Acute Effects of Size Dependent Low-Density Polyethylene Microplastics on Zebrafish

Microplastics have increasingly become a global menace, pervading aquatic ecosystems and exerting profound biological impacts on marine life. The breakdown of synthetic fabrics, consumer plastics and industrial trash is the source of these contaminants. Due to an inappropriate disposal and fragmentation procedures, these plastic waste materials end in aquatic bodies. While numerous studies have focused on studying the effects of various plastics, limited research has focused on low-density polyethylene (LDPE) MPs and their unique way of interaction with biota. In this study, pigmented LDPE plastics were separated into three distinct size ranges (> 10 µm, 10–15 µm, and 15–25 µm), characterized and exposed to zebrafish for 48 h at a concentration of 1 µg/ml. The following developmental endpoints were analyzed and assessed: histopathological changes, gastrointestinal enzyme activity (trypsin, chymotrypsin, carboxypeptidase A, α-amylase, and lipase), biochemical responses (superoxide dismutase, lipid peroxidation, and catalase) and embryo survival and hatching rates. Although LDPE MP exposure did not cause embryo death, it did cause a decrease in hatching rate, an increase in heart rate, a considerable accumulation of MPs in the gut and significant tissue damage, especially by the smallest particle size. These results demonstrate how colored LDPE MPs may jeopardize aquatic creatures’ biological integrity, posing a growing risk to aquatic ecosystems and public health.