Ecological effects of chemical contaminants adsorbed to microplastics

Microplastics (MPs) have become a global concern, owing to frequent detection in aqueous and soil eco-systems. Their transport, release, and the influence of MPs-bound chemical contaminants on aquatic life and soil organisms have been widely investigated. Research studies have confirmed interaction of both organic and inorganic contaminants towards MPs. Weak bond formation of contaminants such as toxic metals and antibiotics with MPs, leading to rapid desorption whereas strongly bound contaminants are taken along with the microplastic particles as a carrier both in aquatic and terrestrial environments. However, polymer type, color, particle size, and weathering degree are factors affecting both adsorption and desorption capacities of contaminants. MP’s behavior as a vector has influenced the transport of molecules such as pharmaceuticals, i.e., antibiotics from one place to another, which may develop antibiotic resistance in microbes. Moreover, toxicological effects have been identified on aquatic vertebrates and invertebrates, resulting in digestive tract obstructions and inflammation; however, they cannot be delineated from MPs or due to the adsorbed contaminants. Biosolid application to farmlands may transport MPs-bound contaminants to the soil system, reducing the plant performance. At the same time, these contaminants can be taken up and accumulate in crops. Constant exposure to chemical contaminants from MPs leads to bioaccumulation of toxic compounds in plants and animals.