Low Doses of
Herbicides/Pesticides Matter
“there may not be an identifiable no-effect level” *
*Understanding Pesticides
Endocrine Disruptors: When Less is More
Journal of Pesticide Reform/ Winter
2006, Vol 26, No. 4
Excerpts:
The
unfolding discovery of how endocrine disrupting chemicals work challenges the
most basic assumptions about how pesticides should be regulated. Endocrine disruptors are chemicals that at
very low doses interfere with the hormonal systems in humans and wildlife. Hormones control and coordinate many of the
body’s functions, especially those related to reproduction and brain chemistry.
(1)
What
makes endocrine disruptors so significant is that they
are not bound by the classic assumption that “the dose makes the poison,” that
by lowering the dose, at some point the chemical will no longer be toxic. This
threshold-based system of determining pesticide toxicity, used in regulations
and by industry, is simply not capable of identifying and protecting people and
wildlife from endocrine disrupting chemicals.
Many
pesticides are believed to be endocrine disruptors. The European marine
protection organization, the OSPAR Commission, has identifies fifteen endocrine
disrupting pesticides or groups of pesticides that are of concern to marine
life. (2) But dozens more are being looked at as threats to humans and wildlife
as well. (3) Some so-called inert ingredients found in pesticide products,
already identified as hazardous by EPA but not listed on product labels, also
show up on lists of suspected endocrine disruptors. …
What Damage is Caused?
Studies
have shown that endocrine disruptors are linked to fetal deaths, hypospadias (a birth defect of the penis), compromised
immune systems in children, lower sperm counts, and early onset
puberty.(4) Their role in causing cancer
is suspected though not proven.
Especially sobering is the fact that every human being alive today
contains measurable levels of endocrine disruptors (5). Even polar bears and Inuits living in the Far North have them (6). The website
of the authors of Our Stolen Future,
the book that first documented the effects of endocrine disrupting chemicals on
wildlife, discusses the health and environmental effects of endocrine
disruptors in detail. (7)
Throw Out Your Old Dose-Response Curves
Until
the discovery of endocrine disruptors, toxicologists worked on the assumption
that higher doses would always have more of an effect than lower doses. This is called a monotonic dose response
curve. It turns out that endocrine disruptors are often more active at lower doses than at higher doses…..
(1) National
Institute of Environmental Health Sciences. 2006 Endocrine
Disruptors. http://www.niehs.nih.gov/oc/factsheets/pdf/endocrine.pdf
(4)
Scientific findings of the impacts of endocrine disrupters at low dose. http://www.ourstolenfuture.org/NewScience/lowdose/lowdose.htm
(5) http://www.ourstolenfuture.org/NewScience/ubiquitous/ubiquitous.htm
(6) Pilar,F., J.O. Grimalt. 2003 On the global distribution of persistent
organic pollutants. Chimia57(9)514-521