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Report weighs methods of gauging pesticide impacts

Published on May 3, 2013 3:01AM

Last changed on May 3, 2013 1:49PM


Capital Press


An eagerly awaited report about endangered species has managed the rare feat of pleasing both environmentalists and the pesticide industry.

The National Academy of Sciences report examines processes used by federal agencies to evaluate the risk that pesticides pose to protected species.

Recommendations within the report, which is more than 100 pages, focus on improving the government's analysis of species exposure to the chemicals, as well as their effects.

The suggestions can be interpreted favorably by both sides of the pesticide debate, said Aimee Code, environmental health associate with the Northwest Center for Alternatives to Pesticides.

"You find what you want to in a report like this," she said. "It's really like a Rorschach test. You see what you see."

That's partly because the report lays out a blueprint for dealing with the multiple variables involved in pesticide effects, she said.

Such chemicals are applied by numerous people, using multiple forms of equipment, across many regions and climates. The risk analysis is therefore much different than for other actions that affect the environment.

"Using pesticides is nothing like building a bridge, which is why this is so challenging," Code said.

Hopefully, the report will help federal agencies build a regulatory framework that's more resistant to environmentalist lawsuits challenging how pesticides are studied, said Jay Vroom, CEO of the CropLife America pesticide industry group.

"We think it's a really good road map," he said. "I've always seen litigation as a blunt instrument when it comes to public policy."

One aspect of the report that has generated enthusiasm is the recommendation that agencies switch from a "deterministic" approach of gauging risk to a "probabilistic" approach.

With the deterministic approach, the agency figures out the level at which a pesticide will kill fish and how much it must be diluted for the water to be considered safe, said Code.

The reality of pesticide use is much more complicated, with chemical levels potentially changing over time.

For that reason, a probabilistic approach -- which takes more variables into account -- would be preferable, she said. "I think it's better for everyone."

The upside for environmentalists, as well as pesticide users, is that a probabilistic approach would provide a more realistic view of pesticide effects, said Jeff Jenkins, toxicology professor at Oregon State University.

Protections for species could be more effective while relying less on strict assumptions that err heavily on the side of caution, he said.

However, the notion of using a probabilistic approach is hardly earth-shattering, Jenkins said.

The problem with using probabilistic methods to measure risk is that they require more data and resources, he said. Such models rely on hundreds of input variables, requiring an amount of study the U.S. Environmental Protection Agency hasn't seen as practical for all pesticides, Jenkins said.

Aside from that issue, farmers also have privacy concerns about divulging pesticide use data needed for such models, he said.

"It's going to have to be a pretty detailed data set to get it right," Jenkins said. "They need really strong data that is fairly detailed."


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