These are some of the current issues being discussed in America and around the world that involve thinking about the relationship between the individual and the natural world. Click on an issue to go to information on that topic:
Compounds and the Environment
Jeanne Small (Chemistry) writes:
I became interested in the book "Our Stolen Future" after reading a review of it in my trade journal, "Chemical and Engineering News" (C&EN). I'm a biophysical chemist by training, and have never before taken interest in environmental issues relating to chemistry. While I had heard of Rachel Carson's 1962 book, "Silent Spring," many times, I had never read it. Now I'm the owner of "Silent Spring" and "Our Stolen Future," and am very observant of articles emerging in the sciences related to environmental contamination by synthetic chemicals. What follows is a synopsis of recent articles on the topics, from earliest to latest.
(1) CHEMICAL AND ENGINEERING NEWS, April 1, 1996 , pp. 34-35
"Hormone Mimics in the Environment: Like 'Silent Spring,' new book synthesizes work from many fields to see a major environmental problem that chemists need to take seriously."
"Our Stolen Future" reviewed by W.R. Moomaw
"The individual pieces of research they have assembled come from field-specific peer-reviewed literature and are carefully documented in extensive endnotes. However, the links they propose between these research findings and the overall hypothesis they present have received relatively little attention from the scientific community. That hypothesis, in a nutshell, is that low concentrations of chemicals now widespread in the environment can cause endocrine disruption, especially during fetal development."
"One of the most important issues this book raises is the need for large-scale synthesis of information buried in separate scientific specialties. That was the great contribution of 'Silent Spring,' and it's an important message of this book, as well. To a chemist such as myself, steeped in the relationship between molecular structure and chemical properties, it's hard to imagine the complex dynamic that can allow such structurally different compounds as estradiol (the natural estrogen in humans and virtually all other animals) and DES or PCBs to bind to the same endocrine receptor to produce similar biological effects."
"The book shows clearly how scientists and the agencies that fund them become captives of existing paradigms. One example is the imbalance between the amount of money spent to find 'cancer genes,' about which we can do little, and the low level of support to study the sources and mechanisms of cancers caused by diet and agents in the environment. Most of the regulatory debate of the past 20 years has been shaped by the powerful intellectual idea that chemically induced alterations to DNA can cause mutation, birth defects, and cancer. Consequently, that is where most of the research effort has gone. But if the authors of 'Our Stolen Future' have interpreted the evidence they present correctly, dioxins are more likely to be dangerous because of their effects on the endocrine system than on DNA."
"Both the public and the chemical industry have moved a long way since 'Silent Spring' was published in 1962. At that time the response of a defensive industrial community was denial, and even 'Chemical & Engineering News' joined in by titling its review of the book 'Silence, Miss Carson.' "
"The chemical industry of today is far more responsive and responsible. The days are past of dumping Kepone into the James River, casually spreading millions of pounds per year of persistent pesticides and chlorofluorocarbons into the environment, or assuming that a Bhopal accident was not possible. With successful industry-sponsored programs like Responsible Care, private-sector initiatives like ISO 14000, pledges such as the Business Charter for Sustainable Development, and general compliance with the Environmental Protection Agency's Toxics Release Inventory, it's hard to imagine a return to industry's reflexive lashing out against 'Silent Spring.' "
"Although some aspects of the book will undoubtedly be annoying to many chemists, ignoring or dismissing its message would be a serious mistake. Neither the public nor political leaders are likely to ignore an issue as critical as an alleged threat to the reproductive future of our own species. 'Our Stolen Future' raises important questions that are unlikely to be ignored even though much research still needs to be done. Undoubtedly the book has already played a role in the decision to convene a panel of the National Academy of Sciences to conduct a two-year evaluation of endocrine disrupters. The American Chemical Society, recognizing both chemistry's power to contribute to the debate and its limitations, should form joint task forces with appropriate biological, toxicological, and medical societies to evaluate research findings and recommend new avenues of investigation....To do otherwise will jeopardize not only the credibility of chemists but also the public's tolerance of the chemical industry and its products."
(2) SCIENCE, 22 November 1996, Letters section
An earlier report about possible "increase in potency of weakly estrogenic compounds when used in combination" is said to have "aroused considerable interest."
Excerpts from Michael Joffe's letter:
"The report by S.F. Arnold. et al. (7 June, p. 1489) demonstrating an increase in potency of weakly estrogenic compounds when used in combination has aroused considerable interest. A number of aspects of the report, however, are unclear."
Excerpts from response from John A. McLachlan:
"Joffe inquires about the selection of the compounds used in our study of the synergistic action of weakly estrogenic chemicals. The pesticides (endosulfan and others) were chosen because they had been shown to function individually as estrogens in mammalian cells and to stimulate greater-than-additive responses when combined....By studying the activity of 'naturally' occurring combinations, we can begin to understand the activity of chemical mixtures. In fact, because of the varied endocrine defects reported in the literature that have been associated with environmental agents, it is likely that synergy in estrogen signaling and also in other endocrine systems is partly responsible for the reported effects."
SCIENCE, 13 December 1996, pp. 1837-1838
"ENDOCRINE DISRUPTERS: Scientists Angle for Answers"
Excerpts of the article by Jocelyn Kaiser:
"A few years ago, British biologists noticed something odd about the fish they pulled from the sewage-laced River Lee near London: The testes of males were laden with eggs. Scientists suspected that something in the water was acting like a sex hormone, skewing reproductive development. And soon, the gender-bent fish became one of the poster species in the still-unfolding controversy over 'hormone disrupters,' chemicals thought to derail developmental processes in wildlife and perhaps even humans."
"But now two studies are shedding new light on the hermaphroditic fish. One, a survey sponsored by the U.S. Geological Survey (USGS), finds that fish from many streams across the United States also appear to have unusual levels of sex hormones. The other, by British researchers, suggests that, in many cases, natural hormones in women's urine--not industrial chemicals--may be disrupting fishes' reproductive health....'It's a very good example of: Don't have a preconceived idea of what the result should be.' "
On the natural hormones in women's urine:
"To their surprise, the researchers discovered that the estrogenic compounds were not industrial pollutants, but three hormones found in women--17beta-estradiol, estrone, and ethynyl estradiol. The last, which was present in vanishingly small amounts, is a potent synthetic hormone in birth control pills. One reason the researchers didn't expect to find these substances in the water is that before they are excreted in urine, the kidneys tack on a chemical group--a glucoronide or sulfate--that renders the compounds biologically inactive. Sumpter speculates that during sewage treatment, enzymes from bacteria may be clipping off the chemical group. The researchers then showed in the lab that the tiny amounts of hormones found in the effluent can cause male fish to produce vitellogenin [a protein involved in egg-laying that normally is only found in females]. They are now exposing young fish to effluent to see whether it will cause them to develop into hermaphrodites."
"Sumpter says their result doesn't mean industrial chemical aren't also harming fish in some heavily polluted rivers. For example, he believes that high vitellogenin levels found in male fish in some U.K. rivers will turn out to be caused primarily by nonylphenol, a chemical discharged by textile factories. But, he says, because sewage is the dominant source of pollution in U.K. rivers, these substances in urine are probably largely responsible for the country's hermaphroditic fish. And that's a lesson for other researchers studying endocrine disrupters , Sumpter says: 'I would almost certainly have voted for synthetic man-made chemicals, and that would have turned out to be wrong.' Toxicologist Steven Safe of Texas A&M University in College Station agrees: 'This points out that we have to be pretty careful in jumping to conclusions.' "
(4) SCIENCE, 17 January 1997, pp. 405-406
"TECHNICAL COMMENTS: Potency of Combined Estrogenic Pesticides"
Excerpts from letter by Kavita Ramamoorthy et al.:
"Steven F. Arnold et al. found 150- to 1600-fold synergistic interactions between binary mixtures of the weakly estrogenic pesticides endosulfan, dieldrin, toxaphen, and chlordane in competitive estrogen receptor (ER) binding assays and in an estrogen-responsive assay in yeast....On the basis of these data, it was suggested 'that the estrogenic potency of some environmental chemicals, when tested singly, may be underestimated'....[Discussion of their attempts to duplicate the results]...The recent scientific, regulatory, and public concern regarding the potential adverse environmental and human health impacts from synergistic estrogen responses induced by organochlorine pesticide mixtures should be tempered by our results, which demonstrate that these compounds are weakly estrogenic and, in combination, their activities are additive."
Response from John A. McLachlan et al.:
"It is difficult to compare the results of the study by Ramamoorthy et al. to ours because the assays they used, while appearing to be similar to ours, were in each case different. The differences, however, have been instructive in helping us frame some of the parameters that may be important in determining the synergistic action of weakly estrogenic chemicals....We look forward to the continued clarification of this important issue."
(5) CHEMICAL AND ENGINEERING NEWS, January 20, 1997, p. 9
"Endocrine disrupter screens on the way"
by Bette Hileman
"New findings reported last week may contribute substantially to the creation of tests for detecting chemicals that disrupt hormone systems. These chemicals have the potential to shape the development of the fetal reproductive system, and the Environmental Protection Agency, by law, must develop a screening and testing program for them by August 1998."
"Scientists led by toxicologist Michael D. Shelby at the National Institute of Environmental Health Sciences report that a set of three existing tests, when used in combination, provides a rapid assessment of a chemical's potential to mimic the hormone estrogen [Environ. Health Perspect., 104, 1296 (1996)]. When the three tests are run at the same time, results can be obtained in three to five weeks at a cost of about $15,000, Shelby says. Conventional cancer bioassays using animals can take one to two years and cost $1 million to $2 million...."
"Another research group, headed by John A. McLachlan of Tulane-Xavier Center for Bioenvironmental Research, New Orleans, has found that some combinations of hormone-disrupting chemicals act synergistically [Environ. Health Perspect., 104, 1318 (1996)]. This may mean that any testing program that is developed will need to account for such interactions."
"The Tulane researchers base their conclusion on lab studies on how chemicals--alone and in combination--interfere with alligators' sex hormones. These studies show how DDT and Dicofol caused major reproductive problems among alligators in Florida's Lake Apopaka (C&EN, May 13, 1996, page 28)."
(6) CHEMICAL AND ENGINEERING NEWS, February 3, 1997, p. 31
"Calculating total risk is likely to doom some pesticide products," by David Hanson
"The Environmental Protection Agency is wrestling with how to implement the landmark Food Quality Protection Act of 1996, which requires it to consider total risk from all uses of a pesticide when it sets pesticide tolerances on food. The new aggregate risk assessment rule could force growers to stop using some pesticides on some crops."
"This could happen when EPA combines all the different possible routes of exposure to a pesticide and calculates the potential risk to human health or the environment from multiple exposures. If the aggregate risk is found to be more than the agency can allow by law, a decision will have to be made to drop some agricultural uses of the pesticide, leaving some growers in the lurch."
"The metaphor used is that of a cup being filled by each additional portion of risk. When the risk cup gets 100% filled, no additional risk can be added. In practical terms, if exposure to a pesticide from all possible uses generates too much risk, then some uses of that product must be eliminated."
(7) CHEMICAL AND ENGINEERING NEWS, February 3, 1997, p. 5
Guest editorial by John E. Akitt, executive vice president of Exxon Chemical Co.
Excerpts from " 'A Natural' for Industry":
"Deeply troubling questions are being asked about the potential health effects of chemicals on human and wildlife populations. So far, the scientific evidence linking chemicals to health problems is murky. But one thing is crystal clear: Denying the public's concern is not an acceptable option. Recognizing and responding to the public's concerns about chemicals is a major component of Responsible Care. In addition, it is the industry's responsibility to leverage its scientific expertise, collaborate with experts from government and academia, and work together to develop and provide information based on sound scientific research."
"Chemical companies have long conducted research regarding health effects of their products. Last month, the Chemical Manufacturers Association (CMA) board of directors made a two-year, $16 million commitment to further investigate the basic mechanisms by which chemicals react with the human body. CMA's investment in basic research is the first stage of a long-term coordinated process to better understand the risks chemical pose to humans and wildlife."
"CMA's reasons for funding health and environmental effects research are compelling:
(8) CHEMICAL AND ENGINEERING NEWS, February 24, 1997, p. 11
"Nations move to coordinate endocrine disrupter research."
Excerpts from article by Bette Hileman:
"Development of an international research program on endocrine-disrupting chemicals headed the agenda of the Intergovernmental Forum on Chemical Safety (IFCS), held earlier this month in Ottawa...At the meeting, but independent of its formal proceedings, the U.S. Environmental Protection Agency and the European Union announced a joint effort to avoid duplication in research on endocrine disrupters. A working group will be set up to 'determine the basis for research cooperation and develop an agenda for dealing' immediately with these chemicals."
(9) CHEMICAL AND ENGINEERING NEWS, March 10, 1997, pp. 35-36
"Emerging Health Crises in Children: Conference focuses on asthma and cancer as federal agencies gear up programs to address possible environmental causes."
Excerpts of article by Bette Hileman
[Death rates for asthmatic children have more than doubled between 1980 and 1993; cancer incidence among children under 19 is rising 1% a year; although 80% of pediatric cancer is cured, more children die of it than of any other disease.]
"Causes for the rapid rises in asthma and cancer are not known, researchers said. One hypothesis is that prenatal exposure to endocrine disrupting or other chemicals programs the developing fetus for cancer or asthma in early life."
" 'There is a fundamental difference between environmental exposure in a developing system and a mature system,' John A. McLachlan, director of the Tulane Xavier Center for Bioenvironmental Research at Tulane University in New Orleans, told the meeting. For example, 'If you start giving the synthetic estrogen diethylstilbestrol (DES) to a month-old mouse and continue throughout its lifetime, you never get any effect,' he said. But if DES is given to a pregnant mouse or human, it alters gene expression in the fetus permanently, and causes abnormalities in the reproductive tract of the offspring."
"Therefore, exposure to estrogenic and other hormone disrupting chemicals are much more important for the fetus than for the adult, McLachlan explained. Adverse effects in the offspring can be produced by very small doses of some chemicals if they are given at a critical time during pregnancy."
"Because of these considerations, risk assessments of chemicals
have to change, insisted Philip J. Landrigan, chief of the Department of
Community Medicine at Mount Sinai Medical Center. 'Previous risk assessments
have been based on protecting 21-year-old white males,' he said. 'In the
past, we dosed "teenage" or adult animals for two years, then
sacrificed the animals. That simply misses the point.' Animals need to
be dosed in the womb, by exposing the mother, and then followed into old
age, he said."
For more than a hundred years Americans have been debating whether to preserve or utilize different parts of our "natural world." Even among the preservationists there have been many divisions: some favor "planned use," some support recreation but not industry in the wilderness, others would like to bar all but hikers from vast tracts of wilderness. Rival views of the proper relationship between individuals and the natural world in the area of wilderness use and preservation provide news stories almost daily.