Volume 17, Number 1, Jan 1995, p.9
You may have read about it here first (the May WAAC Newsletter). Perhaps you read the articles in Newsweek or Time magazines or the series in the Los Angeles Times newspaper. Maybe you have heard about it from a colleague. Or perhaps you saw the television special.
It is a new topic and a new worry. The vocabulary hasn't even had a chance to become standardized. Some articles refer to estrogen mimics, others to estrogenic chemicals, and still others, xenoestrogens or endocrine disrupters.
The worry is that there are a number of chemicals, some known to be dangerous and others thought to have been harmless, which mimic estrogen in the bodies of living creatures. Many of these chemicals you already know, DDT, PCB's, DES, and dioxin, for example. Others are in the category "formerly thought to be harmless," chemicals I had never worried about: nonylphenol and octylphenol and their derivatives. The octylphenol derivative that should catch the attention of most conservators is Triton X-100.
Estrogen is a female sex hormone, present in both males and females, which plays an important role in regulating metabolism, particularly sexual development, maturation and function. Xenoestrogens interfere with the normal functioning of estrogen in the body. It is not clear if these compounds block estrogen receptors, inhibiting natural estrogen's function; or if they bind to the receptors, triggering estrogen mediated processes.
In September, the Discovery Channel (on cable) broadcast the US premier of a BBC documentary called Assault on the Male. It was chilling. The documentary showed example after example of seemingly unrelated cases of abnormal development in male animals, including humans. Male rainbow trout exposed to estrogenic chemicals in river water in England were found to produce proteins that only female trout normally produce. Alligators and turtles in Lake Apopka in Florida are being effected by a pesticide spill 10 years ago, 25 to 30% of male alligators have deformed or undersized penises and the females have double the normal levels of estrogen. The list of environmental problems goes on and on.
A more disturbing case was that of Dr. Ana Soto, a researcher in the Department of Cellular Biology at Tufts University School of Medicine. She was studying the growth of human breast cancer cell cultures in response to components in blood. Suddenly, all the test results came out positive -- there was something causing the breast cancer cells to grow as though exposed to estrogen. The cause was traced to a new batch of polystyrene vials. When the manufacturer was contacted, they acknowledged that the composition of the plastic had been changed, but wouldn't divulge the nature of the change because the formula was a trade secret. (Have you ever heard that one before?) Analysis traced the active component to nonylphenol that was added to the plastic as an antioxidant.
The video cuts back to Professor Sumpter of the Department of Biology and Biochemistry at Brunel University in England and his male trout that produce vitellogenin, a female protein, when exposed to estrogenic pollutants in river water near sewer outlets. He tested trout in tanks and found that nonylphenol and octylphenol produced these same reactions in the fish. What is really troubling is that these effects show up at extremely small doses. At 50 ppb nonylphenol is very estrogenic to the trout. At exposures of 30 ppb it increases the vitellogenin levels in male trout 1,000 fold; 30 ppb of octylphenol (the building block of the Triton X series of surfactants) increases the levels over 1,000,000 fold.
There is much research to be done to better understand the connections between estrogenic chemicals and problems in humans. There is compelling evidence that fetal exposure to estrogenic chemicals at crucial stages of development can cause serious problems in later life. There is at least some evidence that links xenoestrogens to the following findings in humans. A Danish study shows that sperm counts have dropped by 50% over the last 50 years and that the percentages of abnormal sperm have increased. Incidents of testicular cancer have increased 3 fold in the US and Britain in the last 30 years and is now the most common cancer in young men. Prostrate cancer has doubled in the last decade. There are increasing occurrences of undescended testicles and urethra abnormalities in newborn boys. There were only 21 reported cases of endometriosis 70 years ago -- now there are 5 million in the US. Breast cancer incidences have been increasing at the rate of 1% per year for the last 50 years.
The Alkylphenol & Ethoxylate Panel of the Chemical Manufacturers Association, has prepared a position paper "Alkylphenol Ethoxylates in the Environment: An Overview." The 10 page document includes many valid arguments that cast doubt on the environmental problems associated with Triton X and its cousins, alkylphenol ethoxylates or APEs. (They also impair their credibility with statements like "All chemicals, including water, are toxic at certain concentrations.") They point out that there is no indication that workers who come in contact with APEs on regular basis suffer adverse health effects. Most of the report discusses levels of APEs in river, lake, and drinking water and shows that levels of nonylphenol are well below concentrations where estrogenic effects are manifest in even the most sensitive animals.
I had always assumed Triton X-100 was one of the safest chemical we use. If you look up Triton X-100 in The Merck Index, you will find it is a spermatocide, closely related to Nonoxynol-9, the active ingredient in contraceptive creams and condom lubricants. What, I thought, could be more carefully studied than a pharmaceutical product that is approved for prolonged contact with very sensitive areas of the body. I did always wonder why a nonionic detergent would be so lethal to millions and millions of sperm. One can easily imagine how an estrogenic surfactant could be an effective spermatocide.
Recent studies on dioxin indicate that there may be a threshold level for exposure to these types of chemicals. The theory is that before the dioxin can cause any biological effect, it must first bind to literally thousands of receptors on the cell. However, it appears this threshold level for dioxin, if it exists, is very near the levels to which we are already exposed. In Assault on the Male, Dr. Theo Colborn, a Senior Scientist with the World Wildlife Fund, says that "It isn't just one product that is causing the problem, it is a host of products ... it is not only the pesticides, and it isn't only the chemicals that we have been releasing in the past, that we have banned and restricted, but that are still out there."
What should we do? Personally, I have stopped using Triton in my practice (see Technical Exchange for discussion of a substitute). Octylphenol exhibits estrogenic effects in some animals at 30 ppb which is roughly 0.000009% Triton X-100 or one drop in 275 liters of water. However, in 1990, 450 million pounds of nonylphenol and octylphenol based surfactants were produced in the US. It is all around us already. If you are concerned about using Triton, remember that contraceptive products contain 2% Nonoxynol-9. (It should be noted that small amounts of Triton are degraded in waste treatment facilities. Dumping large amounts down the drain is probably illegal and could lead to foaming in the treatment plant and possibly endanger aquatic life. Should you decide to stop using TritonX-100, please use a chemical disposal service or take it to a municipal hazardous waste round-up.)
Alkylphenol & Ethoxylates Panel, "Alkylphenol Ethoxylates in the Environment: An Overview", Chemical Manufacturers Association, August 1994.
Sharon Begley with Daniel Glick, "The Estrogen Complex", Newsweek, 21 March 1994, pp. 76-77.
Sharon Begley with Mary Hager, "Don't Drink the Dioxin", Newsweek, 19 September 1994, p 57.
Deborah Cadbury (writer/director), Mary Fitzpatrick (assistant producer), Assault on the Male, BBC, 1993.
Marla Cone, "Sexual Confusion in the Wild"; "Pollution's Effect on Sexual Development Fires Debate"; and "Battle Looms on Chemicals that Disrupt Hormones", Los Angeles Times, series Sunday - Tuesday, October 2 - 4, 1994, front page and following. The Discovery Channel, News Release, 4 August 1994.
Anna Kramer with Sheryl Loeffler, "Gender Benders", Men's Confidential, October 1994, pp. 11-13.
J. Madeleine Nash and Mia Schmiedeskamp, "Not So Fertile Ground", Time, 19 September 1994, pp. 68-70.
Thanks to Carrie Ann Calay, Max Saltzman and Conservation Materials, Ltd. for supplying information.
Timestamp: Thursday, 11-Dec-2008 13:02:33 PST
Retrieved: Friday, 21-Jul-2017 20:31:45 GMT