CropLife America (CLA) announced it is dismayed by the alleged connection that researchers with the University of California, Davis have made between pesticide applications and neurodevelopmental disorders such as autism among children.

Neurodevelopmental Disorders and Prenatal Residential Proximity to Agricultural Pesticides: The CHARGE Study” was published in Environmental Health Perspectives on June 23, 2014. The study draws inaccurate and scientifically questionable connections between proximity to pesticides and neurodevelopmental disorders, according to CLA.

Pregnant women up to more than one mile of an agricultural pesticide application were tabulated as the CHARGE study group being denoted as affected in one way or another.

“The authors have created unnecessary fears among parents and contributed nothing to an understanding of the etiology of autism and other developmental disorders in children,” CLA emphatically contends.

CLA points out that a number of elements needed for scientifically robust research results are lacking in the study. The modeling used in this study to measure proximity must be grounded in real measures of exposure such as biomarkers in blood or urine (Chang et al. 20141). The study did not do this. Also, using addresses as a proxy for the location of pregnant women when the pesticide applications occurred assumes the women were at that address and outdoors precisely when the pesticides were being applied. The study did not investigate the possibility that these women may have been away from their residences, indoors or otherwise guarded from potential exposure. 

Importantly, “exposure” does not equate to “harm.” Harm can only occur if the exposure, or dose, is sufficiently high to have an effect. Pesticides are rigorously regulated by the U.S. Environmental Protection Agency (EPA) to ensure that real-life exposure across a variety of situations is not sufficient to cause harm. This includes ensuring pesticides cannot drift beyond the target organism in the field and onto other people at levels that cause harm.

“This study, by equating proximity to exposure, incorrectly assumes the pesticides drifted impossibly far distances and at impossibly high concentrations,” CLA also emphasized.

Study authors neglected to consult experts from the California Department of Pesticide Regulation to better understand real-life pesticide applications, instead choosing to misconstrue publicly available data on pesticide use and create statistical significance out of thin air. The study also fails to reference the vast amount of publicly available regulatory data the EPA requires before it will register a pesticide for use, including data on toxicity and drift.

Mothers who have children with autism spectrum disorders need meaningful and helpful advice for dealing with these difficult and distressing conditions. Failing to include the multiple, more significant factors that may contribute to the occurrence of neurodevelopmental disorders such as nutrition and inherited genetic predisposition does them a disservice and leaves them with skewed and biased advice.

“Assumptions made by the study investigators are incorrect and irresponsible. Proximity to pesticide applications does not equate to exposure. Furthermore, a single exposure is insufficient to cause harm,” said Dr. Clare Thorp, senior director of human health policy for CLA. “All pesticides are regulated by EPA using an extensive battery of acute, chronic and sub-chronic toxicity and exposure testing, including neurological effects. These tests examine the dose and route of exposure and are conducted across a range of species, including their offspring. Recommended rates of use in the field are set far below a level at which there would be any harmful effect.”

“Protecting the well-being of expectant mothers, infants and elderly individuals is a top priority for EPA, as well as farmers and members of the crop protection industry who have families of their own,” added Jay Vroom, CLA’s president and CEO. “The registration process for pesticides is conducted with families fully in mind. Once in the field, crop protection products are applied responsibly, according to label instructions.”

“It cannot be stated loudly or plainly enough: EPA takes every possible measure to ensure that pesticides are thoroughly tested and that they are made available to applicators only when the Agency concludes they can be used without risk to human health,” Thorp said. 

CLA condemns the repeated use of junk science that draws questionable associations from cherry-picked data. CLA encourages the public to review all scientific literature with a critical eye and consider criteria such as whether the raw data is publicly available or if the study underwent a sufficiently rigorous and comprehensive peer-review process.

More information on EPA’s pesticide registration process and efforts to protect public health is available at http://www.epa.gov/pesticides/health/public.htm.  

1 Validity of geographically modeled environmental exposure estimates. Ellen T. Chang 1,2, Hans-Olov Adami 3,4, William H. Bailey 1, Paolo Boff etta 5, Robert I. Krieger 6, Suresh H. Moolgavkar 1, and Jack S. Mandel 1Crit Rev Toxicol, 2014; 44(5): 450–466 © 2014 Informa Healthcare USA, Inc. DOI: 10.3109/10408444.2014.902029