Microplastic and Heavy Metal Accumulation in Cultured Fish: Concerns for Food Safety

Abstract

Microplastic (MP) and heavy metal contamination in aquatic ecosystems pose serious risks to environmental and human health due to their toxic effects. This study investigates the presence of microplastics (MPs) and heavy metals in five cultured freshwater fish species collected from aquaculture ponds in Rajshahi, Bangladesh, and evaluates related environmental and human health risks. MPs were found in the gastrointestinal tracts and edible tissues of 96% and 88% of the sampled fish, respectively, with an average of 1.52 particles/g GIT and 0.54 particles/g flesh. Pangasius pangasius exhibited the highest MP levels. The most common types of MPs were blue fibers less than 1 mm in size. FTIR analysis identified that the MPs consisted of polyethylene (PE), polypropylene (PP), and polyethylene terephthalate (PET). The pollution load index (PLI) indicated significant MP contamination (PLI > 1). Heavy metal analysis showed elevated levels of Cr, Mn, Cd, and Pb in fish tissues, exceeding FAO/WHO guidelines. Human health risk assessments revealed non-carcinogenic risks (HI > 1) and carcinogenic risks (TCR > 1.0 × 10^-4) from consuming fish. The Metal Pollution Index (MPI) ranked P. pangasius as the most contaminated species. Positive correlations between contaminant levels and fish size suggest that larger fish are more vulnerable. The findings emphasize the importance of improved waste management, pollution control, and ongoing monitoring to protect food safety and the environment.