title: Factors regulating the bioavailability of methylmercury to breeding rusty blackbirds in northeastern wetlands.
abstract: Rusty blackbirds are undergoing rapid population decline and have elevated Hg concentrations while breeding in the Acadian ecoregion of North America. Factors regulating the bioavailability of methyl-Hg (MeHg) within this population's habitat were determined using water, invertebrates, and blood from adult rusty blackbirds collected for Hg-speciation, along with additional water column parameters: MeHg and THg, dissolved organic carbon, pH, dissolved oxygen, conductivity, redox potential, and temperature. Both DO(2) and pH were negatively related to biota MeHg, while water MeHg concentrations were positively related. Both invertebrate MeHg concentration and %MeHg increased with trophic level. Invertebrate MeHg concentrations were among the greatest reported when compared with those reported elsewhere for wetlands and waterbodies-often several times greater for similar taxa-while percent MeHg of THg were similar. An environment with high bioavailability of MeHg in combination with a high trophic position best explains elevated Hg concentrations for this species regional population.
authors.affiliation: K.C. Irving Environmental Science Centre, Department of Earth and Environmental Sciences, Acadia University, Wolfville, NS B4P 2R6, Canada. sam.edmonds@briloon.org
authors.forename: Samuel Trower
authors.initials: ST
authors.lastname: Edmonds
authors.forename: Nelson J
authors.initials: NJ
authors.lastname: O'Driscoll
authors.forename: N Kirk
authors.initials: NK
authors.lastname: Hillier
authors.forename: Jonathan L
authors.initials: JL
authors.lastname: Atwood
authors.forename: David C
authors.initials: DC
authors.lastname: Evers
mesh_terms: D000818:Animals; D059001:Aquatic Organisms / Q000378:metabolism; D004784:Environmental Monitoring; D004785:Environmental Pollutants / Q000378:metabolism / Q000633:toxicity*; D020387:Food Chain; D008767:Methylmercury Compounds / Q000378:metabolism / Q000633:toxicity*; D046109:Passeriformes / Q000378:metabolism* / Q000502:physiology; D012098:Reproduction / Q000187:drug effects*; D053833:Wetlands
chemical_list: D004785:Environmental Pollutants; D008767:Methylmercury Compounds