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Pesticide residue risks recalculated

By Dennis T. Avery
web posted March 26, 2012

For the past 15 years, the Environmental Working Group (EWG) has been trying to scare U.S. consumers about pesticide residues on the fruits and vegetables in supermarkets. The EWG annually selects a "dirty dozen" produce items that they say pose the most pesticide residue danger to consumers and their kids.

Now, however, two courageous researchers at the University of California/Davis say they've also tested the fruits and vegetables -- and found the pesticide residues on these produce items are essentially a million times below the "No Effect" levels found in the animal toxicity tests. That's how much safety factor is built into the government's reference doses and Acceptable Daily Intake recommendations.

The EWG says consumers can lower their pesticide consumption by nearly four-fifths by buying expensive organic produce. Drs. Carl Winter and Josh Katz say the EWG methods don't even measure consumer exposure against the Acceptable Daily Intake. Such findings "suggest that the potential consumer risks are negligible and cast doubts as to how consumers avoiding conventional forms of fresh produce are improving their health status." 

The most potent risk that Winter and Katz found in the "Dirty Dozen" was an exposure only 50 times lower than the Reference Dose for methamidophos -- but that reference dose includes a 1,000–fold uncertainty factor for extrapolating the results of the most sensitive animal studies. For three commodities -- blueberries, cherries, and kale -- the Reference Doses were more than 30,000 times higher than the exposure estimates for all of the ten most frequently detected pesticides on those commodities.

Nor did the research team find much merit in the obvious EWG efforts to target commodities that showed traces of several pesticides. "Such effects still require exposure . . . to be at a level of high enough risk to cause a biological effect. Results from this study strongly suggest that consumer exposure to the ten most common pesticides found on the "Dirty Dozen" produce items are several orders of magnitude below levels required to cause a biological effect in any test animals." Thus the likelihood of the various residues "synergizing" into high risks is also negligible. The research team seems to think the multiple-exposure items were included because they sound scarier to food-buyers.

This study says "buying organic" won't much reduce your risks of getting cancer. In fact, Dr. Bruce Ames, also of the University of California/Berkeley, who received the National Medal of Science from President Clinton, says 99.9 percent of the carcinogens we swallow are natural compounds produced naturally by our fruits and vegetables to help protect them as they grow. Ames says "going organic" will reduce your exposure to carcinogens by about one ten-thousandth of one percent. More to the point, Dr. Ames says the human body shrugs off life's minor insults, such as the tiny amount of carcinogenic psoralens in your celery stalk. And be aware that organic produce also contains those same natural pesticides.

If you are still worried, stomach cancer seems not to be triggered by ingesting pesticide residue, but by a stomach bacteria (helicobacter pylori) infection. H. pylori is found in about 2/3 of all persons worldwide and is usually harmless. However, infected bacterium is spread through contaminated water and poor living conditions. This is why stomach cancer rates have dropped drastically in First World countries as sanitation improves.

Why does your newspaper not tell you about studies like these?  Ask them. ESR

Dennis T. Avery, a senior fellow for the Hudson Institute in Washington, D.C., is an environmental economist. He was formerly a senior analyst for the Department of State. He is co-author, with S. Fred Singer, of Unstoppable Global Warming Every 1500 Years. Readers may write to him at PO Box 202 Churchville, VA 2442; email to cgfi@hughes.net. Visit our website at www. cgfi.org.





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