A new study underscores the wisdom of reducing the risks of mercury and other pollutants rather than relying on risk avoidance measures such as fish consumption advisories. Mercury’s adverse effects are not limited to human health; its harms are felt throughout our ecosystems. According to this most recent study, released today by the Biodiversity Research Institute, mercury harms a broader swath of wildlife than previously recognized, including many bird species that are not piscivorous. This finding echoes those of studies in the Great Lakes published this fall, which concluded that a larger number of species were adversely affected by mercury contamination than previously understood by scientists.
From a regulatory perspective, the harms of mercury contamination might be addressed by risk reduction – measures that require the sources of mercury pollution to reduce or prevent mercury releases into the environment – or by risk avoidance – measures that leave it to those who are exposed to protect themselves from mercury permitted to enter or remain in the environment. The EPA’s recent rule regulating coal-fired power plants’ mercury emissions is an example of the former approach. An example of the latter approach was the George W. Bush administration’s suggestion, upon proposing an exceedingly lax rule for power plants (ultimately vacated by the D.C. Circuit), that people protect themselves from the continued mercury contamination by consulting national and local fish consumption advisories.
I have elaborated the many perils of relying on risk avoidance in lieu of risk reduction elsewhere. Among the limitations of depending on risk avoidance measures such as fish consumption advisories, ozone alerts, and “keep out” signs, are the facts that these measures are unjust and ineffective in practice. They simply don’t result in “the same amount” of protection for human health, as proponents of such measures hope.
Today’s study highlights another problem: risk avoidance is myopic. Because risk avoidance measures target only specific, direct threats to human health, they fail to address adverse effects on any non-human components of ecosystems. Signs erected along our bays and lakes warning that fish intake should be limited due to mercury contamination obviously don’t reach the eagles, bears, and other species that depend on fish. Websites are not consulted by a wood thrush.
Such myopia is at odds with the understanding that human health is but one end of our environmental law and policy goals – an understanding enshrined in many of our nation’s environmental statutes. Moreover, even if one were concerned chiefly with impacts to human health, a reliance on risk avoidance fails to appreciate the myriad ways in which human health is indirectly impacted when non-human health is impaired. As the Great Lakes studies found, mercury’s adverse impacts on piscivorous fish include harms to their reproductive success and survival – resulting, of course, in depletion of species relied upon by humans for food.
Human health is inextricably linked with ecological health. Today’s study underscores the importance of reducing mercury and other toxic contamination at the source.