Do Health Risks from Mercury Justify Stringent Regulations on Coal-Fired Power Plants?
by Timothy Terrell,
 [Editor’s Note: The announcement December 27, 2018, by the United States Environmental Protection Agency (EPA) that it is revising cost findings behind its Mercury and Air Toxics Standards (MATS) ignited a firestorm of complaints on the ground that mercury is a known neurotoxin that can cause brain damage in infants and young people. While that is true, it’s also true that the risk depends greatly on the degree of exposure—and there is compelling evidence that mercury emissions from coal-fired power plants pose no significant risk. In his paper The Cost of Good Intentions: The Ethics and Economics of the War on Conventional Energy, published by the Cornwall Alliance in 2011, Dr. Timothy Terrell, an environmental regulatory economist, included an appendix that quantified that risk, rebutting claims by the Evangelical Environmental Network and others that the risk was large and the MATS rule was therefore well justified. We present that appendix here. Its lessons were timely then, and they are timely again now, demonstrating that the EPA’s action is well justified.—E. Calvin Beisner]
Theoretically, some mercury emitted from various human activities, such as those that require burning fossil fuels, could wind up in human blood through the consumption of fish that have accumulated mercury.[1] This is the source of the Evangelical Environmental Network’s recent objections to coal-fired power plants. The risks, however, are being overstated, as are the damage estimates.
Defining Risk, Risk Dose, and Population at Risk
Part of the misunderstanding of the hazards of mercury may result from the EPA’s methods of establishing the level of mercury in one’s blood above which people are said to be at a risk level providing reason for concern. This level, called the “reference dose,” is what the EPA has determined to be the highest daily dose that the most sensitive people in the population can be exposed to over a lifetime without adverse effects. Since 1995, the EPA has set a limit of 1 mcg (microgram) per kg (kilogram) per day of body weight.[2] For concentrations of mercury in blood, this is equivalent to a maximum of 5.8 mcg/L of blood, or approximately 5.8 parts per billion (ppb).[3] It is important to understand how the EPA arrived at this limit.
The EPA benchmark relies on a long-term study in the Faroe Islands,[4] which was based on evaluation of methylmercury levels in umbilical cord blood and hair samples taken in childhood. This study indicated some effects from methylmercury exposure, which for one of five tests started at 85 (not 5.8) mcg/L of umbilical cord blood. That is an estimate, and as with any statistical work, there is some uncertainty associated with that number. The actualconcentration of methylmercury leading to detectable results for that particular test was probably close to 85 mcg/L, lying somewhere between 58 and 112 mcg/L. The EPA chose the lower limit of 58.[5] Then the EPA divided by 10 to account for remaining uncertainties, obtaining the reference dose of 5.8 mcg/L. In short, the “reference dose” is not necessarily the same as “the level which causes harm to unborn children.” The EEN’s unequivocal statement that “700,000 babies are born with harmful levels of mercury in their blood” is based on a misinterpretation of the statistics.
There are other problems with the 700,000 figure. The 1999–2000 National Health and Nutrition Examination Study (NHANES) indicated that about 7.8 percent of U.S. women of childbearing age (16–49) had levels of mercury exceeding the EPA’s reference dose (5.8 mcg/L, not the benchmark dose, 85 mcg/L, the lowest at which adverse effects were observed).[6] Fecundity statistics allow us to estimate the babies born to this group at about 317,000 annually, at that time. This number is approximately doubled to account for the fact that umbilical cord blood has about 1.7 to 1.8 times the mercury concentration that the mother’s blood does. This implies that the limit of 5.8 mcg/L applied to the umbilical cord corresponds to only 3.5 mcg/L in the mother’s blood. The number of women who had levels of mercury in their blood exceeding 3.5 mcg/L is about 15.7 percent of the 16–49 age group, and assuming that this group also accounts for 15.7 percent of the births, this group would account for around 630,000 births each year. This helps us understand where the EPA’s occasional use of a larger number[7] came from and where the EEN obtained its 1 in 6 (or about 700,000) babies figure.
However, as older women tend to have more mercury in their blood than younger women, and also have fewer children,[8] fewer than 15.7 percent of the women actually giving birth in the U.S. have mercury levels over the 3.5 mcg/L level (see Table 1). The 700,000 or 1 in 6 figure is, for this reason alone, an overestimate. A quick comparison of the percentage of women in various age groups having mercury concentrations over 3.5 mcg/L according to NHANES and the Census data on births to (approximately) those same age groups indicates that the actual number “at risk” based on these data is at least 100,000 fewer than EEN supposes.
Continue reading on the Stewards Blog.
FREE to You: A Book that Demolishes Fears of Overpopulation!
 Fears of “overpopulation”—because it allegedly causes resource depletion and environmental degradation through pollution—have roots deep in history, and they continue today.
About ten generations after Noah, when the whole world’s population might not have been much over 5 million, Abraham and his nephew Lot parted ways because they were convinced that the land God had promised to Abraham couldn’t support them and their families and servants (perhaps totaling a few hundred) and flocks (perhaps totaling a few thousand). (Today, that portion of the modern state of Israel supports something on the order of 1 to 2 million people, at much higher levels of consumption and prosperity—and with far less exposure to disease.)
The early church father Tertullian in the third century wrote, “Our numbers are burdensome to the world, which can hardly support us . . . . In very deed, pestilence, and famine, and wars, and earthquakes have to be regarded as a remedy for nations, as the means of pruning the luxuriance of the human race.”
Thomas Robert Malthus, in his Essay on the Principle of Population (1798), argued 220 years ago that because human population grows exponentially (2, 4, 8, 16, 32, …) but food supplies and other resources grow only arithmetically (2, 4, 6, 8, 10, …), procreation must be controlled intentionally, or else population would suffer repeated crashes caused by disease, famine, and war.
In more modern times, the theme has continued, with William Vogt’s Road to Survival (1948), Paul Ehrlich’s The Population Bomb (1968), Paul and Anne Ehrlich’s The Population Explosion (1991), and many other books and thousands of articles in scholarly and popular publications.
Many people have found such common complaints unpersuasive because of the fairly obvious fact that despite tremendous growth of human population, human flourishing has increased even more. The average person has had more and better food to eat, more and better clothing, more and better shelter, more and better transportation and communication, more and better medical care—the list could go on and on. And the result has been that they live healthier, longer, and generally happier lives.
But the prophets of fear haven’t given up. In recent decades, they have expressed their fears in ways that sound more sophisticated:
- I = PAT: A formula meaning that environmental Impact = Population x Affluence x Technology, so the more people there are, and the wealthier they are, and the higher their technological level, the greater impact (always considered negative!) they’ll have on the environment.
- Carrying Capacity: the notion that the earth has a limited carrying capacity and that human population has already met or exceeded it, with catastrophic consequences to come.
- Ecological Footprint: the magnitude of a person’s ecological impact (again, always considered negative), varying positively with his or her affluence. Americans’ “ecological footprint” is many times larger than that of people in poorer countries—and indeed expanding theirs to ours would devastate the planet. This gave rise to the claim on the Earth Overshoot Day website that by August 2, 2017, humans had already “used more from nature than our planet can renew in a whole year”—a practice that obviously couldn’t be sustained.
- Planetary Boundaries: the belief that there are nine earthly “boundaries” that humans, with our high levels of consumption and pollution, have crossed or soon will.
Such ideas are the driving force behind continued demands for abortion-on-demand, forced or highly incentivized sterilization, and tax policies that punish people for having “too many children,” as curbs to population growth.
If someone confronted you with these claims, could you explain what’s wrong with them? Not many people could. But Pierre Desrochers and Joanna Szurmak do it, brilliantly, in their book Population Bombed! Exploding the Link Between Overpopulation and Climate Change.
This outstanding book covers a lot more ground, too, and if you read it, you’ll understand more than the vast majority of Americans, even most scholars, about population, resources, the environment, and how they all relate to climate change.
That’s why I want to give you a FREE copy of Population Bombed! as my thanks for a donation of any size to the Cornwall Alliance by the end of January.
This is a book you’ll want to read carefully and thoroughly yourself—and then pass on, especially to high school or college students you know, or to public school teachers in the social sciences, who desperately need its corrections to widespread myths about population.
So, please, right now, request your own copy by mentioning promo code 1901 when you make your donation. You can make your gift at our secure online website, or by phoning 703-569-4653, or by sending your check to Cornwall Alliance, 9302-C Old Keene Mill Rd., Burke, VA 22015. Don't forget to mention Promo Code 1901!
 God Bless You,
Megan (Toombs) Kinard
Director of Communications
The Cornwall Alliance for the Stewardship of Creation seeks to magnify the glory of God in creation, the wisdom of His truth in environmental stewardship, the kindness of His mercy in lifting the needy out of poverty, and the wonders of His grace in the gospel of Jesus Christ. A coalition of theologians, pastors, ministry leaders, scientists, economists, policy experts, and committed laymen, the Cornwall Alliance is the world’s leading evangelical voice promoting environmental stewardship and economic development built on Biblical principles. The Cornwall Alliance is a non-profit religious, charitable, and educational organization. All gifts are tax deductible.
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