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Temporal trends of mercury, cesium, potassium, selenium, and thallium in arctic char ( Salvelinus alpinus ) from Lake Hazen, Nunavut, Canada: Effects of trophic position, size, and age
Author(s) -
Gantner Nikolaus,
Power Michael,
Babaluk John A.,
Reist James D.,
Köck Günter,
Lockhart Lyle W.,
Solomon Keith R.,
Muir Derek CG.
Publication year - 2009
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 - 10.1897/08-054.1
Subject(s) - trophic level , arctic char , salvelinus , bioaccumulation , mercury (programming language) , arctic , environmental chemistry , chemistry , ecology , environmental science , biology , fishery , trout , fish <actinopterygii> , computer science , programming language
Arctic char ( Salvelinus alpinus L.), the top predator in High Arctic lakes, often is used as a bioindicator of Hg contamination in Arctic aquatic ecosystems. The present study investigated effects of trophic position, size, and age of Arctic char in Lake Hazen, the largest lake in the Canadian High Arctic (81°50′N, 70°25′W), on Hg bioaccumulation. In addition, several essential (Se, K) and nonessential elements (Tl, Cs) in char muscle tissue were examined to compare their behavior to that of Hg. Trophic position of Arctic char was identified by stable isotope (δ 15 N) signature. Temporal trends of Hg from seven sampling campaigns over a 16‐year period (1990–2006) were investigated for the overall data and for one trophic class. Concentrations of Hg were not correlated with age but were positively related to fork length and trophic position. Large char with greater δ 15 N signatures (>12‰) had larger Hg concentrations (0.09–1.63 μg/g wet wt) than small char with smaller δ 15 N signatures (<12‰, 0.03–0.32 μg/g wet wt), indicating that Hg concentrations increased with trophic position. Nonessential Cs and Tl showed relationships to age, length, and trophic position similar to those of Hg, indicating their potential to bioaccumulate and biomagnify. Essential Se and K did not show these relationships. Concentrations of Hg were adjusted using δ 15 N, leading to less within‐year variability and a more consistent temporal trend. The δ 15 N‐adjusted trend showed no decline of Hg in Arctic char from Lake Hazen (1990–2006) in the overall data set and in the small morphotype. Trends for the same period before the adjustment were not significant for the overall data set, but a slight decrease was apparent in the small morphotype. The results confirm the need to consider trophic position and fish size when monitoring temporal trends of Hg, particularly for species with different morphotypes.