Effluent Limitations Guidelines and Standards for the Dental Category; Extension of Comment Period

EPA received requests for an extension of the period for providing comments on the proposed rule entitled, “Effluent Limitations Guidelines and Standards for the Dental Category,” published in the Federal Register on October 22, 2014. EPA is extending the comment period from December 22, 2014 to February 20, 2015.

FR extending the comment period may be found at http://insideepa.com/sites/insideepa.com/files/documents/dec2014/epa2014_2393.pdf

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A national statistical survey assessment of mercury concentrations

The U.S. EPA conducted a national statistical survey of fish fillet tissue with a sample size of 541 sites on boatable rivers =>5th order in 2008–2009. This is the first such study of mercury (Hg) in fish tissue from river sites focused on potential impacts to human health from fish consumption to also address wildlife impacts. Sample sites were identified as being urban or non-urban. All sample mercury concentrations were above the 3.33 ug kg1 (ppb) quantitation limit, and an estimated 25.4% (±4.4%) of the 51663 river miles assessed exceeded the U.S. EPA 300 ug kg1 fish-tissue based water quality criterion for mercury, representing 13144 ± 181.8 river miles. Estimates of river miles exceeding comparable aquatic life thresholds (translated from fillet concentrations to whole fish equivalents) in avian species were similar to the number of river miles exceeding the human health threshold, whereas some mammalian species were more at risk than human from lower mercury concentrations. A comparison of means from the non-urban and urban data and among three ecoregions did not indicate a statistically significant difference in fish tissue Hg concentrations at p < 0.05.

The report can be accessed at http://www.sciencedirect.com/science/article/pii/S0045653514012636

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Gaseous Oxidized Mercury Dry Deposition Measurements in the Southwestern USA: A Comparison between Texas, Eastern Oklahoma, and the Four Corners Area

You can read the study at http://www.hindawi.com/journals/tswj/2014/580723/

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Mercury in the Soil of Two Contrasting Watersheds in the Eastern United States

Abstract: Soil represents the largest store of mercury (Hg) in terrestrial ecosystems, and further study of the factors associated with soil Hg storage is needed to address concerns about the magnitude and persistence of global environmental Hg bioaccumulation. To address this need, we compared total Hg and methyl Hg concentrations and stores in the soil of different landscapes in two watersheds in different geographic settings with similar and relatively high methyl Hg concentrations in surface waters and biota, Fishing Brook, Adirondack Mountains, New York, and McTier Creek, Coastal Plain, South Carolina. Median total Hg concentrations and stores in organic and mineral soil samples were three-fold greater at Fishing Brook than at McTier Creek. Similarly, median methyl Hg concentrations were about two-fold greater in Fishing Brook soil than in McTier Creek soil, but this difference was significant only for mineral soil samples, and methyl Hg stores were not significantly different among these watersheds. In contrast, the methyl Hg/total Hg ratio was significantly greater at McTier Creek suggesting greater climate-driven methylation efficiency in the Coastal Plain soil than that of the Adirondack Mountains. The Adirondack soil had eight-fold greater soil organic matter than that of the Coastal Plain, consistent with greater total Hg stores in the northern soil, but soil organic matter – total Hg relations differed among the sites. A strong linear relation was evident at McTier Creek (r2 = 0.68; p<0.001), but a linear relation at Fishing Brook was weak (r2 = 0.13; p<0.001) and highly variable across the soil organic matter content range, suggesting excess Hg binding capacity in the Adirondack soil. These results suggest greater total Hg turnover time in Adirondack soil than that of the Coastal Plain, and that future declines in stream water Hg concentrations driven by declines in atmospheric Hg deposition will be more gradual and prolonged in the Adirondacks.

A copy of this paper may be downloaded at PLOS One – http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0086855

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Mercury and methylmercury stream concentrations in a Coastal Plain watershed: A multi-scale simulation analysis

Abstract: Mercury is a ubiquitous global environmental toxicant responsible for most US fish advisories. Processes governing mercury concentrations in rivers and streams are not well understood, particularly at multiple spatial scales. We investigate how insights gained from reach-scale mercury data and model simulations can be applied at broader watershed scales using a spatially and temporally explicit watershed hydrology and biogeochemical cycling model, VELMA. We simulate fate and transport using reach-scale (0.1 km2) study data and evaluate applications to multiple watershed scales. Reach-scale VELMA parameterization was applied to two nested sub-watersheds (28 km2 and 25 km2) and the encompassing watershed (79 km2). Results demonstrate that simulated flow and total mercury concentrations compare reasonably to observations at different scales, but simulated methylmercury concentrations are out-of-phase with observations. These findings suggest that intricacies of methylmercury biogeochemical cycling and transport are under-represented in VELMA and underscore the complexity of simulating mercury fate and transport.

A copy of the paper may be obtained from Science Direct – http://www.sciencedirect.com/science/article/pii/S0269749114000025

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Dietary Predictors of Maternal Prenatal Blood Mercury Levels in the ALSPAC Birth Cohort Study

2013-10 Research Dietary predictors of maternal prenatal blood Hg levels EHP

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Status Report on Select Products, Processes and Technologies Utilizing Mercury

The Quicksilver Caucus has published a report (2013 QSC Report on Select Products Processes Technologies Utilizing Mercury) that addresses:

Polyurethane Elastomer Production (Catalyst Use)

Rotational Balancing Products 

Skin-lighteners, Face Creams and Other Cosmetics

Tattoo Inks


Photovoltaic Products

Veterinary Vaccines

Novelty Products

Biotechnology/Genetics Research Laboratories

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Mercury in wetlands at the Glacial Ridge National Wildlife Refuge, northwestern Minnesota, 2007-9

The Glacial Ridge National Wildlife Refuge was established in 2004 on land in northwestern Minnesota that had previously undergone extensive wetland and prairie restorations. About 7,000 acres of drained wetlands were restored to their original hydrologic function and aquatic ecosystem. During 2007–9, the U.S. Geological Survey, in cooperation with the U.S. Fish and Wildlife Service and the Red Lake Watershed District, analyzed mercury concentrations in wetland water and sediment to evaluate the effect of wetland restoration on mercury methylation.

You may find a copy of the report at http://pubs.usgs.gov/sir/2013/5068/pdf/sir2013-5068.pdf

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Gaseous oxidized mercury dry deposition measurements in the Four Corners area and Eastern Oklahoma, U.S.A.

Gaseous oxidized mercury (GOM) dry deposition measurements using surrogate surface passive samplers were collected in the Four Corners area and eastern Oklahoma from August, 2009–August, 2011. Using data from a six site area network, a characterization of the magnitude and spatial extent of ambient mercury pollution in the arid Four Corners area was accomplished, which included the observation of a strong regional signature in the GOM dry deposition data set. GOM dry deposition rate estimates ranged from 0.4–1.0 ng/mh at the six Four Corners area monitoring sites, while the GOM dry deposition rate estimate at the eastern Oklahoma monitoring site was lower at 0.2 ng/mh. The highest GOM dry deposition estimates were recorded during the spring and summer while the lowest GOM dry deposition estimates were recorded during the fall and winter. During the second year of this study the highest annual GOM dry deposition estimate so far measured in the United States (U.S.) with smooth–edge surrogate surface passive samplers, 10 889 ng/m, was recorded at the Mesa Verde National Park site, a site at which the two– year cumulative GOM dry deposition estimate exceeded the mercury wet deposition estimate. GOM dry deposition estimates during the second year of the study were statistically significantly higher than the first year of the study at six of the seven sites. The data from this study provide a two–year baseline of GOM dry deposition data in the Four Corners area and eastern Oklahoma immediately before the current implementation of new U.S. power plant and boiler mercury control regulations which will significantly reduce mercury emissions from those two sectors of local and regional anthropogenic mercury emission sources.

 Click following link to download copy of the report: APR-13-017

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Two Mercury and Dental Reports

Attached are two recent reports by two different NGOs:

  1. 1.       “Occupational Exposure to Elemental Mercury in Odontology/Dentistry” – This was produced under an EPA/OPPT grant by UMass Lowell, in collaboration with an NGO in Ecuador and a university in Mexico.
  2. 2.       “Mercury in Dental Amalgam and Resin-Based Alternatives: A Comparative Health Risk Evaluation” – This was produced by Health Care Without Harm and others.


  1. 2012-06 Report Hg_in_Dental_Amalgam Health Risk Evaluation HCWH
  2. 2012-04 Report Reducing Hg in Dental Clinics UMassLowell

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