Mercury Contamination of Aquatic Birds in Northwestern Ontario

Fimreite, Norvald

doi:10.2307/3800207

Cited by 165 publications

(75 citation statements)

References 10 publications

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“…Riverine habitats tend to have higher levels of MeHg availability than estuaries, but tend to have lower levels when compared to lakes. Comparisons of MeHg availability between adjoining riverine and lake habitats based on crayfish, fish, and birds consistently show greater Hg exposure on lakes (Fimreite, 1974). Flushing abilities within riverine systems are a driving force for these differences.…”

Section: Hg Patterns In Aquatic Habitatsmentioning

confidence: 97%

“…Benthic-based MeHg transfer through bivalves has been investigated using various diving species of waterfowl (Ohlendorf et al, 1986;Henny et al, 1991;Braune et al, 1999;Cohen et al, 2000;Wayland et al, 2002), while such transfer through macroinvertebrates (larval and adults) (Bishop et al, 1995;Wolfe and Norman, 1998;Reynolds et al, 2001;Gerrard andSt. Louis 2002, Adair et al, 2003) and vegetation has also been described (Fimreite, 1974;Langis et al, 1999).…”

Section: Species Hg Exposure Patternsmentioning

confidence: 99%

“…Based on such past studies (Dustman et al, 1972;Fimreite, 1974;Langis et al, 1999) and our data sets, Hg exposure can be approximately predicted by foraging guilds. An all-purpose ranking from low to high Hg exposure for birds is: terrestrial herbivores, aquatic herbivores, terrestrial insectivores, benthivore-bivalves, benthivore-macroinvertebrates, small piscivores, and large piscivores.…”

Section: Species Hg Exposure Patternsmentioning

confidence: 99%

“…The use of piscivorous birds as bioindicators of MeHg availability and risk in freshwater systems is common (e.g., Fimreite, 1974;Barr, 1986;Scheuhammer, 1987;Rumbold et al, 2001;Henny et al, 2002;Evers et al, 2003), although insectivorous birds are increasingly being used as well (Wolfe and Norman, 1998;Gerrard and St. Louis, 2001;Adair et al, 2003). Historically, Hg exposure was primarily determined by killing birds and was therefore based on organs analysis (Thompson, 1996).…”

Section: Using Birds As Bioindicators Of Mehg Availabilitymentioning

confidence: 99%

“…Many past and even current inputs of waterborne Hg sources occur throughout North America and the Northeast. These are related to past improper waste disposal of Hg at weapons facilities (Halbrook et al, 1999), chlor-alkali plants (Fimreite, 1974;Gardner et al, 1978;Barr, 1986;Adair et al, 2003), mercury, gold, and silver mines Henny et al, 2002;Seiler et al, 2004;Weech et al, 2004) and governmental storage facilities (Moore et al, 1999) as well as current inputs from wastewater treatment plants .…”

Section: Introductionmentioning

confidence: 99%

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Patterns and Interpretation of Mercury Exposure in Freshwater Avian Communities in Northeastern North America

et al. 2005

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Abstract. A large data set of over 4,700 records of avian mercury (Hg) levels in northeastern North America was compiled and evaluated. As Hg emissions remain poorly regulated in the United States and Canada, atmospheric deposition patterns and associated ecological responses continue to elicit interest by landscape managers, conservation biologists, policy makers, and the general public. How avian Hg exposure is interpreted greatly influences decision-making practices. The geographic extent and size of this data set is valuable in understanding the factors that affect the exposure of Hg to birds. Featured are differences found among tissues, major aquatic habitats and geographic areas, between age class and gender, and among species. While Hg concentrations in egg and blood reflect short-term Hg exposure, Hg concentrations in liver and feather provide insight into long-term Hg exposure. Blood is a particularly important matrix for relating site-specific exposure to methylmercury (MeHg). The level of MeHg is generally 5-10x greater in adults compared to nestlings. Age also influences MeHg bioaccumulation, particularly for individuals where MeHg intake exceeds elimination. Gender is of interpretive concern when evaluating Hg exposure for species exhibiting sexual dimorphism and niche partitioning. Based on two indicator species, the belted kingfisher (Ceryle alcyon) and bald eagle (Haliaeetus leucocephalus), we found MeHg availability increased from marine, to estuarine and riverine systems, and was greatest in lake habitats. A large sample of >1,800 blood and egg Hg levels from the common loon (Gavia immer) facilitated a suitable comparison of geographic differences. Although some clusters of highly elevated Hg exposure (i.e., blood levels >3.0 lg/g, ww and egg levels >1.3 lg/g, ww) were associated with hydrological and biogeochemical factors known to increase MeHg production and availability, others were not. Geographic areas without a relationship between Hg exposure and biogeochemical processes were associated with emission or waterborne point sources. Differences in Hg exposure among species are primarily correlated with trophic position and availability of MeHg. Although piscivorous species were repeatedly *To whom correspondence should be addressed: Tel.: 207-839-7600; Fax: 207-839-7655; E-mail: david.evers@briloon.org Ecotoxicology, 14, 193-221, 2005 Ó 2005 shown to have some of the highest MeHg levels of the 38 species analyzed, insectivorous birds in both aquatic and terrestrial habitats (such as montane areas) were also found with elevated MeHg levels. A better understanding of the factors confounding interpretation of Hg exposure provides an effective basis for choice of indicator species and tissues according to 12 selected scenarios. This and the national need for spatiotemporal monitoring of MeHg availability require careful consideration of indicator species choice. Only then will local, regional, continental, and even global monitoring efforts be effective.

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Section: Hg Patterns In Aquatic Habitatsmentioning

confidence: 97%