Read a Q&A with Health & Society Scholar Sammy Zahran, PhD, about his study that finds children may be exposed to lead through contaminated soil.
To explain the potential impact of gene-based environmental science, Sara Shostak, PhD, MPH, told a straightforward tale about health disparities in a Mississippi town. Shostak, a sociologist and Robert Wood Johnson Foundation (RWJF) Health & Society Scholar (2004-2006), chose the case of Tamiko Jones v. Northern Lead Industries—the story of five mothers who sued on behalf of their 14 children.
The mothers contended that aging, lead-based paint in their Greenwood, Miss., housing complex had poisoned their children causing mental retardation, learning disabilities and behavioral problems. “All 14 children had lead levels above 10 micrograms [many studies have found that this level can harm physical and cognitive health]. All of the environmental health scientists who testified in the case supported the plaintiff’s claims,” Shostak said.
“The defense countered by bringing in a geneticist to test the children. All of the genetic and chromosomal analyses came back negative. But the defense claimed, based on family pedigree charts, that the children, who were all African American and poor, were genetically predisposed to be mildly retarded, have trouble learning or have behavior problems, whether or not they were exposed to lead,” Shostak explained. Northern Lead Industries won the case.
In this instance, genetic claims were used to argue that blood levels of lead were insufficient to cause disease. This contradicts decades of research on the known health risks of lead poisoning. “Blaming children’s genetic inheritance is now a strategy across toxic tort cases, with defendants often citing African American ancestry as an alleged risk,” Shostak said.
Yet in increasing numbers, environmental scientists who are passionately committed to protecting the public’s health are conducting research seeking genetic explanations for health problems related to environmental exposures. To understand why, Shostak interviewed more than 80 environmental health scientists, policy-makers, and environmental justice advocates for her book, Exposed Science: Genes, the Environment, and the Politics of Population Health (University of California Press, 2013).
A Defensive Science
“I wanted to understand why environmental scientists were using new genetic technologies and concepts to focus deep within the human body. The field has developed in the service of public health and with an intent to inform policy,” Shostak said, so why the shift?
Environmental scientists have to constantly defend their findings against attack.” - Sara Shostak
One of the first and perhaps most important answers Shostak found is that “environmental scientists have to constantly defend their findings against attack. The tension between industry and regulation has become the drumbeat to which the entire field is working. Scientists told me that if they find that a chemical has harmful effects on human health, the industry in question is going to launch scientific and legal challenges to discredit the work before policy or health concerns can even be addressed.”
If you consider, Shostak added, “that we live in a chemical soup, the fact that scientists are caught up battling over one chemical at a time gives us very little opportunity to understand the full range of interactions between the environment and our health.”
The Impact on Vulnerable Populations
Even when an environmental toxin is identified, research shows that policy-makers are less likely to take it seriously enough to carry out the most effective—and health sparing—solutions in poor communities. “We know that communities of color have higher rates of exposure to environmental hazards, but those hazards are far less likely to be dealt with in the same way they are in wealthier communities,” Shostak explained.
“There are significant constraints in how these scientists work. That is not in the best interest of the most vulnerable populations,” she said.
Explanations for the Shift
While many scientists told Shostak they simply felt caught up in a fast-moving wave of new genetic technologies, others expressed an interest in using knowledge about gene-environment interactions to identify new biomedical markets, additional sources of funding for their research, and methods of treating or preventing environment-related diseases.
“Environmental health scientists turned to genetic research to solve problems of power that are central to their field,” Shostak said. “Research on gene-environment interaction is compelling to environmental health scientists insofar as it promises a diverse array of strategies for redressing the field’s structural vulnerabilities. The biomedical turn is part of that shift.”
Are Gene-based Studies the Answer?
Learning more about how the body responds to environmental hazards will, to some degree, bolster the authority of environmental health scientists, concluded Shostak, who credits her mentors from the RWJF Health & Society Scholars program with helping her see how to advance public health. But, she added, it would not rescue them from the controversial political battles that so often accompany their work or protect the poor. “We must find new ways to strengthen the environmental health sciences without losing sight of the lives and life chances of our most vulnerable citizens.”