Chapter 2 - Toxicological impacts of microplastics on marine bivalves

Abstract

With the massive production (approximately 367 million tons in 2020) and improper discharge, large quantities of plastics have entered the aquatic environment, especially the ocean, making it the largest vessel for plastic waste. At present, microplastics (MPs) are extensively discovered in the marine environment. Owing to the characteristics that MPs have, such as hydrophobicity, small size, large specific surface area, and resistance to natural degradation, MPs have become one of the most concerned emerging contaminants and pose a severe threat to marine organisms as well as the ecosystem; therefore escalating and intensive emphases are placed on MP pollution. As one of the largest groups of animals in the ocean, marine bivalves play critical roles in the marine ecosystem and possess important commercial value. However, due to their limited mobility abilities and filter-feeding habits, marine bivalves are vulnerable to the pervasive presence of MPs. Numerous studies have shown that MPs can be ingested in marine bivalves; thus MPs can exert various detrimental effects on all kinds of vital processes in marine bivalves. Therefore in this chapter, the toxicological effects of MPs on the life processes (reproduction, embryonic development, metabolism and growth, immune responses, and neuroendocrine system) of marine bivalves, the accumulation of MPs in marine bivalves, and the “Trojan Horse Effect,” as well as interactions between MPs and other pollutants, are summarized.