Insecticides, fungicides, and herbicides are staples of modern agricultural production in the United States. Over the past three decades, substantial efforts have been made to protect farmers and farm workers from the hazards posed by overexposure to pesticides. Toxicity testing, strict labeling procedures, certification and training, improved application equipment, and personal protective gear makeup an elaborate program of risk management designed to minimize this hazard. As the rules governing occupational pesticide exposures were strengthened, it generally was assumed that, so long as chemicals were handled and stored properly, children would not be placed in harm’s way.
In the past decade, new insights into the more subtle means of toxicity along with the unique vulnerability of children to environmental pollutants, have led health researchers to focus on this group. An important wake-up call came in 1996 as an Executive Order: It directed all federal agencies to develop an explicit strategy for the inclusion of children’s health in their evaluations. Passage of the Food Quality Protection Act of 1996 put the spotlight directly at pesticide health risks and children. This law, approved by a unanimous vote of Congress, requires the Environmental Protection Agency to review the toxicity of every pesticide, and to determine both the acute and chronic health risks these chemicals pose to children.
This increased scrutiny has led to new questions about children, especially toddlers, who are magnets to chemicals in our environment. Studies have shown that even small amounts of toxic chemicals, such as lead, can have a great effect on young children. The research points out that this age group is the most susceptible to take-home exposure. Toddlers spend a lot of time on floors and often wear little clothing during the summer spraying season. Children’s typical hand-to-mouth behavior increases their chances of inadvertently eating pesticides, chemicals their young systems may have greater difficulty clearing. Those under the age of three remain quite vulnerable to damage because their fragile nervous system is developing rapidly.
Since 1991, the University of Washington has investigated pesticide exposures among Washington children of agricultural families, focusing on the organophosphorous insecticides. In 1996, the Pacific Northwest Agricultural Safety and Health Center was established with funding from the National Institute for Occupational Safety and Health. This center has conducted considerable research into ‘take-home’ pathways of pesticide exposure. Colleagues at Fred Hutchinson Cancer Research Center have joined this work, along with investigators at the University of Washington Center for Child Environmental Health Risks Research.
In our work, we’re trying to find answers to what seem like simple questions. It’s a challenge to arrive at definite answers in the face of scientific data that is not always definitive. Just how do workplace chemicals enter the home? Can washing work clothes with the family laundry transfer pesticide residues to children’s clothing? When pesticides are sprayed, do the chemicals move off-target to residential areas?
We have also investigated new approaches to minimize children’s exposure to pesticides. Our early studies in central Washington state demonstrated that agricultural pesticides measured in house dust were elevated in the homes of agricultural workers compared to other homes in the same community. A follow-up study collected urine samples from preschool children, and found that children of pesticide applicators had higher levels of pesticide metabolites than did children of non-agricultural workers. These studies led us to conclude that a ‘take-home’ pathway for pesticide exposure does exist for children of agricultural producers and workers.
Our most recent study of this pathway sampled the dust in commuter vehicles of more than 150 farm workers, together with dust from their residences. We found a strong association between home and vehicle dust for a number of pesticides, providing further support for the take home exposure pathway. Recent efforts have focused on an intervention to improve individual’s hygienic practices in these communities so as to reduce pesticide residue levels in the home.
In addition, our studies have found that children who live near pesticide-treated farmland may have higher exposures than children living further away from spray activities. The most striking finding in this regard came from a study of 44 preschool children living in the tree fruit region of the state. We collected urine samples from these children over the course of a year, and found that levels of pesticide metabolites in the urine increased during periods of active spraying, and returned to normal levels when the spraying ended. It appears from these results that agricultural spraying can have a community-wide effect on children’s pesticide exposures.
Recent findings, released by Fred Hutchinson Cancer Research Center researchers, indicate that one particular organophosphorus pesticide, azinphos-methyl, is found more frequently in the residences of orchard thinners than in the residences of other agricultural workers. Orchard thinners have long been recognized as an important work group in terms of pesticide exposure, since they have substantial physical contact with pesticide residues on foliage. We do not yet know if the pesticide levels found in these and other workers’ residences represent a health risk to young children, but we hope to conduct further studies to begin to answer this critical question.
It’s not just agricultural workers and their families who are exposed to toxic chemicals. Children of lead-exposed construction workers were six times more likely to have blood lead levels over the recommended limit as compared to children whose parents did not work in lead-related industries. (Research by the National Institute for Occupational Safety and Health drew this conclusion.)
We can learn from others, namely from industries that have taken specific measures to minimize risks. Workers themselves have an important role to play in protecting their families from take-home contamination. Workers need to incorporate and follow these basic precautions:
Pacific Northwest Agricultural Safety and Health Center
Department of Environmental and Occupational Health Sciences
School of Public Health and Community Medicine
University of Washington
PO Box 357234, Seattle, WA 98195-7234
t: (800) 330-0827, f: (206) 616-2687
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