With the ever-increasing risk of man-made hazards to the human population, the field of epidemiology has quickly become one of the most critical and pressing disciplines in medical research. Synthetic organic pesticides, which are being sprayed on American crops, eventually infiltrate our homes, workplaces, atmosphere and bodies alike.
Throughout the last two decades, UC Berkeley Public Health faculty member Dr. Brenda Eskenazi and her team have worked diligently on the longest-running longitudinal birth cohort study of pesticides in the world.
The CHAMACOS, or the Center for the Health Assessment of Mothers and Children of Salinas, Study is an epidemiologically based investigation that looks at the implications of agricultural pesticide use on farmers and their children.
But a recent proposal by former administrator of the Environmental Protection Agency Scott Pruitt could prove detrimental to epidemiological inquiries similar to the CHAMACOS Study.
Within this study, researchers inquire as to how pregnant women and their children are exposed to pesticides, what effects they have on the individual’s health and development, and how exposure to harmful environmental toxins can be reduced.
“We enrolled pregnant women from the farmworker community in the Salinas Valley in 1999-2000 and have followed these women and their children to age 18,” Associate Director of the CHAMACOS Study Dr. Kim Harley said in an email.
Because of the sheer volume of the study, Harley noted the importance of a large staff and sufficient resources, as well as the massive amount of work that it takes to collect data.
“When the CHAMACOS mothers were pregnant, we conducted interviews with them and collected urine samples, blood samples, dust samples from their homes and more to measure their chemical exposures.” Harley said in the email. “We have then seen their children at multiple times during childhood. At each visit, we conduct a questionnaire with the mother and a detailed neurodevelopmental test battery and basic health exams with the child.”
Epidemiological studies such as CHAMACOS look at human health on a populationwide scale, investigating the causes and outcomes of diseases and other phenomena. Often the results of such studies are used on a nationwide scale to influence policy passed by environment-monitoring organizations. And although significant decisions based in health research seem to be in the best interest of the public, these critical policies are often entangled in polarizing politics.
When policy and science collide
The “Strengthening Transparency in Regulatory Science” proposal, presented by Pruitt three months before his resignation, would allow the EPA to make decisions and generate policy only based on studies where the data is available to the public. Though in theory this rule sounds like a positive development for policymaking, it has different implications for researchers.
“When the CHAMACOS mothers were pregnant, we conducted interviews with them and collected urine samples, blood samples, dust samples from their homes…” — Kim Harley
“Epidemiologists and medical researchers are required by law to protect the confidentiality of the people in their studies and to only use the data for the specific purposes that the participants gave consent for,” Harley said in her email. “We can’t make the data publically available without violating the promises we have made to our participants.”
Studies such as CHAMACOS are critical to agriculture policy decisions, which disproportionately affect migrant workers. Based on surveys taken in the early 2000s, it is estimated that about 75 percent of California’s agricultural workforce was born in Mexico. Of these workers, about half are undocumented, according to a 2009 California Department of Food and Agriculture document. Immigration policy, labor laws and health research are inseparably intertwined in agriculture.
Oftentimes, individuals and their families immigrate from Mexico, leaving their homes and risking their lives in search of work and better living conditions. These individuals lack a voice in the national politics that are most applicable to them. Furthermore, if they are exposed to harmful pesticides and subsequently fall ill, it may be difficult for them to obtain the necessary health care because of their undocumented status. The CHAMACOS Study’s name pays homage to this underrepresented population; the Spanish term “chamacos” translates to “little children.”
When asked about the relationship between politics and epidemiology research, Harley asserts that while the current political climate does not affect the procedural aspects of the team’s research, politics do impact the way their research is used and interpreted.
She further notes that the CHAMACOS Study’s findings have been referenced by policymakers at the California Department of Pesticide Regulation and in decisions regarding the health risks of pesticides on a national scale.
Since July, the EPA has been reviewing public feedback on Pruitt’s proposition — the expected date for a decision is currently unknown, according to the EPA webpage on the proposal.
The road ahead
In contrast to Pruitt’s proposal, other, more recent cases involving the regulation of pesticides and environmental health have experienced positive developments, as the judicial branch has proven its willingness to challenge EPA rulings.
.,, while the current political climate does not affect the procedural aspects of the team’s research, politics do impact the way their research is used and interpreted.
At the beginning of August, the United States Court of Appeals for the Ninth Circuit took the environmentally significant step of ordering the EPA to finalize a ban on chlorpyrifos within 60 days, according to publicly released court documents. Use of this neurotoxic pesticide in the U.S. has increased over the last half-century, as it is estimated that U.S. farmers spray about 10 million pounds annually on row crops such as corn, wheat and apples.
Although other nations, such as the UK in 2016, have banned the use of chlorpyrifos, a proven neurological development inhibitor, Pruitt had reversed Obama-era progress on the ban in addition to denying a 2017 pro-ban petition assembled by prominent U.S. environmental groups.
Though national politics continue to complicate and decelerate debates around salient issues such as immigration, health care and worker’s rights, Harley explains that the significance of the CHAMACOS Study’s findings in conjunction to similar epidemiology studies can not be understated.
“Epidemiology is important because there is only so much we can tell from laboratory studies,” Harley said in her email. “No one epidemiologic study can prove an association. It takes a combination of multiple epidemiologic and laboratory studies to garner evidence on the health effects of different chemicals.”
For Eskenazi, Harley and the rest of the CHAMACOS team, the work continues.