Читать книгу Plastic and Microplastic in the Environment - Группа авторов - Страница 50

MPs can readily absorb harmful chemicals from the atmosphere and pathogenic contaminants due to its surface deposition (Verla et al. 2019). Along with their own harmful impacts, this MP has more associated risk when exposed to the environment, as they are breeding grounds for pathogens (Lu et al. 2019).

Plastic polymers are manufactured using chemical additives and other smaller monomer units, which give them the desired shape, structure, strength, and durability. These additives include wide ranges of chemicals like heavy metals; e.g. mercury, plasticizers, flame‐retardants, pigments, heat stabilizer filler, UV stabilizers, and many more, and this accounts for 4% of their total weight (Ambrogi et al. 2017). These chemicals tend to deposit over the MPs rather than dissolve in the water bodies (Ziccardi et al. 2016). When these chemicals leach into the environment due to photolysis chemical, and physical breakdown processes, they exhibit harmful impacts in every possible environment (air, water, or soil) as most of them are carcinogenic (Abdel‐Shafy and Mansour 2016). These MPs slowly degrade, and their surface area to volume ratio increases, which increases the chemical leaching (Chamas et al. 2020). These leached chemicals are mixed with the surrounding matrix and are transferred to the organism, causing bioaccumulation of these chemicals in them (Figure 3.3). If these MPs are directly eaten by primary consumers like zooplankton and then become prey by high trophic level, there is a high chance of bioaccumulation (Ziccardi et al. 2016).

Figure 3.3 Associated chemical toxicants entering marine organisms have potential health impacts.

Fecal matter of zooplankton is an important component of marine organic matter and plays a significant role in the biological pump. The biological carbon pump is helpful in the transportation of carbon, nutrients, and energy to the deeper water sediments (Cisternas‐Novoa et al. 2019). Due to feeding on the MPs contaminated meals, their fecal pellets are highly susceptible to the persistent pollutants, hydrocarbons, and petroleum residue. Moreover, benthos feed upon these contaminated meals and are highly prone to bioaccumulation and biomagnification of these harmful chemicals.