Statistically Speaking: Mercury Rising? Why?
posted by Erica Rowell (Editor)
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We’ve come a long way since the “mad hatter” days, but mercury pollution is no tea party. When fish ingest methylmercury, it builds up in their bodies, where it can harm humans who consume the fish. http://health.state.tn.us/Environmental/mercury.html
A report [pdf] released this month from the Government Accounting Office shows American power plants could slash their mercury emissions by more than half. That’s a lot of toxicity to let slip out of the smokestack.
Consider the numbers…
The amount of mercury needed to contaminate a 25-acre lake to the point where fish are unsafe to eat: 1/70th of a teaspoon
Miles of U.S. streams under mercury advisories in 2008: 1,254,893
Acres of U.S. lakes under mercury advisories in 2008: 16,808,032
Number of states that issued fish-consumption advisories for mercury in 2006: 48
Percentage of fish from 291 U.S. waterways tested for mercury that were found to contain mercury: 100 [pdf]
Where Is the Mercury Coming From?
Total annual tons of both naturally occurring and human-produced emissions
of mercury: ~ 4,400–7,500
Portion of mercury in the environment from human-produced emissions: ~ 2/3
China’s total human-produced mercury emissions in tons per year: ~ 500
Total U.S. human-produced mercury emissions in tons: ~ 100 [pdf]
Fossil-fuel combustion is the single largest source of anthropogenic mercury.
Percentage of human-produced emissions from burning fossil fuels (primarily coal) ~ 45 [pdf]
Annual fossil fuel emissions from China (in tons): 200 - 400 [pdf]
Annual fossil fuel emissions from United States (in tons): ~ 50 [pdf]
Should We Be Concerned About Local Sources?
When it comes to mercury emissions, China is the world’s leading polluter — it’s not even close.
Does that mean that all our mercury pollution problems are caused by China and we are powerless to do anything about it? Probably not because many studies have shown that environmental and health effects of mercury in the United States correlate with proximity to our own coal-fired power plants. These include:
- Autism rates in Texas, which were found to diminish by 1–2 percent for every additional 10 miles from plant
- Mercury contamination in catfish in Pennsylvania
- Mercury concentrations in rain and snow in Indiana
- Deposition of mercury in rainfall in Steubenville, Ohio
Can Mercury Emissions From Power Plants Be Decreased?
Annual U.S. coal emissions in tons: 48 [pdf]
Annual U.S. coal emissions (in tons) if all coal-fired power plants had sorbent-injection
emissions controls: 7.5 [pdf]
Current number of U.S coal-fired plants with sorbent-injection emissions control: 14 out of 491 [pdf]
I guess the answer to that last one is yes.
Further Reading
- Fish advisories - EPA
- Mercury study volumes - EPA
- What You Need to Know About Mercury in Fish and Shellfish - EPA
- Don't Mess with Mercury - EPA
- Mercury and Your Health - Agency for Toxic Substances and Disease Registry
- Mercury: A Persistent Toxin - Grok post
