Comparative accumulation and effects of microplastics and microplastic-associated PCB-153 in the white hard clam (Meretrix lyrata) and giant river prawn (Macrobrachium rosenbergii) following chronic exposure

Global environmental abundance of microplastics (MPs) is increasing. MPs may sorb hydrophobic organic contaminants (HOCs), accumulate in and cause deleterious effects on exposed organisms. This study investigated and compared the accumulation and effects of MPs and MP-associated PCB in the two indigenous aquatic organisms in Viet Nam, the white hard clams, Meretrix lyrata, and the giant river prawns, Macrobrachium rosenbergii. The test organisms were exposed to either polyethylene microbeads (PEMBs), waterborne polychlorinated biphenyl 153 (PCB-153), or PEMB-associated PCB-153 (PEMB-PCB) over 28 days. Organismal MP accumulation, survival, and weight gain were examined at various sampling intervals. In general, MP accumulation was significantly greater in the clams than in the prawns. A significant quantity of MPs was observed in the digestive systems of the organisms after 0.5-day and during 28-day exposure. Although the effect of MPs and MP-associated PCB-153 on mean survival rate was not statistically significant, this effect was significant towards the end of the 28-day exposure. In addition, while MP-associated PCB-153 did not significantly affect the weight gain of the prawns, it significantly reduced weight gain in clams. Given the global increases of MPs and HOCs (and in southeast Asia specifically), and the importance of the hard clams and giant river prawns in the Indo-Pacific region, this present study provides valuable data to enhance our understanding of the effects of MPs and HOCs on these species.