Assessing the feasibility of Fenton's reagent for microplastic extraction from mussels and its application to coastal pollution monitoring in Zhejiang, China.

The use of mussels as bioindicators for monitoring marine microplastic pollution has broad application prospects. However, the lack of standardized protocols for extracting microplastics from mussel tissues hinders the comparability of results across studies. Capitalizing on the efficient organic matter degradation capacity of Fenton's reagent, this study investigated its applicability for extracting microplastics from mussel tissues. Experimental results demonstrated that Fenton's reagent efficiently digests mussel tissues, achieving a digestion efficiency exceeding 88% even with a tissue mass of 12 g. Moreover, Fenton's reagent did not alter the morphology of six common marine microplastic types nor interfere with their identification. The method was further applied to wild mussel samples from the coast of Zhejiang to assess microplastic pollution. The results revealed microplastic abundances ranging from 1.8 to 9.0 items per g (wet weight), with 63% to 100% of the microplastics smaller than 50 µm. The predominant microplastics in mussels were chlorinated polyethylene (40.7%), polyvinyl chloride (32.2%), polyethylene terephthalate (6.8%), polyethylene (5.1%), and polyurethane (4.2%). The composition of microplastics in mussels is highly correlated with the characteristics of microplastics in the surrounding environment, confirming that mussels can be effectively used to monitor marine microplastic pollution. This study provides a valuable assessment of Fenton's reagent application for monitoring marine microplastic pollution and offers a reliable technical foundation for standardizing methods using bivalves as indicator organisms.