Microplastics in different fish and shellfish species in the mangrove estuary of Bangladesh and evaluation of human exposure

The water bodies in Bangladesh thrive from plastic pollution. Estuaries are pools of environmental contaminants, and the world's largest mangrove forest, Sundarbans' estuary, is no exception. Thus, for the first time, we investigate MPs abundance in the muscle and gastrointestinal tract (GIT) of twenty estuarine species of fish and shellfish of the Sundarbans, as well as the human health risk. MPs abundance was evident in all the samples ranging from 5.37 +/- 1.07 to 54.30 +/- 16.53 MP items/g wet body weight (dw) in muscle samples and 7.33 +/- 1.89 to 205.61 +/- 136.88 MP items/g (dw) in GIT samples. The estimated health risk from MPs is substantial, where the average human intake will be 85,710.08 items of MPs per year per capita for the population of Bangladesh. The dominant polymer types ob-served using ATR-FTIR are PP and PE (17.5 %), PA (17.5 %) in the muscle tissues, and PP and PE (11.11 %), and EVA (11.11 %) in the GITs. Bottom-feeding species, such as demersal and benthic species, are more contaminated. How-ever, the level of MPs in the species shows a negative correlation with the length and weight of the species. This study reveals that MP pollution is widespread and concerning in Bangladesh's Sundarban mangrove estuarine zone.

Automated summary

Water bodies in Bangladesh, including the Sundarbans mangrove estuary, are heavily polluted by plastic. This study investigates the abundance of microplastics (MPs) in the muscle and gastrointestinal tract (GIT) of various estuarine fish and shellfish species in the Sundarbans, as well as the associated human health risks. MPs were found in all samples, with concentrations ranging from 5.37 to 54.30 MP items/g wet body weight in muscle samples, and from 7.33 to 205.61 MP items/g in GIT samples. The estimated annual intake of MPs per capita for the population of Bangladesh is 85,710.08 items. The dominant polymer types observed were PP, PE, and PA in muscle tissues, and PP, PE, and EVA in GITs. The contamination level of species is negatively correlated with their length and weight, with bottom-feeding species being more affected. This study highlights the widespread and concerning MP pollution in the Sundarbans mangrove estuarine zone in Bangladesh.