Recent Declines in Atmospheric Mercury Deposition in the Upper Midwest

Engstrom, Daniel R.; Swain, Edward B.

doi:10.1021/es9600892

Cited by 234 publications

(196 citation statements)

References 30 publications

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“…Trends of mercury deposition derived from sediment [Engstrom and Swain, 1997], ombotropic peat bog [Benoit et al, 1994] and ice core analyses [Boutron et al, 1998] suggest similar temporal profiles but with an earlier onset of the decrease in 1970s, , and at about 1960, respectively. The sediment analyses by Engstrom and Swain [1997] show, however, that the onset of the deposition decrease depended on the location, with two of the three most remote locations in southeastern Alaska showing no decrease until 1990.…”

Section: Resultsmentioning

confidence: 99%

Worldwide trend of atmospheric mercury since 1977

Šlemr

Brunke

Ebinghaus

et al. 2003

Geophysical Research Letters

196

138

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The inventories of global anthropogenic emissions of mercury for years from 1979/1980 to 1995 suggest a substantial reduction in the 1980s and almost constant emissions afterwards. In contrast to emission inventories, measurements of atmospheric mercury suggest a concentration increase in the 1980s and a decrease in the 1990s. Here we present a first attempt to reconstruct the worldwide trend of atmospheric mercury concentrations from direct measurements since the late 1970s. In combination, long term measurements at 6 sites in the northern, 2 sites in the southern hemispheres, during 8 ship cruises over the Atlantic Ocean (1977–2000) provide a consistent picture, suggesting that atmospheric mercury concentrations increased in the late 1970s to a peak in the 1980s, then decreased to a minimum at about 1996, and have been nearly constant since. The observed trend is not consistent with the published inventories of anthropogenic emissions and the assumed ratios of anthropogenic/natural emissions, and suggests the need to improve the mercury emission inventories and to re‐evaluate the contribution of natural sources.

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Section: Resultsmentioning

confidence: 99%

Worldwide trend of atmospheric mercury since 1977

Šlemr

Brunke

Ebinghaus

et al. 2003

Geophysical Research Letters

196

138

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“…edu/mdn/), Hg deposition back to pre-industrial times can be estimated from sediment, peat, and ice cores (Schuster et al 2002). Dated depth profiles of Hg in sediment cores show changes in Hg accumulation rates over time that correlate well with documented Hg utilization and environmental releases and have been shown to be an accurate record of changes in external loading (Krabbenhoft et al 2007;Lockhart et al 2000;Lamborg et al 2002;Pirrone et al 1998;Engstrom and Swain 1997). Declining Hg accumulation rates in lake sediments and bog peat have been reported for many areas of the USA from 1970 through 1990 (Norton et al 1997;Engstrom and Swain 1997;Balogh et al 1999;Lorey and Driscoll 1999;Kamman and Engstrom 2002;Van Metre et al 2004;Perry et al 2005;Mahler et al 2006).…”

Section: Comparison To Sediment Coresmentioning

confidence: 99%

Mercury trends in fish from rivers and lakes in the United States, 1969–2005

Chalmers

Argue

Brigham

et al. 2010

Environ Monit Assess

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A national dataset on concentrations of mercury in fish, compiled mainly from state and federal monitoring programs, was used to evaluate trends in mercury (Hg) in fish from US rivers and lakes. Trends were analyzed on data aggregated by site and by state, using samples of the same fish species and tissue type, and using fish (1996)(1997)(1998)(1999)(2000)(2001)(2002)(2003)(2004)(2005) were compared to wet Hg deposition data from the Mercury Deposition Network (MDN) over the same period. Downward trends in Hg concentrations in fish from data collected during 1969-1987 exceeded upward trends by a ratio of 6 to 1. Declining Hg accumulation rates in sediment and peat cores reported by many studies during the 1970s and 1980s correspond with the period when the most downward trends in fish Hg concentrations occurred. Downward Hg trends in both sediment cores and fish were also consistent with the implementation of stricter regulatory controls of direct releases of Hg to the atmosphere and surface waters during the same period. The southeastern USA had more upward Hg trends in fish than other regions for both site and state aggregated data. Upward Hg trends in fish from the southeastern USA were associated with increases in wet deposition in the region and may be attributed to a greater influence of global atmospheric Hg emissions in the southeastern USA. No significant trends were found in 62% of the fish species from six states from 1996 to 2005. A lack of Hg trends in fish in the more recent data was consistent with the lack of trends in wet Hg deposition at MDN 176 Environ Monit Assess (2011) 175:175-191 sites and with relatively constant global emissions during the same time period. Although few significant trends were observed in the more recent Hg concentrations in fish, it is anticipated that Hg concentrations in fish will respond to changes in atmospheric Hg deposition, however, the magnitude and timing of the response is uncertain.

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“…Global concerns stem from the broad geographic extent of contamination, the increasing global signal of Hg deposition, and, until recently, a general lack of regulations to control many uses and the disposal of Hg (United Nations Environment Programme, 2003). In North America, decades of increasing Hg deposition appear to have reversed in some areas (Engstrom and Swain, 1997;Schuster et al, 2002;Fevold et al, 2003), including the Northeast (Kamman and Engstrom, 2002), but the need to identify and monitor ecological changes remains a high priority (Mason et al, 2005). Federal, state and/or provincial regulation of atmospheric mercury emissions in the United States and Canada is in place for some industrial sectors (i.e., municipal and medical waste incineration), but is currently lacking for others (i.e., coalfired electrical generators and mining).…”

Section: Introductionmentioning

confidence: 99%

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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Recent Declines in Atmospheric Mercury Deposition in the Upper Midwest

Cited by 234 publications

References 30 publications

Worldwide trend of atmospheric mercury since 1977

Worldwide trend of atmospheric mercury since 1977

Mercury trends in fish from rivers and lakes in the United States, 1969–2005

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

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