Modern and historic atmospheric mercury fluxes in both hemispheres: Global and regional mercury cycling implications

Lamborg, Carl H.; Fitzgerald, William F.; Damman, A. W. H.; Benoit, Janina M.; Balcom, Prentiss H.; Engstrom, Daniel R.

doi:10.1029/2001gb001847

Cited by 209 publications

(179 citation statements)

References 48 publications

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“…Although anthropogenic sources have increased loadings of Hg(II) to near-shore deposits , it is unclear if shelf sediments more distant from human and fluvial sources have been impacted similarly. Atmospheric deposition is the principal source of Hg in remote locations (Fitzgerald et al, 1998), and atmospheric Hg loadings have increased 2−4 fold globally since the Industrial Revolution (Lamborg et al, 2002). If atmospheric deposition were the primary source of Hg to continental shelf sediments, then it is likely that the production, sedimentary mobilization, and accumulation of MMHg in marine biota have increased proportionately.…”

Section: Discussionmentioning

confidence: 99%

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

Hammerschmidt

Fitzgerald

2006

Geochimica et Cosmochimica Acta

169

127

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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.

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Section: Discussionmentioning

confidence: 99%

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

Hammerschmidt

Fitzgerald

2006

Geochimica et Cosmochimica Acta

169

127

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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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“…Relatively high Hg concentrations were found in remote areas with no proximate sources of pollution, such as the Artic region (Hylander and Goodsite 2006). Since the industrial revolution, anthropogenic Hg fluxes have increased compared to the pre-industrial levels (Lamborg et al 2002). Hg can enter aquatic systems via several pathways: dry and wet atmospheric deposition, surface runoff and/or directly from locally polluted wastewater.…”

Section: Background Aim and Scopementioning

confidence: 99%

Historical record of mercury contamination in sediments from the Babeni Reservoir in the Olt River, Romania

Bravo

Loizeau

Ancey

et al. 2008

Environ Sci Pollut Res

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Background, aim and scope Mercury (Hg) is a ubiquitous and hazardous contaminant in the aquatic environment showing a strong biomagnification effect along the food chain. The most common transfer path of Hg to humans is contaminated fish consumption. In severely exposed humans, Hg poisoning may lead to damage in the central nervous system. Thus, it is important to examine current and past contamination levels of Hg in aquatic milieu. The Olt River is the largest Romanian tributary of the Danube River. The use of Hg as an electrode in a chlor-alkali plant contributed to the contamination of the aquatic environment in the Rm Valcea region. The purpose of this study was to compare the current state of Hg contamination with the past contamination using a historical record obtained from a dated sediment core from one of the Olt River reservoirs (Babeni) located downstream from the chlor-alkali plant. To our knowledge, no published data on Hg contamination in this region are available. The Babeni Reservoir was selected for this study because it is situated downstream from the chlor-alkali plant, whilst the other reservoirs only retain the pollutants coming from the upstream part of the watershed. Preliminary analyses (unpublished) showed high Hg concentrations in the surface sediment of the Babeni Reservoir. One core was taken in the upstream Valcea Reservoir to provide a local background level of Hg concentrations in sediments. Results and discussion Sediment texture was uniform in the cores from both reservoirs. Laminated sediment structure, without any obvious discontinuities, was observed. Hg concentrations in the sediment core from the Valcea Reservoir were low and constant (0.01-0.08 mg/kg). In Babeni Reservoir sediments, Hg concentrations were very high in the deeper core section (up to 45 mg/kg in the longest core) and decreased to lower concentrations toward the top of the cores (1.3-2.4 mg/kg). This decrease probably reflects technological progress in control of emissions from the Hg-cell-based chlor-alkali industry. Two strong peaks could be distinguished in older sediments. The mean rate of sedimentation (5.9 cm/year) was calculated from the depth of the 137 Cs Chernobyl peak. This was in good agreement with the sedimentation rate estimated at this site from a bathymetric study. Assuming a constant sedimentation rate, the two Hg peaks would reflect two contamination events in 1987 and 1991, respectively. However, it is also possible that the two peaks belong to the same contamination event in 1987 but were separated by a sediment layer richer in sand and silt. This layer had a low Hg concentration, which can be interpreted as a mass deposition event related to a major flood bringing Hg-free sediments. Conclusions Whilst the chlor-alkali plant partly switched to a cleaner technology in 1999, no obvious decrease of Hg concentrations was observed in recent decade. Results from the sediment core reflected the historical trend of Hg release from the chlor-alkali plant, revealed important contamination e...

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Modern and historic atmospheric mercury fluxes in both hemispheres: Global and regional mercury cycling implications

Cited by 209 publications

References 48 publications

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

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

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

Historical record of mercury contamination in sediments from the Babeni Reservoir in the Olt River, Romania

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