From: Chuck French/RTP/USEPA/US

To: Chuck French/RTP/USEPA/US@EPA

Cc: Amy Branning/DC/USEPA/US@EPA, "King, Heidi R." <Heidi_R._King@omb.eop.gov>, Paula VanLare/DC/USEPA/US@EPA, Sharon Nizich/RTP/USEPA/US@EPA, Steve Fruh/RTP/USEPA/US@EPA, Wendy Blake/DC/USEPA/US@EPA

Date: 04/13/2010 08:38 PM Subject: RE: Interagency comments under EO 12866 on the Gold Ore Processing NESHAP Draft NPRM

Hi Heidi, Attached below is the revised health section with more information about the global pool, global emissions, etc....I reordered the paragraphs, as we discussed.I added new text to explain the global picture. I also moved a few sentences around and added a little text to try to improve the flow and clarify the discussion. I highlighted (in yellow) the substantive new text. Please let me know ASAP if you have any more comments or questions. Thanks. Chuck (See attached file: Gold_Mine_Health

‐ section

‐ revised

‐ 4

‐ 13

‐ 2010.doc)1

B. What are the health benefits of reducing mercury emissions? Mercury is emitted to the air from various man-made and

natural sources. These emissions transport through the atmosphere and eventually deposit to land or water bodies. This deposition can occur locally, regionally, or globally, depending on the form of mercury emitted and other factors such as the

weather. The form of mercury emitted varies depending on source type and other factors. Available data indicate that the majority of air e missions from gold mine ore processing and production facilities are in the form of gaseous elemental

mercury . This form of mercury can be transported very long distances, even globally , to regions far from the emissions

source (becoming part of the global “pool”) before deposition

occurs . However, this source category also emits some gaseous inorganic ionic mercury forms (such as mercuric chloride) , and smaller amounts of particulate bound mercury . These forms have a shorter atmospheric lifetime and can deposit to land or water bodies closer to the emissions source. Furthermore, e lemental mercury in the atmosphere can undergo transformation into ionic mercury, providing a significant pathway for deposition of emitted elemental mercury. As mentioned previously, the gold mine ore processing and production source category emitted about 2.5 tons of mercury to the air in 2007 in the U.S. Based on the EPA’s National Formatted: Indent: First line: 36 pt Formatted: Highlight

Formatted: Highlight Deleted:

Deleted: The Deleted: e Deleted: , which Deleted: Deleted: The remaining emissions are in the form of Deleted: Deleted: or bound to emitted particles Deleted: will Deleted: E Deleted: Once deposited, the mercury form can change (primarily by microbial metabolism) to methyl mercury, which has the capacity to collect in organisms (bioaccumulate) and to concentrate up food chains (biomagnify), especially in the aquatic food chain (fish and marine mammals).¶

Deleted: ¶

Deleted: Potential exposure routes to mercury emissions include both inhalation and ingestion (e.g., through the consumption of fish containing mercury compounds).

. The toxicity to humans and other organisms depends on the chemical form, the amount, the pathway of exposure, and the vulnerability of the person exposed. Chronic inhalation exposure to relatively low levels of mercury vapor is associated with various neurotoxic effects, including increases in memory disturbance and slight subjective and objective evidence of autonomic dysfunction. For example, studies of occupationally exposed humans have shown adverse effects on the central nervous system at long-term air levels of 25-30 micrograms per cubic meter. Likewise, chronic ingestion exposures to mercury in fish can cause, among other things, developmental neurotoxic effects. Moreover, acute mercury inhalation exposure, to sufficiently elevated levels, is associated with nervous system damage, kidney damage, and gastrointestinal and respiratory effects. ¶2

Emission Inventory, about 103 tons of mercury were emitted from all anthropogenic sources in the U.S. in 2005. Moreover, the United Nations has estimated that about 2100 tons were emitted worldwide by anthropogenic sources in 2005. 1 We believe that total mercury emissions in the U.S. and globally in 2007 were about the same magnitude as in 2005. Therefore, we estimate that in 2007 the gold mine ore processing and production source category emitted about 2.5 percent of the total anthropogenic mercury emissions in the U.S. and about 0.12 percent of the global emissions. As described above, mercury that has been emitted to the air eventually settles into water or onto land where it can be washed into water. Once deposited, certain microorganisms can change it into methylmercury, a highly toxic form that builds up in fish, shellfish and animals that eat fish. Fish and shellfish are the main sources of methylmercury exposure to humans. Methylmercury builds up more in some types of fish and shellfish than others. The levels of methylmercury in fish and shellfish depend on what they eat, how long they live and how high they are in the food chain. Mercury concentrations in fish

1 United Nations Environment Programme/Arctic Monitoring and Assessment Program (UNEP/AMAP). Study on mercury-emitting sources, including emissions trends and cost and effectiveness of alternative control measures: “UNEP Paragraph 29 study.” 2008

. Available at: http://www.chem.unep.ch/mercury/Paragraph29/Zero%20Draft%20Repor t%20March%208.doc Formatted: Highlight

Formatted: Highlight Formatted: Highlight

Formatted: Highlight

Formatted: Indent: First line: 36 pt3

vary widely. Local freshwater fish typically contain some methylmercury, which can be due, at least partly, to local emissions sources. However, the majority of fish species consumed in the U.S. are ocean species and the methylmercury concentrations in these species are primarily influenced by the global mercury pool. Potential exposure routes to mercury emissions include both inhalation and subsequent ingestion through the consumption of fish containing methylmercury. However, the primary route of exposure to mercury of potential concern due to emissions from industrial sources is generally indirectly through the consumption of fish containing methylmercury after the mercury has deposited to land and water bodies, changed form, and subsequently accumulated in fish through the process described above. Nevertheless, research shows that most people’s fish consumption does not cause a health concern. However, certain sub-populations are at higher risk because of their routinely high consumption of fish and shellfish (e.g., tribal and other subsistence fishers and their families who rely heavily on fish for the majority of their diet). It has been demonstrated that high levels of methylmercury in the bloodstream of unborn babies and young children may harm the developing nervous system, making the child less able to think and learn. Moreover, Formatted: Highlight Formatted: Highlight Formatted: Highlight

Formatted: Highlight

Formatted: Highlight Formatted: Highlight Formatted: Highlight Formatted: Highlight Formatted: Highlight Formatted: Highlight4

mercury exposure at high levels can harm the brain, heart, kidneys, lungs, and immune system of people of all ages. 2 Overall, t his regulation will reduce mercury emissions by about 1,650 pounds per year from current levels and, therefore, contribute to reductions in mercury exposures and health

effects.

2 For more information see http://www.epa.gov/mercury/about.htm. Deleted: T