The Mercury Scare
Source: Power America
by Don Dears
The threat from mercury is being overly hyped by the EPA in its efforts to demonize and close coal-fired power plants. There are two reasons why the threat is far less than the EPA claims.
First, does mercury cause harm?
As reported by the Wall Street Journal, “The gold standard in mercury research is a University of Rochester study that tracked a group of Seychelles Island children from birth to nine years old. While their mothers ate fish similar to that consumed in the U.S., they ate 10 times as much and had an average of six times as much mercury in their bodies. Yet researchers found no negative effects in their children.”
The alarmists refer to a study of Faroe Island children that has been discredited for not having a statistical correlation of test results and because the mothers consumed other toxins such as DDT. The main cause for high mercury levels in Faroe Island women was whale meat – not a likely source of food in the U.S.
The following quote puts the issue in perspective.
“We do not believe that there is presently good scientific evidence that moderate fish consumption is harmful to the fetus. However, fish is an important source of protein in many countries and large numbers of mothers round the world rely on fish for proper nutrition. Good maternal nutrition is essential to the baby’s health. Additionally, there is increasing evidence that the nutrients in fish are important for brain development and perhaps for cardiac and brain function in older individuals”. – Dr. Gary Meyers, (Pediatric Neurologist, University of Rochester)
Test results of 1,709 women in the U.S. of child bearing age showed that 92% had mercury levels falling below the EPA’s reference dose (RfD) of 5.8 ppb, which is 14 times lower than the World Health Organization’s (WHO’s) 83 ppb, the point at which WHO believes there is a health risk.
The EPA established a Bench Mark Dose Lower Limit (BMDL) of 58 ppb, which was set so that there was 95% confidence that there would be no health risks from mercury at that level. The RfD was set at one tenth (10%) of the BMDL, to establish a further factor of safety.
The considerable negative publicity surrounding mercury and fish has led a number of people to complain that health warnings based on the RfD are causing harm. Typical of these comments is that of John Middaugh, State Epidemiologist of Alaska, who warned the FDA:
“Advisories based upon risk assessment without consideration of well-established public health benefits of fish consumption have great potential to harm public health if reductions in fish consumption occur.”
The evidence suggests that the health threat from mercury has been overblown.
(A 2004 State of Alaska, Epidemiology Bulletin, contains considerable information on the studies cited above, as well as additional relevant information.)
Second, the amount of mercury emitted by coal-fired power plants in the U.S. is small, and could be characterized as being very small.
Global emissions of mercury are 9,100 tons per year, of which at least half come from natural sources – not anthropogenic sources. Compare this to mercury emissions from U.S. coal-fired power plants of 41 tons per year.
There is also the fact that only 0.03% of the mercury deposited in the U.S from power plant emissions is converted to methyl mercury which is the form that can affect human health.
Furthermore, it appears as though the levels of mercury in fish haven’t increased very much.
Deep sea fish caught in the Western Atlantic between the 1880s and the 1970’s have shown little change in the amount of methyl mercury in their tissues. (The Western Atlantic is the area closest to the largest number of coal-fired power plants in the U.S.) This could indicate that methyl mercury in fish isn’t likely to be affected by changes in mercury emissions from coal.
There were also no differences in mercury levels of Yellowfin tuna between 1971 and 1998; increases would have been expected from increased mercury emissions. Also, there were no increases in mercury between 1970 and 2000 for striped bass caught in the San Francisco Bay area, though there were reductions in DDT and chlordane levels.
If the health risks from mercury are overblown, and the amount of mercury emitted by coal-fired power plants is very small, shouldn’t the EPA alter how it is targeting mercury emissions from coal-fired power plants? Coal generates low-cost electricity which benefits the economy.
This administration is conducting a vendetta against coal-fired power plants because they emit CO2, and the EPA’s actions with respect to mercury are merely a part of this vendetta.