louis martin
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North Coast, California--

There is a fundamental rule of risk assessment that states: risk equals toxicity times exposure, or R=T*E. But a group of Native Americans says it doesn't want to be part of that equation.

The California Department of Pesticide Regulation has a grant from the National Forest Service to study the effect of pesticides on basket weavers. Many Native American basket weavers collect their material from National forests that are treated with pesticides, and 3 years ago the DPR was asked by the California Basket Weavers Association to look at exposure due to pesticides.

The study is to focus on the Klamath River along the California North Coast.

But a problem has developed. "Some of the members of CIBA," said Dr. Tobi Jones, Special Assistant to the DPR, "objected to our using standard risk assessment processes."

Basket weavers collect plants that have not been studied by the DPR, and they handle them in ways that standard agricultural crops are not handled. For instance, some materials for basket weaving are run through the mouth to soften the material.

Since the beginning of the discussions with CIBA, said Jones, the terminology of "risk assessment" had been used by DPR.

But now some members of CIBA don't believe in the concept, she said. "They presented us with papers by a woman named Mary O'Brien, who writes off risk assessment because it doesn't cover all the parameters. She poses an impossible question."

The "impossible question" is a common theme of the environmental community when dealing with pesticides or toxic materials. Questions about multiple chemical exposure, as well as the interaction and synergy of chemicals, are currently difficult, if not impossible, for toxicologists to answer.

Risk assessments studies use "the best science possible," according to Jones. But she said the criticism of risk assessment goes "beyond the current state of toxicology."

In the equation for risk assessment, T--or toxicity of the chemical--is known. Exposure is a matter of two factors: the amount of residue left on the plant after the application and how the plant is handled.

The DPR has been developing laboratory methods for measuring residue on the types of plants collected in the forest. That was necessary, said Jones, because "the residue methods that we usually work with at DPR are relevant to food crops."

But DPR also needs to know how the plants are handled. "We were hoping to work with the members of CIBA so that we could better understand how plant materials are collected."

But so far CIBA has declined to be part of the equation.



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