Organophosphates can impair our children's neurological development -- it's time to ban them, new research says.
A team of researchers from the University of California (UC) Davis says there's enough evidence available to warrant a ban on organophosphates, a widely-used class of pesticides. Prenatal exposure to the compounds put children at risk for neurodevelopmental disorders, they explain, calling for immediate government intervention to phase out these products.
"There is compelling evidence that exposure of pregnant women to very low levels of organophosphate pesticides is associated with lower IQs and difficulties with learning, memory or attention in their children," said lead author Irva Hertz-Picciotto, professor of public health sciences, director of the UC Davis Environmental Health Sciences Center and researcher with the UC Davis MIND Institute.
"Although a single organophosphate -- chlorpyrifos -- has been in the national spotlight, our review implicates the entire class of these compounds."
Organophosphates are very, very good at killing pests. The compounds work by blocking nerve signaling. Essentially, they bind to and inactivate the chemical compound that neurons use to send signals to one another. Today, this pesticide class is used to control insects in a variety of settings -- farms, golf courses, even shopping malls and schools.
Given their popularity, environmental levels of organophosphates are quite significant. They've been detected in the vast majority of U.S. residents, according to Hertz-Picciotto, who come into contact with the pesticides through food, water, and the air they breathe.
This is a problem, the team explains. There are limits set in place to reduce exposure to organophosphates but it's not nearly enough. Drawing on over 30 epidemiologic studies, scores of experimental studies with animal models, and cell cultures, they report that prenatal exposure to the chemicals -- even at 'safe' levels -- is associated with poorer cognitive, behavioral and social development.
"It should be no surprise that studies confirm that these chemicals alter brain development, since they were originally designed to adversely affect the central nervous system," Hertz-Picciotto said.
Part of why these chemicals remain in use -- despite recommendations from the U.S. Environmental Protection Agency -- may be because low-level, ongoing exposures typically don't cause visible, short-term clinical symptoms, the team explains. Since people can't see a definite effect from interacting with these substances, many simply assume they aren't dangerous, says Hertz-Picciotto.
"Acute poisoning is tragic, of course, however the studies we reviewed suggest that the effects of chronic, low-level exposures on brain functioning persist through childhood and into adolescence and may be lifelong, which also is tragic," Hertz-Picciotto explained.
Beyond the findings, the team also offers a few recommendations that should help dramatically reduce organophosphate exposure:
- Removing organophosphates from agricultural and non-agricultural uses and products.
- Proactively monitoring sources of drinking water for organophosphate levels.
- Establishing a system for reporting pesticide use and illnesses.
Until a ban is set in place, the team recommends offering medical staff more in-depth education regarding the substance, to help them improve treatment for and patient education on avoiding exposures. They also believe that teaching agricultural workers how to properly handle and apply organophosphate pesticides would help limit exposure -- such courses should be held in the workers' native language, they add. Finally, increasing use of other, less-toxic alternatives should help prepare farmers for an eventual ban.
The paper "Organophosphate exposures during pregnancy and child neurodevelopment: Recommendations for essential policy reforms" has been published in the journal PLOS Medicine.