DPR's Risk Assessment fails to address neurodevelopmental harm, Scientific Review Panel finds
Five months after the California Department of Pesticide Regulation (DPR) issued its weak and inadequate draft Risk Assessment for the brain-harming pesticide chlorpyrifos, a group of independent scientists that make up the state's Scientific Review Panel (SRP) ordered DPR back to the drawing board to produce a much stronger draft that properly considers the risk of harm to the developing brain.
A contingent of fifteen CPR members from as far away as Ventura, Kern, and Tulare was on hand in January to cheer the panel's decision. The presence of community members from California's farmworking communities ensured that the often-esoteric substance of the hearing was firmly grounded in the lived reality of the people affected by decisions made in Sacramento.
"We're hopeful that DPR's next draft will lead to meaningful restrictions on the use of chlorpyrifos in California," said CPR Co-director Mark Weller. "In the meantime, we're calling on the state to suspend it immediately while they continue to examine the science. We know enough already to take decisive action now."
Chlorpyrifos became California's problem after US EPA Administrator Scott Pruitt reversed a proposed federal ban last March.
DPR's highly anticipated but hugely disappointing draft risk assessment for chlorpyrifos was released in August and revised in
December 2017, based on public comment and comment from Dow Chemical, the principal manufacturer of chlorpyrifos.
The latest draft ignores the US EPA's November 2016 scientific findings that chlorpyrifos causes developmental neurotoxicity even in tiny doses. Instead, DPR uses cholinesterase inhibition as the "endpoint" (ie the impact their regulation is required to mitigate), even though cholinesterase inhibition occurs only at very high levels of exposure, far greater than the level that is believed to cause neurodevelopmental harm in young children. The risk assessment then establishes allowable exposure levels based on this endpoint, many thousands of times higher than EPA scientists consider safe for young children and pregnant women.
As an example of the inadequacy of their risk assessment, using cholinesterase inhibition as the endpoint allows DPR to declare that children under 2 years of age are at zero risk of harm from food residues - because the risk of cholinesterase inhibition is zero. By contrast, the US EPA found that food residues expose children under 2 to levels 14,000% higher than the level at which neurodevelopmental harm occurs. Children in agricultural regions face far higher exposures.
In November 2017, in a surprise move, the Office of Environmental Health Hazard Assessment (OEHHA) announced their decision to list chlorpyrifos as a reproductive toxicant under Proposition 65, a decision based in part on the same studies that the US EPA had relied on in proposing a federal ban - studies which DPR summarily dismissed for their draft risk assessment. OEHHA, like DPR, is a department within CalEPA.
At the all-day hearing in January, the SRP grilled DPR on their rationale for using cholinesterase inhibition as the endpoint and ignoring the far more harmful and sensitive endpoint, developmental neurotoxicity. At the conclusion of the meeting, the SRP told DPR that their risk assessment would have to be revised with developmental neurotoxicity as the new end point.