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Document prepared by Consumer Union Washington, D. C. Office
Comments Submitted March 24, 1998 to the
FIFRA Scientific Advisory Panel
On Behalf of Consumers Union
By
Dr. Edward Groth
Ms. Jeannine Kenney
Dr. Charles Benbrook
Consumers Union submits the following comments regarding the Food Quality Protection Act requirement to consider a common mechanism of toxicity for consideration by the March 24-25th FIFRA Scientific Advisory Panel.
For over 30 years federal law has called upon federal agencies to consider the possibility that different pesticide active ingredients, food additives and other chemicals found in food might pose risks through a common mode or mechanism of action. Since the formation of the EPA in 1970, the need for considering additive and possibly synergistic impacts of pesticides has remained near the top of the list of unmet risk assessment challenges.
Passage of the "Food Quality Protection Act" in 1996 formally requires the EPA to take into account aggregate exposure to pesticides that pose risks to humans through a common mechanism of action. Technical issues that arise in the course of doing so are a focus of this two-day SAP meeting.
The scientific justification for the common mechanism of action provision written into the FQPA was set forth in the 1993 National Academy of Sciences report "Pesticides in the Diets of Infants and Children." As the FQPA was drafted, Consumers Union was among the many organizations urging Congress to adhere closely to the recommendations in this key NAS report.
Organophosphates and Carbamates
There are about 45 important organophosphates and carbamate insecticides currently registered by EPA . The 1993 NAS report concluded that these compounds pose risks to pregnant women, infants and children through a common mechanism of action of cholinesterase inhibition. In the case of the OPs, the recent International Life Sciences Institute review conducted for EPA reached the same conclusion, as have many other expert bodies. There seems little reason to further debate this judgment.
While it is clear that organophosphate and carbamate insecticides pose human health risks through at least one common mode of action, these compounds pose widely different levels of risk per unit of exposure, and also per acre-treated. For example, the LD-50 (amount of chemical which causes death in half of the exposed population) of the most toxic organophosphates and carbamates are under 5 mg/kg (ppm in the diet), while the least toxic OPs have LD-50s over 1,000 mg/kg. Similarly in terms of Reference Doses and chronic risks, the most toxic OPs are on the order of 1,000-fold more toxic than the least toxic OP active ingredients. While this point is not germane to the common mechanism of action judgment, it is of considerable significance when EPA assesses the share of the risk cup accounted for by different OPs and carbamates, and crafts regulatory actions to bring total exposure and risks within the level consistent with the FQPA's "reasonable certainty of no harm" standard.
Consumers Union feels it is important to build into pesticide regulatory decision-making the extra protections for pregnant women, infants and children, and without excessive delays. To do so, the EPA must continue to implement the Act by reassessing OPs and carbamates as sharing a common mechanism of toxicity. While some difficult scientific judgments will have to be made along the way, OP and carbamate common mechanism of action decisions clearly do not fall in this category and EPA should begin reassessing the tolerances associated with these pesticides assuming a common mechanism of action.
We ask the panel to clearly state its concurrence with three key conclusions.
The agenda before the panel today and tomorrow is evidence of the many issues in exposure and risk assessment that the EPA must resolve as the agency moves forward with applying the FQPA safety standard to the OPs and carbamates. We urge the panel to speak decisively on this issue where, in our judgment, the preponderance of evidence strongly supports the above three conclusions.
Thank for you the opportunity to present these comments.
