Molecular and cellular effects of nano- and microplastics on oysters: a review

Plastics are a growing environmental concern due to the widespread pollution of nanoplastics (NPs) and microplastics (MPs), originating from both artificial synthesis and environmental weathering. Although these pollutants have been recognized for decades and their global use continues to increase, their bioavailability, ecotoxicological effects, and associated chemical additives remain poorly understood in aquatic mollusks, particularly oysters. Oysters are also a valuable bioresource and play a crucial ecological, economic, and scientific role in marine ecosystems. Given the continuous production and environmental presence of NPs and MPs, understanding their effects on edible oysters is a priority for both scientific research and regulatory efforts. This review examines the pathways by which NPs and MPs enter oysters and their ecotoxicological impacts, synthesizing existing literature and case studies to identify critical knowledge gaps. A review of the collected literature indicates that exposure to NPs and MPs at concentrations higher than those typically found in the environment can cause numerous detrimental effects on oyster physiology, as well as on molecular and cellular processes. However, there is a notable lack of research on the molecular and cellular impacts of NPs and MPs at environmentally relevant concentrations. Only a few studies have examined biochemical responses, and those were conducted at concentrations exceeding ecologically realistic levels. The knowledge gaps in molecular and cellular effects of NPs and MPs at environmentally relevant levels in these species suggest the need for further in-depth research to better understand their potential impact on aquatic mollusks and to improve predictions of their environmental consequences.