Accelerating recovery of the mercury-contaminated Wabigoon/English River system

Parks, J. W.; Hamilton, Andy

doi:10.1007/978-94-009-4053-6_19

Cited by 12 publications

(8 citation statements)

References 26 publications

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“…Other loss mechanisms included partitioning to particles and sediments and, to a lesser extent, to periphyton. Spike Hg partitioned to main environmental compartments within days to weeks, which is also in agreement with previous studies (26,29). Within 3 weeks, we observed production of MeHg from the Hg(II) added to the mesocosms.…”

Section: Discussionsupporting

confidence: 92%

Effect of Loading Rate on the Fate of Mercury in Littoral Mesocosms

Orihel

Paterson

Gilmour

et al. 2006

Environ. Sci. Technol.

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The effects of changes in atmospheric mercury (Hg) deposition on aquatic ecosystems are poorly understood. In this study, we examined the biogeochemical cycling of Hg in littoral mesocosms receiving different loading rates (7-107 microg Hg m(-2) year(-1)). We added a 202Hg-enriched preparation to differentiate the experimentally added Hg from the ambient Hg in the environment. This approach allowed us to follow the distribution and methylation of the isotopically enriched ("spike") Hg in the mesocosms. Within 3 weeks, spike Hg was distributed throughout the main environmental compartments (water, particles, periphyton, and sediments) and began to be converted to methylmercury (MeHg). Concentrations of spike total Hg and MeHg in these compartments, measured after 8 weeks, were directly proportional to loading rates. Thus, Hg(II) availability was the limiting factor for the major processes of the biogeochemical Hg cycle, including methylation. This is the first study to demonstrate a proportional response of in situ MeHg production to atmospherically relevant loading levels. On the basis of mass balances, we conclude that loading rate had no effect on the relative distribution of spike Hg among the main compartments or on the fraction of spike Hg converted to MeHg. Therefore, loading rate did not change the relative magnitude of biogeochemical pathways competing for Hg within the mesocosms. These data suggest that reductions of Hg deposition to lake surfaces would be equally effective across a broad range of deposition rates.

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Section: Discussionsupporting

confidence: 92%

Effect of Loading Rate on the Fate of Mercury in Littoral Mesocosms

Orihel

Paterson

Gilmour

et al. 2006

Environ. Sci. Technol.

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“…This issue is poorly understood, but previous declines in Hg loading suggest that MeHg levels in fish in some aquatic ecosystems begin to respond within a few years of Hg reductions. For example, Hg concentrations in fish decreased significantly within 3-5 years after aqueous Hg discharges from chloralkali plants or other industries were drastically reduced or stopped (23)(24)(25)(26)(27)(28). Mercury levels in fish at some of these contaminated sites, however, remained higher than background levels for more than a decade (26)(27)(28).…”

Section: Discussionmentioning

confidence: 99%

Experimental Evidence of a Linear Relationship between Inorganic Mercury Loading and Methylmercury Accumulation by Aquatic Biota

Orihel

Paterson

Blanchfield

et al. 2007

Environ. Sci. Technol.

109

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Developing effective regulations on mercury (Hg) emissions requires a better understanding of how atmospheric Hg deposition affects methylmercury (MeHg) levels in aquatic biota. This study tested the hypothesis that MeHg accumulation in aquatic food webs is related to atmospheric Hg deposition. We simulated a range of inorganic Hg deposition rates by adding isotopically enriched Hg(II) (90.9% 202Hg) to 10-m diameter mesocosms in a boreal lake. Concentrations of experimentally added ("spike") Hg were monitored in zooplankton, benthic invertebrates, and fish. Some Hg(II) added to the mesocosms was methylated and incorporated into the food web within weeks, demonstrating that Hg(II) deposited directly to aquatic ecosystems can become quickly available to biota. Relationships between Hg(II) loading rates and spike MeHg concentrations in zooplankton, benthic invertebrates, and fish were linear and significant. Furthermore, spike MeHg concentrations in the food web were directly proportional to Hg(II) loading rates (i.e., a percent change in Hg(II) loading rate resulted in, statistically, the same percent change in MeHg concentration). This is the first experimental determination of the relationship between Hg(II) loading and MeHg bioaccumulation in aquatic biota. We conclude that changes in atmospheric Hg deposition caused by increases or decreases in Hg emissions will ultimately affect MeHg levels in aquatic food webs.

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“…Fish Hg concentrations are affected by the rate of Hg loading to a waterbody (Munthe et al, 2007 review). This is clearly evident in studies of point source contamination in freshwater systems (Parks and Hamilton, 1987), coastal and estuarine systems (Herut Francesconi et al, 1997), and has been demonstrated for smaller changes in ecosystem Hg loading relevant to changes in atmospheric Hg deposition (Harris et al, 2007). It is therefore critical to quantify the current sources of Hg to the Gulf, which can be broadly grouped as atmospheric, terrestrial and Atlantic inputs.…”

Section: Hg Sources To the Gulfmentioning

confidence: 98%

Mercury in the Gulf of Mexico: Sources to receptors

Harris¹,

Pollman²,

Landing

et al. 2012

Environmental Research

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Gulf of Mexico (Gulf) fisheries account for 41% of the U.S. marine recreational fish catch and 16% of the nation's marine commercial fish landings. Mercury (Hg) concentrations are elevated in some fish species in the Gulf, including king mackerel, sharks, and tilefish. All five Gulf states have fish consumption advisories based on Hg. Per-capita fish consumption in the Gulf region is elevated compared to the U.S. national average, and recreational fishers in the region have a potential for greater MeHg exposure due to higher levels of fish consumption. Atmospheric wet Hg deposition is estimated to be higher in the Gulf region compared to most other areas in the U.S., but the largest source of Hg to the Gulf as a whole is the Atlantic Ocean (>90%) via large flows associated with the Loop Current. Redistribution of atmospheric, Atlantic and terrestrial Hg inputs to the Gulf occurs via large scale water circulation patterns, and further work is needed to refine estimates of the relative importance of these Hg sources in terms of contributing to fish Hg levels in different regions of the Gulf. Measurements are needed to better quantify external loads, in-situ concentrations, and fluxes of total Hg and methylmercury in the water column, sediments, and food web.

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Accelerating recovery of the mercury-contaminated Wabigoon/English River system

Cited by 12 publications

References 26 publications

Effect of Loading Rate on the Fate of Mercury in Littoral Mesocosms

Effect of Loading Rate on the Fate of Mercury in Littoral Mesocosms

Experimental Evidence of a Linear Relationship between Inorganic Mercury Loading and Methylmercury Accumulation by Aquatic Biota

Mercury in the Gulf of Mexico: Sources to receptors

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