Herbicides, like cigarettes, won't kill you on the spot.
In his Oct. 16 guest viewpoint, Michael Newton decries the earlier guest viewpoint of Barbara Kelley and Kim Kauffman as "incorrect" and containing "frightening allegations."
Newton's commentary goes on to inform us that our lives are full of risks. However, he assures us that we needn't consider exposure to 2,4-D and 2,4,5-T - the principal components of Agent Orange - among those risks.
As Newton suggests, there is little doubt that Paracelsus' famous maxim on toxicology - namely, that "the dose makes the poison" - is indeed true. However, I think it bears some consideration that our understanding of toxicology has deepened considerably in the nearly 500 years since Paracelsus' death.
We now have an appreciation of how toxic chemicals affect us at the molecular level, while in Paracelsus' time the concept of a molecule itself was still centuries away.
Paracelsus had no conception of the endocrine system. He was ignorant of the manner in which hormones act, and - more importantly for the current discussion - how hormone mimics such as those found in many modern pesticides can severely, even catastrophically, disrupt the finely tuned biochemical cascades that govern the quality (and ultimately, the quantity) of our existence.
The chemical compound 2,4-D is a potent broadleaf herbicide. However, to suggest that the only physiological effect it exerts is the targeted killing of weeds is to neglect the extent to which seemingly disparate organisms - even organisms as different as dandelions and humans - share common biochemical pathways.
In fact, 2,4-D is a potent mimic of the hormone estrogen. While estrogen is something all humans (even males) need, it is definitely a case of "a little goes a long way."
It is the nature of hormones that it takes only minuscule amounts to have the desired biological effect.
Chemicals such as 2,4-D have been shown to disrupt the sensitive pathways our bodies rely on to carry out functions basic to our survival, with potentially dire consequences.
Without directly addressing the considerable "margin of safety" Newton wants to associate with exposure to pesticides such as 2,4,-D and 2,4,5-T, it is interesting that the only mechanism of toxicity his commentary endeavors to consider worthy of our concern is that of acute toxicity.
The article seems to suggest that if we come into contact with something and fail to take ill on the spot, the hazard associated with that contact rightly should be considered as negligible.
I'm a bit more cautious than that. I've never seen anyone drop dead on the spot from a single cigarette, but I've seen too many succumb to cancer following years of smoking.
Unlike Paracelsus, I have an understanding and healthy appreciation of the cumulative detrimental effects of 10,000 sub-lethal events. Such an understanding tempers my willingness to write off any exposure to potent bioactive agents as no big deal.
Are 2,4-D and 2,4,5-T really benign? Suffice it to say that while Newton may believe so and would reassure us based on his belief, the United States Department of Veteran Affairs takes a completely different viewpoint.
Upon consideration of peer-reviewed evidence from the Institute of Medicine (a part of the National Academy of Sciences), Veteran Affairs has put policies in place to provide a broad range of medical benefits and services to veterans who were exposed to Agent Orange.
That doesn't seem the sort of path one would expect a careful institution such as Veteran Affairs to follow if it actually considered 2,4-D and 2,4,5-T to be harmless.
Paracelsus also believed that diseases were caused by poisons from the heavens, and in a very modern sense, he may have been on the right track. In situations where so much is unknown (and that is most definitely the case here), others may prefer to trust that what isn't yet known is of no concern.
However, it is our ability to question that has been, and will continue to be, the strongest asset humans have in our effort to ensure that we do not become victims of our own ignorance.
Jay Gregory is a biochemist and principal consultant with Jay Gregory Consulting in Eugene. Gregory is also a volunteer researcher with the Northwest Center for Alternatives to Pesticides, found online at www.pesticide.org).