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Heavy Metals: A Centuries-Old Story

Pollution in People Report - Chapter 3 - Arsenic, Lead, Mercury

Denis Hayes-lgSince 1970, when he coordinated the first Earth Day, Denis Hayes has been dedicated to making our planet a healthy place. Raised in Camas, Washington, marked by the grandeur of the Columbia River and the pollution of a major pulp mill, he grew up with an appreciation for nature and an understanding of how humans can degrade it.

Today, Denis is the chair of the International Earth Day Network; he also presides over the conservation-minded Bullitt Foundation, and in various posts has spent decades promoting renewable energy sources around the world. His accolades are impressive:  he’s been named a “Hero of the Planet” by Time magazine, awarded the Sierra Club’s John Muir Award, and dubbed one of the twentieth century’s environmental heroes by the National Audubon Society.

Although he recently began sporting a buzz cut to please his wife, Denis generously donated enough hair for the Pollution in People study to discover that he has accumulated a significant amount of mercury in his body—in fact, the highest level in our group. At 2020 ppb, his hair mercury level is more than three times the median for his age and gender1 (EQI 2005). Most likely his high level results from his fish-rich diet, not uncommon in the Pacific Northwest. Figure 3 shows our study participants’ levels, which ranged from 59.5 to 2020 ppb, with a median of 887 ppb.

 Figure 3 - Mercury Levels in Washingtonians

Figure 3:  Mercury levels in participant hair.

We also tested our participants for lead and arsenic. Four tested positive for arsenic; one, nurse Karen Bowman, tested positive for lead2.

Karen also had the second-highest mercury level, and the highest among the study’s women. Her level of 1880 ppb puts her above EPA’s reference dose, or “safe” level, for women of childbearing age (1100 ppb)(National Academy of Sciences 2000). The National Academy of Sciences has concluded that exposures above this level may harm neurological development in the developing fetus. Bill Finkbeiner’s mercury also exceeded the safe level, and Lisa Brown’s mercury, at 1080 ppb, is just below the benchmark.

For centuries, humans have known that heavy metals such as mercury, lead, and arsenic can seriously harm our health. Lead’s effects on the brain were noted as early as the second century B.C.E., and arsenic has been notorious as a poison since the Middle Ages. The ancient Romans noted mercury’s harmful effects when slaves mined the metal in Spain. The Incas used mercury to extract gold in the 1500s, and despite a well-developed reputation for harming the brain and causing birth defects, mercury continues to be used in mining, in addition to other industries and consumer products. Mercury, lead, and arsenic are naturally occurring elements, but our bodies don’t need them in any way. And at very low levels, all three can be toxic.


1 Participants in this study were self-selecting volunteers, and may not reflect the age and racial/ethnic background distribution in the general population.
2 The laboratory detection limit for lead was 3 µg/dL, and 10 ppb for arsenic.