Gender-bender chemicals pollute the James, and U.K rivers

Sharon Bricker

Just now, more than 700 research projects around the world are underway to help find an answer for this question: Why are fish from rivers in the United Kingdom and in Virginia blurring the line between male and female?

A group of chemicals tagged "endocrine disruptors" have been implicated in the creation of gender-bent fish, as well as a collection of other adverse physical and neurological effects in animals and, perhaps, in humans.

Some fish that are born male begin to show characteristics that are typically only found in females, and it happens more often in waters downstream of sewage treatment plants, according to a study of roach and gudgeon fish by researchers at Brunel University in the U.K., published in 1998.

When the research team first discovered the phenomenon in 1988, they were so surprised that they repeated the experiments three times to make sure they hadn't made a mistake, Brunel University reproductive physiologist Charles Tyler told OUTLOOK recently.

The surprise was that the male fish were producing and retaining vitellogenin, the egg yolk protein produced by female fish. Subsequent studies reported that at some study sites, 100 percent of the male fish had testes carrying developing egg cells -- some of which were well-formed enough to grow into baby fish if fertilized, Tyler said. This condition is called intersexuality.

Geoff Brighty, environmental toxicology manager for the U.K.'s Environment Agency, reacted similarly: "I thought, this is not possible. I still have to pinch myself sometimes. But the results are really compelling."

Similar effects have been found in the James River, where 40 percent of mature catfish caught in a 1998 study had no mature sex organs, said Peter deFur, an environmental physiologist at the Center for Environmental Studies at Virginia Commonwealth University.

The catfish had residues of potent chemicals, DDT, PCB and TBT, in their systems. All of these are now banned or regulated chemicals, partly owing to the chemicals' resistance to being broken down and disappearing from the environment. Each of these endocrine disrupting chemicals (EDCs) is also known to have similar effects in various animals, deFur said.
There is still an advisory on eating too much fish from the James River because the river was contaminated with Kepone (or chlordecone) in the 1970s, said Khizar Wasti, director of regional health hazards control with the Virginia Department of Health. Kepone was considered a threat because it is a neurotoxin and a carcinogen. It is also an insecticide with endocrine-disrupting properties, deFur said.

aerial view of the James River

DeFur said although the global effort to investigate EDCs has been broadened, it's still not enough. In the case of some substances, such as TBT, the question is not whether it has detrimental effects, he said. The questions are, how can it be controlled, and what is a safe level?

Some places in Virginia, including sections of the Potomac River, have PCB advisories, Wasti said. The James River in Richmond does not have a high enough contamination level to warrant an advisory, he said. The maximum allowable level is around 600 parts per billion in most jurisdictions. (By comparison, the salt in the ocean is usually about 35 parts per thousand.)

But Wasti said there is no set standard limit for Virginia. The Virginia Department of Health also considers the percentage of fish that are found to be contaminated -- more than half definitely warrants attention, he said -- and human use of the river. The Federal Department of Agriculture's approved limit for PCBs in fish is 2000 parts per billion (or 2 parts per million).
Intersexuality in the U.K. rivers and the James River is more than just an identity crisis for roachfish and catfish.

Entire wildlife communities in rivers may be affected if species have trouble reproducing, deFur said. Some chemicals, like DDT, hang around so long they are passed through the food chain to birds, crabs, and maybe even people.

Research is underway to identify specifically what happens to the animals (and humans) at each step of the way. These chemicals do damage in living things by acting like hormones, especially the estrogen type, and interacting with the hormone system. The chemicals may mimic natural hormones, block the operation of the real hormones, or act like a hormone but trigger an incorrect response from the body.

Hormones are the body's way of communicating messages about a wide range of functions. The endocrine system sends the rest of the body hormonal instructions for how to control body growth, organ development, metabolism, and processes such as kidney function and body temperature, deFur said.

In the U.S., most sewage treatment uses tertiary and quaternary processes to remove most of these compounds, but treatment in the U.K. doesn't usually reach that level, Tyler said. The U.S. also has more extensive waterways into which the sewage effluent can be dumped, allowing for better dilution.

In Richmond, treated sewage effluent is released into the James River. The wastewater treatment plant in Richmond has tertiary treatment, which includes a series of sand filters, then chlorination to kill harmful microorganisms, Superintendent of Operations Clair Watson said.

Watson was unaware of measures to test the effluent for estrogenic chemicals, but an independent laboratory does run tests to make sure sea life can live safely in the effluent, and the plant runs a battery of tests for metals, ammonia, suspended solids and other products, he said.

He estimated that building the tertiary treatment system cost the plant millions of dollars, but "you can't put a price on keeping the James River and the Chesapeake Bay clean," he said.
Watson said that there aren't many pesticides coming through the treatment plant, and the plant checks on industries to make sure their contributions of pollutants are within limits. Synthetic EDCs from pesticides that contaminate the James probably leached off of fields years ago and became trapped in bottom sediments of the river, he said.

Even barring tertiary and quaternary treatment, the U.S. has the benefit of a population that is more dispersed, and waste water does not need to be recycled as much, Brighty said.
"There are 20,000 sewage works in [the U.K.]," he said. "The American philosophy on wastewater treatment is dilute and disperse. Here, we don't have that luxury.
"Thirty percent of our drinking water comes from recycled waste water. Water use is going through the roof, so we have to take more water out of the system. We have to improve [treatment]." Endocrine disruption is one of the consequences of how the country has had to manage its water supply, he said.

Researchers' knowledge of the link between human disorders and EDCs is still largely hypothetical. The Environmental Protection Agency suggested in 1996 that EDCs may contribute to certain cancers, reproductive and developmental effects such as genital malformation, neurological effects such as behavior and learning, and suppression of the immune system.

Most examples of human health conditions allegedly caused by EDCs involved high exposures to these chemicals. The EPA cited the temporary sterility of workers exposed to especially high amounts of Kepone in Hopewell, Virginia in the 1970s.
Other accounts link consistent, lower-dose exposures with adverse effects. A 1996 study from the New England Journal of Medicine followed children with in-utero exposure to PCBs. The mothers of the children had eaten two or three fish meals a month in the six years before pregnancy.

The fish came from Lake Michigan, known to be contaminated with PCBs. The children with the most exposure to in utero PCBs had lower I.Q. scores at age 11 than the average population.

But researchers have published very few studies that confirm EDC-caused ailments. There are many recorded cases of correlation between exposure and human defects, but causation is difficult to establish.

In fish, there is a lack of knowledge on normal populations and how they change naturally, Brunel University's Tyler said. This problem is the same for most other organisms, including humans. Other interviewees for this article said that background knowledge of how specific hormones and mixtures of chemicals work is not strong yet, either.

Also, hormones are effective in vanishingly small amounts. As little as one-half or one-tenth of a nanogram in a liter of water can have biological effects, Tyler said. One-tenth of a nanogram is equal to one part in ten billion, or 1 / 10,000,000,000. This is a smaller amount than most methods can even detect, and is comparable to one step on the way to the moon, or about ten times the radius of a hydrogen atom.

Despite the difficulties, increased attention to the possible threat from EDCs has generated worldwide research efforts and funding, as well as large cooperative committees to evaluate the course of study for both humans and wildlife.

The United States and the European Union have both been compiling new standards for chemical testing, both to examine existing chemicals for endocrine-disrupting properties, and to prevent new EDCs from becoming widely used.

There are currently about 70,000 chemicals in commerce, deFur said. The EPA's guidelines recommend a two-part screening process that begins with suspected chemicals and may end with the eventual phasing out of dangerous substances.

Alkylphenols, chemicals resulting from the breakdown of industrial detergents, are already being phased out in Europe.

The problem is not just related to industrial chemicals. Studies in 1998 indicated that natural estrogens secreted in women's urine, and synthetic estrogens, the main ingredients in the contraceptive pill, were causing the fish to produce vitellogenin. The sewage effluent in that study was mostly domestic in origin.

While chemicals are being researched for endocrine-disrupting effects, improvement of sewage treatment plants in the U.K. would improve their water quality. That solution, however, would be very expensive, Tyler said.

"The sewage treatment companies are still waiting to see where the weight of the evidence will be," he said. Since the issue is still a new one, data for many different animal populations is still missing, and studies lack the benefit of repetition.

Water authorities in the U.K. may also be concerned about maintaining consumer confidence in the quality of drinking water. Brighty said drinking water is produced in a very effective purification process, and should not be the primary cause for concern.

Industry is the most shrewd critic of the studies, Tyler said, "and understandably so." Tom Hutchinson, an ecotoxicologist who works for Astra-Zeneca, a pharmaceutical company, said that overall, industry has responded positively. Views on research may differ depending on who you talk to, he said.

Some industrial companies are very research-oriented, he said. But other companies have taken longer to "wake up to the fact that [endocrine disruption] is a real issue and not just an environmental fashion," he said.

"Some chemicals [suspected to be EDCs] are used throughout industry, and it's taken longer to get new chemicals online," he said. "It takes longer to find to find suitable substitutes, and the scale is bigger. It's like a large ship that takes longer to turn around."

The first research into estrogenic (or mimicking a natural estrogen) sewage effluent in 1994 focused on chemicals from the contraceptive pill and the breakdown products of detergents, or alkylphenols, Hutchinson said.

This provoked questions regarding the effects of natural estrogen. A study to investigate the influence of natural estrogens, co-funded by the U.K. government and in collaboration with Brunel University, produced results suggesting that natural compounds and the estrogenic component of the Pill were the ingredients in the sewage effluent responsible for vitellogenin synthesis.

Tyler said, "Those compounds definitely contribute to the estrogenic effects and vitellogenin production. But I personally ­ and I think my colleagues would agree here ­ don't think those are necessarily the main causative agents of intersexuality. We don't really know if it's a single chemical or a mixture of chemicals which are causing this disruption in gonad development, causing males to produce these female eggs."

The reason? Out of the rivers his team has studied so far, the sites with the greatest effects on fish were the sites which received more industry-produced effluent, as opposed to domestic effluent. Industrial effluent would have more synthetic EDCs, while domestic effluent would have more natural EDCs. But the team hasn't been able to identify what chemical component of the industrial effluent has the strongest effects, he said.

Lately, the most debated aspect of the EDC research is how to interpret a regional study for a global problem, Hutchinson said. "It's important to keep an open mind to the natural and synthetic chemicals which may be important," he said.

Brighty said science must first identify the offending substances, then determine why they are used, where they come from and if they can be prevented from entering the water system. Some may be banned and others may be regulated, with nations of the world deciding on their own policies. Expensive improvements for U.K. treatment facilities may be necessary.
Also, the effect of reproductive abnormalities on human and animal populations needs to be evaluated. If the abnormalities don't affect the populations at all, the problem may not be as serious, Tyler said.

Hutchinson said it's important to research how well the new chemical testing methods perform in real life, he said. The investigation of how mixtures of chemicals work compared to single ones is also a hot issue.

Still, the science has come a long way. Toxicologists were once dealing primarily with acutely toxic chemicals in the U.K. waterways, Brighty said. "It's sort of like peeling an onion," he said.

"We dealt with the chemicals that cause death, so you peel that layer off. Then you find the sub-lethal chemicals, the ones that take a longer time to appear. As the biology improves, we'll get to a level where what we can measure in the water is not a problem. I hope we can get there in the next 20 years."

In the U.K., municipalities, chemical industries, farmers, hospitals and others will be affected by the developments, Hutchinson said. But researching endocrine disruption and combating the problem will be a challenge for everyone around the globe, he said.

"If only one group addresses the problem," he said, "it's not doing justice to the environment. At the national and regional levels, all of the stakeholders need to work together."