The oral bioavailability and toxicokinetics of methylmercury in common loon (Gavia immer) chicks

Fournier, François; Karasov, William H.; Kenow, Kevin P.; Meyer, Michael W.; Hines, Randy K.

doi:10.1016/s1095-6433(02)00140-x

Cited by 101 publications

(99 citation statements)

References 35 publications

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“…Ingestion of dietary MeHg appears to be readily absorbed into the blood (83% in common loons, Fournier et al, 2002) and is thereafter distributed to various body tissues, namely the liver, kidney, brain, spleen, and muscle. Some tissues, such as the liver, are terminal endpoints where MeHg is largely unavailable for remobilization, whereas MeHg deposited in muscle tissue is available and remobilizes during feather molt.…”

Section: Selecting the Correct Tissuementioning

confidence: 99%

Section: Tissue Interpretationmentioning

confidence: 99%

“…Mercury in blood is primarily MeHg (>95%) in both piscivores (Fournier et al, 2002) and insectivores (Rimmer et al, 2005). The half-life of MeHg in the blood of chicks undergoing feather molt was three days in common loons (Fournier et al, 2002) and 5-6 days in Cory's shearwaters (Monteiro and Furness, 2001). In non-molting adults, the half-life of MeHg in the blood was greater: for Cory's shearwater (Calonectris diomedea) the half-life was 40-60 days (Monteiro and Furness, 2001) and for the mallard was 74 days (Heinz and Hoffman, 2004).…”

Section: Tissue Interpretationmentioning

confidence: 99%

“…Blood and feather MeHg levels are highly correlated when blood is sampled during feather molt. Birds have the ability to rapidly transfer dietary uptake of MeHg from red blood cells to growing feathers (Fournier et al, 2002;. The physiological capacity of birds to process MeHg this way appears to be great.…”

Section: Age Affects Hg Exposurementioning

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: Selecting the Correct Tissuementioning

confidence: 99%

Section: Tissue Interpretationmentioning

confidence: 99%

Section: Tissue Interpretationmentioning

confidence: 99%

Section: Age Affects Hg Exposurementioning

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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“…The UF L was set to 1.0 because the common loons study provided a NOAEL rather than a LOAEL (Kenow et al 2007a ) . According to pharmacokinetic studies of absorption and elimination of MeHg in common loon chicks (Fournier et al 2002 ) , the result of a study of common loons, with a duration of 15 weeks, was accepted as being a chronic exposure study. Thus, a UF S of >1.0 was deemed to be unnecessary (Kenow et al 2007a ) .…”

Section: Reasonableness Of Trvs and Trcsmentioning

confidence: 99%

Toxicity Reference Values and Tissue Residue Criteria for Protecting Avian Wildlife Exposed to Methylmercury in China

Zhang

et al. 2012

Reviews of Environmental Contamination and Toxicology

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The use of novel biomarkers to determine dietary mercury accumulation in nestling waterbirds

Clarkson

Erwin

Riscassi

2012

Enviro Toxic and Chemistry

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Mercury (Hg) depuration into growing feathers is a well-studied phenomenon in waterbirds. Although the kinetics of Hg excretion in relation to molt and diet has been studied extensively, the relationship between the individual nutritional condition of nestlings and dietary Hg accumulation has not been investigated. In the present study, a body-condition index (BCI) and nutritional condition index (NCI) for nestlings of two waterbird species occupying different trophic positions on the aquatic food web were determined and used to predict Hg accumulation through diet. Candidate models consisting of these indices and nestling age were compared using Akaike's information criterion corrected for small sample sizes. For both species, the top-performing model contained the sole parameter of nutritional condition index (NCI). The relationship between Hg and NCI was stronger in the species foraging higher on the trophic web, which experienced higher rates of Hg depuration into feathers. Models containing BCI could not be discounted (AICc < 2) for one of the species and the utility of this index is discussed.

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The oral bioavailability and toxicokinetics of methylmercury in common loon (Gavia immer) chicks

Cited by 101 publications

References 35 publications

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

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

Toxicity Reference Values and Tissue Residue Criteria for Protecting Avian Wildlife Exposed to Methylmercury in China

The use of novel biomarkers to determine dietary mercury accumulation in nestling waterbirds

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