Trout, monitors of the Great LakesTrout, monitors of the Great Lakes

Abstract

ENVIRONMENT Trout, monitors of the Great LakesTrout, monitors of the Great Lakes ShareShare onFacebookTwitterWechatLinked InRedditEmail C&EN, 2017, 95 (46), p 30November 20, 2017Cite this:C&EN 95, 46, 30(Credit: iStockphoto)Figure1of2Figure1of2Lake trout (Salvelinus namaycush) are the largest member of the char family and occupy the top of the food web in deep, cold lakes across the upper reaches of North America. Prized by anglers, lake trout often live up to 20 years, reaching more than 60 cm in length and 10 kg in weight with high body-fat content. All these characteristics make lake trout perfect for biomonitoring because they accumulate pollutants in their bodies at levels indicative of their environmental exposure.In the Great Lakes, the world’s largest freshwater system, lake trout have been under surveillance for more than 40 years by the U.S. Environmental Protection Agency and Environment & Climate Change Canada. At the onset of monitoring in the 1970s, the focus was on the “dirty dozen” persistent organic pollutants listed by the 2001 Stockholm Convention. These recognizable compounds, now banned from production and use, include the pesticides DDT and lindane as well as industrial chemicals such as polychlorinated biphenyls (PCBs). Although the levels of most of these chemicals of concern as measured in lake trout have decreased significantly, demonstrating the desired effects of global restrictions, some are still present at easily detectable and potentially detrimental concentrations.In the past 15 years, monitoring has evolved to include newer classes of chemicals like polybrominated diphenyl ether flame retardants and fluorinated alkyl substances used for their stain-resistant, water-repellent, and nonstick properties. The lake trout data and data from other fish species sampled globally help facilitate risk assessments of chemicals in the environment and measure the effectiveness of risk-management regulatory actions.Sources:Thomas M. Holsen and Chuanlong Zhou, Clarkson University; Daryl McGoldrick, Environment & Climate Change Canada Did you know?Trout can be aged from their ear bones, called otoliths, which have growth rings like trees do.“Lake trout are long-lived and far-ranging top predators that integrate exposure to bioaccumulative chemicals in their bodies, providing us with a window into which chemicals are impacting the environment.”—Thomas M. Holsen, Clarkson University and EPA’s Great Lakes Fish Monitoring & Surveillance Program Data bite Canadian-U.S. monitoring of lake trout in the Great Lakes since the 1970s has tracked changes in the concentrations of legacy pollutants and emerging pollutants of concern. These graphs provide a snapshot of the recent trends for two of them (Environ. Sci. Technol. 2017, DOI: 10.1021/acs.est.7b00982).