12
May
Exposure to Heavy Pesticide Use Can Impact Neurobehavioral Performance in Children
(Beyond Pesticides, May 12, 2017) Researchers from the University of California San Diego, School of Medicine, in collaboration with scientists from Ecuador and Minnesota, have found that exposure to heavy pesticide use during peak periods can impact neurobehavioral performance in children. The study focused on exposure to organophosphate pesticides, which have been associated with a broad range of diseases in both children and adults.
The study, published in NeuroToxicology, involved 308 non-worker Ecuadorian children between the ages of 4 and 9. Neurobehavioral performance for each child was tested once between 63 and 100 days after the Mother’s Day flower harvest, which is a period of high pesticide use in Ecuador. The researchers found that children examined sooner after Mother’s Day had lower scores than children who were tested later. “Children examined sooner after the flower harvest displayed lower performance on most measures, such as attention, self-control, visuospatial processing (the ability to perceive and interact with our visual world) and sensorimotor (eye-hand coordination) compared to children examined later in a time of lower flower production and pesticide use,” said Jose R. Suarez-Lopez, MD, PhD, and lead author of the study, to ScienceBlog.
Dr. Suarez-Lopez continued, “This discovery is novel because it shows that pesticide spray seasons can produce short-term alterations in neurobehavioral performance in addition to the long-term alterations that have been previously described. This is troublesome because the altered mental functions observed are essential for children’s learning, and in May-July, students typically take their end-of-year exams. If their learning and performance abilities are affected in this period, they may graduate from high school with lower scores which may hinder their ability to access higher education or obtain a job.”
Organophosphates are pesticides that were used in World War II as nerve agents. As potent neurotoxicants, organophosphates are extremely harmful to the nervous system. They are cholinesterase inhibitors and bind irreversibly to the active site of an enzyme essential for normal nerve impulse transmission, but lower levels of exposure that do not cause cholinesterase inhibition have also been found to produce serious neurotoxic effects. Their impacts have been studied in the in the long-term Center for the Health of Mothers and Children in Salinas (CHAMACOS) study. A 2016 report from CHAMACOS found lower IQs (intelligence quotients) in children born to mothers who during their pregnancy were living in close proximity to chemical-intensive agricultural lands where organophosphate pesticides were used. A 2015 report, also based on participants from CHAMACOS, found that a decrease in lung function in children was linked to exposure to organophosphates early in life. Another 2015 report found that prenatal exposure to chlorpyrifos, a potent organophosphate, is linked to tremors in children.
Other studies have found similar results, linking birth defects to peak pesticide usage. At the 28th National Pesticide Forum, Paul Winchester, M.D., delved into his experiences studying the connection between agricultural pesticides and birth defects. According to Dr. Winchester, birth defects for the entire US increase in women who conceive in the month of highest pesticide usage. He found that the counties with the highest pesticide rates have the highest rates of birth defects. Going even further, a colleague from Purdue University found that the closer the mother is to a cornfield when a child is conceived, the more likely it is that the child will have a birth defect. Dr. Winchester also found that when pesticides are measured in pregnant women, the ones with the highest levels have the shortest gestations, resulting in babies being born sooner and are smaller. According to Dr. Winchester, the size of the baby is the best predictor of brain size and ultimately the lifetime risk of being on welfare, having a job, and so on.
These studies are all consistent with a metastudy by Ross et al. published in 2013 that looked at long-term exposures to organophosphates in occupational settings and found, “The majority of well designed studies found a significant association between low-level exposure to OPs and impaired neurobehavioral function which is consistent, small to moderate in magnitude and concerned primarily with cognitive functions such as psychomotor speed, executive function, visuospatial ability, working and visual memory.”
Unfortunately, the US agencies and regulations meant to protect citizens from harm are severely lacking. The Environmental Protection Agency (EPA)’s own risk assessment process fails to look at chemical mixtures (or “inert” ingredients) and synergistic effects of common pesticide products, as well as certain health endpoints (such as endocrine disruption), disproportionate effects to vulnerable population groups, and regular noncompliance with product label directions. These deficiencies contribute to EPA’s severe limitations in defining real world poisoning, as captured by epidemiologic studies in Beyond Pesticides’ Pesticide-Induced Diseases Database.
Just recently, EPA rejected the conclusions of its own scientists, and independent scientific literature, and reversed a tentative decision from 2015 to revoke food residue tolerances of chlorpyrifos due to the chemical’s neurotoxic impacts. This would have effectively banned chlorpyrifos from agriculture, but the reversal now leaves the door open for continued neurotoxic dangers for humans, especially children.
Ultimately, the widespread adoption of organic management is necessary to protect consumers and the environment in the long-term. Beyond Pesticides has long sought a broad-scale marketplace transition to organic practices that, as a default, prohibits the use of synthetic pesticides by law (unless subject to rigorous health and environmental standards and recommended by the National Organic Standards Board) and requires a systems-based approach that is protective of health and the environment. This approach never allows the use of highly toxic synthetic pesticides, such as the toxic organophosphates, and advances a viable, scalable path forward for growing food. Find out more about why organic is the right path forward for the future of farming by going to Beyond Pesticides’ organic agriculture webpage.
Source: ScienceBlog; ScienceDirect
All unattributed positions and opinions in this piece are those of Beyond Pesticides.
