Long-term changes in fish mercury levels in the historically impacted English-Wabigoon River system (Canada).
The English-Wabigoon River system in Northwestern Ontario, Canada, was one of the most heavily mercury-contaminated waterways in the world due to historical discharges in the 1960s from a chlor-alkali plant. This study examines long-term (1970-2010) monitoring data to assess temporal trends in mercury contamination in Walleye, Northern Pike and Lake Whitefish, three species important for sport and subsistence fishing in this region, using dynamic linear modeling and piecewise regression. For all lakes and species, there is a significant decline (36-94%) in mercury concentrations through time; however, there is evidence that this decline is either slowing down or levelling off. Concentrations in the English-Wabigoon fish are elevated, and may still present a potential health risk to humans consuming fish from this system. Various biotic and abiotic factors are examined as possible explanations to slowing rates of decline in mercury concentrations observed in the mid-1980s.
Department of Ecology and Evolutionary Biology, University of Toronto, 25 Willcocks Street, Toronto, Ontario, Canada.
Margaret R
MR
Neff
Satyendra P
SP
Bhavsar
George B
GB
Arhonditsis
Rachael
R
Fletcher
Donald A
DA
Jackson
D000818:Animals; D004784:Environmental Monitoring; D005398:Fisheries / Q000706:statistics & numerical data; D005399:Fishes / Q000378:metabolism*; D005506:Food Contamination / Q000706:statistics & numerical data; D006801:Humans; D008628:Mercury / Q000032:analysis / Q000378:metabolism*; D009864:Ontario; D045483:Rivers / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000378:metabolism*; D014877:Water Pollution, Chemical / Q000706:statistics & numerical data*
D014874:Water Pollutants, Chemical; D008628:Mercury