CO-EXPOSURE OF MICROPLASTICS AND POLYCHLORINATED BIPHENYLS IN AQUATIC ECOSYSTEMS: A SYSTEMATIC REVIEW OF IMPACT MECHANISMS AND RESEARCH DIRECTIONS

Abstract

Microplastics (MPs) and polychlorinated biphenyls (PCBs) pollution represents a major global environmental challenge that requires comprehensive understanding of their combined effects. Recent research shows that MPs can transport PCBs into aquatic organisms, creating complex synergistic interactions that may exceed the toxicity of individual pollutants. This systematic review examines the combined effects of MP-PCB exposure on aquatic organisms based on data from Web of Science, Scopus, PubMed, Science Direct databases. Our analysis revealed that polyethylene and polystyrene were the most studied MP types, with PCB concentrations on MPs ranging from nanograms to micrograms per gram. However, most studies used MP concentrations 2 - 7 orders of magnitude higher than environmental levels, limiting their environmental relevance. Experimental designs have evolved from basic exposure methods to complex models simulating food chain interactions, with exposure durations ranging from acute to chronic timeframes. Bioaccumulation studies demonstrate that MPs act as vectors for PCBs transport, extending PCB residence time by 10 - 20 fold compared to individual exposure. The biomarker assessment systems have expanded to include 33 multidimensional indicators, with antioxidant enzymes and detoxification enzymes showing the highest sensitivity to combined exposure effects. Histological assessments provide additional evidence of severe tissue damage in liver and intestine. Current research faces important limitations including unrealistic exposure scenarios and methodological inconsistencies that reduce environmental relevance. Future research should adopt standardized procedures using environmentally realistic concentrations and integrated multidisciplinary approaches to enhance understanding of impact mechanisms and inform effective management strategies.