COLUMN ONE : Sexual Confusion in the Wild : From gators to gulls, scientists say, pollution may be playing havoc with animals’ hormones. Some males try to lay eggs; some females nest together. Certain species may risk extinction.

In the gender-bending waters of Lake Apopka, alligators aren’t quite male. They aren’t quite female either. They may be both. Or neither.

This sexual confusion in the wild, discovered in this steamy Florida swamp last year, is so disturbing to scientists that they keep performing test after test on the scaly reptiles, trying to prove themselves wrong. But the more they look, the more evidence they find. In fact, hardly any young alligators with normal sexuality can be found in this vast lake on the suburban outskirts of Orlando.

Elsewhere around the world, the same astonishing phenomenon is turning up in a menagerie of fish, birds and other wild animals. Testosterone levels have plummeted in some males, while females are supercharged with estrogen. Both sexes sometimes are born with a penis and ovaries, and some males wind up so gender warped they try to produce eggs.

“Everything is really fouled up. It is indeed real, and it is scary,” said Tim Gross, a University of Florida wildlife endocrinologist on the team that discovered the feminized alligators. “We didn’t want to believe it, in all honesty.”

This is no fluke of Mother Nature, no quirk of evolution. This is probably a legacy of pollution.

Wildlife scientists have uncovered persuasive evidence that artificial pesticides and industrial chemicals are infiltrating wombs and eggs, where they send false signals imitating or blocking hormones, which control sexuality. Although the parents are unharmed, their embryo’s sexual development is disrupted, and some male offspring are left chemically castrated and females sterile.

The potential consequences, if unabated, are almost unthinkable.

If males aren’t male and females aren’t female, they cannot reproduce, and some outwardly healthy populations could be a generation away from extinction.

“Biologically, this is the most significant thing that could impair species and populations across the continent and across the globe,” said Timothy Kubiak, chief of contaminant prevention and investigations at the U.S. Fish and Wildlife Service.

So far about 45 chemicals, many of them organochlorine pesticides widely used by farms and households to kill insects and weeds, have mimicked estrogen or inhibited testosterone in laboratory tests and in wild animals.

No one knows what this portends for humans--who often encounter the same chemical residues in their food and water. But because hormones play a role in the human body identical to other creatures, some scientists are alarmed by the potential of adults passing infertility and other reproductive defects such as prostate cancer on to their children.

The ability of these chemicals, called endocrine disrupters, to leave the parents unharmed but afflict the unborn is so alarming it was not even imagined by author Rachel Carson, who warned of pesticides run amok in her 1962 environmental classic, “Silent Spring.”

The most insidious aspect is that the damage easily goes undetected; the animals look healthy, even to experts. Their bizarre sexuality is discovered only if their internal genitalia are examined or their hormones are tested.

Although the threat of environmental hormones is newly recognized, many scientists and government agencies have given it a rare urgency. Other researchers, however, remain skeptical, saying more evidence is needed to comprehend the scope of the threat and pinpoint the chemicals to blame.

Many of the scientists’ findings are so new they have yet to be reviewed by their peers and published. Nonetheless, 21 biologists recently took the unprecedented step of warning in a position paper that “impacts on wildlife and laboratory animals . . . are of such a profound and insidious nature” that swift government action is warranted. In response, the National Academy of Sciences is hastily convening a panel to analyze the findings and guide research.

“My fear is that we will find more and more instances of this as we learn what to look for,” said Ohio University reproductive biologist Brent Palmer, who found male cormorants in the Great Lakes and possibly some male frogs in California producing female egg proteins. “It doesn’t seem like a few isolated incidents. The problem keeps snowballing and getting worse and worse.”

Sexual Messengers

Estrogen and testosterone are the body’s sexual messengers, ordering embryos how to grow. When a pregnant animal is exposed to even a minuscule dose of a hormone during the onset of its embryo’s sexual development, the gender of the offspring can be irreversibly altered, biologists say. In some cases, the father could be passing the defect to his young via his sperm or semen.

Because hormones also regulate the embryo’s immune system and brain development, the offspring might also be prone to disease and behavioral disorders.

“It is the hand-me-down poison, from parents to offspring,” said World Wildlife Fund senior scientist Theo Colborn.

Certainly, most populations of animals seem nowhere near collapse.

But many animals that are dependent on heavily polluted waters for their food are suffering serious reproductive defects that have been linked to environmental hormones--alligators and turtles in Lake Apopka, sea gulls and some fish off the coast of Southern California, great blue herons in British Columbia, terns in Massachusetts, sturgeon in the Missouri River, trout in Great Britain, seals in the Netherlands, and an array of fish, birds and mammals in the Great Lakes.

“When it’s bad enough to scare us, it’s bad. And when I sit down and think about this, it scares me stiff,” said Charles Facemire, a Fish and Wildlife Service toxicologist in Atlanta who has investigated contaminants for nearly 20 years.

Wildlife biologists also have begun studying whether hormone-disrupting chemicals are behind the unexplained declines of some creatures, such as frogs that are vanishing throughout much of the Western United States, and several endangered and threatened species. Many bald eagles are failing to reproduce along the Great Lakes and the Pacific Northwest’s Columbia River. In South Florida, a feud has erupted over whether environmental hormones are to blame for sperm and testicular disorders in the last living 30 to 50 Florida panthers.

Across the nation, the severity of pollution has dramatically declined since the 1970s, when die-offs and birth defects in eagles, pelicans and other animals prompted chemical bans and cleanups. But zoologists suspect that smaller volumes of pesticides and other chemicals originally thought to be benign may be gradually depleting populations.

At the Great Lakes, 4 parts per million of polychlorinated biphenyls, or PCBs, will kill an eagle’s embryo. But a much tinier amount--perhaps measured in parts per billion--during a key stage of development might be enough to alter the newborn’s hormones and leave it sterile, experts say.

“If contaminants prevent an animal from reproducing, it will not replace itself,” said zoologist David Crews at University of Texas, Austin, who created hermaphroditic pond turtles by painting eggs with 1 p.p.m. of PCBs. “No normal animal will be born there.”

To the U.S. Environmental Protection Agency, which regulates chemicals, most worrisome is the abundance of commercially sold substances that seem capable of altering hormones.

Among those are the world’s most widely used herbicides, including alachlor, atrazine and 2,4-D. About 170 million pounds of the three herbicides are sprayed each year on U.S. corn, soybeans and other crops, as well as gardens and lawns. Nonylphenols, popular industrial compounds used in plastics and detergents, also were identified.

“A lot of these are things you can buy off the shelf at your local hardware store,” Facemire said. “We’re finding more all the time.”

For many of these chemicals, evidence of their ability to tamper with hormones is based on laboratory tests. In wild animals, including Florida alligators, the most compelling proof has been detected in waters polluted with either DDT, a pesticide that blocks testosterone, or PCBs, which imitate estrogen. Used in enormous volumes until they were banned in the United States in the 1970s, these chemicals still pollute hundreds of lakes, streams and coastal waters.

Although the impact on animals is documented, the human implications remain highly theoretical. Some reproductive scientists suspect that exposure to environmental hormones could be lowering sperm counts in men and contributing to sharp increases in prostate and testicular cancer as well as breast cancer and endometriosis in women.

But veterinary toxicologist Stephen Safe of Texas A&M; University is skeptical. Although he acknowledges that the wildlife data in highly polluted waterways is convincing, he is skeptical about inferring any impact on humans or on wildlife in less contaminated areas. People, he says, constantly are barraged with naturally occurring hormones in plants and food with no ill effects.

“The environment and organisms, including humans, have tremendous resiliency,” said John McCarthy, vice president for science and regulatory affairs at the American Crop Protection Assn., which represents pesticide manufacturers. “It doesn’t mean you should go out and bombard them unnecessarily, but it just doesn’t seem like we’re going downhill fast and headed toward a crash in a generation or two.”

But most scientists look to animals as sentinels for environmental quality and human health. Holding out for more proof before restricting the chemicals, Kubiak said, “is like waiting for the gangrene that started in your legs to go up your arms before cutting off your legs.”

Gulls a Tip-Off

Few people were paying attention when the first hint of trouble arose more than 20 years ago, off the coast of Los Angeles.

Sea gulls on Santa Barbara Island--a major breeding area--were showing peculiar sexual behavior. Females were pairing up and sharing nests. Upon closer examination, two Southern California scientists found the reason.

They counted as many as 19 female gulls on the island for every male.

Where, they wondered, had all the males gone?

Because of the skewed gender ratio, the island’s colony of Western gulls started to collapse, dropping from 3,000 pairs in the 1950s to about 700 by the mid-1970s.

Avian toxicologist Michael Fry of UC Davis had a theory.

He wondered if DDT, notorious for thinning the eggshells and killing the embryos of Southern California pelicans and cormorants, could be to blame for the missing males. Between 1950 and 1970, about 4 million pounds of the pesticide was pumped into the ocean at the Torrance headquarters of Montrose Chemical Corp.

Gulls, unlike pelicans and cormorants, had seemed to be unharmed by DDT. They had no visible birth defects or other physical disorders. But looking further, Fry was shocked to find many gulls had both testes and ovaries. To confirm his finding, he injected gull eggs from uncontaminated Mono Lake with amounts of DDT comparable to that found on Santa Barbara Island. In his laboratory, he crafted hermaphroditic birds.

“It turned out that DDT has two very different effects,” Fry said. “In gulls, DDT in eggs caused abnormal development of the males. Chemical neuterization.”

Fry’s work--published in the journal Science in 1981--was the first evidence that environmental contaminants seemed to be feminizing wildlife.

While some scientists noted it, most shrugged it off.

At the time, common wisdom held that contamination that did not kill or maim animals was harmless. If an animal was alive, it was assumed to be healthy and fertile. Most biologists dismissed Fry’s discovery as an inexplicable quirk at a uniquely contaminated spot.

3,000-Mile Parallels

But 3,000 miles away, Quebec scientist Glen Fox was intrigued. Fox, a Canadian government wildlife toxicologist, had noticed female herring gulls sharing nests at Lake Michigan and Lake Ontario--also contaminated with DDT as well as PCBs. He called the California toxicologist for help, and Fry found the identical half-male, half-female phenomenon. Still, their work was met with skepticism.

“I had a great difficulty convincing the scientific community that this was a real thing,” Fry said.

Six years later, zoologist Theo Colborn was researching a book on Great Lakes wildlife for a conservation group when she began turning up studies indicating more than a dozen birds, fish and mammals were suffering ailments linked to heavy DDT and PCB contamination.

The oddest part, she thought, was that problems weren’t showing up in adults that grew up in the 1960s and 1970s, when pollution had peaked. Instead, cormorants born more than a decade later had twisted, mutated bills, and the only healthy eaglets seemed to have parents that had just migrated to the lakes. Most young trout and other fish had disappeared, except for those that had been stocked.

“It was very evident that the problems affecting wildlife around the Great Lakes were not in the adult animals, but their offspring. The offspring that survived were not in very good shape,” said Colborn, now a senior scientist with the World Wildlife Fund.

Tapping into an electronic database, Colborn pulled together hundreds of scientific reports. She learned reproductive problems had been detected in almost every developed country since modern chemicals were introduced after World War II.

But because the reports came from scientists from a wide array of disciplines who rarely see or hear about each other’s work, no one had noticed the similarities.

“By the fall of 1988, it became very overwhelming that there was something really wrong,” Colborn said. “As I put it all together, I had to do something with it.”

Finally, in the summer of 1991, Colborn convened a meeting of 21 North American and European zoologists, pathologists, immunologists and other scientists researching the endocrine systems of humans and animals.

After three days, they issued an alarming six-page statement. “Many wildlife populations are already affected by these compounds,” the scientists concluded. “It is urgent to move reproductive effects to the forefront. . . . A major research initiative on humans must be undertaken.”

Last December, at a follow-up workshop, the warnings only intensified. Rarely does such a clear consensus emerge in science.

But even Fry had assumed the worst of the reproductive damage was over. PCBs and DDT were banned in the 1970s, and contamination levels in fish and wildlife have gradually decreased.

Then last year, when he visited New Bedford Harbor--a bird breeding area near Cape Cod contaminated with PCBs--11 of 15 terns he examined had the same bizarre sex organs he had seen in California a decade earlier.

His colleagues have become believers.

‘A Big Whodunit’

As the sun rises over Florida’s Lake Woodruff, three air boats slice through the tranquil morning mist, their engines roaring like Cessnas rising from a runway.

H. Franklin Persival races his craft across the swamp’s overgrown carpet of water lilies and pulls up to a pink nylon banner tied to a cypress. The banner means an alligator nest, spotted from the air, is hidden just offshore.

Grabbing a pair of wooden stakes, a wire loop, a magnet and some dental floss, Persival bounds onto the muddy banks. He deftly sidesteps saw-like blades of marsh grass, fist-sized spiders and mounds of fire ants, approaching a small clearing, where he finds a five-foot-wide nest woven like a basket from grasses and branches.

Quickly, Persival sets up a crude radio-activated trap atop the nest, hoping the unsuspecting mother alligator will crawl through and get her snout snared.

The research is grueling in merciless 98-degree heat, but the six-man team stops its alligator rodeo only long enough to dodge late-afternoon lightning storms. They know they have little time to waste if they want to save the lake’s alligators from extinction. So many questions, so few answers--”a big whodunit,” says Persival, a National Biological Survey scientist.

Each summer, the team collects eggs, blood and tissue from alligators at both Lake Apopka and Lake Woodruff, a national refuge on the St. Johns River about 50 miles north of Orlando. Woodruff is considered a healthy lake, useful for comparing estrogen and testosterone in its alligators to those from Lake Apopka, one of Florida’s most contaminated waterways.

In 1980, Tower Chemical Co. spilled a large quantity of Kelthane, a pesticide containing DDT, along Lake Apopka’s banks. Fertilizers and insecticides routinely flow off nearby citrus groves and other farms, while little fresh water is allowed in. Even Hurricane Andrew took a swipe at Apopka and stirred up its polluted sediments.

“Everything that could happen to a lake has happened to this one,” said University of Florida alligator biologist Ken Rice.

Since the early 1980s, alligator births at the lake have dropped fivefold, which prompted the scientific team to begin exploring the cause. Apopka provides an ideal test case, since the population crash was fairly recent, and the research offers the most convincing proof so far that chemicals still are causing hormonal damage in wildlife.

The first breakthrough in finding why alligators are vanishing came in the fall of 1992, when endocrinologist Tim Gross, conducting routine sex typing on Apopka’s turtles, couldn’t tell males from females.

The following March, zoologist Louis Guillette Jr. and Gross examined 6-month-old alligators hatched in their laboratory from eggs from the lake. Males had the high estrogen and low testosterone typical of a female, while females had double the normal estrogen and were laying clutches that, instead of containing the usual one egg, had as many as seven, all dead. A few months later, the scientists confirmed sexual abnormalities in gators born in the wild--four of 12 had part-male, part-female genitals.

“It sent up signals and flags and fireworks and we knew something was going on there,” said Guillette, director of the University of Florida’s reproductive analysis laboratory. “ . . . We now know that every single animal that we thought was a female in Lake Apopka had abnormal gonads.”

DDE, a metabolite of DDT, was found in the tissues, and the team replicated the link in the laboratory when they painted eggs with minute amounts--as low as 10 parts per billion--and the young were born with abnormal hormones.

In comparison, not a single alligator at Lake Woodruff had hormonal or sexual defects.

Still unconvinced, the researchers returned to both lakes this summer. At night, they kicked around every imaginable theory, even an unlikely one they jokingly named the “shanty-town girl hypothesis”--that perhaps Lake Apopka is a magnet for poor, weak female gators. “We wanted to be 100% sure,” Gross said, “before we opened our big mouths.”

In August, they finally published their findings in a scientific journal, warning that their two years of studies “have only begun to address what we believe could be a serious, widespread threat to wildlife populations” and perhaps humans.

Vital questions remain. How is the damage physically passed from mother or father to embryo? How many chemicals are to blame, and at what concentrations?

“What we have is circumstantial evidence, but if you want to indict a certain chemical, we need a whole lot more evidence,” Persival said. “Even if we then find what chemical it is, then what do we do about it?”

Gross suspects that “anything that eats anything off that lake potentially can be affected.” But his fears go further. “I think Lake Apopka is just one case. I don’t think it’s even the worst case. Those (chemicals) have been used worldwide over a lot of environments.”

Hundreds of species, from grebes at Southern California’s Salton Sea to dolphins along the Atlantic Coast, suffer from mysterious ailments that could be linked to environmental hormones. Hoping to determine the national scope, Interior Secretary Bruce Babbitt is seeking federal research funds in 1996.

Perhaps future generations are in better shape today because DDT and PCB pollution levels have receded. Or is the worst yet to come because other chemicals that might be creating sexual chaos still are used?

The answers, scientists say, lie hidden in the unborn.

“The seeds for the next generation are already planted,” Gross said, “and that is what’s scary.”

NEXT: The implications for humans.

Tracing the Damage

Many wild animals exposed to endocrine-disrupting chemicals are suffering severe reproductive problems, including hermaphroditic sex organs and abnormally low birth rates. Substantial evidence has been found that contamination has caused disorders in alligators in Florida’s Lake Apopka, sea gulls in California’s Channel Islands, terns in Massachusetts and various fish and birds at the Great Lakes. With some species, such as Florida panthers that have low sperm counts, wildlife experts only suspect a link to pollutants.

A) Location: Columbia River

Species affected: Bald eagles

B) Location: Salton Sea

Species affected: Egrets, stilts, white-faced ibises, cormorants

C) Location: Channel Islands

Species affected: Western gulls

D) Location: Missouri River

Species affected: Pallid sturgeon

E) Location: Tennessee River

Species affected: Osprey

F) Location: Great Lakes

Species affected: Bald eagles, herring gulls, cormorants, perch, otters and trout

G) Location: Lake Apopka, north Florida

Species: Turtles, alligators

H) Location: Naples, south Florida

Species: Panthers

I) Location: New Bedford, Mass.

Species affected: Terns

Imitating Hormones

Hormone-imitating chemicals in the environment can cause infertility or other reproductive disorders that can devastate wildlife populations for generations. Here is how they work:

* Pollutant accumulates: A female animal eats food, such as fish, contaminated with an environmental pollutant that accumulates in her tissues.

* False signal: During an embryo’s development, the pollutant from the mother invades a reproductive cell and binds to its receptor, which sends a false signal mimicking estrogen. To the cell, the signal from a fake hormone is indistinguishable from a natural one.

* Proteins manufactured: The signal turns on the manufacture of certain proteins, such as those that produce egg yolks. A male fetus could then develop both a penis and ovaries. Such an offspring would be unable to reproduce.