Years ago, when Associate Professor Robert Sprinkle started teaching a new graduate course, “Human Health and Environmental Policy," something bothered him. A paper on his course list, published in 2009, showed reproductive deformities in male rat pups after low-dose gestational exposure to a mixture of four environmental contaminants differing in their mechanisms of action.
"Well, so what?" said Sprinkle. "The 'so-what' was low-dose synergistic environmental toxicity. From a medical perspective this was no surprise; clinical pharmacology brimmed with drug-interaction effects. However, from statutory, regulatory, jurisprudential and liability perspectives this paper along with similar papers should have been transformative if ever taken as prompts to action."
Except there wasn't any action. Sprinkle wanted to know why. So he, along with Devon Payne-Sturges, an associate professor of environmental health sciences in the School of Public Health, set out to find the answer.
"Then began seven years of burrowing through the National Archives and through PubMed.gov and through the memories of participant experts and then writing, revising, submitting, and—after multiple rounds of peer review—publishing a paper that explained the evolution, and in key respects the maladaptation, of policies pertaining to serious and interrelated problems: mixture toxicity, cumulative risk and environmental justice," Sprinkle explained.
Sprinkle and Payne-Sturges looked at the ways that environmental health policy is made and the ongoing obstacles to translating science into sensible regulations to safeguard our health. In the article, published in Environmental Health, Sprinkle and Payne-Sturges say that while the EPA has known much about the negative impacts of chemical exposures for many years, little has been done because of historical and internal barriers which hinder the agency’s ability to protect our health.
“In the face of all the knowledge about exposure to multiple chemicals, why is it that the agency [EPA] hasn’t been more vocal that this is a significant public health issue?,” Payne-Sturges said. “They haven’t made the effort to utilize their existing authorities. The information is put out there to describe a known problem over and over and over again.”
Sprinkle's work focuses on the intersection of politics and the life sciences. He is the author or coauthor of papers and chapters in clinical medicine, bioethics, health policy, bioengineering, environmental policy, political theory and biosecurity and is the author of one book, Profession of Conscience: The Making and Meaning of Life-Sciences Liberalism (Princeton University Press, 1994), an intellectual history of political-ethical thought in the life sciences.
Payne-Sturges has been a leading voice on the need to address the cumulative impacts of pollution, with particular attention to the most vulnerable communities, where issues like poverty, a lack of access to healthy food and other social stressors may compound the negative health impacts of toxic exposures. Environmental health issues disproportionately affect low-income populations and communities of color and the continuing impasse in environmental policymaking means that these communities continue to be left behind.
In the article, Mixture toxicity, cumulative risk, and environmental justice in United States federal policy, 1980–2016, Sprinkle and Payne-Sturges examine the historical and contemporary science and political barriers that are preventing policy advancements.
Among the problems detailed in the latest article, the federal guidelines on regulating chemical mixtures have prevented the EPA from assessing chemicals in combination.
“Environmental impacts on human health are never caused by just one pollutant, chemical or hazard. Yet, this is how our government regulates environmental health risks, one pollutant at a time,” Payne-Sturges said.
The article also details how industry corruption has historically derailed efforts to implement regulations of toxic substances. “The lobbyist groups for industry have a vested interest to make sure that things don’t stand in their way,” explained Payne-Sturges. “They get their points across and their perspectives end up being the inspiration for lack of action or changes to policy documents.”
Another significant internal problem has been that the scientific challenges of studying complex mixtures involving numerous toxicants led some at the EPA to believe that they could not act meaningfully to regulate them.
"'Why, with much known, was little done?' our subtitle asked," Sprinkle said. "Simple question. Complex answer."