Beyond occurrence: A comprehensive review of microplastic pollution, risk dynamics, and management priorities in Bangladesh’s aquatic ecosystems

Microplastics (MPs) are emerging contaminants that threaten aquatic ecosystems due to their persistence, bioavailability, and ecotoxic potential. Although studies on MPs in Bangladesh have increased, evidence remains fragmented across environmental matrices, limiting comprehensive risk assessment and management. This review systematically synthesizes the occurrence, characteristics, sources, and risks of MPs in Bangladesh's aquatic environments using a quantitative evidence synthesis approach. The Mean ± Standard Error of the Mean (SEM) of MPs were 26.69 ± 6.52 MPs/L in surface water, 805.24 ± 301.21 MPs/kg in sediment, and 16.78 ± 3.33 MPs/individual in biota. Dominant MPs characteristics included particle sizes of 0.1–0.5 mm, fibrous shapes, transparent/blue/black colors, and polymers such as polyethylene (PE), polypropylene (PP), and polystyrene (PS). Pollution load index (PLI) values indicated high contamination in surface water (36.75), sediment (25.68), and biota (13.65), while the polymer hazard index (PHI) indicated high to very high polymer-associated hazard levels. Marine organisms showed the highest MPs accumulation (1.26 MPs/g), followed by estuarine, pond, and riverine species. Estimated daily intake (EDI) suggested children are exposed to MPs at levels 3.21 times higher than adults through contaminated biota consumption. These findings support standardized monitoring, source-specific mitigation, and evidence-based microplastic management in Bangladesh.