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Mercury concentrations in fish from forest harvesting and fire‐impacted Canadian Boreal lakes compared using stable isotopes of nitrogen
Author(s) -
Garcia Edenise,
Carignan Richard
Publication year - 2005
Publication title -
environmental toxicology and chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.1
H-Index - 171
eISSN - 1552-8618
pISSN - 0730-7268
DOI - 10.1897/04-065r.1
Subject(s) - biomagnification , mercury (programming language) , methylmercury , trophic level , environmental science , environmental chemistry , δ15n , food chain , isotopes of nitrogen , taiga , boreal , nitrogen , hydrology (agriculture) , ecology , stable isotope ratio , δ13c , chemistry , bioaccumulation , biology , geology , physics , geotechnical engineering , organic chemistry , quantum mechanics , computer science , programming language
otal mercury (Hg)concentration was determined in several piscivorous and nonpiscivorous species of fish from 38 drainage lakes with clear‐cut, burnt, or undisturbed catchments located in the Canadian Boreal Shield. Mercury concentrations increased with increasing fish trophic position as estimated using stable isotopes of nitrogen (N; r 2 = 0.52, 0.49, and 0.30 for cut, reference, and burnt lakes, respectively; p < 0.01). Mercury biomagnification per %‰ δ 15 N varied from 22 to 29% in the three groups of lakes. Mercury availability to organisms at the base of the food chain in lakes with cut catchments was higher than that in reference lakes. In cut lakes, Hg concentrations in fish were significantly related to ratio of the clear‐cut area to lake area (or lake volume; r = +0.82 and +0.74, respectively, p < 0.01). Both impact ratios were, in turn, significantly correlated with dissolved organic carbon. These findings suggest that differential loading of organic matter–bound Hg to lakes can affect Hg cycling. In addition, Hg concentrations exceeded the advisory limit for human consumption (0.5 μg/g wet wt) from the World Health Organization in all top predatory species (northern pike, walleye, and burbot) found in cut and in two partially burnt lakes. Thus, high Hg concentrations in fish from forest‐harvested and partially burnt lakes may reflect increased exposure to Hg relative to that in lakes not having these watershed disturbances.