Serving fish for dinner? You could be eating more than protein. As reported in Environmental Science & Technology, a team of researchers used a mass spectrometry technique to test seafood purchased from a market in Australia—and every sample contained traces of microplastics, including polyethylene and polyvinyl chloride, aka PVC.

We still don’t know how ubiquitous these microplastics are in the American seafood supply and what, if anything, this is doing to our long-term health. But considering just how much plastic is being dumped into our oceans and other waterways, there’s reason to find out if this may cancel out some of the health benefits (like omega-3s) we expect to gain from eating seafood.

See also: There’s Trouble Brewing with Microplastics in Tea