Microplastics contamination in freshwater and marine ecosystems, its impacts, and sustainable mitigation pathways in Bangladesh: a systematic review

Plastic pollution, particularly microplastics (MPs), has emerged as a critical environmental and public health issue in Bangladesh. This systematic national-scale review synthesizes findings from 50 peer-reviewed studies published up to December 2024, retrieved using the PRISMA framework from databases including Google Scholar, Web of Science, and Scopus. Results indicate widespread MPs contamination in water, sediment, biota, fish feed, fertilizers, and table salt. Polyethylene (PE), polypropylene (PP), and polystyrene (PS) are the most frequently detected polymers, with textile-derived fibers identified as a dominant source. Alarmingly, tea bags in Bangladesh have been reported to contain the highest levels of MPs, underscoring the severity of local contamination. Health implications include oxidative stress and immunotoxicity in aquatic organisms, and potential human exposure via dietary intake, especially through fish and salt. Compared to other South Asian countries such as India and Pakistan, Bangladesh exhibits higher contamination levels in specific matrices, though comparable polymer types and sources persist across the region. Despite growing evidence, key knowledge gaps remain, particularly in spatial analyses of MPs distribution and quantification of population-level exposure. We recommend regionally coordinated research into polymer-specific toxicity, stricter enforcement of the 2023 Plastic Waste Management Act, promotion of biodegradable alternatives, and culturally tailored awareness initiatives. These steps are essential for mitigating MPs pollution and protecting ecological and human health in Bangladesh.