Ignoring troubling data, California closes the book on toxic pesticide water contamination

In a surprising move this week, California officials closed their reevaluation of the toxic pesticide chlorpyrifos in state waterways, concluding that their recent designation of chlorpyrifos as "restricted use" would solve water contamination problems just days after these new rules went into effect on July 1, 2015.

The California Environmental Protection Agency's Department of Pesticide Regulation (DPR) indicated that the recent restricted use designation is intended to reduce water contamination; however, it's unclear how that would occur because, as I blogged about previously, the restricted use designation is not likely to reduce chlorpyrifos use generally and restricted material permit requests are rarely denied. Furthermore, though DPR issued "recommended permit conditions" for chlorpyrifos, there's no change in the existing buffer zones that are already required for bodies of water. A buffer zone is a set distance required between the edge of the pesticide application and water, intended to reduce unwanted movement of the pesticide into water.

The existing buffers don't seem adequate to prevent chlorpyrifos water contamination, as DPR's most recent water monitoring data for 2014 still shows chlorpyrifos contamination above established safety standards in almost 20% of the samples tested. DPR should have waited for water monitoring results from 2015-16, after the restricted use designation has been in effect, to confirm whether or not the rules actually reduce water contamination. Instead, they pre-emptively closed the evaluation of chlorpyrifos water contamination without knowing that the problem is actually solved.

The decision is also unexpected because it comes right on the heels of an announcement from the US Environmental Protection Agency (US EPA) that they are considering a ban on chlorpyrifos, due in part to toxic water contamination.

The conclusions from US EPA and DPR on chlorpyrifos water contamination are at odds. US EPA notes that additional data is needed, and that far more stringent restrictions than the existing buffer zones may be required: "With such information, EPA can develop appropriate risk mitigation for these watersheds, such as prohibiting all use or changing the way chlorpyrifos is allowed to be used in a watershed." In contrast, DPR jumps to the conclusion that the restricted use designation, which doesn't change how chlorpyrifos is used near water, is sufficient: "DPR has determined that no additional restrictions are necessary at this time. Therefore, this reevaluation is concluded."

Finally, it's important to note that neither DPR's restricted use designation nor the now-closed reevaluation address the numerous health risks that chlorpyrifos presents to workers, kids and communities. In their response to comments on the restricted use rule, DPR stated that they separately continue "...to evaluate additional studies and...to review data," related to human health concerns. That health assessment is critically needed in order to finally put protections in place that communities need and deserve, and we urge DPR to move expeditiously on that front.

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