The Paths of Chlorpyrifos - Quantifying Aggregate Exposures
Subject: The Paths of Chlorpyrifos - Quantifying Aggregate Exposures
Date: Thu, 7 Mar 2002 16:54:14 -0500
From: Stephen Tvedten <steve@getipm.com>
Organization: Get Set Inc. (www.getipm.com)
To: Paul Helliker <phelliker@cdpr.ca.gov>
Director, State of
California, Department of Pesticide Regulation
cc: Christine Whitman whitman.christine@epa.gov
Dear Mr. Helliker, I thought you might like to read an article from the Environmental Health Perspectives Volume 110, Number 3, March 2002 entitled: The Paths of Chlorpyrifos - Quantifying Aggregate Exposures.
Chlorpyrifos, once one of the most widely used pesticides
in the
In 1995-1996, Pang and the other NHEXAS-Maryland researchers measured chlorpyrifos concentrations in indoor air, carpet dust, exterior soil, and diet samples from 80 people over age 10 who lived in Baltimore and the surrounding counties. None of the participants used pesticides for six months before or during the study. The team combined the measured chlorpyrifos concentrations in each medium with self-reported time spent indoors at home, time and frequency in contact with carpet, frequency of contact with soil, and amounts of pesticide in the diet samples to derive the exposure to chlorpyrifos for each medium as well as the average daily aggregate exposure.
They found that aggregate daily exposures for chlorpyrifos ranged from 13.5 ng/day to 12,821.0 ng/day, with a mean daily aggregate exposure of 1,390.0 ng/day. Inhalation of indoor air accounted for 76.1% of the aggregate exposure to the population, while solid food intake contributed 22.8% of the population exposure. The importance of the inhalation pathway was somewhat surprising to the authors because chlorpyrifos is not very volatile. They also point out that little is known about how much chlorpyrifos is actually absorbed through inhalational exposure.
The distribution of chlorpyrifos concentrations in each medium varied by over three orders of magnitude. This variation and the concentrations for indoor air, carpet dust, and soil measured in this study were in the same range as those measured in earlier comparable studies. The aggregate exposure estimates determined in this study are lower than some previous exposure estimates, according to the authors. But some of the previous estimates reflected exposures following pesticide applications and those for young children, whose crawling and mouthing behaviors could lead to higher exposures.
The study indicates that a single short-term measurement of exposure may not yield an accurate estimate of an individual's long-term exposure, but that knowing the relationship between short-term exposure measurements and long-term exposure could be used to improve the efficiency of future epidemiologic study designs. The study also showed that multiple environmental media are important contributors to aggregate exposure, so epidemiologists should account for both dietary and nondietary exposure in their assessments. Finally, better quantification of aggregate exposure to pesticides will help environmental health scientists to evaluate the utility of biological markers of exposure for future epidemiologic studies.
Rebecca Renner - http://ehpnet1.niehs.nih.gov/docs/2002/110-3/ss.html#path
Well Mr. Helliker, I just received an e-mail comment that fits the above story like a glove. "Do you remember the book "All I Really Need to Know I Learned in Kindergarten," written by Robert Fulghum in 1989. Here's part of his list:
-- Don't hurt people.
-- Say you're sorry when you hurt someone.
-- Play fair.
-- Clean up your own mess.
There are no complicated concepts here. No rocket science. No six-syllable words, as in: "Take responsibility for all your actions." Just plain, decent ideas that the average two or three year old can understand and put into practice. I know, because at that age my son and most of his friends were well on the way to learning all these ideas. Of course, there were a few kids whose moral development was slow or stunted, but we were sure that with enough firmness and love they could become good people, like the other kids.
How is it possible that people at the developmental level of a morally stunted three-year-old can be running Monsanto and Dow? I guess they must teach their own kids: "It's okay to hurt anyone you want. Just get a bunch of high-priced lawyers, and tell them to bend and break any rules you don't like. And when you mess up someone's life, never clean up the mess, because that would be admitting you're sorry."
People are sick and dying from your "registered" POISONS - when are "you" going to learn what "you" should have learned in Kindergarten?
Respectfully,
Stephen L. Tvedten
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