**7. Effect of microplastics on aquatic biota**

Microplastics are of special concern because they can be ingested throughout the food web more readily than larger particles. It is to be noted that the impact of microplastics on public health and aquatic ecosystems is not yet fully understood, but there is increasing number of reports which indicate negative impact of microplastics on marine and freshwater biota.

With increased focus on microplastics debris, several groups have studied the influence of microplastics uptake by different organisms. As microplastics invasion appear to occur across all ecosystem from terrestrial to marine environment in different trophic level not only invertebrates but vertebrates also seem to be affected by their presence [66, 67]. Organism ingests these microplastics debris while swallowing their food. And with due course of time bioaccumulation of microplastics results in diverse negative impact on various organism like disruption of organ system, rupturing of digestive system, weakening of immune system, impotency, various respiratory and circulatory problems, even failure of organ and in extreme cases led to death of organism [51, 68, 69]. However, continuous accumulation of these deadly microplastics in various systems of the body is possible through food chain via ingestion as well as by accumulation around gill aperture (or around respiratory apertures) and appendages of body by diverse aquatic organisms [70, 71]. However, situation

become direr for the predators and humans which directly or indirectly consume microplastics affected aquatic organisms [72]. As reported by Wright et al. [5], there are various consequences from ingestion of plastics and MPs by various species such as planktons, copepods, zooplanktons, crabs, small fishes, turtles, fish larvae, sea birds and mammals.

#### **7.1 Effect of microplastics on marine ecosystem**

Marine microplastics debris is a global threat because of its abundance, persistence and mobility across scale, with subsequent widespread distribution potential, geophysical and biological impact [73]. Across the globe, research on the ingestion of microplastics by biota has predominantly focused on wide range of marine species with different feeding strategies [74–76]. As microplastics have been shown to obstruct feeding appendages and limit food intake, physical injury and oxidative stress, reduced energy allocation in various aquatic organisms and in some cases damages in the alimentary canal were also observed [77]. Alteration in the feeding behavior of some group of crustaceans was also studied such as in copepods which feed on algae, but when these copepods feed on natural assemblage of algae with the addition of polystyrene microbeads they showed a significant decrease in herbivory which further results in decrease in growth rate of organism [5, 78]. However, it is not just growths which microplastics injection can disrupt, but also observable change in physical development of organism. An alternation was observed in life cycle of sea urchin *Paracentrotus lividus* which depicted alterations in shape of pelagic planktotrophic pluteus larva when Microplastics were ingested [79]. Another study of Kaposi et al. [80] by examining short term exposure of Polyethylene on the sea urchin *Tripneustes gratilla*, which was done by using fluorescent labels green PE Microspheres having diameter 10-45 μm, with exposure of time ranged between 15 min to 5 d. There was decrease in injection rate even when phytoplankton food was provided.

While some of the chemicals associates with microplastics, which possess endocrine disruptive activity and are responsible for the hormonal imbalance in organisms [81]. In a study by Sussarellu et al. [82] on Oysters which is a keystone species with high ecological and economic value. When adult oysters were exposed to microplastics polystyrene of diameter about 2 μm during a critical point of their reproductive stage adults were preparing for production of gametes. And after the exposure, there was an alteration in the feeding as well as absorption efficiency of food. Reproductive changes were also observed that there is reduction in the quality of oocytes and sperm swimming speed as well as fecundity. Moreover, these impacts had clear carryover effect on offspring quality and further reduced growth in their larval progeny. Similar effects were observed in planktonic copepods when exposed to micropolystyrene for prolonged period followed by reduced food consumption and resulting in reduced reproductive outputs [83].

However, Corals which occur in both deep sea and Antarctic system are not untouched by the effect of microplastics as some of the corals known to ingest microplastics and demonstrably negatively impact occurs both in terms of energy level, growth and pathogen frequency of reefs [84, 85].

#### **7.2 Effect of microplastics on fresh water ecosystem**

It's is not only marine wildlife that can take up microplastics, bioavailability of microplastics for freshwater fauna (for both invertebrates and fishes) has also been observed. Although there are few freshwater studies so far, A study by Rehse et al. [86] shows that immobilization has occurred in freshwater

**237**

microplastics.

*Sources, Fate, and Impact of Microplastics in Aquatic Environment*

zooplankton (*Daphnia magna)* after ingestion of polyethylene microplastics of about 1 mm, however due to the smaller size of this freshwater zooplankton, it was not able to engulf microplastics of more than 1 mm size. It is also observed that small size microplastics usually possess large surface area to volume ratio which differentiates the property of microplastics from meso and macroplastics.

In freshwater habitat, the different POPs (persistent organic pollutants) that is PCBs (polychlorinated biphenyls), HCBs (hexachlorobenzenes), PBDEs (polybrominated diphenyl ethers) and metals are present in significantly higher concentrations. And the adsorption ratio of POPs to microplastics is different in freshwater as compared to marine ecosystems due to the proximity to the sources and use of these chemicals. As organism in freshwater ecosystem are more exposed to POPs and microplastics due to occurrence of industrial and populous area nearby. Study by Rochman et al. [87] revealed that freshwater fishes experience hepatic stress due to ingestion of polyethylene which ultimately led to bioaccumulation and toxicity in fishes. A significant amount of POPs to microplastics could accumulate in adult zebrafish gills and zebra fish embryos [88]. Another observation in the study of European perch *Perca fluviatilis* by Lönnstedt and Eklöv [89], suggested the effect of microplastics when larva of European perch were exposed to different concentrations of 10,000 or 80,000 particles/meter which resulted in inhibition of hatching and reduced growth rates. There were alterations in the feeding and innate behavior as compared to normal individuals which were not exposed with

Microplastics can also act as an artificial substrate for microorganisms. This has raised concern about the potential ecological effect on freshwater habitat, which is utilized for anthropogenic activities as well as by the wildlife organisms. Microplastics form biofilms by providing surface for microorganisms and rafting the colonized organisms over long distances. It has also been shown that biofilms containing potentially pathogenic microorganisms which can develop on plastic in the marine system. Some microorganisms in the biofilm are assumed to be potentially opportunistic (human) pathogens, for example, members of the genus *Vibrio* have been found on the particles and making microplastics vector for pathogens, toxic algae, bacteria and invasive species. Various studies are performed on different rivers for the estimation of assimilation of microplastics by aquatic organisms. A study conducted by McGoran et al. [90], in the river Thames, revealed that up to 75% of sampled European flounder (*Platichthys flesus)* has plastic fibers in their gut compared to 20% of European smelt (*Osmeruseperlanus)* however it is estimated that this huge difference in the concentration is due to the feeding habitats of both the fishes as European flounder are benthic feeders while European smelt are pelagic feeder and these observations also suggested the relative distribution of

In study of microplastics in freshwater, Au et al. [92], investigated the ingestion and effects of PE (fluorescent blue PE microplastics particles, 10–27 μm) and PP (black polypropylene microplastics fibers from marine rope, 20–75 mm in length) on the growth and mortality of the freshwater amphipod *Hyalella azteca.* The LC50 of PE and PP in *H. azteca* after a 10-d exposure were 4.6 × 104 and 71 microplastics/mL respectively. The effects of chronic exposure to PE and its influence on the reproduction of amphipods were analyzed. Chronic exposure of *H. azteca* to PP fibers, even at

To evaluate the process of trophic transfer and toxicological effects of microplastics at different trophic levels, a number of factors need to be considered that

microplastics in different strata of riverine system [91].

a low concentration, significantly decreased growth and reproduction.

**7.3 Toxic effects of microplastics shown by trophic transfer**

*DOI: http://dx.doi.org/10.5772/intechopen.93805*

#### *Sources, Fate, and Impact of Microplastics in Aquatic Environment DOI: http://dx.doi.org/10.5772/intechopen.93805*

*Emerging Contaminants*

birds and mammals.

was provided.

**7.1 Effect of microplastics on marine ecosystem**

and resulting in reduced reproductive outputs [83].

level, growth and pathogen frequency of reefs [84, 85].

**7.2 Effect of microplastics on fresh water ecosystem**

become direr for the predators and humans which directly or indirectly consume microplastics affected aquatic organisms [72]. As reported by Wright et al. [5], there are various consequences from ingestion of plastics and MPs by various species such as planktons, copepods, zooplanktons, crabs, small fishes, turtles, fish larvae, sea

Marine microplastics debris is a global threat because of its abundance, persistence and mobility across scale, with subsequent widespread distribution potential, geophysical and biological impact [73]. Across the globe, research on the ingestion of microplastics by biota has predominantly focused on wide range of marine species with different feeding strategies [74–76]. As microplastics have been shown to obstruct feeding appendages and limit food intake, physical injury and oxidative stress, reduced energy allocation in various aquatic organisms and in some cases damages in the alimentary canal were also observed [77]. Alteration in the feeding behavior of some group of crustaceans was also studied such as in copepods which feed on algae, but when these copepods feed on natural assemblage of algae with the addition of polystyrene microbeads they showed a significant decrease in herbivory which further results in decrease in growth rate of organism [5, 78]. However, it is not just growths which microplastics injection can disrupt, but also observable change in physical development of organism. An alternation was observed in life cycle of sea urchin *Paracentrotus lividus* which depicted alterations in shape of pelagic planktotrophic pluteus larva when Microplastics were ingested [79]. Another study of Kaposi et al. [80] by examining short term exposure of Polyethylene on the sea urchin *Tripneustes gratilla*, which was done by using fluorescent labels green PE Microspheres having diameter 10-45 μm, with exposure of time ranged between 15 min to 5 d. There was decrease in injection rate even when phytoplankton food

While some of the chemicals associates with microplastics, which possess endocrine disruptive activity and are responsible for the hormonal imbalance in organisms [81]. In a study by Sussarellu et al. [82] on Oysters which is a keystone species with high ecological and economic value. When adult oysters were exposed to microplastics polystyrene of diameter about 2 μm during a critical point of their reproductive stage adults were preparing for production of gametes. And after the exposure, there was an alteration in the feeding as well as absorption efficiency of food. Reproductive changes were also observed that there is reduction in the quality of oocytes and sperm swimming speed as well as fecundity. Moreover, these impacts had clear carryover effect on offspring quality and further reduced growth in their larval progeny. Similar effects were observed in planktonic copepods when exposed to micropolystyrene for prolonged period followed by reduced food consumption

However, Corals which occur in both deep sea and Antarctic system are not untouched by the effect of microplastics as some of the corals known to ingest microplastics and demonstrably negatively impact occurs both in terms of energy

It's is not only marine wildlife that can take up microplastics, bioavailability of microplastics for freshwater fauna (for both invertebrates and fishes) has also been observed. Although there are few freshwater studies so far, A study by Rehse et al. [86] shows that immobilization has occurred in freshwater

**236**

zooplankton (*Daphnia magna)* after ingestion of polyethylene microplastics of about 1 mm, however due to the smaller size of this freshwater zooplankton, it was not able to engulf microplastics of more than 1 mm size. It is also observed that small size microplastics usually possess large surface area to volume ratio which differentiates the property of microplastics from meso and macroplastics.

In freshwater habitat, the different POPs (persistent organic pollutants) that is PCBs (polychlorinated biphenyls), HCBs (hexachlorobenzenes), PBDEs (polybrominated diphenyl ethers) and metals are present in significantly higher concentrations. And the adsorption ratio of POPs to microplastics is different in freshwater as compared to marine ecosystems due to the proximity to the sources and use of these chemicals. As organism in freshwater ecosystem are more exposed to POPs and microplastics due to occurrence of industrial and populous area nearby. Study by Rochman et al. [87] revealed that freshwater fishes experience hepatic stress due to ingestion of polyethylene which ultimately led to bioaccumulation and toxicity in fishes. A significant amount of POPs to microplastics could accumulate in adult zebrafish gills and zebra fish embryos [88]. Another observation in the study of European perch *Perca fluviatilis* by Lönnstedt and Eklöv [89], suggested the effect of microplastics when larva of European perch were exposed to different concentrations of 10,000 or 80,000 particles/meter which resulted in inhibition of hatching and reduced growth rates. There were alterations in the feeding and innate behavior as compared to normal individuals which were not exposed with microplastics.

Microplastics can also act as an artificial substrate for microorganisms. This has raised concern about the potential ecological effect on freshwater habitat, which is utilized for anthropogenic activities as well as by the wildlife organisms. Microplastics form biofilms by providing surface for microorganisms and rafting the colonized organisms over long distances. It has also been shown that biofilms containing potentially pathogenic microorganisms which can develop on plastic in the marine system. Some microorganisms in the biofilm are assumed to be potentially opportunistic (human) pathogens, for example, members of the genus *Vibrio* have been found on the particles and making microplastics vector for pathogens, toxic algae, bacteria and invasive species. Various studies are performed on different rivers for the estimation of assimilation of microplastics by aquatic organisms. A study conducted by McGoran et al. [90], in the river Thames, revealed that up to 75% of sampled European flounder (*Platichthys flesus)* has plastic fibers in their gut compared to 20% of European smelt (*Osmeruseperlanus)* however it is estimated that this huge difference in the concentration is due to the feeding habitats of both the fishes as European flounder are benthic feeders while European smelt are pelagic feeder and these observations also suggested the relative distribution of microplastics in different strata of riverine system [91].

In study of microplastics in freshwater, Au et al. [92], investigated the ingestion and effects of PE (fluorescent blue PE microplastics particles, 10–27 μm) and PP (black polypropylene microplastics fibers from marine rope, 20–75 mm in length) on the growth and mortality of the freshwater amphipod *Hyalella azteca.* The LC50 of PE and PP in *H. azteca* after a 10-d exposure were 4.6 × 104 and 71 microplastics/mL respectively. The effects of chronic exposure to PE and its influence on the reproduction of amphipods were analyzed. Chronic exposure of *H. azteca* to PP fibers, even at a low concentration, significantly decreased growth and reproduction.

#### **7.3 Toxic effects of microplastics shown by trophic transfer**

To evaluate the process of trophic transfer and toxicological effects of microplastics at different trophic levels, a number of factors need to be considered that are involved in ingestion, bioaccumulation and biomagnification of microplastics and their associated chemicals.

Resemblance in shape and size of microplastics with many species of planktons and other type of food particles is usually observed. Hence sometimes microplastics are normally ingested by aquatic filter feeders along with some associated contaminants led to bioaccumulation and trophic transfer to higher organisms [93]. The size and shape of plastic particles are the two most important parameters which determine the extent of microplastics retention. This is because smaller particles are more likely to be ingested and particles with angular shapes may be harder to egest. The available body of evidence indicated that trophic transfer of microplastics may occur [94, 95]. Hence, pollutants may be transferred along with microplastics by means of oral ingestion as well as other pathways, which include ventilation or simple microplastics attachment and resuspension into the water column [88, 96].

Setälä et al. [7], observed the trophic transfer of polystyrene microplastics to macrozooplankton occurred after only 3 hrs of exposure to mesozooplaktons that had previously infested PS microplastics. Studies also revealed that uptake of microplastics can be influenced by the surface characteristics of plastic particles. As MP that was neutrally or positively charged had a higher binding affinity for algal cell wall than negatively charged microplastics. And hence they adhere to surface of seaweeds like *Fucus vesiculosus,* resulting in their consumption by grazing gastropods which further eventually led to trophic transfer of microplastics [97]. Microplastics are ingested by organism at lower trophic level and are further transferred to higher trophic level and ultimately results in bioaccumulation in higher organism and causes ill effects which may be life threating for them.

The impact of microplastics on humans is not yet fully understood, however many studies depict that there are many chemicals that are used in plastic production show toxic effect on living organism some of these chemicals are bisphenol A (BPA), polybrominated diphenyl ethers (PBDE), and tetrabromobisphenol (TBBPA). Studies have already detected these chemicals in human tissues and biological fluids [27]. It has also been reported that additives, for example, di(2-ethylhexyl)phthalate (DEHP), can leach from medical supplies made of PVC and accumulate in the blood of hemodialysis patients [98]. Moreover, the presence of microplastics in seafood, for example, bivalves cultured for human consumption has already been shown [28, 99]. It should be further investigated whether beverage or food products act as possible microplastics sources which is can further enter food web and results in bioaccumulation in living organism.

#### **8. Management of microplastics**

To get the problem under control, the society has to take initiatives which includes significantly curtailing unnecessary single-use plastic items such as water bottles, plastic shopping bags, straws and utensils, stringent policies should be implemented by the governments ensuring the need to strengthen garbage collection and recycling systems to prevent waste from leaking into the environment to improve recycling rates. New ways to break plastic down into its most basic units, which can be rebuilt into new plastics or other materials should be considered.

#### **9. Conclusion**

Production and applications of microplastics resulted to an enhanced incidence of plastics debris and microplastics, in the aquatic environment. Not only one

**239**

**Author details**

and Pooja Chadha\*

Amritsar, India

Sukanya Mehra, Khushboo Sharma, Geetika Sharma, Mandeep Singh

\*Address all correspondence to: poojachadha77@yahoo.co.in

provided the original work is properly cited.

Cytogenetics Laboratory, Department of Zoology, Guru Nanak Dev University,

© 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,

*Sources, Fate, and Impact of Microplastics in Aquatic Environment*

increasing microplastics levels on the world's aquatic bodies.

mechanism such as the weathering-related fracturing and surface embrittlement of plastics in beach environments is the root cause of generation of microplastics but industrial waste also constitute the major sources of them. As microplastics are recalcitrant in nature, only small fraction of the microplastics present in aquatic body imposes a serious threat to aquatic life. As microplastics are potentially ingestible by aquatic organisms including micro and nano plankton species, the delivery of toxins across trophic levels via this mechanism is very common. The efficiency of such transfer will depend on the bioavailability of microplastics and the residence time of meso or microplastics in the organisms. Endocytosis of plastic nanoparticles by micro- or nanofauna can also result in adverse toxic endpoints. As aquatic species constitute the very foundation of the aquatic food web, any threat to these can have serious and far-reaching effects in the world oceans. There is an urgent need to quantify the magnitude of these potential outcomes and assess the future impact of

*DOI: http://dx.doi.org/10.5772/intechopen.93805*

#### *Sources, Fate, and Impact of Microplastics in Aquatic Environment DOI: http://dx.doi.org/10.5772/intechopen.93805*

*Emerging Contaminants*

and their associated chemicals.

are involved in ingestion, bioaccumulation and biomagnification of microplastics

organism and causes ill effects which may be life threating for them.

The impact of microplastics on humans is not yet fully understood, however many studies depict that there are many chemicals that are used in plastic production show toxic effect on living organism some of these chemicals are bisphenol A (BPA), polybrominated diphenyl ethers (PBDE), and tetrabromobisphenol (TBBPA). Studies have already detected these chemicals in human tissues and biological fluids [27]. It has also been reported that additives, for example, di(2-ethylhexyl)phthalate (DEHP), can leach from medical supplies made of PVC and accumulate in the blood of hemodialysis patients [98]. Moreover, the presence of microplastics in seafood, for example, bivalves cultured for human consumption has already been shown [28, 99]. It should be further investigated whether beverage or food products act as possible microplastics sources which is can further enter food web and results in bioaccumu-

To get the problem under control, the society has to take initiatives which includes significantly curtailing unnecessary single-use plastic items such as water bottles, plastic shopping bags, straws and utensils, stringent policies should be implemented by the governments ensuring the need to strengthen garbage collection and recycling systems to prevent waste from leaking into the environment to improve recycling rates. New ways to break plastic down into its most basic units, which can be rebuilt

Production and applications of microplastics resulted to an enhanced incidence

of plastics debris and microplastics, in the aquatic environment. Not only one

Resemblance in shape and size of microplastics with many species of planktons and other type of food particles is usually observed. Hence sometimes microplastics are normally ingested by aquatic filter feeders along with some associated contaminants led to bioaccumulation and trophic transfer to higher organisms [93]. The size and shape of plastic particles are the two most important parameters which determine the extent of microplastics retention. This is because smaller particles are more likely to be ingested and particles with angular shapes may be harder to egest. The available body of evidence indicated that trophic transfer of microplastics may occur [94, 95]. Hence, pollutants may be transferred along with microplastics by means of oral ingestion as well as other pathways, which include ventilation or simple microplastics attachment and resuspension into the water column [88, 96]. Setälä et al. [7], observed the trophic transfer of polystyrene microplastics to macrozooplankton occurred after only 3 hrs of exposure to mesozooplaktons that had previously infested PS microplastics. Studies also revealed that uptake of microplastics can be influenced by the surface characteristics of plastic particles. As MP that was neutrally or positively charged had a higher binding affinity for algal cell wall than negatively charged microplastics. And hence they adhere to surface of seaweeds like *Fucus vesiculosus,* resulting in their consumption by grazing gastropods which further eventually led to trophic transfer of microplastics [97]. Microplastics are ingested by organism at lower trophic level and are further transferred to higher trophic level and ultimately results in bioaccumulation in higher

**238**

**9. Conclusion**

lation in living organism.

**8. Management of microplastics**

into new plastics or other materials should be considered.

mechanism such as the weathering-related fracturing and surface embrittlement of plastics in beach environments is the root cause of generation of microplastics but industrial waste also constitute the major sources of them. As microplastics are recalcitrant in nature, only small fraction of the microplastics present in aquatic body imposes a serious threat to aquatic life. As microplastics are potentially ingestible by aquatic organisms including micro and nano plankton species, the delivery of toxins across trophic levels via this mechanism is very common. The efficiency of such transfer will depend on the bioavailability of microplastics and the residence time of meso or microplastics in the organisms. Endocytosis of plastic nanoparticles by micro- or nanofauna can also result in adverse toxic endpoints. As aquatic species constitute the very foundation of the aquatic food web, any threat to these can have serious and far-reaching effects in the world oceans. There is an urgent need to quantify the magnitude of these potential outcomes and assess the future impact of increasing microplastics levels on the world's aquatic bodies.
