title: Major correlates of mercury in small fish and common loons (Gavia immer) across four large study areas in Canada.
abstract: We investigated mercury (Hg) concentrations in small fish (mainly yellow perch, Perca flavescens; ∼60% of fish collected) and in blood of common loons (Gavia immer) that prey upon them during the breeding season on lakes in 4 large, widely separated study areas in Canada (>13 lakes per study area; total number of lakes = 93). Although surface sediments from lakes near a base metal smelter in Flin Flon, Manitoba had the highest Hg concentrations, perch and other small fish and blood of common loon chicks sampled from these same lakes had low Hg concentrations similar to those from uncontaminated reference lakes. Multiple regression modeling with AIC analysis indicated that lake pH was by far the most important single factor influencing perch Hg concentrations in lakes across the four study areas (R(2) = 0.29). The best model was a three-variable model (pH + alkalinity + sediment Se; Wi = 0.61, R(2) = 0.85). A single-variable model (fish Hg) best explained among-lake variability in loon chick blood Hg (Wi = 0.17; R(2) = 0.53). From a toxicological risk perspective, all lakes posing a potential Hg health risk for perch and possibly other small pelagic fish species (where mean fish muscle Hg concentrations exceeded 2.4 μg/g dry wt.), and for breeding common loons (where mean fish muscle Hg concentrations exceeded 0.8 μg/g dry wt., and loon chick blood Hg exceeded 1.4 μg/g dry wt.) had pH < 6.7 and were located in eastern Canada.
authors.affiliation: Environment and Climate Change Canada, National Wildlife Research Centre, 1125 Colonel By Drive, Ottawa, Ontario, K1A 0H3, Canada. Electronic address: tony777@rogers.com.
authors.forename: A M
authors.initials: AM
authors.lastname: Scheuhammer
authors.affiliation: University of Waterloo, Department of Biology, 200 University Ave. W., Waterloo, ON, N2L 3G1, Canada.
authors.forename: S I
authors.initials: SI
authors.lastname: Lord
authors.affiliation: Environment and Climate Change Canada, 115 Perimeter Rd, Saskatoon, SK, S7N 0X4, Canada.
authors.forename: M
authors.initials: M
authors.lastname: Wayland
authors.affiliation: Environment and Climate Change Canada, 6 Bruce St, Mount Pearl, NL, A1N 4T3, Canada.
authors.forename: N M
authors.initials: NM
authors.lastname: Burgess
authors.affiliation: Environment and Climate Change Canada, 1550 avenue D'Estimauville, QC, G1J 0C3, Canada.
authors.forename: L
authors.initials: L
authors.lastname: Champoux
authors.affiliation: Environment and Climate Change Canada, 5421 Robertson Rd, Delta, BC, V4K 3N2, Canada.
authors.forename: J E
authors.initials: JE
authors.lastname: Elliott
mesh_terms: D000818:Animals; D001717:Birds / Q000097:blood*; D002170:Canada; D005399:Fishes; D006863:Hydrogen-Ion Concentration; D060106:Lakes / Q000737:chemistry; D008628:Mercury / Q000032:analysis*; D018482:Muscle, Skeletal / Q000737:chemistry; D010471:Perches; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D014874:Water Pollutants, Chemical; D008628:Mercury
keywords: Acidification; Common loon; Fish; Mercury; Perch; Toxicity