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 emissions 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, elemental 

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 

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in the form of 

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particles

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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).¶

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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

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3

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, 

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mercury exposure at high levels can harm the brain, heart, 

kidneys, lungs, and immune system of people of all ages.2

 Overall, this 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. 

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