Trends of Short- and Medium-Chain Chlorinated Paraffin Concentrations in Top Predator Fish Tissues from The Great Lakes

In November 2021, the Environment and Climate Change Canada and the United States Environmental Protection Agency (US EPA) released a draft binational strategy for short-chain chlorinated paraffins (SCCPs) risk assessment to focus efforts on implementing risk mitigation and management options to reduce SCCPs in the Great Lakes basin. In accordance with this strategy, SCCPs have been added to US EPA’s Great Lakes Fish Monitoring and Surveillance Program (GLFMSP). To provide a better understanding of the current state of the Great Lakes, homologue-based concentrations and overall trends of SCCPs and medium-chain chlorinated paraffins (MCCPs) in top predator fish tissues were assessed over the past decade, 2010 to 2020. Results show no obvious trends in CP concentrations in Lakes Ontario, Michigan, Huron, and Superior. Lake Erie exhibited a possible increasing trend for MCCPs, but no trend for SCCPs. The total concentrations of chlorinated paraffins (CPs) over the 10-year period for Lake Erie ranged from 3 to 19 ng/g wet weight (ww), in Lake Ontario from 6 to 18 ng/g ww, in Lake Huron from 7 to 26 ng/g ww, in Lake Michigan from 10 to 39 ng/g ww, and in Lake Superior from 0.6 to 18 ng/g ww.