From a Global Archived Data Perspective: Larger Bivalves Mean More Microplastics?

Bivalves are a significant source of seafood for people, but so far there have been many studies revealing the presence of microplastics (MPs) in bivalves, yet the role of bivalve biometric parameters in link with MP burden in bivalves remains underexplored. Here we collected published data and found that the study region for MPs in bivalves was spread across the globe, reporting approximately 40,000 bivalves and comprising 102 species in 22 families. A linear positive correlation was obtained between average MP abundance (items/individual) and average shell length of bivalves, while a negative exponential relationship between average MP abundance (items/g) and average shell length of bivalves was found. This suggested that larger bivalves tend to contain more MPs (items/individual), but MP abundance (items/g) tends to be lower in larger bivalves. It was conservatively estimated that the annual dietary intake of MPs of bivalves from global 21 countries reached 6.39 × 10¹² MPs in 2022. Besides, the study found that the soft tissue wet weight of bivalves is an available parameter to estimate the abundance of MPs in bivalves from markets and aquafarms. The findings of this study will provide valuable information that would help to better understand the global bivalve MP contamination character.