Ecotoxicological effects of microplastics: Examination of biomarkers, current state and future perspectives

Interest about interactions between microplastics and organisms is on the rise. Accessing organisms' responses to these chemically "inert" compounds plays an important role in determining their potential toxicity. Microplastics from the environment tend to accumulate and move through living organisms, inducing a variety of biological effects, such as disturbances in energy metabolism, oxidative balance, antioxidative capacity, DNA, immunological, neurological and histological damage. In the present review, we summarized the adverse effects of different size, concentrations and types of microplastics on animals' antioxidative system, energy metabolism and nervous system. Results showed that microplastics can: induce oxidative damage (increased lipid peroxidation and DNA strand breaks); alter antioxidative system (superoxide dismutase, catalase and glutathione peroxidase were parameters with the highest and significant changes in activities) and metabolism (isocitrate dehydrogenase and lactate dehydrogenase activity); and have neurotoxic effects (inhibition of acetylcholinesterase activity). The effects were depending on size and dose of used microplastics, and/or their interaction with other xenobiotics. We examined also potential strategies and offer research priorities for current and future studies.