Is the Ghost of Waste Management’s Past Coming Back to Haunt Us In Our Seafood?

Plastic debris is recognized globally as a persistent contaminant, littered across multiple habitats worldwide. Most striking is its occurrence in wildlife. Plastic has been recovered from hundreds of species across multiple trophic levels and in animals we consider seafood. This has led policy-makers to ask about the extent that our seafood is contaminated with plastic debris and associated contaminants. To help address these policy-relevant and emerging scientific questions, we first measured the simple presence of anthropogenic debris in many different species of fish and one species of shellfish sold as seafood at local fish markets in Half Moon Bay, California, USA and Makassar, Sulawesi, Indonesia. We found anthropogenic debris in roughly 25% of all animals purchased, demonstrating that some seafood items are contaminated with plastic debris, including some that we consume whole (e.g., anchovies and oysters). Next, to understand if plastic debris can act as a vector for organic pollutants to move through the food chain and indirectly into the meat of fish at higher trophic levels, we designed a laboratory dietary exposure to measure the bioaccumulation of sorbed PCBs in Asian clams (Corbicula fluminea) and the biomagnifications in white sturgeon (Acipenser transmontanus). Asian clams were exposed for 30 days to separate treatments of microplastic (polyethylene terephthalate, polyethylene, polyvinyl chloride and polystyrene) with and without sorbed PCBs. Next, diets were formulated using purified ingredients and clams from the first exposure and fed to their predators (sturgeon) for 30 days. Chemical analyses, allowing us to understand how chemical contaminants from plastics move through food chains, will be presented. Combined, this work demonstrates the presence of plastic debris in seafood and will help us understand whether plastic acts as a vector for chemicals to transfer through aquatic foodwebs, including our own.