EPA Proposes Hormone Tests for Chemicals

By MARLA CONE

May 2, 1996 12 AM PT

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TIMES ENVIRONMENTAL WRITER

As concern mounts that chemical pollutants are feminizing animals and perhaps depleting human sperm, the U.S. Environmental Protection Agency has proposed new guidelines requiring pesticide manufacturers to screen their products for the ability to alter hormones.

The EPA’s move is the government’s first step toward trying to protect the public from some of the risk posed by an array of chemicals, known as endocrine disrupters, that mimic estrogen or block testosterone.

Under the new guidelines, chemical manufacturers would look for abnormal estrogen cycles and sperm counts and malformed genitals of adult laboratory rats and their offspring after exposure to pesticides. Discovery of significant effects could lead to restrictions on new pest-killing products and perhaps some already used by farmers, home gardeners and others.

The guidelines--part of a broader package of changes to update the EPA’s methods of screening pesticides for health effects--are expected to be approved by the agency’s Science Advisory Board in September and could be implemented by the end of this year.

The proposal comes at the crest of a wave of worldwide concern among many scientists about the effects that gender-warping pollution may be having on fertility and reproductive organs.

Scientific studies have shown that many wild animals have half-male, half-female sex organs and abnormal estrogen and testosterone levels because of pesticides and industrial chemicals that act like hormones. Included are birds on California’s Channel Islands and in the Great Lakes, alligators in Florida, otters in the Pacific Northwest’s Columbia River and trout in British rivers.

In humans, some researchers suspect that the hormone-mimicking chemicals could be causing a sharp decline in male fertility and an increase in rates of testicular and breast cancer, endometriosis and other reproductive disorders.

Several studies of European men show that average sperm counts have dropped by nearly half in the past 50 years--the same era in which modern chemicals emerged. Two new studies in the United States, however, found no such decline over 20 years, puzzling experts and stirring up a controversy about whether male fertility is declining.

Despite such uncertainties, Assistant EPA Administrator Lynn Goldman called the risks posed by hormone-altering pollution “a very important environmental problem to the Clinton administration.” The EPA is especially worried about the threat to infants, since the chemicals appear to have the ability to pass through the mother’s womb to damage the reproductive organs and fertility of unborn children, she said.

“We at the EPA cannot sit here and say, ‘These tests have worked for us for 20 years and we’re going to keep on using them.’ We have to update them as knowledge improves,” said Goldman, who oversees pesticide and toxics control.

The tests would be used to screen all new pesticide products before they are sold, but they would be required only on a limited basis for the hundreds of compounds already in use.

“These tests are two-generation toxicity tests. They take a long time, they are very expensive, and not every chemical is going to need to run through it,” Goldman said.

Every year, commercial farmers and residential gardeners in the United States apply hundreds of millions of pounds of pesticides that have imitated estrogen or impaired testosterone in some laboratory tests. Included are atrazine, a herbicide used on corn; endosulfan, used to kill insects on many fruits and vegetables, and the farm and yard weedkiller 2,4-D.

Chemical manufacturers acknowledge that wild animals in some highly contaminated areas are in danger of altered hormones, but they say the threat to people, who are exposed to far less pesticide residue, is hypothetical. More research is needed, they say, before it is known whether there is any threat of problems with human sperm or reproduction.

Pesticide industry officials said they support the EPA proposal to update the guidelines, although they say their current tests have been effective in screening chemicals for serious reproductive problems.

“It’s a natural evolution of upgrading our ability to refine these tests--do a little bit better, if you will,” said John McCarthy, a vice president of the American Crop Protection Assn., which represents major pesticide companies, including Monsanto, DuPont and Rhone-Poulenc. “But I don’t think it’s going to find adverse effects we couldn’t find before with the standard tests we’ve used all along.”

Current pesticide screening tests had been designed to examine whether a chemical causes the more obvious forms of health damage--cancerous tumors, low birth rates and birth defects. But new research has shown that pollution is capable of causing biological damage in animals--such as defective sperm--that is more subtle and could be missed under the EPA’s basic tests.

“Now they are beginning to look at organ function, actually getting into the testes and looking at sperm production. In the past, if the baby was alive, and had arms and legs, it was assumed the chemical was safe,” said Frederick vom Saal, a reproductive biologist at the University of Missouri at Columbia.

But vom Saal said the EPA’s new guidelines are inadequate to ensure that pesticides are safe and could miss some of the very effects they are designed to screen.

With hormone-like chemicals, damage to sperm and testicles occurs at very low levels of pesticide exposure, while high levels produce entirely different effects. The doses manufacturers use in the EPA-ordered tests may be too large to reflect the hormone damage that people face, he said.

“The concept that more is worse may apply to cancer, but absolutely not to hormones,” vom Saal said. “High doses don’t predict what lower amounts do. The American public wants to know the consequence of the amount of a chemical they are actually exposed to. Essentially that’s what really matters.”

Vom Saal said the pesticide industry has put pressure on the EPA to dilute and delay earlier, more stringent versions of the new guidelines.

“Industry has been pounding on this, to put it mildly,” he said. “These new guidelines should have been out a long time ago.”

EPA officials acknowledge that the tests are not definitive in detecting hormone damage, but say they are better than the current ones.

“This will improve our ability to detect reproductive effects,” said Penelope Fenner-Crisp, deputy director of the EPA’s Office of Pesticide Programs. “These changes are prompted primarily because the last time we had written test guidelines for reproductive and developmental effects was over a decade ago. It’s not simply because we were responding to this particular [hormone] issue.”

The main purpose of the new guidelines, in the works for several years, is to detect damage that crosses generations. In most cases, a man or woman exposed to a pesticide that mimics estrogen or blocks testosterone would be unharmed, but the woman could give birth to children with abnormal hormones, which leads to depleted sperm or reproductive disorders when they reach adulthood.

Researchers suspect that environmental chemicals have an effect similar to those that resulted when pregnant women took the anti-miscarriage drug DES in the 1950s and 1960s. The drug, a synthetic hormone, left their daughters and sons with reproductive problems.

Fenner-Crisp said existing pesticides would undergo the sperm and estrogen tests only in cases where there already are signs of reproductive trouble, such as malformed testicles.

“If a study was done on an old chemical two or three years ago and it is considered adequate according to the standards at the time . . . I would not likely ask for anything to be done again,” Fenner-Crisp said. “The pesticide industry is concerned that we may choose to have them do everything to every chemical. My personal opinion is it won’t come to that.”

The pesticide companies support the EPA’s case-by-case approach.

“We don’t think that you have to, just as a matter of policy, go back and retest everything,” McCarthy said. “It wouldn’t be a prudent use of resources. I don’t think that’s compromising public health.”

A widely used fungicide, vinclozolin, may be one of the first to face restrictions under the new guidelines. Earlier tests by the manufacturer, BASF, showed that male offspring of rats exposed to the fungicide had abnormal testicles, but no one knew why until 1994, when the EPA discovered that the substance blocks development of testosterone.

The new tests “could lead us to identify the need for lower levels of exposure” to vinclozolin, Fenner-Crisp said. From 300,000 to 500,000 pounds are applied annually on U.S. crops.

Finding sperm or estrogen abnormalities does not necessarily mean the EPA will ban a pesticide. Restrictions are imposed only if the agency concludes that the levels people are actually exposed to in their food or environment pose a substantial health risk.

McCarthy said the pesticide industry “will not object” to new restrictions on products if hormonal problems are identified in “well-conducted scientific studies.”

The EPA is trying to shift away from animal experiments and toward simpler petri-dish tests that take advantage of advances in molecular biology, but reliable ones for detecting hormonal changes have not yet been developed.

“Right now, we are still dependent upon testing in animals to understand what may happen in the human being,” Fenner-Crisp said. “Until we have something better, they are a first line of defense.”

(BEGIN TEXT OF INFOBOX / INFOGRAPHIC)

Pesticide Risks

These are some of the most widely used pesticides that have been shown to disrupt hormones in animals or cells studied in laboratory tests. Some imitate estrogen, while others block testosterone.

HERBICIDES

NAME: 2,4-D

USES: Widely used in agriculture and as yard weedkiller

ANNUAL U.S. PRODUCTION: 40-65 million pounds

NAME: Alachlor

USES: Corn, peanuts, soybeans,sorghum, ornamental plants

ANNUAL U.S. PRODUCTION: 55-70 million pounds

NAME: Atrazine

USES: Primarily corn

ANNUAL U.S. PRODUCTION: 70-80 million pounds

NAME: Trifluralin

USES: Many fruits, vegetables, plants, outdoor home uses