Health Effects: The State of the Science

Birth Defects :: This April 2009 study reports that birth defect rates in the United States are highest among women conceiving in the spring and summer, a time period correlated with increased levels of pesticides in surface water.

Developmental Neurotoxicity/IQ reduction :: Fetal and childhood exposures to widely used organophosphate pesticides, especially chlorpyrifos, have raised concerns about developmental neurotoxicity. In 2011, several independent studies documented cognitive effects of in uteru dietary exposure, including significant IQ reduction. A study of Yaqui Indian children in Mexico found that an array of impaired brain and nervous system functions, including social behaviors and the ability to draw, are correlated to pesticide exposure during development.

Brain Development :: Many developmental effects are not measurable at birth, or even later in life, because brain and nervous system disturbances are expressed in terms of how an individual behaves and functions. Reviewing the literature on pesticide exposure at various points in neurological development, this article finds that current pesticide risk assessment strategies are ill-equipped to measure or protect against the many kinds of exposure faced by developing fetuses, infants and children.

Childhood Brain Cancer :: Brain cancer is the second most common type of cancer in children, and it has been on the rise, but why it develops remains unclear. This February 2009 study finds that children who live in homes where their parents use pesticides are twice as likely to develop brain cancer versus those that live in residences in which no pesticides are used.

Autism Spectrum Disorder :: Researchers found a sixfold increase in risk factor for autism spectrum disorders (ASD) for children of women who were exposed to organocholorine pesticides, this study was one of the first to link in utero pesticide exposure to ASD.

Attention-Deficit/Hyperactivity Disorder & dietary pesticide exposure :: A May 2010 study out of Harvard shows that even tiny, allowable amounts of a common pesticide class can have dramatic effects on brain chemistry. Organophosphate pesticides (OP’s) are among the most widely used pesticides in the U.S., they work by interfering with brain signaling in insects. OPs have long been understood to be particularly toxic for children, but this is the first study to examine their effects across a representative population with average levels of exposure.

Acta Pediatrica, Vol. 98, Issue 4, 2009

Developmental Effects Beyond Neurotoxicity: Immediate & Delayed-Onset Effects on Heart & Liver Function :: The fetal and neonatal neurotoxicity of chlorpyrifos (CPF) and related insecticides is a major concern. Developmental effects of CPF involve mechanisms over and above cholinesterase inhibition, notably events in cell signaling that are shared by nonneural targets. This study finds that the developmental toxicity of CPF extends beyond the nervous system, to include cell signaling cascades that are vital to heart and liver functioning.

Low Birth Weight :: Pregnant women in upper Manhattan who were heavily exposed to two common insecticides had smaller babies than their neighbors. Recent restrictions on the two substances quickly lowered exposure and increased babies' size.