The scale of the global plastic problem provides the backdrop. Humanity has manufactured more than 8 billion tons of plastic since 1950, and only about 9 percent has been recycled. Global production reached roughly 350 million tons in 2017, and projections warn that by 2050 the oceans could carry more plastic than fish by weight. Researchers classify plastic debris by size, from megaplastics larger than 50 centimeters down to microplastics between 1 micron and 5 millimeters and nanoplastics below 1 micron. Fibers, granules, fragments, and pellets are the most common microplastic forms in the environment. Because these particles are lightweight, winds and currents scatter them widely, and polymer density determines whether they float at the surface, drift through the water column, or settle into sediments. Studies estimate that between 4.8 and 12.7 million metric tons of plastic enter the ocean every year, and a 2017 analysis found that just five Asian countries accounted for 80 percent of mishandled plastic reaching the sea.

Bangladesh’s vulnerability stems from a combination of geography, economics, and governance. The country spans 148,460 square kilometers and is home to roughly 166 million people, with a plastic manufacturing sector that has expanded rapidly over the past two decades. An extensive network of inland canals, combined with weak waste management infrastructure, funnels plastic debris into rivers that ultimately drain into the Bay of Bengal. Recycling remains in its infancy, and disposal in open areas, riversides, and roadsides is common. Thin polyethylene bags remain popular because they are cheap and no affordable alternative has achieved wide adoption. The government banned polyethylene bags thinner than 55 micrometers in 2002 and mandated jute packaging in 2010, yet enforcement has been inconsistent, and the share of plastic in Dhaka’s landfills rose from 1.74 percent in 1992 to 6.5 percent in 2014.

The review’s technical inventory reveals the diversity of contamination. Across water, sediment, and biological samples, the most frequently detected polymers were polyethylene, polypropylene, polystyrene, polyamide, polyethylene terephthalate, polyvinyl chloride, high-density and low-density polyethylene, polyurethane, ethylene vinyl acetate, and acrylonitrile butadiene styrene. Particle sizes ranged from below 0.5 millimeters to 5 millimeters, and most particles were transparent or white, followed by black, blue, green, and a spectrum of other colors. Detection methods varied: most studies relied on Fourier Transform Infrared spectroscopy, some used Attenuated Total Reflectance-FTIR, and a few applied micro-FTIR, while stereomicroscopy and scanning electron microscopy supported imaging and sizing. Boxplot analyses in the review showed high variability in abundance across riverine, coastal, wastewater, and sediment samples, with coastal riverine sediments and agricultural soils amended with textile sludge among the most contaminated, and coastal fish showing elevated particle loads.

Perhaps the most alarming finding concerns the dinner table. The authors calculated the Estimated Daily Intake of microplastics using mean contaminant concentrations, national consumption rates, and an average adult body weight of 60 kilograms. With average fish consumption at 55 grams per day and salt intake at 9 grams per day, fish and salt emerged as the largest dietary contributors. Benchmarked against World Health Organization thresholds, dietary exposure in Bangladesh falls into the moderate to high-risk categories depending on the food item. The evidence extends beyond seafood: a Dhaka investigation found 343 plastic particles per kilogram in samples of five well-known and two off-brand sugars, mostly particles larger than 300 micrometers. Tea bags fared even worse, with an empty bag containing 477 microplastic particles and a filled bag 505, reportedly the highest levels recorded anywhere, underscoring how deeply the particles have penetrated everyday consumer products.

The ecological consequences are equally troubling. Microplastics adsorb heavy metals, pathogens, and polycyclic aromatic hydrocarbons, delivering toxic cargo to the organisms that swallow them. Aquatic animals suffer oxidative stress, reduced nutrient uptake, suffocation, internal abrasions, and impaired movement. Crustaceans are the most studied taxonomic group, followed by fish, mollusks, worms, echinoderms, and rotifers, organisms that occupy every tier of aquatic food webs. Filter-feeding mollusks are particularly efficient at accumulating particles and toxins, and because they are widely eaten by humans, they form a direct bridge between contaminated ecosystems and human diets. Laboratory work shows that microplastics accumulate in the digestive systems, gills, and stomachs of crabs and fish, damage genetic material in mussels, and cause immunotoxicity, neurotoxicity, and genotoxicity when particles carry adsorbed pollutants.

Polymer chemistry determines the specific hazards. PVC commonly contains phthalate plasticizers that can leach into the environment and disrupt endocrine function, contributing to reproductive toxicity and carcinogenicity. PET, ubiquitous in beverage packaging, is synthesized with antimony trioxide, leaving residual antimony that can migrate into stored liquids at elevated temperatures and pose oxidative and endocrine risks; PET also releases acetaldehyde, an irritant and potential carcinogen, when heated. PE, though relatively stable, fragments into micro- and nanoplastics that infiltrate dust, river sediments, and salt. Experiments on food-contact plastics heated to 70 degrees Celsius for two hours documented significant migration of lead, cadmium, mercury, chromium, and antimony, with PET samples exceeding European limits for antimony and chromium, a chronic exposure concern given how widely such packaging is used in Bangladesh.

For human health, the picture is one of persistence and accumulation. Microplastics have long half-lives in tissues, weakening immune cells and causing chronic inflammation, swelling, obstruction, and cell death. Oxidative stress, cytotoxicity, and tissue translocation have all been linked to exposure, and patients with inflammatory bowel disease show markedly higher microplastic burdens than the general population. Laboratory studies report disrupted mitochondrial membrane potential and reduced growth of Caco-2 intestinal cells after exposure. Particles can also act as carriers for microorganisms and can absorb or release chemicals from their matrices, meaning the dose, the polymer, and the adsorbed contaminants together dictate the harm.

The review closes with a roadmap rooted in existing law rather than new frameworks. The authors urge stricter enforcement of the 2023 amendment to the Plastic Waste Management Act, which formalized Extended Producer Responsibility, and propose an implementation roadmap including a dedicated regulatory body, a centralized registration and reporting platform, and Producer Responsibility Organizations to coordinate collection and recycling. They recommend scaling up jute-based packaging under the Mandatory Jute Packaging Act of 2010, which requires bulk commodities to be bagged in jute with penalties of up to one year in prison or a fine of roughly 409 US dollars, and promoting innovations such as the biodegradable jute cellulose Sonali Bag. Regionally coordinated research into polymer-specific toxicity, a national monitoring network, investment in recycling infrastructure, public education campaigns, and engagement in international plastic agreements complete the strategy. Compared with India and Pakistan, Bangladesh shows higher contamination in some matrices, though polymer types and sources are broadly similar across South Asia, making coordinated regional action essential to protect both ecosystems and public health.

Subject of Research: Microplastics contamination of freshwater and marine ecosystems and human dietary exposure in Bangladesh

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

Article References: Bhuyan, M. S., Nayan, A. H., Chowdhury, S., Chowdhury, S. U. M. B., Mondal, M. A. I., Islam, M. T., Karim, S. M. R., Meraj, G., & Abouleish, M. Y. (2025). Microplastics contamination in freshwater and marine ecosystems, its impacts, and sustainable mitigation pathways in Bangladesh: a systematic review. Discover Toxicology, 2(1), Article 14. https://doi.org/10.1007/s44339-025-00034-w

Image Credits: AI Generated

DOI: 10.1007/s44339-025-00034-w

Keywords: microplastics, Bangladesh, marine pollution, freshwater ecosystems, polyethylene, polypropylene, textile fibers, food contamination, human health, Extended Producer Responsibility, plastic waste management, PRISMA review