Tissue contaminants and wild fish health in the St. Clair River Area of Concern – Part 2: Spatial trends and temporal declines in organics A.F. Muttray a,b , D.C.G. Muir b , G.R. Tetreault b , M.E. McMaster b , J.P. Sherry b, ⁎ a Environmental Resources Management Canada, 1111 West Hastings St., Vancouver, BC V6E 2J3, Canada b Aquatic Contaminants Research Division, Environment Canada, Water Science & Technology Directorate, 867 Lakeshore Rd, Burlington, ON L7R 4A6, Canada HIGHLIGHTS • Fish tissue concentrations of persistent organics have decreased over last 12- years. • Little evidence of contaminant-linked health effects in fish in 2014. • Non-legacy PCBs may be increasing in yellow perch in the region of Stag Island. • Tissue concentrations reflected life his- tory and food chain position of fish species. GRAPHICAL ABSTRACT abstract article info Article history: Received 30 September 2019 Received in revised form 2 January 2020 Accepted 3 January 2020 Available online xxxx Editor: Damia Barcelo Keywords: St. Clair River Area of Concern PCB Organochlorine Tissue concentration Shorthead redhorse Yellow perch Emerald shiner Temporal decline Spatial tend We explored tissue concentrations of polychlorinated biphenyls (PCBs), chlorinated pesticides, and rele- vant organochlorines and fish health in the following adult wild fish in the St. Clair River Area of Concern (Ontario, Canada): shorthead redhorse (Moxostoma macrolepidotum), yellow perch (Perca flavescens), and emerald shiner (Notropis atherinoides). We collected adult fish from sites within the river's industrial zone (Stag Island), a downstream site adjacent to Walpole Island (Chenal Écarte), and an upstream refer- ence site in Lake Huron in 2002/2003 and 2014. We tested for trends in tissue concentrations of organic con- taminants across sites and over time; we assessed the potential effects of contaminants on morphological indicators of fish health across sites by year. Over the 12-year period, the tissue concentrations of most PCBs declined at the river sites, except for some non-legacy PCBs (PCB11 and 185), which increased in yel- low perch at Stag Island, a new observation for fish in the St. Clair River AOC. There was little difference be- tween the concentrations of calculated toxic equivalents (TEQs) of the Lake Huron and the St. Clair River fish in 2014, except for emerald shiners from Stag Island which had elevated ΣPCB and TEQs. Each fish species at all sites exceeded the Canadian tissue residue guideline for PCBs for the protection of mammalian wildlife consumers of aquatic biota, but fish-derived TEQs indicated little potential health risk to fish. Over time, hexachlorobutadiene and hexachlorobenzene concentrations increased in some fish at Stag Island by about 8- and 4-fold, respectively, whereas they decreased at other sampling locations. Principal Component Analysis followed by Linear Discriminant Analysis of the 2014 SHRH data suggested that although the fish Science of the Total Environment xxx (xxxx) xxx ⁎ Corresponding author. E-mail address: jim.sherry@canada.ca (J.P. Sherry). https://doi.org/10.1016/j.scitotenv.2020.136525 0048-9697/© 2020 Elsevier B.V. All rights reserved. Contents lists available at ScienceDirect Science of the Total Environment journal homepage: www.elsevier.com/locate/scitotenv