Of biome blues

  • 30/08/1996

Of biome blues a report highlighting a progressive decline in sperm counts in men over a period of time has recently created a sensation the world over. Carried in The British Medical Journal (March, 1996), it says that researchers in Edinburgh studied 577 men in Scotland and reported that those born after 1970 had a sperm count that was 25 per cent lower than the ones born before 1959 - which points to an average decline of 2.1 per cent per year. Stewart Levine, head of the research team, says: "There is as yet no evidence that male fertility is declining, but the absence of an evidence is not evidence of absence."

A comprehensive recent analysis done by Danish endocrinologist Niels Skakkebaek of the National University Hospital, Copenhagen, involving a sample size of 150,000 men culled out from 21 different countries reiterated the equability of the pattern.The studies show that sperm counts of men in a number of European countries have decreased by half in the last 30 years, and that sperm counts in the rapidly industrialising countries of east Asia are falling faster. Besides, apart from the decline in counts, indications are firm that the quality of sperm - the quotient of healthy vigorous cells as opposed to lethargic and malformed ones - is also dropping with aconcomitant rise in incidences of testicular cancer and undescended testicles. Together, these factors do add up to a significant drop in male fertility.

Roots Skakkebaek says, "This remarkable change (the decline in sperm count) has probably been due to an environmental factor," - a theory that has found support from the writers of a recently published controversial work. Theo Colborn, Dianne Dumonsky and John Peterson Myers, the authors of Our Stolen Future (Dutton, New York, 1996) give a single prescriptive message: a wide range of reproduction related ills may be caused by chemical pollutants in the environment, including ddt , dioxins, pcbs (polychlorinated biphenyls) and a number of other synthetic substances. They add, "The idea is that exposure to even traces of these chemicals in the womb can interfere with the proper development of the reproductive system leading to serious consequences, years or decades later."

Carrying an us vice presidential endorsement, the book elucidates an absorbing but disturbing account of the havoc wreaked by modern synthetic chemicals on the reproductive and other vital abilities and faculties of humans and other animals. Comparing it with Silent Spring (1962), Rachel Carson's legendary contribution which successfully called world attention to the wonder chemical ddt's devastating potential to disrupt health and the environment, vice president Al Gore commented, "Our Stolen Future takes up where Carson left off... linking synthetic chemicals to abberant sexual development and behavioural and reproductive problems."

Today, animals and people are forced to undergo continuous buffeting by the subtle yet disastrous effects of chemicals found in pesticides, plastics and industrial pollutants, which are regularly contaminating food and water supplies. Sandra and Joseph Jacobson, psychologists from Wayne State University in Detroit, us, reported that pregnant women who ate the Great Lakes' fish presumably carrying high concentrations of pcbs, gave birth to children who weighed less, had smaller heads, short-term memories and in some cases, even lower iqs. Investigators at the Mount Sinai Medical Center in New York discovered that the blood of women suffering from breast cancer had a higher amount of a ddt by-product (dde) than that of healthy women. Colborn points out, "I really did not expect to find what we have uncovered. This is going to lead to a whole new way of thinking about epidemiology, toxicology, risk, health and the way we do business."

Although, as is usual with scientific inquiry, many researchers in the government, industry and academics are quick to criticise and, in some instances, dismiss outrightly many of the book's authors' more alarming admonitions - including the use of plastic food containers. "It is hypothesis masked as fact," says Michael A Gallo, a professor of toxicology at the Robert Wood Johnson Medical School in New Jersey, us. This assessment was shared by Bruce Ames, a professor of biochemistry and molecular biology at the University of California, Berkeley in us. "It is a political movement and is based on lousy science," he said.But the very fact that the National Academy of Sciences has stepped into the fray is evidence that at least some of Colborn's concerns merit serious attention. "There is a legitimate need to study the impact of these (synthetic) chemicals beyond their usual, more easily detectable impacts such as cancer or birth defects," says Robert Kovloch, a toxicology researcher at the us Environmental Protection Agency (epa). "The claims of Dr Colborn and others cannot and should not be ignored, although exactly how widespread is the danger is simply not known," he adds.

The research compiled in Our Stolen Future looks at whether several classes of widely used synthetic chemicals are able to interrupt the normal activities of hormones like estrogen (the female hormone) and testosterone (the male hormone). Dubbed hormone mimics or disrupters, many of these chemicals such as dioxins, des (diethylstilbestrol) and the infamous ddt can actually snap onto sites of receptors that normally recognise estrogen and other natural hormones crucial to the development of animal functions. The book details the disrupted sex lives of fish, birds and other animals exposed to ddt, dioxins or pcbs and chemicals from frequently used herbicides, fungicides, insecticides and detergents.

Debate of destruction
What seems to be complicating the issue is that almost all of these reports have been countered by findings that suggest the opposite. Harry Fisch of Columbia-Presbyterian Medical Center in New York argues that the reported decline in sperm counts was probably due to previously unappreciated regional variations in the counts. "I can explain all the decline in the sperm counts by geographical variability," says Fisch. Supporting his views, Stephan Safe, a toxicologist at Texas a&m University, us, said, "What we have here are regional differences; they do not correlate in any way with chemicals in the environment."

"People should try to find out what is going on," Safe suggests. He worries that the book will create a "toxic hysteria". "Mothers may be especially confused by the authors' warning that breast feeding exposes infants to a number of known hormone disrupters. So what should women do? Because we know too little how to judge the undeniable benefits of breast feeding against the risk, it is premature to advise against breast feeding," Safe concedes.

However, regardless of the public reaction to the book, scientists feel the debate will not die out so simply. "There is a significant evidence in fish and wildlife suggesting these chemicals can generate problems," says Linda Birnbaum, an epa researcher. "Whether the problems we are also beginning to see in people are due to these chemicals or something else, needs to be determined. Theo and others have produced a hypothesis that deserves to be explained."

On their part, chemical manufacturers conveniently dismiss these speculations arguing that nobody has come close to demonstrating a cause-and-effect relationship and that evidence for a chemical-disease-infertility link does remain largely circumstantial. However, well-documented evidences spin a different tale. On the evening of November 14, 1989, a few miles outside Tampa, Florida in the us, the insecticide 'Mevinphos' was sprayed on the Goodson farm's 6.5 ha of cauliflower. The following morning, labourers who went to work in the farm complained of headaches, dizziness, blurred vision, slurred speeches and breathing difficulties. By late afternoon, 112 farmworkers were treated at the scene or at the local hospital. Even after a month following the incident, dozens of workers continued to suffer discomfiting symptoms and one pregnant woman miscarried. Florida doctors confirmed a case of pesticide poisoning. However, the use of Mevinphos continued under a different brand name - 'Phosdrin'.

A report from the National Academy of Sciences, usa, has concluded that infants and children are often at greater risk than adults from dietary exposure to carcinogens. Every year, 25 million people, primarily in the southern hemisphere, are poisoned through occupational exposure to pesticides. Of these, 220,000 die, according to who estimates. In the us alone, 300,000 farm workers are poisoned every year.

Ironically, as humans are taken ill or killed by pesticides, more strains of insects, mites, weeds and rodents are developing immunity to these chemicals. Rachel Carson found that 137 species of insects and mites worldwide had already become pesticide resistant; today, the number has climbed to more than 500. According to Cornell University professor David Pimentel, the amount of crops lost to insects in the us "has almost doubled during the last 40 years, despite a more than 10-fold increase in the amount and toxicity of the synthetic pesticides used".

Despite this apparent truth, growers in the us as well as abroad are becoming increasingly reliant on pesticides. "My greatest concern is the expanding use of pesticides - the doubling (in the us) in the last 30 years - and the effect it can have on our children, our water, air and land," says epa administrator Carol Browner. "And it is outrageous," she adds, "that a product banned here (in the us) can be sold in other countries."

Scores of studies and press accounts show that workers are given little or no training in handling the chemicals. Farmers, especially those in countries beset by illiteracy and poverty, cannot read the labels on pesticide packages, frequently mix the chemicals with their bare hands, and carry home the poisons on their bodies and clothings. Hazardous chemicals spill, or are dumped into fields, rivers or ponds and the poison-laced containers are often reused for storing food, water or seeds. "It is very difficult to have safe use under tropical conditions by small farmers wearing back-packs. The pack leaks and it is too hot to wear protective clothing," says who's pesticide expert Robert McConnell.

Some reviewers dismiss the endocrine disrupter hypothesis because there are natural hormone mimicking chemicals in soyabean and broccoli. Our Stolen Future clarifies that natural vegetable hormones, unlike the synthetic ones, are fat-insoluble, get metabolised and therefore do not concentrate in the food chain. "And of course, the presence of toxins in nature is no license to release still more toxins," says environmental commentator Donella H Meadows. "A profound issue is being trivialised and swept away