Thomas Arcury, Ph.D., NIEHS grantee from Wake Forest School of Medicine, discussed his studies of long-term pesticide exposures and migrant farmworker health Jan. 29 at Duke University. His talk, “PACE4: A Study of Sub-clinical Neurological Outcomes of Farmworker Pesticide Exposure,” was part of the Duke Integrated Toxicology and Environmental Health Program seminar series.
According to Arcury, pesticides are applied to almost all of the crops produced in North Carolina, and many are planted and picked by hand by an estimated 100,000-150,000 farmworkers. He said that although the immediate human health effects of exposure to pesticides, which may include sickness and even death, are well-known, the effects of long-term exposure to pesticides are less clear.
Community-based approach is essential
Several factors make it difficult to follow North Carolina farmworkers over time, Arcury said. The workers are migratory, typically from Mexico with limited English, and national estimates suggest that about half don’t have official documents to work in this country.
He emphasized that the research would not be possible without community partners — a method known as community-based participatory research (CBPR). Arcury and his team began the project, Preventing Agricultural Chemical Exposure Among North Carolina Farmworkers (PACE), in 1997 with NIEHS funding.
The primary community partners are the North Carolina Farmworkers’ Project in Benson, and El Buen Pastor Latino Community Services in Winston-Salem. “CBPR means that members of these organizations are co-investigators on the project,” said Arcury. “They help us design the project, conduct the research, and write the papers.”
PACE4 studies long-term exposures and neurological health
The PACE researchers initially focused on workplace pesticide safety and exposures. “Pesticide metabolites are commonly found in the urine samples of these farmworkers, including organophosphate pesticides, carbamates, pyrethroids, and herbicides,” he said. “We have measured as many as eight different pesticides in a single urine sample.”
The current phase, PACE4, involves studying links between long-term pesticide exposures and neurological health. The study has already found consistently higher lifetime and residential pesticide exposure among farmworkers, compared with nonfarmworkers. The research team also reported lower levels of cholinesterase, an enzyme important for proper function of the nervous system, among the farmworkers.
Arcury and his colleagues are currently analyzing data on pesticide exposure and changes in neurological health indicators over time, including balance, sense of smell, and physical changes in the brain, revealed by imaging studies.
Research findings translated into community education
Using study results, the researchers are creating educational materials aimed at those affected by exposures to pesticides. For example, Arcury pointed to a short Spanish video they developed, which explains the concept of epigenetics, “Epigenetica: La historia sobre los genes y el medio ambiente” (Epigenetics: The Story of Genes and the Environment). The video teaches workers that exposures to pesticides and other chemicals can affect a person’s health, and effects may be passed down to children.
The team also prepares briefs to present research results and policy recommendations to legislators and other public audiences.
Arcury TA, Nguyen HT, Summers P, Talton JW, Holbrook LC, Walker FO, Chen H, Howard TD, Galvan L, Quandt SA. 2014. Lifetime and current pesticide exposure among Latino farmworkers in comparison to other Latino immigrants. Am J Ind Med 57(7):776-787.
Quandt SA, Pope CN, Chen H, Summers P, Arcury TA. 2015. Longitudinal assessment of blood cholinesterase activities over 2 consecutive years among Latino nonfarmworkers and pesticide-exposed farmworkers in North Carolina. J Occup Environ Med 57(8):851-857.
(Virginia Guidry, Ph.D., is a technical writer and public information specialist in the NIEHS Office of Communications and Public Liaison.)