Common Pesticide May Pose Risk to Workers Who Apply It

http://www.scientificamerican.com/article/common-pesticide-may-pose-risk-to-workers-who-apply-it/

January 8, 2015 |By Brian Bienkowski and Environmental Health News

An insecticide used on corn and other U.S. crops poses health risks to workers who mix and apply it and also can contaminate drinking water, according to a U.S. Environmental Protection Agency report released this week.

The report is an update, based on new research, to a 2011 assessment of the health impacts of the pesticide chlorpyrifos (pronounced KLOR – pie -ra – phos), which remains one of the most commonly applied organophosphate pesticides. It has been banned for more than a decade for household use but is still used commercially on corn, soybeans, fruit and nut trees and some golf courses.

•••••

The agency did not find any additional risks from airborne or food exposure. It cited the latest U.S. Department of Agriculture data that found “no concerns for chlorpyrifos in food, with the pesticide detected in less than 1 [percent] of samples.”

However, researchers believe inhalation is likely a major exposure route for people living near heavily treated fields, said Janie Shelton, an epidemiologist who led a study linking chlorpyrifos to autism in babies born to moms near treated fields in farm-heavy Northern California last year.

This bystander exposure is likely a “sub-clinical exposure” - where the mom would not experience any effects herself, but the constant chronic exposure in drift or house dust could impact an unborn child, Shelton said.

Chlorpyrifos is a neurotoxin that prevents the synapses of the nerves from stopping activity, causing over-stimulation, Shelton said. It has been linked to birth defects, low birth weights and impaired brain development problems, and endocrine disruption.

Fetuses are at much higher risk from the pesticide, she said.

“Adults have an enzyme that can metabolize organophosphates like chlorpyrifos,” Shelton said. “That is something that only comes online after birth. So babies in the womb don’t have the metabolizing enzyme.

“If they’re exposed to a neurotoxin it would take much lower levels to see observable effects.” The EPA did not return requests to comment on the new report.

Despite household bans, some evidence suggests people are still exposed to the chemicals. A study of Northern California families and floor wipe samples last year found that 99 percent of floor wipes and 65 percent of study participants had some chlorpyrifos in them.

•••••