Microplastics in the Biotic Systems

Microplastics interact with organisms of all trophic levels, from small bacteria to large mammals within the food webs, affecting virtually all the living organisms in the world. Uptake and/or accumulation by ingestion of microplastics by organisms can lead to increased exposure to pollutants and pathogens, and effects on physiological activities linked to nutrient uptake, growth, and survival. Strong sorption of polychlorinated biphenyls to nanoplastics increases the hazard of these particles being transferred to cellular membranes, and they may easily penetrate tissues or accumulate in organs. Airborne microplastics are able to be directly and continuously inhaled into the human body and pose potential threats to human health. The impacts of microplastics on aquatic plants depend on the particle size, polymer type, concentration of microplastics in the aquatic medium, exposure duration, and the type of plant species. The impacts include oxidative stress, inefficient energy exchange, reduction in chlorophyll content, efficiency of photosynthesis, and growth rate. Owing to their higher surface-to-volume ratio, biofilms are formed actively over the surfaces of the microplastics, followed by biologically mediated concentrations of pathogens and synthetic chemicals, all of which make the microplastics act as vectors of biological and chemical contaminants.