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livingontheland - Re: [Livingontheland] Decades after Silent Spring, pesticides remain a menace

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  • From: Harvey Ussery <huboxwood@earthlink.net>
  • To: livingontheland@lists.ibiblio.org
  • Subject: Re: [Livingontheland] Decades after Silent Spring, pesticides remain a menace
  • Date: Mon, 23 Oct 2006 13:38:26 -0400

An important point to add to the discussion about pesticide residues and their potential threats post-Carson: I heard Sandra Steingraber address the issue at PA Assoc for Sustainable Ag annual conf this year. She said that 400 years after Paracelsus, we still accept his dictum "The dose makes the poison." That is, even quite poisonous substances are harmless below a certain dosage--indeed, could even be used beneficially. (Paracelsus used small doses of mercury to treat syphilis, even tho it was know that mercury is quite toxic.) This assumption that has come down from Paracelsus still informs our absurd notion of "threshold" levels of toxins in the environment, below which they're "okay."

Steingraber referred to numerous studies that should make us conclude that it is not "the dose makes the poison," but rather "the timing makes the poison." That is, there are four windows of vastly increased vulnerability in the developmental stages--in utero, the first months of explosive growth, the time of rapid growth and great hormonal changes in puberty, and the emergence into old age. At these points the body is undergoing many changes, quite rapidly, and is thus more sensitive to influence by what would be "below threshold" doses at other stages of life. Thus an embryo in utero might develop birth defects from the water her mother is drinking, even tho said water is having no demonstrable deleterious effects on the mother.

Another change in the nature of toxics used now as opposed to when Carson wrote is that so many of them are hormone analogs/mimics, and the body can react to them as if they were hormones triggering certain responses--but responses that are entirely inappropriate to the body's actual state of development. One especially insidious thing about hormone mimicking toxins is that they can be even *more* dangerous at extremely small doses than in larger ones. This would be counter-intuitive to Paracelsus, but it makes sense: Hormones are active in the body to initiate potent changes at extremely small concentrations. That is the way the body is accustomed to getting that information--in small amounts--and in larger doses it has the wisdom to say, "oh no, that *can't* be right--no way" and discount the information and refuse to unleash the cascade of changes.

I don't know how much attention Carson gave to synergistic effects of the toxins she studied, but of course there are hundreds or thousands more individual chemicals released into the environment today than in her day. Safety studies on these chemicals individually are inadequate, but almost *no* attention has been paid to the later compounds emerging from their combination "in the wild" in completely unpredictable ways. Truly, we have *no idea* what the chemical stew we dump into the environment is doing, or what effects it is having on us.

As Wendell Berry said: "We think we are in the environment. We are wrong: The environment is in us."

~Harvey

--
Harvey in northern Virginia
www.themodernhomestead.us




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