Hormonal horror in the household chemistry lab

Widely used synthetic chemicals linked to reproductive mutation

By: Ron Chepesiuk

  Are synthetic chemicals - which we encounter daily in everything from pesticides to plastic wraps to shampoos - damaging the health of the human species?
  That's a question scientists have been trying to answer since the early 1960s, when researchers first observed some startling mutations in wildlife: panthers born with underdeveloped testicles, alligators with shriveled penises and seagulls born with both male and female organs.
 

New studies conducted during the past year by teams of scientists at the U.S. Environmental Protection Agency (EPA) and the Chemical Industry Institute of Toxicology (CIIT) show a host of common chemicals can emasculate males by a new, ignored route: the blocking of androgens, or male sex hormones

  Decades of studies show similar reproductive and developmental abnormalities are occurring in humans, say Theo Colborn, Dianne Dumanoski and John Peterson Myers in their landmark 1996 book, Our Stolen Future (see www.osf-facts.org).
  Since then, other researchers have attempted to link synthetic chemicals - or endocrine disruptors, as they are known - to an alarming apparent drop in sperm count worldwide.
  The suspected chemicals include phthalates, which are found in plastics, vinyl flooring, adhesives and food packaging; alkylphenols (industrial and domestic detergents and some shampoos); Bisphenol A (resins that coat food cans); organochlorine pesticides (such as DDT, which is still being used in developing countries); and dioxins, produced during incineration and some industrial processes.
  "Endocrine disruptors are ubiquitous in the environment and can be found in virtually every plastic container and detergent," says Peter DeFur, a scientist and professor at Virginia Commonwealth University in Richmond, Va., who has studied the impact of endocrine disruptors on wildlife.
  Earlier research showed that endocrine disruptors were doing damage by mimicking the female sex hormones called estrogens. But new studies conducted during the past year by teams of scientists at the U.S. Environmental Protection Agency (EPA) and the Chemical Industry Institute of Toxicology (CIIT) show a host of common chemicals can emasculate males by a new, ignored route: the blocking of androgens, or male sex hormones.
  "We have found that androgens do block the action of male fetuses so that some of them look like females," explains Dr. Earl Gray, an androgen toxicologist with the EPA, who has co-authored five studies on the subject. "We have males with undeveloped testicles and malformed penises and some have even been born with a vaginal pouch."
  These startling results arise from experiments performed on laboratory rats, leading researchers like Dr. Gray to quickly point out how little direct research there is on the impact of endocrine disruptors on humans.
  Since conducting laboratory experiments on humans would be unethical, Dr. Gray explains, the only remaining course is "to conduct surveys of suspected exposed populations. But they are long, expensive, complicated by some variables and difficult to do."
  Still, the animal experiments do raise some red flags. Those studies suggest that subjects are most vulnerable to the effects of endocrine disruptors in the womb, early infancy, and pre-puberty. Dr. Gray has identified about 10 chemicals as being suspect. "We haven't defined the whole universe yet, butthere seems to be more and more chemicals," he says.
  There is, however, more research on the way. The U.S. government, for instance, has initiated two new projects to learn more about the impact of endocrine disruptors: the National Institute of Health and the Centers for Disease Control and Prevention are collaborating on a project to improve assessment of human exposure to environmental endocrine disruptors, while the EPA began testing protocols to screen for endocrine effects in September 1998.
  Working under congressional mandate, the EPA will attempt to screen some 87,000 chemical compounds by the end of 2000,at a cost of more than $100 million.
  "We will start off with a lot of chemicals - but only a small fraction of them will be screened and tested," says Gary E. Timm, a scientist with the EPA. "That's because a lot of the chemicals aren't produced anymore; others are used to make another substance, and some are polymers, which means they can't get into the (human) system."
  Since 1998, the EPA's Endocrine Screening and Testing Advisory Committee has dismissed fears about 20,000 of the chemicals that were to be screened, but says 60,000 chemicals should continue to be investigated.
  But will the EPA's mega-screening project settle the big question - do widely used synthetic chemicals have a disastrous effect on the reproductive systems of humans?
  Scientists have disagreed about that one for a long time, so don't expect the answer any time soon.

A native of Thunder Bay, Ontario, Ron Chepesiuk is a freelance health writer based in Rock Hill, South Carolina.

Get More/Do More
For more information on endocrine disruption, check out Our Stolen Future, by Theo Colborn, Dianne Dumanoski and John Peterson Myers.

Get the latest findings from the EPA's Endocrine Screening and Testing Advisory Committee website.

 

Seven ways to reduce exposure to endocrine disruptors Drink distilled water Wash hands before eating Reduce your exposure to pesticides by not using them in your home, lawn, or garden, and avoiding areas freshly sprayed with pesticides Reduce consumption of animal fat, since the storage of chemicals in animal fat is a prime means for synthetic chemicals to enter the human body Try to avoid putting plastic wrap in direct contact with food Substitute ceramic containers or heat resistant glass for plastic containers when cooking Buy rechargeable batteries that are mercury free and dispose of them carefully Source: World Wildlife Fund

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