The Role of Microplastics as Carriers of Heavy Metal Cadmium (Cd) in Paphia undulata under different Salinities

The combination of microplastics (MPs) and heavy metals has been documented to result in increased accumulation levels and more severe impacts on organisms. Paphia undulata serves as a bioindicator with a high sensitivity to alterations in salinity. This research examines the involvement of MP particles as carriers of heavy metal cadmium (Cd) pollution in hard clams across various treatment conditions, MP types, and salinity levels. The type of MP particles significantly influences the extent of Cd contamination in hard clams with polypropylene (PP) particles leading to a higher Cd concentration increase compared to other particles. Furthermore, the concentration of heavy metal Cd rises in correlation with increasing water salinity. Clams placed in water with a salinity of 30 parts per thousand exhibited a greater accumulation of MP particles compared to those in lower salinity environments. Our findings underscore the critical role of salinity in conjunction with the interaction and type of MP particles in the transport of heavy metals within aquatic ecosystems.