Winston-Salem, N.C. -- Two studies of immigrant farmworker families in North Carolina and Virginia found evidence of pesticide exposure in young children, and prompted researchers to call for pesticide safety training for workers' spouses.
In the American Journal of Industrial Medicine, researchers from Wake Forest University School of Medicine report that urine samples from 60 children revealed higher levels of pesticide exposure than had been found in similar studies elsewhere. And, in Health Education & Behavior, they conclude that workers' spouses need more education to protect their children from exposure.
"Efforts to reduce the exposure of these children to pesticides must be redoubled," said Thomas Arcury, Ph.D., lead researcher. "While science continues to grapple with the question of 'how much is too much' measures need to be taken to minimize exposure."
In the study of children from six North Carolina counties, urine samples were analyzed for evidence of exposure to organophosphate insecticides, the most widely used pesticides. High levels of exposure can cause coma and death. Long-term exposure at lower levels can increase risk for sterility, birth defects and cancer.
The levels found were higher than those found in other parts of the United States, yet scientists don't know if they are high enough to cause harm.
"Although research has demonstrated a link between pesticide exposure and health effects, the question of how much exposure over what period of time has not yet been answered," said Arcury, a professor of family and community medicine. "Because we don't know how much is safe, we must, as a precaution, assume that no level is safe."
Generally, the risks of exposure are considered greater to children than adults because of their small size and rapid physical and mental development. The study involved children from ages 1 to 6 years from Duplin, Harnett, Johnston, Sampson, Wake and Wayne counties.
The N.C. Employment Security Commission estimated in 2004 that more than 21,000 migrant and seasonal farmworkers were employed in these counties during peak harvest, accounting for 25 percent of the migrant and seasonal workers in the state.
As part of the study, mothers were interviewed to learn more about risk factors for exposure. Researchers learned that 40 percent of mothers and 30 percent of fathers were employed in farmwork, but had not received pesticide training, which would violate Environmental Protection Agency (EPA) regulations. Three in five children lived in households in which farmworkers did not shower immediately after work and four in five lived in households in which workers changed their clothes in the dwelling.
In a separate study, in-depth interviews were conducted with 41 Latino women in farmworker households in five North Carolina counties (Alleghany, Ashe, Avery, Mitchell, and Watauga) and three counties in Virginia (Smyth, Grayson and Carroll). The goal was to learn more about the women's knowledge and perceptions about pesticides.
In general, participants considered smell the most important aspect of pesticides.
"They therefore took few protective measures beyond avoiding or eliminating the smell," wrote the authors. "They did not realize that pesticides and residues often have no detectable odor."
Nearly one-third of the women thought of pesticides as contagious or exposure as an infection. Some mothers allowed their children in the fields, believing that as long as they didn't touch the crops, they weren't at risk of exposure.
"Their perceptions and behavior differ from scientific understanding of how to limit exposure and result in behaviors that may increase children's risk of exposure and health problems," said Arcury.
The researchers called for expanding the EPA regulation requiring pesticide safety training for workers to include those who live with farmworkers, possibly through brochures or videos that can be brought home.
Co-researchers were Stephen Davis, M.A., Alicia Doran, B.A., Joseph Grzywacz, Ph.D., Sara Quandt, Ph.D., Pamela Rao, Ph.D., and Beverly Snively, Ph.D., all with Wake Forest, and Dana Barr, Ph.D., with the Centers for Disease Control and Prevention.
Wake Forest University Baptist Medical Center is an academic health system comprised of North Carolina Baptist Hospital and Wake Forest University Health Sciences, which operates the university's School of Medicine. U.S. News & World Report ranks Wake Forest University School of Medicine 30th in primary care, 41st in research and 14th in geriatrics training among the nation's medical schools. It ranks 32nd in research funding by the National Institutes of Health. Almost 150 members of the medical school faculty are listed in Best Doctors in America.