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Emily Marquez

More evidence links pesticides & falling IQs

A new study from researchers at the University of California, Berkeley found that when pregnant mothers live within one kilometer of fields where certain pesticides are used, their children are more likely to have lower IQs.

A new study from researchers at the University of California, Berkeley found that when pregnant mothers live within one kilometer of fields where certain pesticides are used, their children are more likely to have lower IQs. These findings confirm those in several earlier studies. Which leads me to wonder: just how much evidence do we need before taking action?

This latest study looked at 283 seven-year-olds living in the Salinas Valley, an agriculturally intensive area along the Northern California coast. Researchers found that higher levels of organophosphate (OP) pesticide use in nearby fields during pregnancy lowered IQ scores by about two points. In the specific area of verbal comprehension, a nearly three-point decrease in IQ was observed.

In this study, proximity to agricultural pesticide use was used as a proxy for pesticide exposure. Based on past studies, pesticide use reporting data has been correlated with environmental pesticide concentrations in the home, suggesting that proximity to agricultural pesticide use is a meaningful indicator of pesticide exposure.

The conclusion of the study? Mothers living near agricultural use of neurotoxic pesticides during pregnancy may risk “poorer neurodevelopment” of their children.

Do we need more data?

The families involved in this particular study are part of the CHAMACOS (Center for the Health Assessment of Mothers and Children of Salinas) cohort study, which has been following a group of mothers and their children for about 16 years.

Pesticide use reporting data available from the state of California makes this type of work possible. Unfortunately, California is one of very few states in the country where pesticide use is reported on a yearly basis — and yet, California’s use reporting system has room for improvement. For instance, the study we’re talking about looked at pesticide use within one kilometer of the home. What if researchers had access to data that allowed for analysis at smaller distances (e.g., closer proximity to pesticides)? Would that tell us more?

An important first step is getting more data in other states. My Midwest PAN colleagues are working with a farmer-led coalition in Iowa, for example, that’s pressing for better rules protecting farmers from pesticide drift and statewide pesticide use reporting.

It’s definitely important to have more information, both so researchers can conduct studies with the best data available and also because the public quite simply has the right to know. But when it comes to environmental exposures to OP pesticides and other neurotoxic agents, I think we already have more than enough information to put health-protective policies in place right now. This is an injustice that we can and must address.

The big picture when it comes to kids’ brains

I was part of a group of (mostly academic) scientists that recently issued a consensus statement on neurotoxic chemicals under the name of “Project TENDR,” which stands for Targeting Environmental Neuro-Developmental Risks. OP pesticides were among the chemicals identified as “candidates for action” posing a threat to children’s brain development.

Other candidate chemicals included those with a LOT of data, like lead (just to give you some context, Benjamin Franklin wrote about lead’s neurotoxic properties). Project TENDR also identified candidate chemicals like poly brominated diethyl ether (PBDE) flame retardants, among others.

Project TENDR was convened by Maureen Swanson of the Learning Disabilities Association of America and Irva Hertz-Picciotto, a researcher at the University of California, Davis, in response to the concerning increase in learning and behavioral problems in children — and the fact that increased risks of these problems have been associated with a number of toxic environmental chemicals.

The basic premise of the consensus statement is that the risks to brain and nervous system development from neurotoxic chemicals are unacceptably high, and policies must be put in place to reduce exposures of children and pregnant women to these chemicals. The consensus statement called the current regulatory system “fundamentally broken.”

We don’t have to accept this as the status quo. Pesticide usage doesn’t have to be a given for us to have a thriving agricultural system. But we do need deep changes in our current policies to support the real transformation needed — and this is a real challenge. Luckily, a growing number of farmers and advocates are tackling this challenge, and hopefully these numbers will continue to grow.

Picture of Emily Marquez

Emily Marquez

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