Space, War

excerpted from the book

Living Downstream

a scientist's personal investigation of cancer
and the environment

by Sandra Steingraber

Vintage Books, 1998 (paper)


Industrialized countries have disproportionately more cancers than countries with little or no industry (after adjusting for age and population size. One-half of all the world's cancers occur among people living in industrialized countries, even though we are only one-fifth of the world's population. Closely tracking industrialization are breast cancer rates, which are highest in North America and northern Europe, intermediate in southern Europe and Latin America, and lowest in Asia and Africa. Breast cancer rates are thirty times higher in the United States than in parts of Africa, for example. Breast cancer incidence in the United States is five times higher than it is in Japan, but this gap is rapidly narrowing. Of all the world's nations, Japan has the most rapidly rising rate of breast cancer.

Among the nations of the developed world, similar time trends are in motion for a number of major cancers. Mortality rates of breast cancer and prostate cancer are rising in almost all industrialized countries. The accelerating U.S. rates of brain cancer, kidney cancer, multiple myeloma, non-Hodgkin's lymphoma, and melanoma are replicated in France, West Germany, England, Japan, and Italy.

... a little-known office of the World Health Organization. Located in Lyon, France, the International Agency for Research on Cancer is charged with the daunting job of monitoring cancer incidence around the world. It does so by collecting registry data from as many countries as possible. The United States, for example, sends its Surveillance, Epidemiology, and End Results Program data on to Lyon. The World Health Organization also collects and analyzes cancer mortality data gleaned from death certificates in seventy different countries. From these data, the organization concluded that at least 80 percent of all cancer is attributable to environmental influences.

Coffee consumption, at first glance, seems like a classic lifestyle choice. But the coffee we drink includes the water we pour through the beans-and this may be the same water used for showering and cooking food. If our tap water contains, say, traces of weed killer and dry-cleaning fluids, we are being exposed to environmental carcinogens through multiple pathways and through no individual choice of our own, even as we freely determine our own bathing, cooking, and coffee-drinking habits.

However culturally distinct immigrants may remain in their adopted | country, their cancer rates assimilate. According to the International Agency for Research on Cancer, "The most important single conclusion to derive from migrant studies is that, for a group as a whole, it is the new 'environment' that determines cancer risk and not the genetic component associated with the ethnic stock of the migrants." The quotation marks around that slippery word environment acknowledge its many meanings.

Migrants to Australia, Canada, Israel, and the United States all illustrate this pattern. Consider Jewish women who migrate from North Africa, where breast cancer is rare, to Israel, a nation with high incidence. Initially, their breast cancer risk is one-half that of their Israeli counterparts. But risk rises rapidly with duration of stay: within thirty years, African-born and Israeli-born Jews show identical breast cancer rates. Jewish women from the Middle East and Asia also increase their risk of breast cancer upon arrival in Israel, although the pace at which they do so is considerably slower.

Likewise, in the United States, the breast cancer rates of European, Chinese, and Japanese women immigrants all eventually rise to conform to the U.S. rate, but they do so at different speeds. Polish women assume U.S. rates of breast cancer quickly. Japanese women migrating to the U.S. mainland require two generations to achieve our breast cancer rate. First-generation Japanese immigrants show a rate intermediate between that for Japan and the United States; their daughters, however, reflect the U.S. rates completely.

Happily, the reverse is also true. Women moving to a new country with lower breast cancer rates experience a decline in their chances of contracting the disease-as when, for example, an English woman immigrates to Australia.

These results lead us back to the Mobius strip of lifestyle and environment. Both change simultaneously when someone moves from one part of the world to another. At present, no one understands precisely how these changes interact to create the patterns described ...

People in at least sixty different occupations have elevated death rates from cancer. One of these is farming.

Farmers from industrialized countries around the world exhibit consistently higher rates of many of the same cancers that are also on the rise among the general population. Farmers, in other words, die more often from the same types of tumors that are also afflicting, with increasing frequency, the rest of us. These include multiple myeloma, melanoma, and prostate cancer. Farmers also suffer from rates of non-Hodgkin's lymphoma and brain cancers higher than those of the general population-although these excesses are more modest. In spite of lower overall mortality and lower rates of heart disease, farmers also die significantly more often than the general public from Hodgkin's disease, leukemia, and cancers of the lip and stomach. Likewise, migrant farmworkers suffer excess rates of multiple myeloma, as well as of stomach, prostate, and testicular cancers.

Elevated cancer rates are also found among painters, welders, asbestos workers, plastics manufacturers, dye and fabric makers, firefighters, miners, printers, and radiation workers. People who work in a number of so-called professional jobs are also at higher risk: for example, chemists, chemical engineers, dentists and dental assistants, and-perhaps most ironically-chemotherapy nurses. Many of the chemicals used to treat cancer are themselves carcinogenic, as the high rate of adult cancers among childhood leukemia survivors attests. Thus, we should not be surprised that those who work daily with these substances in an attempt to save others' lives themselves succumb in numbers higher than average.

The children of adults who work in specific occupations also have higher rates of cancer. Childhood brain cancers and leukemias are consistently associated with parental exposure to paint, petroleum products, solvents, and pesticides. Some exposures may occur before birth. Children can also be exposed when these materials are carried into the home on their parents' clothes and shoes, through breast milk (which can be contaminated directly or through maternal contact with the father's clothing), or even through exhaled air: because solvents are, in part, cleared by the lungs, parents can expose their children to carcinogens simply by breathing on them. In this way, a father's homecoming kiss and work-clothed embrace can contaminate his child.

Consider vinyl chloride, which is used in the manufacture of a substance familiar to us all: polyvinvl chloride, otherwise known as PVC or simply vinyl. Credit cards are made of PVC, as are garden hoses, lawn furniture, floor coverings, children's toys, and food packaging materials. PVC, in turn, is made of vinyl chloride molecules all bonded together. Vinyl chloride, a sweet-smelling gas at room temperature, has long been classified as a known human carcinogen. Its cancer-causing properties were discovered when high numbers of male vinyl chloride workers began contracting angiosarcoma, a rare cancer that causes tumors to grow inside the liver's blood vessels. The incidence among vinyl chloride workers was found to be three thousand times higher than among the general population. Animal studies, as well as further studies of male workers, also revealed the ability of vinyl chloride to contribute to lung and brain cancers. In response to these results, allowable workplace air levels of vinyl chloride were drastically reduced. But it was not until researchers also studied female workers that vinyl chloride's potential as a breast carcinogen was uncovered. In a 1977 study, women who breathed vinyl chloride vapors on the job had elevated death rates from breast cancer. Subsequent laboratory studies showed that atmospheric vinyl chloride triggers breast tumors in female rats, even at the lowest dosages; so does ingestion of PVC dust. Such an association is certainly biologically plausible, since vinyl chloride has an affinity for fat tissue.

Evidence for a link between vinyl chloride and breast cancer in women workers has broad implications for the rest of us. While vinyl chloride levels are very much lower outside the factory, significant exposures can occur among residents living near vinyl chloride and PVC facilities. The air currents that blow across hazardous waste sites also contain elevated levels of vinyl chloride. Vinyl chloride is a frequent contaminant of groundwater, where it can remain for months or years because there is no pathway to the atmosphere. The flesh of freshwater fish can also contain vinyl chloride.

According to the U.S. Agency for Toxic Substances and Disease Registry (ATSDR), each of these pathways exposes the general public to "negligible amounts" of this known carcinogen. However, no one knows what the cumulative lifetime risk from all of these negligible exposures is. The ATSDR also states that "exposure to vinyl chloride either in the prenatal period or during early childhood years may result in an increased risk of cancer" later in life. If vinyl chloride caused only a very rare form of liver cancer, perhaps these multiple routes of tiny exposures would be less cause for alarm. However, breast cancer is now the leading cause of death of American women aged thirty-five to fifty, and we are the first generation of women born after World War II, when chlorinated chemicals such as vinyl chloride were first widely dispersed in the general environment.

In spite of all this preliminary evidence, no comprehensive study has ever been undertaken to examine vinyl chloride's contribution to breast cancer. In fact, the 1977 study of women PVC fabricators has never been followed up, even though cohorts of men exposed to vinyl chloride, and who demonstrate excesses of brain, liver, and lung cancer, have been periodically updated. This omission is especially frustrating to Peter Infante, the director of the Health Standards Program at the Occupational Safety and Health Administration, whose job it is to set limits on vinyl chloride levels in workplace air. Lack of interest in investigating a possible vinyl chloride-breast cancer link, says Infante, serves as an example of indifference to the plight of women in the workplace-indeed, to the plight of women everywhere.

... inclusive evidence does not exist on the link between cancer and hazardous waste because money has never been appropriated to conduct the necessary studies. As long as the evidence remains inconclusive, the methods currently used to remediate risks to public health cannot be evaluated. With this evaluation, the notion that there is no proof environmental contamination causes cancer can continue to enjoy common currency.

Men living in hazardous waste counties suffered significantly higher mortality from cancers of the lung, bladder, esophagus, colon, and stomach than did their contemporaries residing in counties without such sites. Women living in hazardous waste counties suffered significantly higher mortality from lung, breast, bladder, colon, and stomach cancers. Indeed, counties with hazardous waste sites were 6.5 times more likely to have elevated breast cancer rates than counties without such sites.

Most of us are also exposed regularly to molecules of [trichloroethylene] TCE. Used by industry to degrease metal parts, TCE is now estimated to be in 34 percent of the nation's drinking water. Most processed foods contain traces as well. TCE is also found in paint removers, spot removers, cosmetics, and rug cleaners. An estimated 3.5 million workers are exposed to TCE on the job. Not so long ago, TCE was also used as an obstetrical anesthetic, a fumigant for grain, an ingredient in typewriter correction fluid, and a coffee decaffeinater. These uses have been phased out, but there is still sufficient release of TCE into the general environment to ensure that traces of vaporized metal degreaser persist in the ambient air that we all breathe...

Since the 1930s, [perchlorethylene (perc)] has been the chemical of choice for dry-cleaning clothes. Compared to the general population, dry cleaners have twice the rate of esophageal cancer and twice the rate of bladder cancer. Thus, a discovery of a bladder cancer cluster among the folk of the Upper Cape should come as no surprise. Further studies of the Upper Cape's water pipes, published in 1993, showed that people's actual exposure to perc varied widely, depending on the length, shape, size, and age of the water pipe, the pattern of water flow, and the person's length of residence in that house. For those people with highest exposure, bladder cancer risk was four times higher and leukemia nearly twice as high when compared to people without such pipes.



One ... is benzene the human carcinogen known to cause leukemia and suspected of playing a role in multiple myeloma and non-Hodgkin's Iymphoma. Another is perchloroethylene, the probable human carcinogen used to dry-clean clothes. A third represents production of vinyl chloride, a known cause of angiosarcoma and a possible breast carcinogen. They all look like ski slopes. After 1940, the lines begin to rise significantly and then shoot upward after 1960.

By the end of the 1980s, total production [of synthetic organic chemicals] had exceeded two hundred billion pounds per year. In other words, production of synthetic organic chemicals increased 100-fold between the time my mother was born and the year I finished graduate school. Two human generations.

The terms organic and synthetic are slippery ones and require explanation. Organic has two definitions that very nearly contradict each other. In popular usage, organic describes that which is simple, healthful, and close to nature. Similarly, in the language of agriculture, organic refers to food grown only with the aid of substances derived from plant and animal matter. Food certified as organic is supposed to be free from manufactured pesticides, antibiotics, hormones, and other additives-that is, fruits, vegetables, meat, eggs, and milk produced without the use of artificial, synthetic chemicals.

In the parlance of chemistry, however, organic simply refers to any chemical with carbon in it. The study of organic chemistry is the study of carbon compounds. The word synthetic means essentially the same as it does in everyday conversation: a synthetic chemical is one that has been formulated in a chemical laboratory, usually by combining smaller substances into larger ones. Most often, these substances contain carbon. Indeed, many organic chemicals now in daily use are synthetic-they do not exist in nature.

Of course, not all organic substances are synthetic. Wood, leather, crude oil, sugar, blood, coal-these are all carbon-based, organic substances found in the natural world. But, insofar as they have carbon atoms in their structures somewhere, the vast majority of synthesized chemicals are also organic. Plastic, detergent, nylon, trichloroethylene, DDT, PCBs, and CFCs are all synthetic organic compounds. The close alignment between organic and synthetic leads to the absurd but truthful concept that organic farmers are those who shun the use of (synthetic) organic chemicals.

Most synthetic organic compounds are derived from either petroleum or coal. Recognizing this fact brings the widely divergent definitions of the word organic together. To a biologist, organic substances are those that come from organisms-living or dead. Long chains of carbon atoms compose the chemical infrastructure of all life forms, including the liquefied organisms and the petrified organisms who lived on the planet eons ago and who have since been extracted from their burial grounds. Nothing manufactured from these so-called fossil fuels is really "unnatural." A molecule of DDT is made up of rearranged carbon atoms distilled from some creature's once-living body.

And here lies the problem. Many synthetic molecules are chemically similar enough to substances naturally found in the bodies of living organisms that, as a group, they tend to be biologically active. Our blood, lungs, liver, kidneys, colon-with the help of an elaborate enzyme system-are all designed to shuttle around, break apart, recycle, and reconstruct carbon-containing molecules. Thus, synthetic organics easily interact with the various naturally occurring biochemicals that constitute our anatomy and participate in the various physiological processes that keep us alive. By design, petroleum-derived pesticides have the power to kill because they chemically interfere with one or another of these processes. DDT, for example, interferes with the conduction of nerve impulses. The weed killer atrazine hinders the process of photosynthesis. The phenoxy herbicides bring about death by mimicking the effect of plant growth hormones.

... chlorofluorocarbons (CFCs), the famous ozone depleters, were exceptional because they did not share this property of biological activity. And because they are so chemically stable, CFC molecules can be swept into the stratosphere in their still intact state. Only when hit by a beam of ultraviolet light do they finally fall apart, releasing the chlorine atom that begins the destructive chain reaction culminating in the loss of ozone. CFCs were invented in 1928 but came into large-scale production only after World War II. Since the 1950s, the total amount of chlorine in the stratosphere has increased by a factor of ten.

Plenty of other synthetic organics are similarly inert in their finished forms. Indeed, this is why they are not biodegradable: their molecules are so large or otherwise so complex that they do not decay. They are thus exempt from the global carbon cycle that is constantly building up and breaking down organic molecules. And, of course, this exemption is what you want in a roof gutter, a water pipe, or a window frame.

For several reasons, however, this unreactiveness is misleading.

First, many of these compounds are themselves synthesized from synthetic chemicals that are highly reactive. By accident or on purpose, these industrial feedstocks are routinely released, dumped, or spilled in the general environment. While PVC plastic is, biochemically speaking, quite lethargic, the vinyl chloride from which it is manufactured exerts striking effects on the human liver. Second, inactive synthetic substances can shed or off-gas the smaller, more reactive molecules from which they are made. Third, new reactive chemicals can be created if these substances are subsequently burned-as when perfectly benign piles of vinyl siding are shoveled into a garbage incinerator, and poisonous dioxin rises from the stack. The incinerator itself, in this case, acts as a de facto chemical laboratory synthesizing new organic compounds from feedstocks of discarded consumer products.

Through all of these routes, we find ourselves facing a rising tide of biologically active, synthetic organic chemicals. Some interfere with our hormones, some attach themselves to our chromosomes, some cripple the immune system, and some overstimulate the activity of certain enzymes. If we could metabolize these chemicals into completely benign breakdown products and excrete them, they would pose less of a hazard. Instead, a good many of them accumulate. In essence, synthetic organic chemicals confront us with the worst of both worlds. They are similar enough to naturally occurring chemicals to react with us but different enough to not go away easily.

A number of these chemicals are soluble in fat and so collect in tissues high in fat content. Synthetic organic solvents, such as perchloroethylene and trichloroethylene, are an example. They are specifically designed to dissolve other oil- and fat-soluble chemicals. In paint, they work well to carry oil-based pigments. As degreasing agents, they work well to clean lubricated machine parts. As dry-cleaning fluids, they excel at dissolving human body oils and greasy fabric stains. They also all work splendidly to dissolve human body oils still on our skin and can thus easily enter our bodies upon touch. In addition, they are readily absorbed across the membranes of our lungs. Once inside, they take up residence in fat-containing tissues.

Many such tissues exist. Breasts are famous for their high fat content and often serve as repositories for synthetic organic chemicals circulating within the female body. But organs less renowned for fat content also collect these chemicals. The liver, for example, is surprisingly high in fat. So is bone marrow, the target organ for benzene. And, amazingly enough, because nerve cells are swathed in a fatty coating, so are our brains. Consider that many solvents have been used as anesthetic gases due to their ability to affect brain functioning. Chloroform is one.

Its medical uses long since discontinued, chloroform continues to be used as a solvent, fumigant, and ingredient in the manufacture of refrigerants, pesticides, and synthetic dyes. U.S. annual production of chloroform is currently about 600 million pounds, and it is found in nearly half of the hazardous waste sites on the Superfund National Priorities List. (s we shall see in Chapter Nine) trace amounts are also formed when drinking water is chlorinated. Chloroform is classified as a probable human carcinogen. Its residence time in the body is actually quite brief. DDT, for example, has a half-life of at least seven years, while that of chloroform is a mere eight hours. (Half-life is the time required to convert half the body's burden of a given substance into excretable by-products.) The problem, then, with chloroform is not so much biological persistence but the fact that we are continuously exposed through multiple routes. All human beings, according to the U.S. Agency for Toxic Substances and Disease Registry' receive at least low levels through water, food, and inhalation.

... in the last half of the twentieth century, cancers of the brain, liver, breast, and bone marrow (multiple myeloma) have been on the rise. These are all human organs with high fat content. In the last half of the twentieth century, the production of fat-soluble, synthetic chemicals has also been on the rise. Many are classified as known, probable, or possible carcinogens. We need to ask what connections might exist between these two time trends.

First synthesized in 1874, DDT languished without purpose until drafted into World War II, and it proved its mettle by halting a typhus epidemic in Naples. My father arrived in this occupied city not long after. According to his wartime account, Naples lay in ruins, its people hungry, dirty, and in great despair. Little wonder they were also vulnerable to typhus. DDT's ability to annihilate the insect carriers of this disease-fleas, lice, and mites-must have seemed miraculous. Shortly thereafter, DDT was loaded onto American bombers and sprayed over the Pacific Islands to control mosquitoes. War production of DDT soon exceeded military requirements, and by 1945, the U.S. government allowed the surplus to be released for general civilian use.

As documented by the historians Thomas Dunlap and Edmund Russell, this decision marked a profound change in purpose. It is one thing to fumigate war refugees falling ill from insect-borne epidemics and quite another to douse the food supply of an entire nation not at risk for such diseases. It is one thing to rain insecticide over war zones ravaged by malaria and quite another to drench suburban Long Island. The skillful advertising that accompanied this transformation advocated a whole new approach to the insect world. Various insect species-some, mere nuisances-were recast in the public's imagination as deadly fiends to be rooted out at all cost. Cohabitation was no longer acceptable. In demonizing the home front's new enemy, one cartoon ad even went so far as to place Adolf Hitler's head on the body of a beetle.

Synthetic pesticide use thus began in the United States in the 1940s. Two other chemicals participated in this debut: parathion and the phenoxy herbicides 2,4-D and 2,4,5-T. Parathion-and its sibling malathion-belong to a group of synthetic chemicals called organophosphates, which are created by surrounding phosphate molecules with various carbon chains and rings. Like the chlorinated pesticides, they attack an insect's nervous system, but they do so by interfering with the chemical receptor molecules between the nerve cells rather than by affecting the conduction of electricity, which is DDT's mode of action. Like the chlorinated pesticides, organophosphate poisons played a starring role during the war-but as villain rather than hero. Developed by a German company as a nerve gas, members of the first generation of organophosphate poisons were tested on prisoners in the concentration camps of Auschwitz.

By contrast, the phenoxy herbicides were an Allied weapon(As we have already seen in Chapter Three) they were mobilized in the 1940s with the goal of destroying enemy crops. Another American invention-the atomic bomb-ended that war before field testing could yield to full-scale chemical warfare. Twenty more years would pass before 2,4-D and 2,4,5-T would reenter combat-this time in Vietnam's rainforests under the nom de guerre Agent Orange. In the meantime, they were introduced into U.S. agriculture for weed control and into forestry for shrub control. By 1960,2,4-D accounted for half of all U.S. herbicide production. The hoe was fast on its way to becoming obsolete.

The graphical picture of pesticide use in the United States closely resembles the graphs of synthetic chemical production: a long, gentle rise between 1850 and 1945 and then, like the side of a mesa rising from the desert, the lines shoot up. Insecticide use begins ascending first; herbicide use closely follows. The line for fungicide use rises more gradually. All together, within ten years of their introduction in 1945, synthetic organic chemicals captured 90 percent of the agricultural pest-control market and had almost completely routed the pest-control methods of the prewar years. In 1939, there were 32 pesticidal active ingredients registered with the federal government. At present, 860 active ingredients are so registered and are formulated into 20,000 different pesticidal products. Current U.S. annual use is estimated at 2.23 billion pounds.

While agriculture consumes the lion's share of this total, with only about 5 percent used by private households, family pesticide use is emerging as an important source of exposure for those of us not living on farms. According to the EPA's National Home and Garden Pesticide Survey, 82 percent of U.S. households use pesticides of some kind. In a survey of families in Missouri, nearly 98 percent said they use pesticides at least once a year, and almost two-thirds said they use them five or more times. Yard and garden weed killers are used by about 50 percent of U.S. families, as are insecticidal flea collars, sprays, dusts, shampoos, and dips for household pets. These kinds of uses place us in intimate contact with pesticide residues, which can easily find their way into bedding, clothing, carpets, and food. Pesticidal residues persist much longer indoors than outdoors, where sunlight, flowing water, and soil microbes help break them down or carry them away. Yard chemicals tracked indoors on the bottoms of shoes can remain impregnated in carpet fibers for years. Some researchers now believe that infants and toddlers experience significant exposure to pesticides by crawling on carpets and ingesting house dust-perhaps even more so than by ingesting pesticide residues on food.

Several studies have linked childhood cancer to home pesticide use. Childhood cancer in Los Angeles was found to be associated with parental exposure to pesticides during pregnancy or nursing. In a 1995 study in Denver, children whose yards were treated with pesticides were four times more likely to have soft tissue cancers than children living in households that did not use yard chemicals. In another case-control study, researchers found statistically significant associations between the incidence of brain humors in children and the use of several household pesticidal products: pest-repelling strips, lindane-containing lice shampoos, flea collars on pets, and weed killers on the lawn. All together, these findings may represent the beginning of an explanation as to why brain cancer in children under age fourteen has risen sharply during the past twenty years.

Formaldehyde serves as an embalming fluid in funeral homes. It is also sprayed on fabric to create permanent press. In the 1970s, formaldehyde-based foams became popular for thermal insulation of houses. But nearly half of formaldehyde's annual production is used for synthetic resins to hold pieces of wood together as plywood and particle board. The subsequent evaporation of formaldehyde vapors from construction materials and furniture makes this chemical a significant contributor to indoor air pollution. As with chloroform, the problem with formaldehyde is not that it accumulates in our tissues but that we are exposed to small amounts of it almost continuously and from so many sources-from our subflooring to our wrinkle-free sheets.

... What formaldehyde shares with the soybean is an ability to act as an adhesive. Before formaldehyde was synthesized in such gargantuan quantities, soybean resins were used to hold particle board and plywood together. Soybean oil was also used in fire-suppressant foam and wallpaper glue, and as a base for paints, varnishes, and lacquers.

Other plant-based oils also played leading roles in industry before the war. Oils extracted from corn, olives, rice, grape seeds, and other plant parts were used to make paint, inks, soaps, emulsifiers, and even floor covering. The word linoleum echoes the name of its original key ingredient: linseed oil. Castor oil, from the tropical castor bean tree, was used to lubricate machine parts.

The rapid birthrate of new synthetic products that began in 1945 far surpassed the ability of government to regulate their use and disposal. Between 45,000 and 100,000 chemicals are now in common commercial use; 75,000 is the most frequently cited estimate. Of these, only about 1.5 to 3 percent (1,200 to 1,500 chemicals) have been tested for carcinogenicity. The vast majority of commercially used chemicals were brought to market before 1979, when the federal Toxics Substances Control Act (TSCA) mandated the review of new chemicals. Thus, many carcinogenic environmental contaminants likely remain unidentified, unmonitored, and unregulated. Too often, this lack of basic information is paraphrased as "there is lack of evidence of harm," which in turn is translated as "the chemical is harmless."

Pesticides are regulated by twin laws: the Federal Food, Drug, and Cosmetic Act (FFDCA) and the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA). FFDCA governs pesticide tolerances on agricultural commodities-that is, it sets legal limits for pesticide residues allowed in foodstuffs ranging from raw vegetables to animal feed. FIFRA, on the other hand, requires companies manufacturing pesticides to test their products for toxicity and submit the results to the federal government. Amendments to FIFRA require reevaluation of old, untested pesticides approved before the current requirements for scientific testing were put into place. Initially scheduled to be completed in 1976, this reregistration process is still under way, has been repeatedly delayed, and is now scheduled for completion in the year 2010. Until then, the old, untested pesticides can be sold and used. As one critic has noted, it is as if the bureau of motor vehicles issued everyone a driver's license but did not get around to giving us a road test until decades later. According to the National Research Council, only 10 percent of pesticides in common use have been adequately assessed for hazards; for 38 percent, nothing useful is known; the remaining S2 percent fall somewhere in between.

... Of all the unexpected consequences of World War II, perhaps the most ironic is the discovery that a remarkable number of the new chemicals it ushered in are estrogenic-that is, at low levels inside the human body, they mimic the female hormone estrogen. Many of the hypermasculine weapons of conquest and progress, are, biologically speaking, emasculating.

This effect occurs through a variety of biochemical mechanisms. Some chemicals imitate the hormone directly, while others interfere with the various systems that regulate the body's production and metabolism of natural estrogens. Still others seem to work by blocking the receptor sites for male hormones, which are collectively called androgens. In 1995, fifty years after its triumphant return from the war and entry into civilian life, DDT again made headlines when new animal studies showed that DDT's main metabolic breakdown product, DDE, is an androgen-blocker.

Our enzymes quickly convert DDT into DDE. But because the next step is much slower (recall DDT's seven-year half-life), we accumulate DDE as we age-much as a fine stream of sand grains gradually forms a heap at the bottom of an hourglass. DDE molecules can cross the human placenta and can also accumulate in breast milk. Thus, those of us too young to have been sprayed by DDT directly nevertheless have accumulated DDE in our bodies through at least two routes: from our mothers (both before and after birth) and our consumption of milk, meat, eggs, and fish. Animals, like the humans who eat them, lack the biochemical hardware needed for efficient conversion of DDE to something excretable.

For boys and men, the consequences may include physical deformities such as undescended testicles, lowered sperm counts, and testicular cancer. No one knows what effect DDE exposure has on the reproductive development of girls or women; no research has been done. The only thing we know for a fact is that DDE is biochemically different enough from anything else in the human body- male or female-that it is not completely metabolized as are our own natural sex hormones. This is one reason why, more than two decades after DDT's forced retirement in the United States, we still have DDE molecules floating around in our tissues.

About half of the synthetic materials known to function as endocrine disrupters belong to a chemical group called organochlorines. Not all estrogenic materials are organochlorines, and not all organochlorines are estrogenic, but the overlap is impressive. Moreover, organochlorines are such a large group-around eleven thousand exist-and they tend to be so persistent in the environment, so reactive within human tissues, and so frequently associated with cancer that they merit special consideration.

... Lindane, DDT, heptachlor, chlordane, PCBs, CFCs, TCE, perc, 2,4-D, methyl chloride, vinyl chloride, polyvinyl chloride, dioxin, and chloroform are all organochlorines. Benzene, formaldehyde, nonylphenol, and phthalates are not.

Organochlorines, which involve a chemical marriage between chlorine and carbon atoms, are not strictly a human invention. A few are formed during volcanic eruptions and forest fires and some by living organisms such as marine algae. For the most part, however, chlorine and carbon move in separate spheres in the natural world-and in the bodies of humans and other mammals. To force the two together, elemental chlorine gas is required.

Although it holds a rightful place in the periodic table of elements, pure chlorine is a human invention. It can be produced by passing electricity through salt water in a procedure that was first undertaken on an industrial scale in 1893. A powerful poison, chlorine gas became known to the world during World War I, but its manufacture grew slowly until World War II, then rose exponentially. About 1 percent of this production is used for disinfecting water and about 10 percent for bleaching paper, and the majority is combined with various carbon compounds, usually derived from petroleum, to make organochlorines.

As a group, organochlorines tend to be persistent in air and water. When they evaporate and are swept into the wind currents, some fall back to the earth close to their origins, while others can circulate for thousands of miles before being redeposited into water, vegetation, and soil. From there, they enter the food chain. Diet is thus believed to be a major route of exposure for us.

Not all organochlorines are deliberately constructed. Whenever elemental chlorine is present, the natural environment will synthesize additional, unwanted organochlorine molecules. These reactions can take place when water containing organic matter, such as decayed leaves, is chlorinated. It can happen in pulp and paper mills during the process of bleaching or when chlorinated plastics are burned. It can happen during the manufacture of other organochlorines. The production of 2,4,5-T, the burning of plastic, and certain methods of bleaching paper all contribute to the birth of dioxin. A chemical of no known usefulness and never manufactured on purpose, dioxin has been linked to a variety of cancers and is now believed to inhabit the body tissues of every person living in the United States.

Sweeping changes are immediately possible in the dry-cleaning industry. Most clothing tagged as "dry-clean only" can in fact be professionally cleaned with the use of water, special soaps, and reengineered washing machines that allow computerized control over humidity, agitation, and heat. (Pressurized carbon dioxide also holds promise as a nontoxic solvent for cleaning textiles.) The Boston area, for example, is home to one such wet-cleaning operation, a pilot project of the Toxics Use Reduction Institute. I recently delivered to this shop a down coat, a silk dress, a badly stained antique kimono, and a pile of my best wool, cashmere, and rayon suits. All came back clean, beautifully pressed, and odor-free. The white streak across the sleeve of the green blazer-the result of an encounter with a freshly painted doorframe-was gone. Best of all, the proprietor, who appeared about eight months pregnant, expressed to me her relief at not having to be exposed to perc.

Most of the perchloroethylene manufactured in the United States is used by the textile and dry-cleaning industry. In 1992 alone, 12.3 million pounds of this organochlorine and suspected carcinogen was released into air, ten thousand pounds to rivers and streams, and nine thousand pounds to land. Thirteen thousand pounds were directly injected into underground wells. The recycling of perchloroethylene produces contaminated sludge and filters, which are subsequently deposited in landfills where they poison soil. Traces of perchloroethylene have been found in breast milk, cow's milk, meat, oil, fruit, fish, shellfish, and algae. Perc has been detected in rainwater, seawater, river water, groundwater, and tap water. More than 650,000 workers are thought to be exposed to perc on the job, and an estimated 99,000 New York City dwellers are exposed to elevated levels just from breathing-many because their office or apartment shares the same building with a dry-cleaner. A 1993 survey found that 83 percent of New York City apartments located above a drycleaning establishment had ambient perc levels in excess of state health guidelines.

Living Downstream

Environment watch

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