August 22, 2003
Chemical Pollution Series (Part 4) - Pesticides could become the ultimate male contraceptive - why?
In 2002, a series of seven, one-page articles appeared in the New York Times.
The primary goal behind them was to alert people to the types of threats we all face
from environmental pollution - specifically from a group of compounds called Persistent Organic Pollutants or POP's.
Since the collection of data on the distribution and concentrations of POP's (also known as EDC's, BPT's and organohalogens)
in the world's oceans is a focus of our work - it seems fitting to present another take on this issue.
We are grateful to the authors and sponsors of these articles for permission to include them here.
For more information and to view all of the articles go to www.childenvironment.org.
Sperm defects, sex
reversals and other
Something is happening to the
reproductive system of the males of
many species. It's happening to male
birds of prey around the Great Lakes
and male alligators in Florida. To male
harbor seals in the Netherlands and
male polar bears in the Arctic. And to
boys and men throughout the
Scientists have amassed a great deal of
evidence linking reproductive system
abnormalities, reduced sperm motility,
sperm defects, sex reversals and altered
sex ratios with exposure to an array
of synthetic chemicals known as
endocrine disruptors. These include
pesticides and certain industrial
chemicals like dioxin, PCBs, and
phthalates, as well as arsenic, lead,
and mercury. Some of these chemicals
"mimic" estrogen; others interfere
with testosterone and some block the
As physicians and scientists, we are
concerned that despite the growing
scientific evidence, these chemicals
are still on the market.
What We Know
Medical studies have indicated that the
sperm counts of males in America and
Europe have decreased over the last
fifty years. Despite gaps in the data,
sperm counts have clearly declined in
many places and are inexplicably low
in others. The most sophisticated
analysis, published in Environmental
Health Perspectives, the journal of the
National Institute of Environmental
Health Sciences, indicates the decline
may be as great as forty percent.
We know that some chemical workers
exposed to endocrine-disrupting
pesticides have been made temporarily,
and in some cases, permanently sterile.
Dioxin, produced in the incineration
of trash containing polyvinyl chloride
plastic and chlorine-treated paper,
has been shown to be responsible for
birth defects and other reproductive
problems in birds of prey around the
Great Lakes. Dioxin is extremely toxic,
and exposure as low as 25 parts per
trillion causes feminizing effects in
animals. A dioxin accident in Seveso,
Italy, was followed by a decrease in the
number of boys being born. The ratio
of boys to girls is also decreasing in the
U.S., Canada, and Denmark. A Danish
study found a link between endocrine
disruptors and the increasing incidence
of undescended testicles in boys.
Endocrine disruptors affect women as
well. Several animal studies link small
exposures to dioxin with endometriosis.
What We Can Do
Parents should limit their children's
exposure to pesticides, both outside
and in the home. Organically produced
foods should be purchased whenever
possible. And care should be taken
to see that no fish from contaminated
waters are consumed. There are
more suggestions on our website,
But we must do more. Though not
the sole cause, it's clear that exposures
to endocrine disruptors can be
contributors to reproductive problems
in both animals and humans. Some
synthetic chemicals already shown to
adversely affect animals and humans
are still being sold today. And other
chemicals in the same chemical families
have not been tested. Wouldn't we all
be better off if chemicals had to be
tested for safety before they were put
on the market? Certainly males would
be better off.
A summary of the supporting
scientific evidence, and a list of
scientific endorsers, can be found
- To download a PDF version of this article - click here
- Read previous reports from this series on chemical pollution - part 1, part 2 & part 3.