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Long‐term changes in legacy trace organic contaminants and mercury in Lake Ontario salmon in relation to source controls, trophodynamics, and climatic variability
Author(s) -
French Todd D.,
Campbell Linda M.,
Jackson Donald A.,
Casselman John M.,
Scheider Wolfgang A.,
Hayton Al
Publication year - 2006
Publication title -
limnology and oceanography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.7
H-Index - 197
eISSN - 1939-5590
pISSN - 0024-3590
DOI - 10.4319/lo.2006.51.6.2794
Subject(s) - oncorhynchus , polychlorinated biphenyl , environmental science , mercury (programming language) , population , environmental chemistry , fishery , chinook wind , zoology , biology , chemistry , fish <actinopterygii> , demography , sociology , computer science , programming language
We used long‐term (20+ yr) datasets to determine how the sum of 209 polychlorinated biphenyl congeners ([ΣPCB]), dodecachloropentacyclodecane ([mirex]), para‐para dichlorodiphenyltrichloroethane ([ p,p '‐DDT]), and total mercury ([Tot‐Hg]) concentrations have changed in Lake Ontario chinook salmon ( Oncorhynchus tshawytscha , 1983‐2003) and coho salmon ( Oncorhynchus kisutch , 1976‐2003). Exponential decay models best describe temporal reductions of persistent organic pollutant concentrations [POPs], including [ΣPCB], [mirex], and [ p,p '‐DDT], in chinook (r 2 = 0.68‐0.77, p < 0.001) and coho (r 2 = 0.68‐0.87, p < 0.001) salmon over the record. In comparison, declines in [Tot‐Hg] were slight, with linear models best describing trends (r 2 = 0.49‐0.50, p = <0.001‐0.001). Rapid declines of [POPs] from the mid‐1970s through the early 1980s were attributed mostly to Canada‐United States bans on usage and sedimentation; subsequent concentration oscillations were linked to salmonine stocking and nutrient abatement programs, climatic cycles, and alewife ( Alosa pseudoharengus ) population dynamics.