Environmental factors affecting the formation of methylmercury in low pH lakes

Winfrey, Michael R.; Rudd, John W. M.

doi:10.1002/etc.5620090705

Cited by 334 publications

(169 citation statements)

References 90 publications

Supporting

Mentioning

152

Contrasting

Unclassified

Order By: Relevance

“…The THQ was calculated for all the studied species in the Augusta Bay using the US-EPA's reference dose (THQa) and the acceptable daily intake determined by the WHO (THQb). In particular, we assumed that the measured mercury is integrally in its methylated form (Winfrey and Rudd, 1990;Fitzgerald, 1990, 1991;Gilmour and Henry, 1991;Horvat et al, 1999;Carbonell et al, 2009).…”

Section: Thq and Ewi Calculationmentioning

confidence: 99%

“…Methylmercury (MeHg) is the most toxic form, able to interfere with thiol metabolism, causing inhibition or inactivation of proteins containing thiol ligands and ultimately leading to mitotic disturbances (Das et al, 1982;Elhassani, 1983). Numerous recent studies indeed have concluded that the majority, if not all, of the Hg that is bioaccumulated through the food chain is as MeHg (Winfrey and Rudd, 1990;Fitzgerald, 1990, 1991;Gilmour and Henry, 1991;Horvat et al, 1999;Carbonell et al, 2009). …”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Mercury in fishes from Augusta Bay (southern Italy): Risk assessment and health implication

Manta

Oliveri

et al. 2013

Food and Chemical Toxicology

View full text Add to dashboard Cite

a b s t r a c tOur study reports on the total mercury (HgT) concentrations measured in the muscles and livers of several benthic, demersal and pelagic fish species caught inside and outside of Augusta Bay (southern Italy), a semi-enclosed marine area, highly contaminated by the uncontrolled (since the 1950s to 1978s) discharge of the largest European petrochemical plant. Mercury levels in fish tissues are discussed with regard to specific habitat, size and/or age of the specimens and HgT distribution in the bottom sediments. Results suggest a still active Hg release mechanism from the polluted sediments to the marine environment. Also, the high HgT concentrations measured in fishes caught in the external area of the bay imply a potential role of Augusta Bay as a pollutant source for the Mediterranean ecosystem. Finally, values of hazard target quotient (THQ) and estimated weekly intake (EWI) demonstrate that consumption of fishes caught inside the bay represents a serious risk for human health. Also, data indicate that intake of fishes caught from the external area of the bay, especially for that concern demersal and benthic species, could be represent a significant component of risk for the local population.

show abstract

Section: Thq and Ewi Calculationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Mercury in fishes from Augusta Bay (southern Italy): Risk assessment and health implication

Manta

Oliveri

et al. 2013

Food and Chemical Toxicology

View full text Add to dashboard Cite

show abstract

“…It is well established that lakes with low pH contain fish with higher levels of Hg than same-size and species of fish in lakes with more circumneutral pH levels (Wiener et al, 1990;Winfrey and Rudd, 1990;Drysdale et al, in press). Oligotrohphic lakes in eastern Canada and parts of New England and New York are susceptible to increased rates of anthropogenically derived sulphur deposition (i.e., acid rain) (Driscoll et al, 2001).…”

Section: Geographic Differences Existmentioning

confidence: 99%

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

et al. 2005

View full text Add to dashboard Cite

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.

show abstract

“…Sediments were sampled in September, when the temperature of water and sediment was near its seasonal maximum, because rates of Hg methylation increase with temperature (Winfrey and Rudd, 1990;. The temperature of water overlying sediments at these locations was about 21 °C at 71north and about 12 °C at stations 71central and 71south.…”

Section: Samplingmentioning

confidence: 99%

Methylmercury cycling in sediments on the continental shelf of southern New England

Hammerschmidt

Fitzgerald

2006

Geochimica et Cosmochimica Acta

169

127

View full text Add to dashboard Cite

Exposure of humans to monomethylmercury (MMHg) occurs primarily through consumption of marine fish, yet there is limited understanding concerning the bioaccumulation and biogeochemistry of MMHg in the biologically productive coastal ocean. We examined the cycling of MMHg in sediments at three locations on the continental shelf of southern New Moreover, the efflux of dissolved MMHg to overlying water (i.e., net production at steady state) is correlated with the gross potential rate of MMHg production in surface sediments. These results suggest that the production and efflux of MMHg from coastal marine sediments is limited by Hg(II), loadings of which presumably are principally from atmospheric deposition to this region of the continental shelf. The estimated diffusive flux of MMHg from the shelf sediments averages 9 pmol m −2 d −1 . This flux is comparable to that required to sustain the current rate of MMHg accumulation by marine fish, and may be enhanced by the efflux of MMHg from nearshore deposits contaminated more substantially with anthropogenic Hg. Hence, production and subsequent mobilization of MMHg from sediments in the coastal zone may be a major source of MMHg to the ocean and marine biota, including fishes consumed by humans.

show abstract

Environmental factors affecting the formation of methylmercury in low pH lakes

Cited by 334 publications

References 90 publications

Mercury in fishes from Augusta Bay (southern Italy): Risk assessment and health implication

Mercury in fishes from Augusta Bay (southern Italy): Risk assessment and health implication

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

Methylmercury cycling in sediments on the continental shelf of southern New England

Contact Info

Product

Resources

About