*2.2.2 Inorganic pollutants*

In the environment due to industry, mining, transportation and urban activities inorganic pollutants are released. Inorganic pollutants can interact both extracellular and intracellular levels respectively and this make it high risk component for environment [14].

#### **Figure 3.**

*Municipal solid waste pollution-municipal solid waste (MSW) on a beach. Such land pollution can contaminate the soil and water and is a health hazard to local communities.*

Some elements known as Micronutrients are essentials for in small amount and become toxic when increase the concentration for example B, Cl, Cu, Fe, Mn, Mo and Zn. Metals like Cd, Cr, Cu, Hg, Ni, Pb, V and Zn, metalloids like As, Bo, and Sb, non- metals like Se, actinoids like U and halogens like I and F are the inorganic contaminants which causes soil pollution when exceed the certain threshold [15].

Some elements are toxic at all concentration for examples Hg, As and Tl and some form organomettalic compound which are highly toxic and lipophilic for example methylmercury and tributyl tin oxides [16].

#### *2.2.3 Organic pollutants*

Organic compounds in which carbon is the main elements in the structure with or without functional groups. Organic pollutants include several groups like pesticides, hydrocarbons, polycyclic aromatic hydrocarbon (PAHs), polychlorinated biphenyl (PCBs), polychlorinated dibenzo-p-dioxins (PCDDs) polychlorinated dibenzofurans (PCDF), polybrominated biphenyls (PBBs), polybrominated diphenyl ethers (PBDEs), surfactants, or pharmaceuticals. This group separately or together pollutes the soil for examples the groups of PCBs include 209 congeners [17, 18].

The compounds are used due to its wide range of physical properties like polarity, solubility, volatility etc. These compounds shows different behaviors in environment and toxicity in organism due to its physical properties even come in same group.

Some of the organic compounds can be degraded or bio transformed but many of them shows resistant to both chemical as well as biochemical transformation and have long half-lives for example polyhalogenated compounds. Due to its molecular stability it remains in soil for very long time and effect environment and can travel to long distance [19, 20].

#### **2.3 Origin and sources of soil pollution**

Soil contaminants can be naturally or anthropogenic. Natural activities like weathering of rocks and volcanic activities or forest fires can produces organic, inorganic or both types of pollutants respectively. Human can also cause soil pollution accidentally or deliberately. Mining, smelting, disposal of wastes, fossil fuel combustion, gaseous works, industries, sports shooting, and application of agrochemicals or sewage are the human activities which cause soil pollution. Nuclear accidents, flooding by rivers or seas, leaks from landfills, or accidental spills are the accidental pollution (**Figure 4**) [22]. Above all examples mining is one of the important sources of toxic elements.

#### **2.4 Effects of soil pollution**

Due to direct or indirect contact with contaminated soil, the health risks increases and causes many diseases. Ecological balance also disturb due to increase in pollution of soil as well as health of many living organisms is also under risk. Soil pollution affects the quality of soil which causes deaths of many organisms which are essential for the growth of plant (e.g., earthworm). Indirectly the soil pollution also affects the life of predators like birds which move to other places in search of food.

People who were living near polluted land are prone to health risk as polluted soil can cause poisoning directly and indirectly i.e. children playing near waste land come in direct contact and food which grow on polluted land cause disease indirectly like migraines, nausea, fatigue, skin disorders and even miscarriages are common symptoms seen in a people which are live near polluted land and drink polluted water [13].

*Nanoparticles: Novel Approach to Mitigate Environmental Pollutants DOI: http://dx.doi.org/10.5772/intechopen.99806*

#### **Figure 4.**

*Anthropogenic sources of soil contamination with toxic metalloids [21].*

### **2.5 Nano remediation of soil pollution**

There is several ways to remediate soil pollution but here we are discussing about remediation of soil pollution by nanoparticles.

In advancement of research, engineered nanoparticles plays a very important role in removal of environmental pollution as they are cheaper and more reactive.

For the treatment of environmental pollution engineered nanoparticles also enhance in situ method. Examples of some engineered nanoparticles used in soil remediation are given below:


#### **Figure 5.**

*The use of nanoparticles for remediation of soil contaminated with heavy metals, pesticides, and persistent organic pollutants (POPs) [23].*

Other nanoparticles, such as carbon nanotubes, bio nanoparticles, polymeric nanoparticles, etc. used for the removal of aromatic and heavy metal contaminant (**Figure 5**) [24].

The above methods are considered as novel work but the effect of these engineered nanoparticles is yet to be studied [25].

From the above examples calcium peroxide is the best option because it releases peroxide very slowly which increases the attenuation time of the remediating reagent but due to its slow effective speed reaction, it shows some drawbacks. The speed of reaction of calcium peroxide nanoparticles can be increase by increase in surface to volume ratio [26].

#### **2.6 Advantages of using nanoparticles**

i.Large surface area – which helps in faster interaction.

ii.Presence of active sites – helps in increasing decontamination efficiency.


*Nanoparticles: Novel Approach to Mitigate Environmental Pollutants DOI: http://dx.doi.org/10.5772/intechopen.99806*

#### **Figure 6.**

*Possible toxicity mechanisms of engineered nanomaterials (ENMs) at the cellular level (top left: Gram-positive (G + ve) bacteria; bottom left: Gram negative (G* − *ve) bacteria; right: Plant cells [29].*

#### **2.7 Disadvantages of using nanoparticles**

i.Difference in function of natural and synthesized nanoparticles.

