis, and yellowing of leaves. The toxicity of metals is influenced by metal concentration, the composition of minerals, and organics in the soil, pH, redox potential, and the existence of other metals in the soil. Metal toxicity is also affected by the association to mineral constituents of the polluted sites. Since, there is a lack of basic understanding of metal behavior for a precise condition a precise protective method toward metal additions to soils is

In addition, the requirement to know the proper metal toxicity in food products and their nutritional intake in evaluating their risk to human well-being is more. However, the problem of metal toxicity persists due to contamination of the environment, which worsens intensively due to negative human activities. Hyperaccumulators grow on metalliferous soils; leaves possess toxic metal accumulation compared with other plant species. Studies aimed regarding these hyperaccumulators to understand their physiological role and molecular mechanisms, and thus, these plants can be used as a tool in removing metals from natural metal-rich soils (ores) and contaminated areas. Metal tolerant species *Hordeum vulgare*, *Brassica juncea*, *Triticum aestivum*, *Brassica napus*, and *Helianthus annuus* accumulates toxic metals in high concentrations

Generally, metals play a significant part in the metabolic pathways in plants during the growth and development in appropriate amounts but lethal in excess. Soil gets contaminated due to several activities such as mining, disposal of solid wastes, automobile exhausts, and engineering activities. Therefore, there is a possibility of augmented uptake of metals by food crops, which cause human health risks, thus affecting food quality and safety. Metals viz., iron (Fe), molybdenum (Mo), copper (Cu), cobalt (Co), manganese (Mn), and zinc (Zn) are crucial for plant growth, categorized as essential micronutrients. The nonessential metals found as pollutants comprise mercury (Hg), chromium (Cr), selenium (Se), uranium (U), nickel (Ni), cadmium (Cd), arsenic (As), lead (Pb), vanadium (V), and wolfram (W). Prior published reports by [74] provided information on the impact of metal on the seed of crops and medicinal plants regarding biochemical and molecular implications, which provide an important role in seed germination. It has been noted that metals applied exogenously in the range of micromolar to milimolar concentrations could affect seed variability. Seeds from metal tolerant plants and hyperaccumulators possess higher threshold toxicity than the seeds of nontolerant plants. Nonetheless, data on their effects on *in situ* seed germination are in the nascent stage, which is required to be investigated. Cd and Cu inhibit water uptake, obligatory for seed germination. One can overcome seed dormancy with metal treatment, although the actual mechanism of action yet to be understood. But the process of deposition and toxicity

*DOI: http://dx.doi.org/10.5772/intechopen.93300*

**7. Effect of metals on the physiological process**

#### **Table 6.**

*Advantages and limitations of phytoremediation.*

*Nanophytoremediation: An Overview of Novel and Sustainable Biological Advancement DOI: http://dx.doi.org/10.5772/intechopen.93300*

## **7. Effect of metals on the physiological process**

*Soil Contamination - Threats and Sustainable Solutions*

efficiency of phytoremediation technique.

in crops viz., rice, soybean, maize, and vegetables.

Plant with high biomass within lesser time should be successful to remove contaminants from soil.

Cost-effective and less disruptive which enhances the

Contaminants/pollutants are transformed into less toxic forms, for example, volatilization of mercury(Hg) by conversion to the elemental form in transgenic *Arabidopsis* and yellow poplars which contains bacterial mercuric reductase (*merA*)

*In situ* (pond floating rafts) or *ex-situ* (tank system);

Absorption and adsorption play an important role

*Advantages and limitations of phytoremediation.*

ecosystem restoration/re-vegetation.

**Phytofiltration**/**rhizofiltration**

**Phytoextraction**

**Phytostabilization**

**Phytovolatilization**

aquatic

**Advantage Limitation**

the remediation of the containment location. The accumulation efficacy of heavy metals in any plant species is calculated via a bioconcentration factor [68]. The willow plant consists of the highest biomass, thus identified itself as an appropriate plant for soil remediation [69]. In a prior experiment, plant species of Brassicaceae family, such as *Brassica juncea* L*.*, *Brassica napus* L*.*, and *Brassica rapa* L*.* are able to accumulate Zn and Cd moderately. In *Brassica juncea*, the nuts showed the bioaccumulation ability toward Cu [70]. *Pistia stratiotes* L. (water lettuce) has the potential to remove Cd from surface water [71]. Canola (*Brassica napus* L*.*) is very effective with respect to Cu, Cd, Pb, and Zn in comparison to *B. juncea* L*.* (Indian mustard). Application of Ethylene diamine tetra acetic acid (EDTA) increases heavy metal availability, thus making the plant uptake showing the prominence of organic chelates in increasing metal solubility/availability, thus applicable to enhancing the

**Table 6** represents the advantages and limitations of phytoremediation technologies. In Brassicaceae family, plants are used for biofumigation. *Helianthus annuus* (Sunflower) has the capability for soil remediation contaminated by Pb. Soybean plants characteristically synthesize homophytochelatins alternative to phytochelatins when heavy metals are exposed. For the soybean seeds and young seedlings, Cr metal is found to be extremely toxic at higher concentrations [72]. Crops are affected as it is seen that soil contamination by heavy metals causes a considerable loss in seed production of soybean canopies [73]. Agricultural soils accumulate toxic metals in edible portions of crops which grow in contaminated soils that described

> 1. Hyperaccumulators exhibit slow growth and less bioproductivity due to shallow

> 2. Biomass/phytomass must be disposed of

1. The requirement of extensive fertilization/soil modification. Proper maintenance is required to prevent leaching

1. Contaminants/hazardous metabolites might accumulate in vegetation viz.,

2. Low levels of metabolites can be found in

1. Constant pH monitoring of the medium is required for optimizing the uptake of

2. Influent chemical speciation and all the species interactions are to be understood

3. Intensive maintenance is needed 4. Large root surface area is usually required

root systems

cautiously

fruits/lumber

plant tissues

metals

**230**

**Table 6.**

Generally, metals play a significant part in the metabolic pathways in plants during the growth and development in appropriate amounts but lethal in excess. Soil gets contaminated due to several activities such as mining, disposal of solid wastes, automobile exhausts, and engineering activities. Therefore, there is a possibility of augmented uptake of metals by food crops, which cause human health risks, thus affecting food quality and safety. Metals viz., iron (Fe), molybdenum (Mo), copper (Cu), cobalt (Co), manganese (Mn), and zinc (Zn) are crucial for plant growth, categorized as essential micronutrients. The nonessential metals found as pollutants comprise mercury (Hg), chromium (Cr), selenium (Se), uranium (U), nickel (Ni), cadmium (Cd), arsenic (As), lead (Pb), vanadium (V), and wolfram (W). Prior published reports by [74] provided information on the impact of metal on the seed of crops and medicinal plants regarding biochemical and molecular implications, which provide an important role in seed germination. It has been noted that metals applied exogenously in the range of micromolar to milimolar concentrations could affect seed variability. Seeds from metal tolerant plants and hyperaccumulators possess higher threshold toxicity than the seeds of nontolerant plants. Nonetheless, data on their effects on *in situ* seed germination are in the nascent stage, which is required to be investigated. Cd and Cu inhibit water uptake, obligatory for seed germination. One can overcome seed dormancy with metal treatment, although the actual mechanism of action yet to be understood. But the process of deposition and toxicity of metals are unknown in developing seeds, to embryos and cotyledons.

Similarly, few experiments have focused on the detoxification of metals by phytochelatins (PC) and metallothioneins (MT). Similarly, Shanker et al. [75] have studied extensively about the chromium toxicity in plants which predominantly hinge on valence states of chromium ions. Cr has toxic effects on plant development which includes modifications in the germination process, development of roots, leaves, and stems which ultimately affects entire dry mass production and yield. Chromium too has harmful effects on the plant's physiological processes such as photosynthesis, water channeling, and mineral nutrition. Shukla et al. [76] inspected the effects of cadmium in wheat (*Triticum aestivum* L.) plant. Gupta and Gupta [77] reported in their publication that nutrient toxicities in crops due to manganese and boron are more compared with other nutrients. The foremost toxicity symptoms in crops include burning, chlorosis, and yellowing of leaves. The toxicity of metals is influenced by metal concentration, the composition of minerals, and organics in the soil, pH, redox potential, and the existence of other metals in the soil. Metal toxicity is also affected by the association to mineral constituents of the polluted sites. Since, there is a lack of basic understanding of metal behavior for a precise condition a precise protective method toward metal additions to soils is warranted [78].

In addition, the requirement to know the proper metal toxicity in food products and their nutritional intake in evaluating their risk to human well-being is more. However, the problem of metal toxicity persists due to contamination of the environment, which worsens intensively due to negative human activities. Hyperaccumulators grow on metalliferous soils; leaves possess toxic metal accumulation compared with other plant species. Studies aimed regarding these hyperaccumulators to understand their physiological role and molecular mechanisms, and thus, these plants can be used as a tool in removing metals from natural metal-rich soils (ores) and contaminated areas. Metal tolerant species *Hordeum vulgare*, *Brassica juncea*, *Triticum aestivum*, *Brassica napus*, and *Helianthus annuus* accumulates toxic metals in high concentrations in their shoot system.

## **8. Transgenic plants usage in phytoremediation**

Transgenic plants with wide geographic distribution are used owing to their enhanced tolerance and phytoextraction potential. Transgenic plants are fast growing and seem to possess high biomass, much-elongated roots, and greener leaves than unmodified plants. Herbivores are repulsive to transgenic plants, thus making it greatly an encouraging candidate in phytoremediation efforts [79].

Transgenic plants, when grown in Cu-contaminated soil, and leaves contain two to –three times more Cu compared to other plants [80]. *Arabidopsis thaliana* also possess greater Cu accumulation as reported by overexpression of a pea MTgene [81]. PsMTA from *Pisum sativum*, when overexpressed in *A. thaliana*, accumulated eight times more Cu in roots [82]. *Nicotiana glauca* (shrub tobacco) has a high tolerance toward Pb and Cd when grown in a metal-contaminated soil; the transgenic plants accumulated higher Pb concentrations in the shoot system (50% more) and in the root system (85% more).

An attempt was made toward transferring and expression of genes from bacteria, yeast, animals, or other plants and improvised for potentially high yield. One of the encouraging advances in transgenic technology is the use of multiple genes (cytochrome P450s, GSH, GT, etc.) for thorough degradation of xenobiotics within the plant system that was involved in metabolism, uptake, and transport of specific pollutants in transgenic plants [1, 83, 84]. A published review focused on the development of transgenic plants for remediation of 2,4,6-trinitrotoluene, hexahydro-1,3,5-trinitro-1,3,5-triazine, and glycerol trinitrate [85] by introducing and expressing bacterial nitro-reductases and cytochrome p450s.

As hyperaccumulators have a high metal tolerant trait, probable detoxification capacity is maximum thus efficiently used in phytoremediation. But there is an alternative to hyperaccumulators due to sluggish growth and condensed biomass production; hence, it requires numerous years for sanitization of contaminated sites. Thus, to facilitate faster decontamination, the remedial property can be extensively improvised by genetic manipulation, plant tissue culture, imbursement of transgenic approaches viz., genes, traits can be manipulated and thus the production of transgenic plants, mainly industrialized for remediating heavy metal contaminated soil sites. Examples include *Nicotiana tabaccum* expressing a yeast metallothionein gene for higher cadmium tolerance or *Arabidopsis thaliana* overexpressing a mercuric ion reductase gene for higher mercury tolerance [86]. Dhankher et al. [87] stated about arsenic sequestration which happens largely in vacuoles by complexation with glutathione (−GSH) and phytochelatins (PCs).

In another example, the arsenic fall was seen in the transgenic plant developed by using bacterial genes ArsC from *E. coli* with co-expression of γ-glutamylcysteine synthetase to provide sufficient -GSH for subsequent conjugation [88]. By the expression of bacterial genes merA gene encoding organo-mercurial lyase, transgenic plants show better resistance against the toxic effects of mercury [89]. When merB was expressed in endoplasmic reticulum, resistance was further improved. Therefore, findings on chloroplast are the primary target for mercury poisoning and are leading the ongoing research in chloroplast genome engineering. Further, the expression of bacterial genes atrazine chlorohydrolase (atzZ) and 1-aminocyclopropane-1-carboxylate deaminase has shown a promising result in the remediation of atrazine and alachlor [90]. Transgenic plants expressing these genes show significantly increased tolerance, uptake, and detoxification of targeted explosives. Expression of cytochrome p450 as in CYP2E1 in tobacco and poplar plants have not only increased TCE metabolism but also is metabolizing vinyl chloride, benzene, toluene, and chloroform [84]. Also, trace element detoxification

**233**

*Nanophytoremediation: An Overview of Novel and Sustainable Biological Advancement*

systems have been implemented at the molecular level in yeast and bacteria. A vivid study and approaches by manipulation of molecular genetic techniques to regulate the discharge of metals as contaminants can be controlled through the use of the

Metal homeostasis is defined as the metal uptake, trafficking, efflux, and sensing pathways, which allows organisms to maintain a narrow intracellular concentration range of essential transition metals. The molecular and genetic basis for these mechanisms will be vital in the development of plants that can be agents for phytoremediation of contaminated sites. One among the recurrent general mechanism requires metal homeostasis, chelation of the metal by a ligand, and subsequent compartmentalization of ligand-metal complex. Plants evolved a variety of mechanisms managing heavy metal stress, which include the synthesis of the sulfur-rich metal chelators, glutathione (GSH), phytochelatins (PCs), and metallothioneins (MTs) [91, 92]. Organic acids such as citrate and maleate which chelate extracellularly have significant tolerance to aluminum. Peptide ligands comprise metallothioneins (MTs) and small gene-encoded, Cysrich polypeptides. GSH, abundantly the low-weight molecular SH-compound in plants, is synthesized through ATP-dependent enzymatic pathway. GSH protects plants from environmental and oxidative stresses, xenobiotics, and heavy metals. Glutathione acts as a precursor of phytochelatins (PCs) during excessive mental stress [93, 94]. The SH-peptide GSH (*ç*-Glu-Cys-Gly) and its variation homoglutathione (h-GSH, *ç*-Glu-Cys-*â*-Ala) has a stimulus in the form and toxicity to heavy metals such as Cu, Cd, As, Hg, and Zn in different ways. Inventive measures of remediation technologies are of paramount importance; thus, plants can be an introduced as supplementary alternative renewable source and thus used in

Metallothioneins (MT) are cytoplasmic proteins [95], a family of small, vastly conserved, cysteine-rich metal-binding proteins (M.W. ∼7000), that are rich in sulfhydryl groups (thiols, make them bind to a number of trace metals) that are significant small proteins that bind toward Zn and Cu homeostasis, small amounts

a.Enhanced Cd tolerance is a result of overexpression of MT genes in tobacco and

b.A 16-fold greater Cd tolerance was observed by MT yeast gene (CUP 1) overex-

c.The yeast metallothionein (CUP1) encourages Cu uptake in tobacco—seven

times more in older leaves than fresh leaves, during Cu stress.

of Fe, Hg and perhaps other heavy metals [96], safeguard against oxidative stress, and buffering against toxic heavy metals. MTs were recognized firstly as Cd-binding proteins in mammalian tissues. Comparably, proteins are recognized in large numbers of animal species [97]. Cysteine-rich proteins are known for their high affinity toward cations Cd, Cu, Zn, etc. and also known for deliberating heavy-

metal tolerance and accumulation in yeast and plants.

*DOI: http://dx.doi.org/10.5772/intechopen.93300*

**9. Metal homeostasis in plants**

transgenic plant.

situ remediations.

To mention,

oilseeds.

pression in cauliflower.

**9.1 Metallothioneins**

systems have been implemented at the molecular level in yeast and bacteria. A vivid study and approaches by manipulation of molecular genetic techniques to regulate the discharge of metals as contaminants can be controlled through the use of the transgenic plant.

## **9. Metal homeostasis in plants**

*Soil Contamination - Threats and Sustainable Solutions*

in the root system (85% more).

nitro-reductases and cytochrome p450s.

phytochelatins (PCs).

**8. Transgenic plants usage in phytoremediation**

Transgenic plants with wide geographic distribution are used owing to their enhanced tolerance and phytoextraction potential. Transgenic plants are fast growing and seem to possess high biomass, much-elongated roots, and greener leaves than unmodified plants. Herbivores are repulsive to transgenic plants, thus making

Transgenic plants, when grown in Cu-contaminated soil, and leaves contain two to –three times more Cu compared to other plants [80]. *Arabidopsis thaliana* also possess greater Cu accumulation as reported by overexpression of a pea MTgene [81]. PsMTA from *Pisum sativum*, when overexpressed in *A. thaliana*, accumulated eight times more Cu in roots [82]. *Nicotiana glauca* (shrub tobacco) has a high tolerance toward Pb and Cd when grown in a metal-contaminated soil; the transgenic plants accumulated higher Pb concentrations in the shoot system (50% more) and

An attempt was made toward transferring and expression of genes from bacteria, yeast, animals, or other plants and improvised for potentially high yield. One of the encouraging advances in transgenic technology is the use of multiple genes (cytochrome P450s, GSH, GT, etc.) for thorough degradation of xenobiotics within the plant system that was involved in metabolism, uptake, and transport of specific pollutants in transgenic plants [1, 83, 84]. A published review focused on the development of transgenic plants for remediation of 2,4,6-trinitrotoluene, hexahydro-1,3,5-trinitro-1,3,5-triazine, and glycerol trinitrate [85] by introducing and expressing bacterial

As hyperaccumulators have a high metal tolerant trait, probable detoxification capacity is maximum thus efficiently used in phytoremediation. But there is an alternative to hyperaccumulators due to sluggish growth and condensed biomass production; hence, it requires numerous years for sanitization of contaminated sites. Thus, to facilitate faster decontamination, the remedial property can be extensively improvised by genetic manipulation, plant tissue culture, imbursement of transgenic approaches viz., genes, traits can be manipulated and thus the production of transgenic plants, mainly industrialized for remediating heavy metal contaminated soil sites. Examples include *Nicotiana tabaccum* expressing a yeast metallothionein gene for higher cadmium tolerance or *Arabidopsis thaliana* overexpressing a mercuric ion reductase gene for higher mercury tolerance [86]. Dhankher et al. [87] stated about arsenic sequestration which happens largely in vacuoles by complexation with glutathione (−GSH) and

In another example, the arsenic fall was seen in the transgenic plant developed by using bacterial genes ArsC from *E. coli* with co-expression of γ-glutamylcysteine synthetase to provide sufficient -GSH for subsequent conjugation [88]. By the expression of bacterial genes merA gene encoding organo-mercurial lyase, transgenic plants show better resistance against the toxic effects of mercury [89]. When merB was expressed in endoplasmic reticulum, resistance was further improved. Therefore, findings on chloroplast are the primary target for mercury poisoning and are leading the ongoing research in chloroplast genome engineering. Further, the expression of bacterial genes atrazine chlorohydrolase (atzZ) and 1-aminocyclopropane-1-carboxylate deaminase has shown a promising result in the remediation of atrazine and alachlor [90]. Transgenic plants expressing these genes show significantly increased tolerance, uptake, and detoxification of targeted explosives. Expression of cytochrome p450 as in CYP2E1 in tobacco and poplar plants have not only increased TCE metabolism but also is metabolizing vinyl chloride, benzene, toluene, and chloroform [84]. Also, trace element detoxification

it greatly an encouraging candidate in phytoremediation efforts [79].

**232**

Metal homeostasis is defined as the metal uptake, trafficking, efflux, and sensing pathways, which allows organisms to maintain a narrow intracellular concentration range of essential transition metals. The molecular and genetic basis for these mechanisms will be vital in the development of plants that can be agents for phytoremediation of contaminated sites. One among the recurrent general mechanism requires metal homeostasis, chelation of the metal by a ligand, and subsequent compartmentalization of ligand-metal complex. Plants evolved a variety of mechanisms managing heavy metal stress, which include the synthesis of the sulfur-rich metal chelators, glutathione (GSH), phytochelatins (PCs), and metallothioneins (MTs) [91, 92]. Organic acids such as citrate and maleate which chelate extracellularly have significant tolerance to aluminum. Peptide ligands comprise metallothioneins (MTs) and small gene-encoded, Cysrich polypeptides. GSH, abundantly the low-weight molecular SH-compound in plants, is synthesized through ATP-dependent enzymatic pathway. GSH protects plants from environmental and oxidative stresses, xenobiotics, and heavy metals. Glutathione acts as a precursor of phytochelatins (PCs) during excessive mental stress [93, 94]. The SH-peptide GSH (*ç*-Glu-Cys-Gly) and its variation homoglutathione (h-GSH, *ç*-Glu-Cys-*â*-Ala) has a stimulus in the form and toxicity to heavy metals such as Cu, Cd, As, Hg, and Zn in different ways. Inventive measures of remediation technologies are of paramount importance; thus, plants can be an introduced as supplementary alternative renewable source and thus used in situ remediations.

## **9.1 Metallothioneins**

Metallothioneins (MT) are cytoplasmic proteins [95], a family of small, vastly conserved, cysteine-rich metal-binding proteins (M.W. ∼7000), that are rich in sulfhydryl groups (thiols, make them bind to a number of trace metals) that are significant small proteins that bind toward Zn and Cu homeostasis, small amounts of Fe, Hg and perhaps other heavy metals [96], safeguard against oxidative stress, and buffering against toxic heavy metals. MTs were recognized firstly as Cd-binding proteins in mammalian tissues. Comparably, proteins are recognized in large numbers of animal species [97]. Cysteine-rich proteins are known for their high affinity toward cations Cd, Cu, Zn, etc. and also known for deliberating heavymetal tolerance and accumulation in yeast and plants.

To mention,


d.Likewise, high accumulation of Cu was found in *Arabidopsis thaliana* by overexpression of a pea MT gene.

#### **9.2 Phytochelatins**

Phytochelatins (PC) are oligomers of glutathione [98] produced by the enzyme phytochelatin synthase from GSH, seen in plants, fungi, nematodes, and all the algal groups including cyanobacteria. Phytochelatins are central for heavy metal detoxification and act as chelators [99], Cysteine-rich metal-chelating (post-translationally synthesized) peptides which suggestively show heavy-metal tolerance in plants and fungi by chelation and thus decrease their unrestricted availability. It is projected that PCs are the functionally alike MTs [100].

PCs are not reported in animal species, which supports that MTs performs normal functions well in animals, as a contribution by PCs in plants. Heavy-metal toxicity in plants is seen in diverse ways; these include chelation, exclusion, compartmentalization of the metal ions, immobilization, and the expression of more stress response mechanisms in general such as ethylene and other stress proteins [11].

To mention,


As PCs are found in tissues of the plants and cell cultures upon open to trace levels of crucial metals and the level of PCs were seen in cell cultures is correlated with the medium by reduction of metal ions. These remarks are inferred to designate the role of PCs in the crucial metal ion metabolism homeostasis [94, 101].

#### **10. Conclusion**

Among several regions of the world, cultivation of plants is significant in the maintenance of the ecosystem. Environmental contamination occurs due to geogenic and anthropogenic activities as discussed in the review paper. Although a few metals are true bio elements at normal concentration, they can cause a potentially hazardous impact on excessive usage causing environmental contamination. There are a variety of measured steps taken through the different aspects of phytoremediation to curb the menace of contaminants and pollution, but there is always a step of further progress which can be implemented in this scenario.

Plants are naturally found to synthesize nanoparticles. Nanophytoremediation is an innovative and encouraging technology which has gathered a wider reception due to its current area of research in plants. As in the review paper, there are several plant families which act in the biosynthesis of nanoparticles. It is significant to

**235**

*Nanophytoremediation: An Overview of Novel and Sustainable Biological Advancement*

technique, thus maintaining the sustainability of the environment.

the manuscript. All the authors contributed to this book chapter.

The authors declare no conflict of interest.

study on metal nanoparticles formation, types of nanoparticles, and derivatives of these nanoparticles, and their action on the physiological process will further eliminate the bioaccumulation of toxic nanoparticles in the plants. Numerous countries globally use plants as a primary source of energy for food; fodder; thus, toxicity and contamination of metals in crops and medical plants may have a huge impact. In our review paper, we have made a significant effort to understand the phytoremediation processes, in general, the nanoparticles occurrence, the need to biomonitor the trace elements in the environment, the physiological effects of the bioelements, transgenic plants which can be used effectively in nanophytoremediation. Thus, in conclusion, nanophytoremediation can be a complementary biological clean-up

Silpi Sarkar, Manoj Kumar Enamala, and Murthy Chavali wrote the chapter; Mannam Krishnamurthy contributed to the scope of the manuscript; Enamala Manoj Kumar planned the review of the literature and reorganized the chapter; verification was done by Subbaroy Sarma and Murthy Chavali critically reviewed

This work was not funded by any organization; the authors have done on their own.

*DOI: http://dx.doi.org/10.5772/intechopen.93300*

**Conflicts of interest**

**Author Contributions**

**Financial and Ethical disclosures**

*Nanophytoremediation: An Overview of Novel and Sustainable Biological Advancement DOI: http://dx.doi.org/10.5772/intechopen.93300*

study on metal nanoparticles formation, types of nanoparticles, and derivatives of these nanoparticles, and their action on the physiological process will further eliminate the bioaccumulation of toxic nanoparticles in the plants. Numerous countries globally use plants as a primary source of energy for food; fodder; thus, toxicity and contamination of metals in crops and medical plants may have a huge impact. In our review paper, we have made a significant effort to understand the phytoremediation processes, in general, the nanoparticles occurrence, the need to biomonitor the trace elements in the environment, the physiological effects of the bioelements, transgenic plants which can be used effectively in nanophytoremediation. Thus, in conclusion, nanophytoremediation can be a complementary biological clean-up technique, thus maintaining the sustainability of the environment.

## **Conflicts of interest**

*Soil Contamination - Threats and Sustainable Solutions*

overexpression of a pea MT gene.

projected that PCs are the functionally alike MTs [100].

**9.2 Phytochelatins**

proteins [11]. To mention,

tions of Pb and Cd.

transgenic seedlings.

**10. Conclusion**

observed in transgenic plants.

d.Likewise, high accumulation of Cu was found in *Arabidopsis thaliana* by

Phytochelatins (PC) are oligomers of glutathione [98] produced by the enzyme phytochelatin synthase from GSH, seen in plants, fungi, nematodes, and all the algal groups including cyanobacteria. Phytochelatins are central for heavy metal detoxification and act as chelators [99], Cysteine-rich metal-chelating (post-translationally synthesized) peptides which suggestively show heavy-metal tolerance in plants and fungi by chelation and thus decrease their unrestricted availability. It is

PCs are not reported in animal species, which supports that MTs performs normal functions well in animals, as a contribution by PCs in plants. Heavy-metal toxicity in plants is seen in diverse ways; these include chelation, exclusion, compartmentalization of the metal ions, immobilization, and the expression of more stress response mechanisms in general such as ethylene and other stress

a.In the *Agrobacterium*-mediated transformation, the induction and overexpression of phytochelatin synthase (PCS1) in *Nicotiana glauca* bring about high concentra-

b.Accumulation of high Pb concentrations in aerial parts and roots were also

c.Longer roots, greener higher leaves than unmodified plants were seen in

increases PC synthesis thus accumulating and tolerating metals.

d.Overexpression of an Arabidopsis PC synthase (AtPCS1) in transgenic which

As PCs are found in tissues of the plants and cell cultures upon open to trace levels of crucial metals and the level of PCs were seen in cell cultures is correlated with the medium by reduction of metal ions. These remarks are inferred to designate the role of PCs in the crucial metal ion metabolism homeostasis [94, 101].

Among several regions of the world, cultivation of plants is significant in the maintenance of the ecosystem. Environmental contamination occurs due to geogenic and anthropogenic activities as discussed in the review paper. Although a few metals are true bio elements at normal concentration, they can cause a potentially hazardous impact on excessive usage causing environmental contamination. There are a variety of measured steps taken through the different aspects of phytoremediation to curb the menace of contaminants and pollution, but there is always a step

Plants are naturally found to synthesize nanoparticles. Nanophytoremediation is an innovative and encouraging technology which has gathered a wider reception due to its current area of research in plants. As in the review paper, there are several plant families which act in the biosynthesis of nanoparticles. It is significant to

of further progress which can be implemented in this scenario.

**234**

The authors declare no conflict of interest.

## **Author Contributions**

Silpi Sarkar, Manoj Kumar Enamala, and Murthy Chavali wrote the chapter; Mannam Krishnamurthy contributed to the scope of the manuscript; Enamala Manoj Kumar planned the review of the literature and reorganized the chapter; verification was done by Subbaroy Sarma and Murthy Chavali critically reviewed the manuscript. All the authors contributed to this book chapter.

## **Financial and Ethical disclosures**

This work was not funded by any organization; the authors have done on their own.

## **Author details**

Silpi Sarkar1 , Manoj Kumar Enamala<sup>2</sup> , Murthy Chavali3,4,5\*, G.V.S. Subbaroy Sarma6 , Mannam Krishna Murthy7 , Abudukeremu Kadier8 , Ashokkumar Veeramuthu9 and K. Chandrasekhar10

1 School of Biotechnology, Vignan Foundation for Science, Technology and Research (VFSTR) University, Guntur, Andhra Pradesh, India

2 Bioserve Biotechnologies Private Limited Unit, Hyderabad, Telangana, India

3 Department of Chemistry (PG Studies), Shree Velagapudi Rama Krishna Memorial College, Guntur, Andhra Pradesh, India

4 PG Department of Chemistry, Dharma Appa Rao College, Krishna District, Andhra Pradesh, India

5 NTRC-MCETRC and Aarshanano Composites Technologies Pvt. Ltd., Guntur District, Andhra Pradesh, India

6 Department of Basic Sciences and Humanities, Vignan Lara Institute of Technology and Science, Guntur, Andhra Pradesh, India

7 Varsity Education Management Limited, Hyderabad, Telangana, India

8 Department of Chemical and Process Engineering, Faculty of Engineering and Built Environment, National University of Malaysia (UKM), Selangor, Malaysia

9 Department of Chemical Technology, Chulalongkorn University, Bangkok, Thailand

10 Green Processing, Bioremediation and Alternative Energies (GPBAE) Research Group, Faculty of Environment and Labour Safety, Ton Duc Thang University, Ho Chi Minh City, Vietnam

\*Address all correspondence to: chavalim@gmail.com; chavalim@outlook.com

© 2020 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

**237**

es980089x

*Nanophytoremediation: An Overview of Novel and Sustainable Biological Advancement*

Implications for phytoremediation and restoration. Environment International. 2004;**30**(5):685-700. DOI: 10.1016/j.

[8] Nzenguang VA, McCutcheon SC. Phytoremediation of perchlorate. In: McCutcheon SC, Schnoor JL, editors. Phytoremediation: Transformation and Control of Contaminants. New Jersey: John Wiley and Sons, Inc.; 2003. pp.

McCutcheon SC. Phytoremediation: An ecological solution to organic chemical contamination. Ecological Engineering. 2002;**18**(2):647-658. DOI: 10.1016/

envint.2003.11.002

[9] Susarla S, Medina VF,

S0925-8574(02)00026-5

hyperaccumulation in plants. Annual Review of Plant Biology. 2010;**6**(1):517-534. DOI: 10.1146/ annurev-arplant-042809-112156

[12] Gupta A, Joia J, Sood A, Sood R, Sidhu C, Kaur G. Microbes as potential tool for remediation of heavy metals: A review. Journal of Microbial and Biochemical Technology.

[13] Mandal A, Purakayastha T, Ramana S, Neenu S, Bhaduri D, Chakraborty K, et al. Status on phytoremediation of heavy metals in India- a review. International Journal of Stress Management. 2014;**5**(4):553-560. DOI: 10.5958/0976-4038.2014.00609.5

[14] Mahimairaja S, Bolan NS, Adriano DC, Robinson B. Arsenic contamination and its risk management in complex environmental settings.

2016;**8**:364-372

[11] Sanità Di Toppi L, Gabbrielli R. Response to cadmium in higher plants. Environmental and Experimental Botany. 1999;**42**(2):105-130. DOI: 10.1016/S0098-8472(98)00058-6

[10] Krämer U. Metal

863-885

*DOI: http://dx.doi.org/10.5772/intechopen.93300*

[1] Van Aken B. Transgenic plants for phytoremediation: Helping nature to clean up the environmental pollution. Trends in Biotechnology. 2008;**26**(5):225-227. DOI: 10.1016/j.

[2] Warrier RR. Phytoremediation for environmental clean-up. Forestry Bulletin. 2012;**12**(2):1-7. Available from: https://pdfs.semanticscholar.org/a855/ 2eb54d818442b99072f5c39676278d9fe

[3] Sinha R, Valani D, Sinha SS, Herat S. Bioremediation of contaminated sites: A low-cost Nature's biotechnology for environmental clean-up by versatile microbes, plants and earthworms. In: Faerber T, Herzog J, editors. Solid Waste Management and Environmental Remediation. NY, USA: Nova Science

tibtech.2008.02.001

**References**

Publisher; 2010. pp. 1-73

InTech; 2012. pp. 75-102

s10535-006-0102-5

[4] Masarovicova E, Králova K. Plant-heavy metal interaction: Phytoremediation, biofortification and nanoparticles. In: Monatanaro G, Dichio B, editors. Advances in Selected Plant Physiology Aspects. Croatia:

[5] Gajewska E, Skłodowska M, Słaba M, Mazur J. Effect of nickel on antioxidative enzyme activities, proline and chlorophyll contents in wheat shoots. Biologia Plantarum. 2006;**50**(4):653-659. DOI: 10.1007/

[6] Lytle CM, Lytle PW, Yang N, Qian JH, Hansen D, Zayed A, et al. Reduction of Cr(VI) to Cr(III) by wetland plants: Potential for in situ heavy metal detoxification. Environmental Science & Technology. 1998;**32**(20):3087-3093. DOI: 10.1021/

[7] Weis JS, Weis P. Metal uptake, transport and release by wetland plants:

eff.pdf

*Nanophytoremediation: An Overview of Novel and Sustainable Biological Advancement DOI: http://dx.doi.org/10.5772/intechopen.93300*

## **References**

*Soil Contamination - Threats and Sustainable Solutions*

, Manoj Kumar Enamala2

Memorial College, Guntur, Andhra Pradesh, India

Krishna District, Andhra Pradesh, India

Guntur District, Andhra Pradesh, India

, Murthy Chavali3,4,5\*,

, Abudukeremu Kadier8

,

, Mannam Krishna Murthy7

1 School of Biotechnology, Vignan Foundation for Science, Technology and

2 Bioserve Biotechnologies Private Limited Unit, Hyderabad, Telangana, India

3 Department of Chemistry (PG Studies), Shree Velagapudi Rama Krishna

5 NTRC-MCETRC and Aarshanano Composites Technologies Pvt. Ltd.,

6 Department of Basic Sciences and Humanities, Vignan Lara Institute of

7 Varsity Education Management Limited, Hyderabad, Telangana, India

8 Department of Chemical and Process Engineering, Faculty of Engineering and Built Environment, National University of Malaysia (UKM), Selangor, Malaysia

10 Green Processing, Bioremediation and Alternative Energies (GPBAE) Research Group, Faculty of Environment and Labour Safety, Ton Duc Thang University,

\*Address all correspondence to: chavalim@gmail.com; chavalim@outlook.com

© 2020 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium,

9 Department of Chemical Technology, Chulalongkorn University, Bangkok,

Research (VFSTR) University, Guntur, Andhra Pradesh, India

4 PG Department of Chemistry, Dharma Appa Rao College,

Technology and Science, Guntur, Andhra Pradesh, India

and K. Chandrasekhar10

**Author details**

G.V.S. Subbaroy Sarma6

Ashokkumar Veeramuthu9

Silpi Sarkar1

**236**

Thailand

Ho Chi Minh City, Vietnam

provided the original work is properly cited.

[1] Van Aken B. Transgenic plants for phytoremediation: Helping nature to clean up the environmental pollution. Trends in Biotechnology. 2008;**26**(5):225-227. DOI: 10.1016/j. tibtech.2008.02.001

[2] Warrier RR. Phytoremediation for environmental clean-up. Forestry Bulletin. 2012;**12**(2):1-7. Available from: https://pdfs.semanticscholar.org/a855/ 2eb54d818442b99072f5c39676278d9fe eff.pdf

[3] Sinha R, Valani D, Sinha SS, Herat S. Bioremediation of contaminated sites: A low-cost Nature's biotechnology for environmental clean-up by versatile microbes, plants and earthworms. In: Faerber T, Herzog J, editors. Solid Waste Management and Environmental Remediation. NY, USA: Nova Science Publisher; 2010. pp. 1-73

[4] Masarovicova E, Králova K. Plant-heavy metal interaction: Phytoremediation, biofortification and nanoparticles. In: Monatanaro G, Dichio B, editors. Advances in Selected Plant Physiology Aspects. Croatia: InTech; 2012. pp. 75-102

[5] Gajewska E, Skłodowska M, Słaba M, Mazur J. Effect of nickel on antioxidative enzyme activities, proline and chlorophyll contents in wheat shoots. Biologia Plantarum. 2006;**50**(4):653-659. DOI: 10.1007/ s10535-006-0102-5

[6] Lytle CM, Lytle PW, Yang N, Qian JH, Hansen D, Zayed A, et al. Reduction of Cr(VI) to Cr(III) by wetland plants: Potential for in situ heavy metal detoxification. Environmental Science & Technology. 1998;**32**(20):3087-3093. DOI: 10.1021/ es980089x

[7] Weis JS, Weis P. Metal uptake, transport and release by wetland plants: Implications for phytoremediation and restoration. Environment International. 2004;**30**(5):685-700. DOI: 10.1016/j. envint.2003.11.002

[8] Nzenguang VA, McCutcheon SC. Phytoremediation of perchlorate. In: McCutcheon SC, Schnoor JL, editors. Phytoremediation: Transformation and Control of Contaminants. New Jersey: John Wiley and Sons, Inc.; 2003. pp. 863-885

[9] Susarla S, Medina VF, McCutcheon SC. Phytoremediation: An ecological solution to organic chemical contamination. Ecological Engineering. 2002;**18**(2):647-658. DOI: 10.1016/ S0925-8574(02)00026-5

[10] Krämer U. Metal hyperaccumulation in plants. Annual Review of Plant Biology. 2010;**6**(1):517-534. DOI: 10.1146/ annurev-arplant-042809-112156

[11] Sanità Di Toppi L, Gabbrielli R. Response to cadmium in higher plants. Environmental and Experimental Botany. 1999;**42**(2):105-130. DOI: 10.1016/S0098-8472(98)00058-6

[12] Gupta A, Joia J, Sood A, Sood R, Sidhu C, Kaur G. Microbes as potential tool for remediation of heavy metals: A review. Journal of Microbial and Biochemical Technology. 2016;**8**:364-372

[13] Mandal A, Purakayastha T, Ramana S, Neenu S, Bhaduri D, Chakraborty K, et al. Status on phytoremediation of heavy metals in India- a review. International Journal of Stress Management. 2014;**5**(4):553-560. DOI: 10.5958/0976-4038.2014.00609.5

[14] Mahimairaja S, Bolan NS, Adriano DC, Robinson B. Arsenic contamination and its risk management in complex environmental settings.

Advances in Agronomy. 2005;**86**:1-82. DOI: 10.1016/S0065-2113(05)86001-8

[15] McGrath SP, Zhao FJ, Lombi E. Plant and rhizosphere processes involved in phytoremediation of metalcontaminated soils. Plant and Soil. 2001;**232**(1):207-214

[16] Dotaniya ML, Thakur JK, Meena VD, Jajoria DK, Rathor G. Chromium pollution: A threat to environment-a review. Agricultural Reviews. 2014;**35**(2):153-157. DOI: 10.5958/0976-0741.2014.00094.4

[17] Wu J, Overton C. Asian ecology: Pressing problems and research challenges. Bulletin of Ecological Society of America. 2002;**83**(3):189-194

[18] Yadav KK, Singh JK, Gupta N, Kumar V. A review of nanobioremediation technologies for environmental clean-up: A novel biological approach. Journal of Materials and Environmental Science. 2017;**8**(2):740-757

[19] Handy RD, Owen R, Valsami-Jones E. The ecotoxicology of nanoparticles and nanomaterials: Current status, knowledge gaps, challenges, and future needs. Ecotoxicology. 2008;**17**(5):315-325. DOI: 10.1007/s10646-008-0206-0

[20] Stampoulis D, Sinha SK, White JC. Assay-dependent phytotoxicity of nanoparticles to plants. Environmental Science & Technology. 2009;**43**(24):9473-9479

[21] Shekhawat GS, Arya V. Biological synthesis of Ag nanoparticles through in vitro cultures of *Brassica juncea* C. zern. Advances in Materials Research. 2009;**67**:295-299. DOI: 10.4028/www. scientific.net/AMR.67.295

[22] Ankamwar B. Biosynthesis of gold nanoparticles (green-gold) using leaf extract of *Terminalia catappa*. E-Journal of Chemistry. 2010;**7**(4):1334-1339. DOI: 10.1155/2010/745120

[23] Beattie IR, Haverkamp RG. Silver and gold nanoparticles in plants: Sites for the reduction of the metal. Metallomics. 2011;**3**(6):628-632. DOI: 10.1039/c1mt00044f

[24] Watlington K. Emerging nanotechnologies for site remediation and wastewater treatment. Report prepared for National Network of Environmental Management (NNEM) studies the grantee under a fellowship from the U.S. Environmental Protection Agency (US-EPA). 2005

[25] Saif S, Tahir A, Chen Y. Green synthesis of iron nanoparticles and their environmental applications and implications. Nanomaterials. 2016;**6**(11):1-26. DOI: 10.3390/ nano6110209

[26] Ponder SM, Darab JG, Mallouk TE. Remediation of Cr (VI) and Pb (II) aqueous solutions using supported, nanoscale zero-valent iron remediation of Cr (VI) and Pb (II) aqueous solutions using supported, nanoscale zerovalent iron. Environmental Science & Technology. 2000;**34**(12):2564-2569. DOI: 10.1021/es9911420

[27] Schrick B, Hydutsky BW, Blough JL, Mallouk TE. Delivery vehicles for zerovalent metal nanoparticles in soil and groundwater. Chemistry of Materials. 2004;**16**(11):2187-2193. DOI: 10.1021/cm0218108

[28] Schrick B, Blough JL, Jones AD, Mallouk TE. Hydrodechlorination of trichloroethylene to hydrocarbons using bimetallic nickel-iron nanoparticles. Chemistry of Materials. 2002;**14**(12):5140-5147

[29] Li C, Zhou L, Yang H, Lv R, Tian P, Li X, et al. Self-assembled exopolysaccharide nanoparticles for bioremediation and green synthesis

**239**

*Nanophytoremediation: An Overview of Novel and Sustainable Biological Advancement*

by multi-walled carbon nanotubes. Journal of Hazardous Materials.

[37] Li Y, Liu F, Xia B, Du Q, Zhang P, Wang D, et al. Removal of copper from aqueous solution by carbon nanotube/

[38] Gong J-L, Wang B, Zeng G-M, et al. Removal of cationic dyes from aqueous solution using magnetic multi-wall carbon nanotube nanocomposite as adsorbent. Journal of Hazardous Materials. 2009;**164**(2-3):1517-1522

calcium alginate composites. Journal of Hazardous Materials. 2010;**177**(1-3):876-880. DOI: 10.1016/j.

[39] Mackay DM, Cherry JA.

636. DOI: 10.1021/es00064a001

polymeric nanoparticles for bioremediation of hydrophobic contaminants. Environmental Science & Technology. 2005;**39**(5):1354-1358

Groundwater contamination: Pumpand-treat remediation. Environmental Science & Technology. 1989;**23**(6):630-

[40] Tungittiplakorn W. Engineered

[41] Liao C, Xu W, Lu G, Liang X, Guo C, Yang C, et al. Accumulation of hydrocarbons by maize (*Zea mays* L.) in remediation of soils contaminated with crude oil. International Journal of Phytoremediation. 2015;**17**(7):693-700. DOI: 10.1080/15226514.2014.964840

[42] Mojiri A. The potential of corn (*Zea mays*) for phytoremediation of soil contaminated with cadmium and Lead. Journal of Biological and Environmental

[43] Bargar JR, Bernier-Latmani R, Giammar DE, Tebo BM. Biogenic uraninite nanoparticles and their importance for uranium remediation. Elements. 2008;**4**(6):407-412. DOI:

[44] Cherian S, Oliveira MM. Transgenic plants in phytoremediation: Recent

Sciences. 2011;**5**(13):17-22

10.2113/gselements.4.6.407

2007;**146**(1-2):283-288

jhazmat.2009.12.114

*DOI: http://dx.doi.org/10.5772/intechopen.93300*

[30] Tan J, Liu R, Wang W, Liu W, Tian Y, Wu M, et al. Controllable aggregation and reversible pH sensitivity of AuNPs regulated by carboxymethyl cellulose. Langmuir. 2010;**26**(3):2093-2098. DOI:

[31] Yin Y, Hu Y, Xiong F. Sorption of Cu (II) and Cd(II) by extracellular polymeric substances (EPS) from *Aspergillus fumigatus*. International Biodeterioration and Biodegradation. 2011;**65**(7):1012-1018. DOI: 10.1016/j.

[32] Feng M, Chen X, Li C, Nurgul R, Dong M. Isolation and identification of an exopolysaccharide-producing lactic acid bacterium strain from Chinese Paocai and biosorption of Pb(II) by its exopolysaccharide. Journal of Food Science. 2012;**77**(6):T111-T117. DOI: 10.1111/j.1750-3841.2012.02734.x

[33] Salehizadeh H, Shojaosadati SA. Removal of metal ions from aqueous solution by polysaccharide produced from *Bacillus firmus*. Water Research. 2003;**37**(17):4231-4235. DOI: 10.1016/

S0043-1354(03)00418-4

2015;**4**(1):44-59

es8006904

[34] Baig T, Nayak J, Dwivedi V, Singh A, Tripathi PK. A review about

dendrimers: Synthesis, types, characterization and applications. International Journal of Advances in Pharmacy, Biology and Chemistry.

[35] Mauter MSC, Elimlech M.

[36] Kandah MI, Meunier J-L. Removal of nickel ions from water

Science & Technology.

Environmental applications of carbonbased Nanomaterials. Environmental

2008;**42**(16):5843-5859. DOI: 10.1021/

of noble metal nanoparticles. ACS Applied Materials & Interfaces. 2017;**9**(27):22808-22818. DOI: 10.1021/

acsami.7b02908

10.1021/la902593e

ibiod.2011.08.001

*Nanophytoremediation: An Overview of Novel and Sustainable Biological Advancement DOI: http://dx.doi.org/10.5772/intechopen.93300*

of noble metal nanoparticles. ACS Applied Materials & Interfaces. 2017;**9**(27):22808-22818. DOI: 10.1021/ acsami.7b02908

*Soil Contamination - Threats and Sustainable Solutions*

of Chemistry. 2010;**7**(4):1334-1339.

[23] Beattie IR, Haverkamp RG. Silver and gold nanoparticles in plants: Sites for the reduction of the metal. Metallomics. 2011;**3**(6):628-632. DOI:

nanotechnologies for site remediation and wastewater treatment. Report prepared for National Network of Environmental Management (NNEM) studies the grantee under a fellowship from the U.S. Environmental Protection

[25] Saif S, Tahir A, Chen Y. Green synthesis of iron nanoparticles and their environmental applications and implications. Nanomaterials. 2016;**6**(11):1-26. DOI: 10.3390/

[26] Ponder SM, Darab JG, Mallouk TE. Remediation of Cr (VI) and Pb (II) aqueous solutions using supported, nanoscale zero-valent iron remediation of Cr (VI) and Pb (II) aqueous solutions

[27] Schrick B, Hydutsky BW, Blough JL, Mallouk TE. Delivery vehicles for zerovalent metal nanoparticles in soil and groundwater. Chemistry of Materials. 2004;**16**(11):2187-2193. DOI:

[28] Schrick B, Blough JL, Jones AD, Mallouk TE. Hydrodechlorination of trichloroethylene to hydrocarbons using bimetallic nickel-iron

nanoparticles. Chemistry of Materials.

[29] Li C, Zhou L, Yang H, Lv R, Tian P, Li X, et al. Self-assembled exopolysaccharide nanoparticles for bioremediation and green synthesis

using supported, nanoscale zerovalent iron. Environmental Science & Technology. 2000;**34**(12):2564-2569.

DOI: 10.1021/es9911420

10.1021/cm0218108

2002;**14**(12):5140-5147

DOI: 10.1155/2010/745120

10.1039/c1mt00044f

[24] Watlington K. Emerging

Agency (US-EPA). 2005

nano6110209

Advances in Agronomy. 2005;**86**:1-82. DOI: 10.1016/S0065-2113(05)86001-8

[15] McGrath SP, Zhao FJ, Lombi E. Plant and rhizosphere processes involved in phytoremediation of metalcontaminated soils. Plant and Soil.

Rathor G. Chromium pollution: A threat to environment-a review. Agricultural Reviews. 2014;**35**(2):153-157. DOI: 10.5958/0976-0741.2014.00094.4

[17] Wu J, Overton C. Asian ecology: Pressing problems and research challenges. Bulletin of Ecological Society of America. 2002;**83**(3):189-194

[18] Yadav KK, Singh JK, Gupta N,

nanobioremediation technologies for environmental clean-up: A novel biological approach. Journal of Materials and Environmental Science.

Valsami-Jones E. The ecotoxicology of nanoparticles and nanomaterials: Current status, knowledge gaps, challenges, and future needs.

Ecotoxicology. 2008;**17**(5):315-325. DOI:

[20] Stampoulis D, Sinha SK, White JC. Assay-dependent phytotoxicity of nanoparticles to plants. Environmental

[21] Shekhawat GS, Arya V. Biological synthesis of Ag nanoparticles through in vitro cultures of *Brassica juncea* C. zern. Advances in Materials Research. 2009;**67**:295-299. DOI: 10.4028/www.

[22] Ankamwar B. Biosynthesis of gold nanoparticles (green-gold) using leaf extract of *Terminalia catappa*. E-Journal

Kumar V. A review of

2017;**8**(2):740-757

[19] Handy RD, Owen R,

10.1007/s10646-008-0206-0

Science & Technology. 2009;**43**(24):9473-9479

scientific.net/AMR.67.295

2001;**232**(1):207-214

[16] Dotaniya ML, Thakur JK, Meena VD, Jajoria DK,

**238**

[30] Tan J, Liu R, Wang W, Liu W, Tian Y, Wu M, et al. Controllable aggregation and reversible pH sensitivity of AuNPs regulated by carboxymethyl cellulose. Langmuir. 2010;**26**(3):2093-2098. DOI: 10.1021/la902593e

[31] Yin Y, Hu Y, Xiong F. Sorption of Cu (II) and Cd(II) by extracellular polymeric substances (EPS) from *Aspergillus fumigatus*. International Biodeterioration and Biodegradation. 2011;**65**(7):1012-1018. DOI: 10.1016/j. ibiod.2011.08.001

[32] Feng M, Chen X, Li C, Nurgul R, Dong M. Isolation and identification of an exopolysaccharide-producing lactic acid bacterium strain from Chinese Paocai and biosorption of Pb(II) by its exopolysaccharide. Journal of Food Science. 2012;**77**(6):T111-T117. DOI: 10.1111/j.1750-3841.2012.02734.x

[33] Salehizadeh H, Shojaosadati SA. Removal of metal ions from aqueous solution by polysaccharide produced from *Bacillus firmus*. Water Research. 2003;**37**(17):4231-4235. DOI: 10.1016/ S0043-1354(03)00418-4

[34] Baig T, Nayak J, Dwivedi V, Singh A, Tripathi PK. A review about dendrimers: Synthesis, types, characterization and applications. International Journal of Advances in Pharmacy, Biology and Chemistry. 2015;**4**(1):44-59

[35] Mauter MSC, Elimlech M. Environmental applications of carbonbased Nanomaterials. Environmental Science & Technology. 2008;**42**(16):5843-5859. DOI: 10.1021/ es8006904

[36] Kandah MI, Meunier J-L. Removal of nickel ions from water by multi-walled carbon nanotubes. Journal of Hazardous Materials. 2007;**146**(1-2):283-288

[37] Li Y, Liu F, Xia B, Du Q, Zhang P, Wang D, et al. Removal of copper from aqueous solution by carbon nanotube/ calcium alginate composites. Journal of Hazardous Materials. 2010;**177**(1-3):876-880. DOI: 10.1016/j. jhazmat.2009.12.114

[38] Gong J-L, Wang B, Zeng G-M, et al. Removal of cationic dyes from aqueous solution using magnetic multi-wall carbon nanotube nanocomposite as adsorbent. Journal of Hazardous Materials. 2009;**164**(2-3):1517-1522

[39] Mackay DM, Cherry JA. Groundwater contamination: Pumpand-treat remediation. Environmental Science & Technology. 1989;**23**(6):630- 636. DOI: 10.1021/es00064a001

[40] Tungittiplakorn W. Engineered polymeric nanoparticles for bioremediation of hydrophobic contaminants. Environmental Science & Technology. 2005;**39**(5):1354-1358

[41] Liao C, Xu W, Lu G, Liang X, Guo C, Yang C, et al. Accumulation of hydrocarbons by maize (*Zea mays* L.) in remediation of soils contaminated with crude oil. International Journal of Phytoremediation. 2015;**17**(7):693-700. DOI: 10.1080/15226514.2014.964840

[42] Mojiri A. The potential of corn (*Zea mays*) for phytoremediation of soil contaminated with cadmium and Lead. Journal of Biological and Environmental Sciences. 2011;**5**(13):17-22

[43] Bargar JR, Bernier-Latmani R, Giammar DE, Tebo BM. Biogenic uraninite nanoparticles and their importance for uranium remediation. Elements. 2008;**4**(6):407-412. DOI: 10.2113/gselements.4.6.407

[44] Cherian S, Oliveira MM. Transgenic plants in phytoremediation: Recent

advances and new possibilities. Environmental Science & Technology. 2005;**39**(24):9377-9390. DOI: 10.1021/ es051134l

[45] Čechmánková J, Vácha R, Skála J, Havelková M. Heavy metals phytoextraction from heavily and moderately contaminated soil by field crops grown in monoculture and crop rotation. Soil and Water Research. 2011;**6**(3):120-130

[46] Baldantoni D, Maisto G, Bartoli G, Alfani A. Analyses of three native aquatic plant species to assess spatial gradients of lake trace element contamination. Aquatic Botany. 2005;**83**(1):48-60. DOI: 10.1016/j. aquabot.2005.05.006

[47] Rizwan M, Singh M, Mitra CK, Morve RK. Ecofriendly application of nanomaterials: Nanobioremediation. Journal of Nanoparticle Research. 2014;**2014**:431787 8, 1-7. DOI: 10.1155/2014/431787

[48] Bharti S, Banerjee TK. Phytoremediation of the coal mine effluent. Ecotoxicology and Environmental Safety. 2012;**81**:36-42. DOI: 10.1016/j.ecoenv.2012.04.009

[49] Chen JC, Wang KS, Chen H, Lu CY, Huang LC, Li HC, et al. Phytoremediation of Cr(III) by *Ipomonea aquatica* (water spinach) from water in the presence of EDTA and chloride: Effects of Cr speciation. Bioresource Technology. 2010;**101**(9):3033-3039. DOI: 10.1016/j. biortech.2009.12.041

[50] Marín CMDC, Oron G. Boron removal by the duckweed *Lemna gibba*: A potential method for the remediation of boron-polluted waters. Water Research. 2007;**41**(20):4579-4584. DOI: 10.1016/j.watres.2007.06.051

[51] El-Khaiary MI. Kinetics and mechanism of adsorption of methylene blue from aqueous solution by nitricacid treated water-hyacinth. Journal of Hazardous Materials. 2007;**147**(1-2):28- 36. DOI: 10.1016/j.jhazmat.2006.12.058

[52] Hasan SH, Talat M, Rai S. Sorption of cadmium and zinc from aqueous solutions by water hyacinth (*Eichhornia crassipes*). Bioresource Technology. 2007;**98**(4):918-928. DOI: 10.1016/j. biortech.2006.02.042

[53] Khataee AR, Movafeghi A, Torbati S, Salehi Lisar SY, Zarei M. Phytoremediation potential of duckweed (*Lemna minor* L.) in the degradation of C.I. acid blue 92: Artificial neural network modelling. Ecotoxicology and Environmental Safety. 2012;**80**(1):291-298. DOI: 10.1016/j.ecoenv.2012.03.021

[54] Pandey VC. Phytoremediation of heavy metals from fly ash pond by *Azolla caroliniana*. Ecotoxicology and Environmental Safety. 2012;**82**:8-12. DOI: 10.1016/j.ecoenv.2012.05.002

[55] Srivastava S, Bhainsa KC, D'Souza SF. Bioresource technology investigation of uranium accumulation potential and biochemical responses of an aquatic weed *Hydrilla verticillata* (L.f.) Royle. Bioresource Technology. 2010;**101**(8):2573-2579. DOI: 10.1016/j. biortech.2009.10.054

[56] Islam MS, Saito T, Kurasaki M. Phytofiltration of arsenic and cadmium by using an aquatic plant, *Micranthemum umbrosum*: Phytotoxicity, uptake kinetics, and mechanism. Ecotoxicology and Environmental Safety. 2015;**112**:193-200. DOI: 10.1016/j. ecoenv.2014.11.006

[57] González I, Neaman A, Cortés A, Rubio P. Effect of compost and biodegradable chelate addition on phytoextraction of copper by Oenothera picensis grown in Cu-contaminated acid soils. Chemosphere. 2014;**95**:111-115. DOI: 10.1016/j. chemosphere.2013.08.046

**241**

*Nanophytoremediation: An Overview of Novel and Sustainable Biological Advancement*

Sagar an anthropogenic lake affected by coal mining effluent. Environmental

[65] Ha NTH, Sakakibara M, Sano S. Accumulation of indium and other heavy metals by *Eleocharis acicularis* an option for phytoremediation and phytomining. Bioresource Technology. 2011;**102**(3):2228-2234. DOI: 10.1016/j.

[66] Sakakibara M. Phytoremediation of toxic elements-polluted water and soils by aquatic macrophyte *Eleocharis acicularis*. AIP Conference Proceedings. 2016;**1744**:1-6. DOI: 10.1063/1.4953512

[67] Sarma H. Metal hyperaccumulation

Journal of Environmental Science and Technology. 2011;**4**(2):118-138. DOI:

[68] Ladislas S, El-Mufleh A, Gérente C, Chazarenc F, Andrès Y, Béchet B. Potential of aquatic macrophytes as bioindicators of heavy metal pollution in urban stormwater runoff. Water, Air, and Soil Pollution. 2012;**223**(2):877-888.

DOI: 10.1007/s11270-011-0909-3

10.1016/0883-2927(95)00082-8

2006;**31**(1):49-56

[70] Ariyakanon N, Winaipanich B. Phytoremediation of copper contaminated soil by *Brassica juncea* (L.) Czern and *Bidens alba* (L.) DC. var. radiata. Journal of Scientific Research, Chulalongkorn University.

[71] Das S, Goswami S, Talukdar AD. A study on cadmium phytoremediation potential of water lettuce, *Pistia* 

[69] Landberg T, Greger M. Differences in uptake and tolerance to heavy metals in Salix from unpolluted and polluted areas. Applied

Geochemistry. 1996;**11**(1):175-180. DOI:

in plants: A review focusing on phytoremediation technology.

10.3923/jest.2011.118.138

Monitoring and Assessment. 2008;**141**(1-3):49-58. DOI: 10.1007/

s10661-007-9877-x

biortech.2010.10.014

*DOI: http://dx.doi.org/10.5772/intechopen.93300*

[58] Sooksawat N, Meetam M, Kruatrachue M, Pokethitiyook P, Nathalang K. Phytoremediation potential of charophytes: Bioaccumulation and toxicity studies of cadmium, lead and zinc. Journal of Environmental Sciences. 2013;**25**(3):596-604. DOI: 10.1016/

S1001-0742(12)60036-9

[59] Siva Kiran RR, Madhu GM, Satyanarayana SV, Bindiya P.

10.4172/2155-6199.1000141

10.1016/j.scitotenv.2012.06.091

Mendil D, Uluozlu OD, Soylak M, Dogan M. Characterization of the biosorption process of As(III) on green algae *Ulothrix cylindricum*. Journal of Hazardous Materials. 2009;**165**(1-3):566-572. DOI: 10.1016/j.

[62] Hua J, Zhang C, Yin Y, Chen R, Wang X. Phytoremediation potential

of three aquatic macrophytes in manganese-contaminated water. Water and Environment Journal. 2012;**26**(3):335-342. DOI: 10.1111/j.1747-6593.2011.00293.x

[63] Maine MA, Duarte MV,

S0043-1354(00)00557-1

macrophytes. Water Research. 2001;**35**(11):2629-2634. DOI: 10.1016/

[64] Mishra VK, Upadhyay AR,

of heavy metals and aquatic

Suñé NL. Cadmium uptake by floating

Pandey SK, Tripathi BD. Concentrations

macrophytes of Govind Ballabh Pant

[61] Tuzen M, Sari A,

jhazmat.2008.10.020

Bioaccumulation of cadmium in bluegreen algae Spirulina (Arthrospira) Indica. Journal of Bioremediation & Biodegradation. 2012;**3**(3):1-4. DOI:

[60] Favas PJC, Pratas J, Prasad MNV. Accumulation of arsenic by aquatic plants in large-scale field conditions: Opportunities for phytoremediation and bioindication. Science of the Total Environment. 2012;**433**:390-397. DOI:

*Nanophytoremediation: An Overview of Novel and Sustainable Biological Advancement DOI: http://dx.doi.org/10.5772/intechopen.93300*

[58] Sooksawat N, Meetam M, Kruatrachue M, Pokethitiyook P, Nathalang K. Phytoremediation potential of charophytes: Bioaccumulation and toxicity studies of cadmium, lead and zinc. Journal of Environmental Sciences. 2013;**25**(3):596-604. DOI: 10.1016/ S1001-0742(12)60036-9

*Soil Contamination - Threats and Sustainable Solutions*

blue from aqueous solution by nitricacid treated water-hyacinth. Journal of Hazardous Materials. 2007;**147**(1-2):28- 36. DOI: 10.1016/j.jhazmat.2006.12.058

[52] Hasan SH, Talat M, Rai S. Sorption of cadmium and zinc from aqueous solutions by water hyacinth (*Eichhornia crassipes*). Bioresource Technology. 2007;**98**(4):918-928. DOI: 10.1016/j.

biortech.2006.02.042

[53] Khataee AR, Movafeghi A, Torbati S, Salehi Lisar SY,

Zarei M. Phytoremediation potential of duckweed (*Lemna minor* L.) in the degradation of C.I. acid blue 92: Artificial neural network modelling. Ecotoxicology and Environmental Safety. 2012;**80**(1):291-298. DOI: 10.1016/j.ecoenv.2012.03.021

[54] Pandey VC. Phytoremediation of heavy metals from fly ash pond by *Azolla caroliniana*. Ecotoxicology and Environmental Safety. 2012;**82**:8-12. DOI: 10.1016/j.ecoenv.2012.05.002

[55] Srivastava S, Bhainsa KC, D'Souza SF. Bioresource technology investigation of uranium accumulation potential and biochemical responses of an aquatic weed *Hydrilla verticillata* (L.f.) Royle. Bioresource Technology. 2010;**101**(8):2573-2579. DOI: 10.1016/j.

[56] Islam MS, Saito T, Kurasaki M. Phytofiltration of arsenic and cadmium by using an aquatic plant, *Micranthemum umbrosum*: Phytotoxicity,

uptake kinetics, and mechanism. Ecotoxicology and Environmental Safety. 2015;**112**:193-200. DOI: 10.1016/j.

Cortés A, Rubio P. Effect of compost and biodegradable chelate addition on phytoextraction of copper by Oenothera picensis grown in Cu-contaminated

biortech.2009.10.054

ecoenv.2014.11.006

[57] González I, Neaman A,

acid soils. Chemosphere. 2014;**95**:111-115. DOI: 10.1016/j. chemosphere.2013.08.046

advances and new possibilities. Environmental Science & Technology. 2005;**39**(24):9377-9390. DOI: 10.1021/

[45] Čechmánková J, Vácha R, Skála J, Havelková M. Heavy metals phytoextraction from heavily and moderately contaminated soil by field crops grown in monoculture and crop rotation. Soil and Water Research.

[46] Baldantoni D, Maisto G, Bartoli G, Alfani A. Analyses of three native aquatic plant species to assess spatial gradients of lake trace element contamination. Aquatic Botany. 2005;**83**(1):48-60. DOI: 10.1016/j.

[47] Rizwan M, Singh M, Mitra CK, Morve RK. Ecofriendly application of nanomaterials: Nanobioremediation. Journal of Nanoparticle Research. 2014;**2014**:431787 8, 1-7. DOI:

es051134l

2011;**6**(3):120-130

aquabot.2005.05.006

10.1155/2014/431787

[48] Bharti S, Banerjee TK. Phytoremediation of the coal mine effluent. Ecotoxicology and Environmental Safety. 2012;**81**:36-42. DOI: 10.1016/j.ecoenv.2012.04.009

[49] Chen JC, Wang KS,

biortech.2009.12.041

Chen H, Lu CY, Huang LC, Li HC, et al. Phytoremediation of Cr(III) by *Ipomonea aquatica* (water spinach) from water in the presence of EDTA and chloride: Effects of Cr speciation. Bioresource Technology. 2010;**101**(9):3033-3039. DOI: 10.1016/j.

[50] Marín CMDC, Oron G. Boron removal by the duckweed *Lemna gibba*: A potential method for the remediation of boron-polluted waters. Water Research. 2007;**41**(20):4579-4584. DOI:

10.1016/j.watres.2007.06.051

[51] El-Khaiary MI. Kinetics and

mechanism of adsorption of methylene

**240**

[59] Siva Kiran RR, Madhu GM, Satyanarayana SV, Bindiya P. Bioaccumulation of cadmium in bluegreen algae Spirulina (Arthrospira) Indica. Journal of Bioremediation & Biodegradation. 2012;**3**(3):1-4. DOI: 10.4172/2155-6199.1000141

[60] Favas PJC, Pratas J, Prasad MNV. Accumulation of arsenic by aquatic plants in large-scale field conditions: Opportunities for phytoremediation and bioindication. Science of the Total Environment. 2012;**433**:390-397. DOI: 10.1016/j.scitotenv.2012.06.091

[61] Tuzen M, Sari A, Mendil D, Uluozlu OD, Soylak M, Dogan M. Characterization of the biosorption process of As(III) on green algae *Ulothrix cylindricum*. Journal of Hazardous Materials. 2009;**165**(1-3):566-572. DOI: 10.1016/j. jhazmat.2008.10.020

[62] Hua J, Zhang C, Yin Y, Chen R, Wang X. Phytoremediation potential of three aquatic macrophytes in manganese-contaminated water. Water and Environment Journal. 2012;**26**(3):335-342. DOI: 10.1111/j.1747-6593.2011.00293.x

[63] Maine MA, Duarte MV, Suñé NL. Cadmium uptake by floating macrophytes. Water Research. 2001;**35**(11):2629-2634. DOI: 10.1016/ S0043-1354(00)00557-1

[64] Mishra VK, Upadhyay AR, Pandey SK, Tripathi BD. Concentrations of heavy metals and aquatic macrophytes of Govind Ballabh Pant

Sagar an anthropogenic lake affected by coal mining effluent. Environmental Monitoring and Assessment. 2008;**141**(1-3):49-58. DOI: 10.1007/ s10661-007-9877-x

[65] Ha NTH, Sakakibara M, Sano S. Accumulation of indium and other heavy metals by *Eleocharis acicularis* an option for phytoremediation and phytomining. Bioresource Technology. 2011;**102**(3):2228-2234. DOI: 10.1016/j. biortech.2010.10.014

[66] Sakakibara M. Phytoremediation of toxic elements-polluted water and soils by aquatic macrophyte *Eleocharis acicularis*. AIP Conference Proceedings. 2016;**1744**:1-6. DOI: 10.1063/1.4953512

[67] Sarma H. Metal hyperaccumulation in plants: A review focusing on phytoremediation technology. Journal of Environmental Science and Technology. 2011;**4**(2):118-138. DOI: 10.3923/jest.2011.118.138

[68] Ladislas S, El-Mufleh A, Gérente C, Chazarenc F, Andrès Y, Béchet B. Potential of aquatic macrophytes as bioindicators of heavy metal pollution in urban stormwater runoff. Water, Air, and Soil Pollution. 2012;**223**(2):877-888. DOI: 10.1007/s11270-011-0909-3

[69] Landberg T, Greger M. Differences in uptake and tolerance to heavy metals in Salix from unpolluted and polluted areas. Applied Geochemistry. 1996;**11**(1):175-180. DOI: 10.1016/0883-2927(95)00082-8

[70] Ariyakanon N, Winaipanich B. Phytoremediation of copper contaminated soil by *Brassica juncea* (L.) Czern and *Bidens alba* (L.) DC. var. radiata. Journal of Scientific Research, Chulalongkorn University. 2006;**31**(1):49-56

[71] Das S, Goswami S, Talukdar AD. A study on cadmium phytoremediation potential of water lettuce, *Pistia* 

*stratiotes* L. Bulletin of Environmental Contamination and Toxicology. 2014;**92**(2):169-174. DOI: 10.1007/ s00128-013-1152-y

[72] Amin H, Arain BA, Amin F, Surhio MA. Analysis of growth response and tolerance index of *Glycine max* (L.) Merr . under hexavalent chromium stress. Advances in Life Sciences. 2014;**1**(4):231-241

[73] Imtiyaz S, Agnihotri RK, Ganie SA, Sharma R. Biochemical response of glycine max(L.) Merr to cobalt and lead stress. Journal of Stress Physiology and Biochemistry. 2014;**10**(3):259-272

[74] Kranner I, Colville L. Metals and seeds: Biochemical and molecular implications and their significance for seed germination. Environmental and Experimental Botany. 2011;**72**(1):93-105. DOI: 10.1016/j. envexpbot.2010.05.005

[75] Shanker AK, Cervantes C, Loza-Tavera H, Avudainayagam S. Chromium toxicity in plants. Environment International. 2005;**31**(5):739-753. DOI: 10.1016/j.envint.2005.02.003

[76] Shukla UC, Singh J, Joshi PC, Kakkar P. Effect of bioaccumulation of cadmium on biomass productivity, essential trace elements, chlorophyll biosynthesis, and macromolecules of wheat seedlings. Biological Trace Element Research. 2003;**92**(3):257-273. DOI: 10.1385/BTER:92:3:257

[77] Gupta UC, Gupta SC. Trace element toxicity relationships to crop production and livestock and human health: Implications for management. Communications in Soil Science and Plant Analysis. 1998;**29**(11-14):1491-1522. DOI: 10.1080/00103629809370045

[78] McBride MB, Sauve S, Hendershot WH. Solubility control of Cu, Zn, Cd and Pb in contaminated

soils. European Journal of Soil Science. 1997;**48**(2):337-346

[79] Gisbert C, Ros R, Haro AD, Walker DJ, Bernal MP, Serrano R, et al. A plant genetically modified that accumulates Pb is especially promising for phytoremediation. Biochemical and Biophysical Research Communications. 2003;**303**:440-445

[80] Thomas JC, Davies EC, Malick FK, Endreszl C, Williams CR, Abbas M, et al. Yeast metallothionein in transgenic tobacco promotes copper uptake from contaminated soils. Biotechnology Progress. 2003;**19**(2):273-280

[81] Pan A, Yang M, Tie F, Li L, Chen Z, Ru B. Expression of mouse metallothionein-I gene confers cadmium resistance in transgenic tobacco plants. Plant Molecular Biology. 1994;**24**:341-351

[82] Evans KM, Gatehouse JA, Lindsay WP, Shi J, Tommey AM, Robinson NJ. Expression of pea metallothionein-like gene PsMTA function. Plant Molecular Biology. 1992;**20**:1019-1028

[83] Abhilash PC, Jamil S, Singh N. Transgenic plants for enhanced biodegradation and phytoremediation of organic xenobiotics. Biotechnology Advances. 2009;**27**(4):474-488. DOI: 10.1016/j.biotechadv.2009.04.002

[84] Doty SL. Enhancing phytoremediation through the use of transgenics and endophytes. The New Phytologist. 2008;**179**(2):318-333. DOI: 10.1111/j.1469-8137.2008.02446.x

[85] Van Aken B. Transgenic plants for enhanced phytoremediation of toxic explosives. Current Opinion in Biotechnology. 2009;**20**(2):231-236. DOI: 10.1016/j.copbio.2009.01.011

[86] Rugh CL, Senecoff JF, Meagher RB, Merkle SA. Development

**243**

*Nanophytoremediation: An Overview of Novel and Sustainable Biological Advancement*

[93] Cobbett C, Goldsbrough P. Phytochelatins and metallothioneins: Roles in heavy metal detoxification and homeostasis. Annual Review of Plant Biology. 2002;**53**(1):159- 182. DOI: 10.1146/annurev. arplant.53.100301.135154

[94] Rauser WE. Phytochelatins and related peptides (structure, biosynthesis

Metallothioneins and Related Chelators (Metal Ions in Life Sciences). Vol. 5. Cambridge, England: Royal Society of Chemistry; 2009. ISBN: 1-84755-899-2

[97] Kagi JHR, Schaffer A. Biochemistry of metallothionein. The Biochemist.

[99] Olena KV, Elizabeth AB, James TW, Philip AR. A new pathway for heavy metal detoxification in animals: Phytochelatin synthase is required for cadmium tolerance in *Caenorhabditis elegans*. The Journal of Biological Chemistry. 2001;**276**(24):20817-20820. DOI: 10.1074/jbc.C100152200.PMID

[100] Grill E, Winnacker E-L, Zenk MH. Phytochelatins, a class of heavy-metal-binding peptides from

[98] Ha S-B, Smith AP, Howden R, Dietrich WM, Bugg S, O'Connell MJ, et al. Phytochelatin synthase genes from Arabidopsis and the yeast *Schizosaccharomyces pombe*. The Plant Cell. 1999;**11**(6):1153-1164. DOI: 10.1105/tpc.11.6.1153.PMC 144235. PMID: 10368185. Retrieved: January 13,

and function). Plant Physiology. 1995;**109**(4):1141-1149. DOI: 10.1104/

[95] Sigel H, Sigel A, editors.

[96] Margoshes M, Vallee BL. A cadmium protein from equine kidney cortex. Journal of the American Chemical Society. 1957;**79**(17):4813- 4814. DOI: 10.1021/ja01574a064

1998;**27**(23):8509-8515

2014

11313333

pp.109.4.1141

*DOI: http://dx.doi.org/10.5772/intechopen.93300*

[87] Dhankher OP, Li Y, Rosen BP, Shi J, Salt D, Senecoff JF, et al. Engineering tolerance and hyperaccumulation of arsenic in plants by combining arsenate reductase and γ-glutamylcysteine synthetase expression. Nature

Biotechnology. 2002;**20**(11):1140-1145.

[88] Assunção AGL, Da CostaMartins P,

Environment. 2001;**24**:217-226. DOI: 10.1046/j.1365-3040.2001.00666.x

[89] Bizily SP, Rugh CL, Meagher RB. Phytodetoxification of hazardous organomercurials by genetically engineered plants. Nature

Biotechnology. 2000;**18**:213-217. DOI:

[90] Wang X, Wu N, Guo J, Chu X, Tian J, Yao B, et al. Phytodegradation of organophosphorus compounds by transgenic plants expressing a bacterial organophosphorus hydrolase. Biochemical and Biophysical Research Communications. 2008;**365**(3):453-458.

DOI: 10.1016/j.bbrc.2007.10.193

10.1007/s11103-007-9158-7

10.1093/jxb/53.366.1

[92] Hall JL. Cellular mechanisms for heavy metal detoxification and tolerance. Journal of Experimental Botany. 2002;**53**(366):1-11. DOI:

[91] Gasic K, Korban SS. Transgenic Indian mustard (*Brassica juncea*) plants expressing an *Arabidopsis* phytochelatin synthase (AtPCS1) exhibit enhanced As and Cd tolerance. Plant Molecular Biology. 2007;**64**(4):361-369. DOI:

10.1038/72678

De Folter S, Vooijs R, Schat H, Aarts MGM. Elevated expression of metal transporter genes in three accessions of the metal hyperaccumulator *Thlaspi caerulescens*. Plant, Cell and

of transgenic yellow poplar for mercury phytoremediation. Nature Biotechnology. 1998;**16**(10):925-928.

DOI: 10.1038/nbt1098-925

DOI: 10.1038/nbt747

*Nanophytoremediation: An Overview of Novel and Sustainable Biological Advancement DOI: http://dx.doi.org/10.5772/intechopen.93300*

of transgenic yellow poplar for mercury phytoremediation. Nature Biotechnology. 1998;**16**(10):925-928. DOI: 10.1038/nbt1098-925

*Soil Contamination - Threats and Sustainable Solutions*

soils. European Journal of Soil Science.

[80] Thomas JC, Davies EC, Malick FK, Endreszl C, Williams CR, Abbas M, et al. Yeast metallothionein in transgenic tobacco promotes copper uptake from contaminated soils. Biotechnology Progress. 2003;**19**(2):273-280

[81] Pan A, Yang M, Tie F, Li L, Chen Z, Ru B. Expression of mouse metallothionein-I gene confers cadmium resistance in transgenic tobacco plants. Plant Molecular Biology.

[82] Evans KM, Gatehouse JA, Lindsay WP, Shi J, Tommey AM, Robinson NJ. Expression of pea metallothionein-like gene PsMTA function. Plant Molecular Biology.

[83] Abhilash PC, Jamil S, Singh N. Transgenic plants for enhanced biodegradation and phytoremediation of organic xenobiotics. Biotechnology Advances. 2009;**27**(4):474-488. DOI: 10.1016/j.biotechadv.2009.04.002

phytoremediation through the use of transgenics and endophytes. The New Phytologist. 2008;**179**(2):318-333. DOI: 10.1111/j.1469-8137.2008.02446.x

[85] Van Aken B. Transgenic plants for enhanced phytoremediation of toxic explosives. Current Opinion in Biotechnology. 2009;**20**(2):231-236. DOI: 10.1016/j.copbio.2009.01.011

Meagher RB, Merkle SA. Development

[86] Rugh CL, Senecoff JF,

[79] Gisbert C, Ros R, Haro AD, Walker DJ, Bernal MP, Serrano R, et al. A plant genetically modified that accumulates Pb is especially promising for phytoremediation. Biochemical and Biophysical Research Communications.

1997;**48**(2):337-346

2003;**303**:440-445

1994;**24**:341-351

1992;**20**:1019-1028

[84] Doty SL. Enhancing

*stratiotes* L. Bulletin of Environmental Contamination and Toxicology. 2014;**92**(2):169-174. DOI: 10.1007/

Surhio MA. Analysis of growth response and tolerance index of *Glycine max* (L.) Merr . under hexavalent chromium stress. Advances in Life Sciences.

[73] Imtiyaz S, Agnihotri RK, Ganie SA, Sharma R. Biochemical response of glycine max(L.) Merr to cobalt and lead stress. Journal of Stress Physiology and Biochemistry. 2014;**10**(3):259-272

[74] Kranner I, Colville L. Metals and seeds: Biochemical and molecular implications and their significance for seed germination. Environmental

and Experimental Botany. 2011;**72**(1):93-105. DOI: 10.1016/j.

[75] Shanker AK, Cervantes C, Loza-Tavera H, Avudainayagam S. Chromium toxicity in plants. Environment International. 2005;**31**(5):739-753. DOI:

10.1016/j.envint.2005.02.003

DOI: 10.1385/BTER:92:3:257

[78] McBride MB, Sauve S,

Hendershot WH. Solubility control of Cu, Zn, Cd and Pb in contaminated

[77] Gupta UC, Gupta SC. Trace element toxicity relationships to crop production and livestock and human health: Implications for management. Communications in Soil Science and Plant Analysis. 1998;**29**(11-14):1491-1522. DOI: 10.1080/00103629809370045

[76] Shukla UC, Singh J, Joshi PC, Kakkar P. Effect of bioaccumulation of cadmium on biomass productivity, essential trace elements, chlorophyll biosynthesis, and macromolecules of wheat seedlings. Biological Trace Element Research. 2003;**92**(3):257-273.

envexpbot.2010.05.005

[72] Amin H, Arain BA, Amin F,

s00128-013-1152-y

2014;**1**(4):231-241

**242**

[87] Dhankher OP, Li Y, Rosen BP, Shi J, Salt D, Senecoff JF, et al. Engineering tolerance and hyperaccumulation of arsenic in plants by combining arsenate reductase and γ-glutamylcysteine synthetase expression. Nature Biotechnology. 2002;**20**(11):1140-1145. DOI: 10.1038/nbt747

[88] Assunção AGL, Da CostaMartins P, De Folter S, Vooijs R, Schat H, Aarts MGM. Elevated expression of metal transporter genes in three accessions of the metal hyperaccumulator *Thlaspi caerulescens*. Plant, Cell and Environment. 2001;**24**:217-226. DOI: 10.1046/j.1365-3040.2001.00666.x

[89] Bizily SP, Rugh CL, Meagher RB. Phytodetoxification of hazardous organomercurials by genetically engineered plants. Nature Biotechnology. 2000;**18**:213-217. DOI: 10.1038/72678

[90] Wang X, Wu N, Guo J, Chu X, Tian J, Yao B, et al. Phytodegradation of organophosphorus compounds by transgenic plants expressing a bacterial organophosphorus hydrolase. Biochemical and Biophysical Research Communications. 2008;**365**(3):453-458. DOI: 10.1016/j.bbrc.2007.10.193

[91] Gasic K, Korban SS. Transgenic Indian mustard (*Brassica juncea*) plants expressing an *Arabidopsis* phytochelatin synthase (AtPCS1) exhibit enhanced As and Cd tolerance. Plant Molecular Biology. 2007;**64**(4):361-369. DOI: 10.1007/s11103-007-9158-7

[92] Hall JL. Cellular mechanisms for heavy metal detoxification and tolerance. Journal of Experimental Botany. 2002;**53**(366):1-11. DOI: 10.1093/jxb/53.366.1

[93] Cobbett C, Goldsbrough P. Phytochelatins and metallothioneins: Roles in heavy metal detoxification and homeostasis. Annual Review of Plant Biology. 2002;**53**(1):159- 182. DOI: 10.1146/annurev. arplant.53.100301.135154

[94] Rauser WE. Phytochelatins and related peptides (structure, biosynthesis and function). Plant Physiology. 1995;**109**(4):1141-1149. DOI: 10.1104/ pp.109.4.1141

[95] Sigel H, Sigel A, editors. Metallothioneins and Related Chelators (Metal Ions in Life Sciences). Vol. 5. Cambridge, England: Royal Society of Chemistry; 2009. ISBN: 1-84755-899-2

[96] Margoshes M, Vallee BL. A cadmium protein from equine kidney cortex. Journal of the American Chemical Society. 1957;**79**(17):4813- 4814. DOI: 10.1021/ja01574a064

[97] Kagi JHR, Schaffer A. Biochemistry of metallothionein. The Biochemist. 1998;**27**(23):8509-8515

[98] Ha S-B, Smith AP, Howden R, Dietrich WM, Bugg S, O'Connell MJ, et al. Phytochelatin synthase genes from Arabidopsis and the yeast *Schizosaccharomyces pombe*. The Plant Cell. 1999;**11**(6):1153-1164. DOI: 10.1105/tpc.11.6.1153.PMC 144235. PMID: 10368185. Retrieved: January 13, 2014

[99] Olena KV, Elizabeth AB, James TW, Philip AR. A new pathway for heavy metal detoxification in animals: Phytochelatin synthase is required for cadmium tolerance in *Caenorhabditis elegans*. The Journal of Biological Chemistry. 2001;**276**(24):20817-20820. DOI: 10.1074/jbc.C100152200.PMID 11313333

[100] Grill E, Winnacker E-L, Zenk MH. Phytochelatins, a class of heavy-metal-binding peptides from plants, are functionally analogous to metallothioneins. Proceedings of the National Academy of Sciences. 1987;**84**(2):439-443. DOI: 10.1073/ pnas.84.2.439

[101] Zenk M. Heavy metal detoxification in higher plants—A review. Gene. 1996;**179**(1):21-30. DOI: 10.1016/S0378-1119(96)00422-2

**245**

**Chapter 14**

**Abstract**

potential contaminants.

**1. Introduction**

sustains all life forms.

Soil Management and

Contamination

*and Victoria Abimbola Adedokun*

Conservation: An Approach to

*Oluwatosin Ayobami Ogunsola, Odunayo David Adeniyi* 

The chapter mainstreamed Soil Management and Conservation approach as a potent remedy for Soil Contamination. Largely, microbial activities play significant role in maintaining balance within the ecosystem however changes in Land-use has a direct influence on soil biota, including the floral and fauna components. The introduction of contaminants, from varying sources such as agrochemicals, petrochemicals, landfills, sludge, effluents, etc., into the soil builds up the amount of heavy metals present in the deposits hence degrading the soil and polluting groundwater. Integrating soil management options to enhance biodiversity and strengthen microbial activities improve the soil ecology thus creating a buffer for neutralizing

**Keywords:** degradation, land-use, ecology, biodiversity, soil conservation

One of the central component of terrestrial ecosystem is soil. Loss in ecosystem is a representation of the degradation of soil. The soil plays a key role in the health of ecosystem, however, over-exploitation of these ecosystem by humans causes considerable degradation and migration of contaminants. The use of land for agriculture occupies 36.5% of the earth's land mass [1]. Though this human activities may be justified to provide greater benefit in other services termed development, but consistent degradation of this ecosystem and exposure of it to various contaminants is not in the best interest of the society and it is detrimental to the environment that

Soil conservation are various practices of farming operations and management

strategies which are conducted with the purpose of controlling soil erosion by avoiding or minimizing soil particle detachment and movement of water or/and air. It also helps in preventing the loss of the top-most layer of the soil and fertility which could also be caused by soil contamination. Understanding the processes and factors that govern soil erosion is very important to implementing its control practice and will help to manage soil erosion thus leading to soil conservation. The mechanics involve fluid (wind/water) detachment or entrainment which is being

Mitigate and Ameliorate Soil

## **Chapter 14**

*Soil Contamination - Threats and Sustainable Solutions*

plants, are functionally analogous to metallothioneins. Proceedings of the National Academy of Sciences. 1987;**84**(2):439-443. DOI: 10.1073/

detoxification in higher plants—A review. Gene. 1996;**179**(1):21-30. DOI: 10.1016/S0378-1119(96)00422-2

[101] Zenk M. Heavy metal

pnas.84.2.439

**244**
