ITD180 1.U5 1976 United States Environmental Protection Agency Office of Public Affairs (A 1071 Washington, D C 20460 May 1976 Pollution and Your Health OOOK76004 ------- ------- There is no way lor society to avoid paying for pollution. If we do not pay for prevention, we pay in other ways—in lost recreational uses of rivers and beaches, in higher treatment costs for drinking water, in damage to crops, forests and buildings and, most importantly, through higher medical bills, time lost because of illness, human suffering and premature deaths. The Department of Health, Education and Welfare puts the total national health bill at about $120 billion a year, most of it for cure rather than prevention. Yet there is an increasing body of evidence and an impressive array of expert opinion that we may be approaching the whole question of human health from the wrong side— that, as a matter of national policy as well as personal practice, an ounce of prevention may well be worth a pound of cure. In the United States the once-dreaded infectious diseases are controlled through sanitation, immu- nization and antibiotics. Today we are plagued with chronic diseases that an increasing number of health experts believe are largely caused by environmental factors—where we work or live, our habits, diets or lifestyles. The more sophisticated and sensitive our monitoring devices become; the more data we accumulate on the health effects of pollutants and other agents in ^ the environment: the worse things look. ^ be fought, not simply in the hospitals and doctors' offices, but in our streets, homes and workplaces; .o in our air and water; in our food and products; cj CD and in our habits and lifestyles. Such a shift in •*- .fc **. emphasis will require a searching re-examination >• ^ O and radical revision of our popular understanding __ E O of, and our public approach to, health care and •£? >, _§ ^ disease. If environmental disease is becoming cu cu ro co "the disease of the century," as it appears to be, g 5 Q ^ then environmental protection must become the £? "^ -c :£ most important ingredient in any national health > ^ 5 ~ program. uj c ^ J? Russell E. Train, C/5 JW O .1- Administrator ^ £} g> -C U.S. Environmental Protection Agency ^ O ------- Introduction T^he principal reason for controlling •*- pollution is to protect human health and the ecological integrity of man's life-support systems. Innumer- able other benefits can result from clean-up measures—financial savings, more efficient productivity, and esthetic pleasure. But fundamentally, the con- cern about environmental pollution is its threat to human health and life. We have been slow to recognize the damage brought about by our activi- ties, almost as slow as the appearances of some environmental after-effects. ------- The impact of environmental deterio- ration on health is often subtle, be- coming apparent only when correction is not always possible. Frequently the results of environmental contami- nation become known so belatedly that few people are likely to associate the effect with its cause. The long-delayed beginnings of ill- nesses caused by pollution makes it difficult for many people to compre- hend the full impact environmental degradation has on their health. The complexities of modern life and the many forms of environmental pollution combine to make the task of protecting public health a major challenge. While much is already known about the health effects of some pollutants, pollution's total impact is difficult to measure. What each pollutant does to a human depends on the physical and chemical properties of the pollut- ant; the length, intensity and method of exposure; and an individual's ability to tolerate the pollutant. Pollutants reach people through vari- ous avenues, each taking its unique toll. But virtually all forms of pollution harm people somehow. Some people are especially susceptible to attack, notably the very young, the old and those weakened by disease. Since resistance to pollution is an individual trait governed by such factors as age, heredity, general health, climate, occu- pation, residence, smoking and dietary habits, it is extremely difficult to assess precisely the general effects upon a large population. Effective and at times stern decisions must be made to solve obvious prob- lems, even though we may not know the full extent of the health threat. There is no way to ascertain abso- lutely the chronic effects of environ- mental pollution. We cannot, for instance, state unequivocally that the continued accumulation of tiny amounts of pesticides in the fatty tissue of humans or other organisms, is a direct cause of disease. Neither can we prove that life is not altered at all as a result. The field of environ- mental health effects is one of cer- tainties mixed with uncertainties. But we must not suspend all judgment while we argue about proof. We know that environmental pollution has significant adverse effects on the physical and emotional health of Americans. The U.S. Environmental Protection Agency (EPA) was created in De- cember 1970 to consolidate, strength- en and coordinate Federal efforts to enhance human health and well- being through environmental reha- bilitation and protection. Since 1970 existing laws have been strengthened and new laws enacted which give EPA the mandate and the means to accomplish these national goals. Much has been accomplished in recent years, but much more remains to be done. As the costs of pollu- tion control become more apparent, it is important to remember that the primary benefit—-good health— is priceless. This booklet is a general discussion of possible threats to human health posed by environmental pollution. It presents some of the background that must be considered as we try to solve the problems of environ- mental health risks. ------- Air Thirty air makes eyes water, burns throats and stifles lungs. Fumes of sulfur and nitrogen oxides, sulfuric acid and photochemical oxidants irritate the respiratory system causing coughing, chest discomfort and impaired breathing. When small particles are breathed in along with these fumes, the irritation—and injury—may increase substantially. Carbon monoxide interferes with the ability of blood cells to carry oxygen. Heart and nerve tissues are parti- cularly susceptible to oxygen defi- ciency, so that carbon monoxide pollution can seriously impair coro- nary and central nervous system functions. On Friday, December 5, 1952, static weather conditions turned the air of London, England, into a deadly menace. A prolonged temper- ature inversion held the city's air close to the ground and an anti- cyclonic high pressure system pre- vented the formation of winds which would have dispersed the pollutants that were accumulating heavily at ground level. For five days the Greater London area was blanketed in airborne muck. Few realized it at the time, but there were 4,000 more deaths than normal for a five-day period, hospital ad- missions were 48 percent higher and sickness claims to the national health insurance system were 108 percent above average. Eighty-four percent of those who died had pre-existing heart or lung diseases. Hospital admissions for respiratory illness in- creased threefold and deaths due to chronic respiratory disease increased tenfold. The same static atmospheric condi- tions had caused a similar incident in Donora, Pennsylvania, in 1948. A town of only 14,000, it had 15 to 20 more deaths than normal during the episode. More than 6,000 ------- of its residents were adversely af- fected, 10 percent of them seriously. Among those with pre-existing illnes- ses, 88 percent of the asthmatics, 77 percent of those with heart disease, and 79 percent of those with chronic bronchitis and emphysema were adversely affected. Allowing for the great difference in population, Donora paid a much higher price for air pollution than London. New York City has experienced similar periods of atmospheric stag- nation on numerous occasions during the last 50 years. During one such episode, in 1953, the city reported more than 200 deaths above normal. Birmingham, Alabama, is another high-exposure area where residents frequently have exhibited a greater-than-avcrage incidence of respiratory irritation symptoms, such as coughing, burning throats or lungs, and shortness of breath. EPA monitoring studies indicated that non-smokers in these two cities de- veloped respiratory symptoms two or three times more frequently than non-smokers in cleaner communities. Unfortunately, the climatic condi- tions and human activities that combine to form critical build-ups ------- of pollutants are by no means un- common in the United States. They occur periodically in various parts of the country and will continue to threaten public health as long as air pollutants are emitted into the at- mosphere in amounts sufficient to accumulate to dangerous levels. Air pollution disasters such as these are alarming. However, many people are even more concerned about the health effects of long-term exposure to air pollution. While we have learned a great deal in recent years about the effects of air pollution, we are still very far from being able to assess accurately what low but persistent levels of air pollution do to human beings. Emphysema and chronic bronchitis—• the chronic obstructive lung diseases —are two of the more significant causes of disability compensated by Social Security. Since these two diseases are commonly responsible for workdays lost to illness, chronic disabilities and premature retire- ments or deaths, they hurt the Nation's physical health and its eco- nomic well-being. Aside from the question of whether or not air pollution causes chronic lung diseases, it certainly aggravates their symptoms and increases the frequency and severity of asthma attacks. It also caused changes in the heart and lung functions of healthy people. Early childhood ex- posure to heavy pollution is believed to contribute significantly to a lowered pulmonary reserve capacity in adults. Children from high exposure areas suffer a greater risk of developing lung disease as adults than children raised in cleaner communities. Statis- tics also show that residents of com- munities with persistently high pollution levels have higher death rates than residents of other com- munities. Particulates and sulfur oxides are not the only major classes of pervasive pollutants. All kinds of combustion produce nitrogen oxides which have been associated with increases in acute respiratory disease. Carbon monoxide is still a problem in today's heavy traffic. Inhalation of carbon monoxide can impair a driver's judgment and his ability to respond rapidly in traffic. Further- more, it can also impair vision, produce headache, and exert a strain on the heart. There arc other air pollutants that in minute amounts can cause severe health effects. Each has its parti- cular adverse characteristics which place unique stress on human beings. The total number of such pollutants commonly found throughout the country is not known but every year thousands of new chemicals are intro- duced into manufacturing processes alone. It is impossible to discuss the potential health effects of all likely pollutants, so here are four examples that suggest the kinds of health ef- fect that may be involved. Inhalation of asbestos fibers has been related to asbestosis, broncho- genie cancer, mesothelioma, and other malignant diseases. Symptoms of mesothelioma, for instance, de- velop about 30 years after the initial exposure to asbestos, and some phy- sicians expect an increase in the disease among persons who worked in or near American shipyards during ------- World War II. Asbestos is used in many products and industrial opera- tions. Beryllium is a metal commonly used in rocket fuels, missile guidance systems, nuclear reactors and atomic weapons. The most deleterious effect of inhaled beryllium is a progressive lung disease. Mercury is commonly used in bat- teries, mildew-proofing and the manufacture of paint, pulp, and paper. Airborne mercury can affect the central nervous system and can lead to weight loss, insomnia, tremors and psychological disturbances. Lead absorption is often prevalent among preschool children in urban areas. In the past, we attributed most of the poisoning to eating lead-based paint chipped from the walls of older dwellings, but recent evidence indicates that other environmental lead sources are also contributing to the problem. High concentrations of lead in dust, soil and vegetation near streets and highways clearly can be attributed to lead emissions from motor vehicles. Precipitation samples from locations throughout the United States show a positive corre- lation between gasoline consumption and the lead content of rain. People who ingest excessive amounts of lead may show neurological impair- ment such as seizures, mental re- tardation and behavioral disorders. Ordinarily we all accumulate lead in our bodies, but urban residents usually have higher average blood levels of lead than rural residents. Children and the newborn may be particularly susceptible to lead damage of the central nervous system. ------- Water "pifty years ago, the United States was plagued by massive outbreaks of typhoid, cholera, dysentery and other water-borne diseases. Better treatment of sewage and drinking water have largely eliminated these epidemics. As a result, Americans have long considered safe drinking water as a natural heritage. We have accepted it much as we regarded the air we breathe—unlimited, free and clean. But, like air, water is not limitless, nor free, nor some- how immune to the pollution which affects other aspects of our environ- ment. Between 1961 and 1973, there were more than 200 known or reported outbreaks of disease or poisoning caused by contaminated drinking water. Twenty-two people died and nearly 55,000 became ill, many of them seriously. And some EPA water supply experts believe that perhaps ten times as many such incidents occur but go unreported for a variety of reasons and that countless indi- vidual sufferers—and their doctors —fail to associate ailments with contaminated water. A 1970 survey of 969 public water supply systems disclosed that 56 per- cent had facility deficiencies relating to equipment design, construction or plant condition; 77 percent of the plant operators were inadequately trained in microbiology and 46 percent were deficient in the chem- istry relating to their assignments; and 79 percent of the systems had not been inspected by State or county authorities during the preceding year. Sources of water pollution are ------- innumerable. Major sources can be found in nearly every kind of in- dustrial, municipal or agricultural operation. There arc thousands of toxic chemical compounds in use today and new chemicals are being developed every year. Chemical con- taminants, such as phosphates, ni- trates, pesticides, detergents, trace amounts of metals, acid from mine drainage, cyanide, phenols, radioactive substances, solvents, and hydro- carbons, are all products of our technological society and potential threats to our water sources. A 1975 EPA survey of drinking water supplies in 80 cities found that small quantities of organic chemicals were present in public water supply systems throughout the country. Some of these were suspected cancer- causing chemicals, if taken in large amounts. Although the survey found very low concentrations of them in the water, their presence is cause for concern. Water supply intakes are also jeopardized from time to time by spills of oil and hazardous materials. Such spills in estuaries often make fish and shellfish unsuitable for food. Oil in water is known to concentrate fat-soluble poisons, such as insecti- cides and certain chemicals, many times higher than would normally occur in water alone. In this way, oil spilled into water can permit highly destructive amounts of pol- lutants to be ingested by organisms in man's food chain. The widespread use of high-nitrate fertilizers and extensive feedlot operations have resulted in an in- creased contamination of both sur- face and ground waters with nitrates. As a result, the nitrate content of much of our ground water now exceeds the drinking water standard. This is highly significant because once an underground water supply source becomes contaminated, it is virtually impossible to purify. In- fants up to three months old run the principal risk of damage from drinking water having a high nitrate content—damage that includes a blood disease that is fatal if not properly treated. Sodium levels also have been rising ------- Solid Wastes in American waters. Increased sodium intake from polluted water, for those who are susceptible, can put a strain on the heart and aggravate cardiovascular (heart and blood vessel) disease. The corrosiveness of water is also linked, statistically, with deaths due to cardiovascular diseases. Water that corrodes pipes causes metals to be swallowed by people drinking the water. Comparatively little is known about the effect on human health of ingesting these metals. Sewage discharges can also contaminate surface waters with harmful bacteria and viruses. Water- borne viruses still cause infectious hepatitis in this country and may be causing some gastroenteritis and salmonellosis. Most hepatitis outbreaks from public supplies occur after the water is purified, and result from contamination of the distribution system due to mechanical inadequacies. Many of our recreational waters, too, are unsafe because of high bacteria counts from sewage discharges. Mismanaged water resources can deteriorate into swamps and stagnant areas that foster the growth of mosquitoes and insects. In the United States, mosquitoes still transmit disease. Encephalitis has occurred in epidemic form, reaching a median of 1,340 reported cases a week during the years 1969-73. "C nvironmental health cannot be compartmentalized. Nowhere is this more evident than in the area of solid waste management. There are only three places to put our wastes: the Earth, its waters, or its atmosphere. The use or misuse of any one is inextricably bound up with the other two. Restrictions on using one medium almost invariably lead to increased burdens on—and frequently to abuse of—others. Certainly, improper management of solid wastes on land creates health hazards from both air and water pollution. For example, water picks up foreign matters as it trickles down through open dumps or improperly designed landfills and pollutes ground or surface waters; open burning of solid wastes and faulty incineration contribute to air pollution. Conversely and somewhat paradoxically, what may be counted as successes for air and water pollution control programs may actually aggravate the public health problems of solid waste management. For example, effective waste water treatment plants produce solid sludges, which must be disposed of. A ban on home incinerators or open burning of yard debris immediately results in a greater burden on the solid waste collection, processing, and disposal system. And as land disposal activities are upgraded, some coastal communities look to the sea for ultimate disposal of their solid wastes. Management of solid wastes, clearly, is a root environmental issue with profound public health implications. Perhaps the most obvious health aspect of waste management is the 10 ------- adverse effect of hazardous wastes— that is, wastes that are toxic, corrosive, flammable, or explosive. These wastes, whether solid, liquid, or sludge, have a unique potential for affecting public health and the environment. Some are hazardous to human health; others adversely affect desirable plants and animals, and, indirectly, man. They require special care in all aspects of their storage, collection, processing, and disposal. Less obvious, though nonetheless important, are the adverse health impacts associated with seemingly "nonhazardous" wastes. The relationship between public health and improper storage and disposal of solid wastes has long been recognized. Rats, flics, and other disease carriers breed in open dumps and in residential areas where food and shelter are available. Many fires begin or are spread by improperly stored trash. Drinking water sources can be contaminated by leaching from dumps and poorly designed landfills. Among the diseases that have been directly or indirectly associated with the open dump are typhoid fever, cholera, dysentery, anthrax, trachoma, and trichinosis. And there are still thousands of open dumps operating in various parts of the country. Modern food-production and marketing techniques have created new potential health hazards. Livestock and poultry production in the United States is commonly concentrated in large-scale, confinement-type operations. These large concentrations of animals have greatly magnified the problem of managing wastes in a way that will minimize health hazards. Among the serious health-related effects possible in feedlot operations are the wholesale reproduction of flies and the contamination of water. The basic health and environmental problems associated with solid waste management are exacerbated by a number of factors related to our social and economic structures, institutions, and attitudes. One result is the incquitability of health impacts on different population groups in the United States. The poor are most likely to suffer ill effects from unsanitary storage and inadequate waste collection. 11 ------- Noise "VToisc is perhaps the most overlooked and underestimated form of environmental pollution. This is partly true because noise has long been regarded as an inevitable accompaniment to modern life. The clamor of machinery and tools, the roar of aircraft and automobiles, the racket of appliances—all have been considered to be the sounds of progress. We have accepted the noise and adjusted to it, without fully recognizing its health effects. It is known that continued exposure to high noise levels results in hearing loss. Some 16 million Americans, in fact, suffer some hearing loss because of noise. Studies show that high noise levels detrimentally affect work 12 ------- performance, cause accidents and foster absenteeism in industry. Perhaps the most serious concern of noise pollution is that it diminishes the quality of life. People, especially urban dwellers, are bombarded daily by the clamor of construction equipment and the roar of traffic. The home is no longer a silent refuge. It reverberates with the cacophony of kitchen appliances, vacuum cleaners, power mowers, radios and television sets. At the very least such noise disturbs sleep, interrupts concentration and conversation, and jangles the nerves. More serious, though, is a buildup of stress which can lead to ulcers, gastrointestinal problems and heart disease. Pollution on the job Pollution: a spreading pall of black smoke; scum-coated water; blue-grey smog- These are familiar pollution images. But the environment is more than the sky, a river or a forest. It is also the places where people work. And too many Americans today work in environments which are not healthy. The National Institute for Occupational Safety and Health esti- mates that as many as 100,000 American workers may die each year from conditions they are exposed to in their jobs. Environmental standards for workplaces are being developed and enforced by the Department of Labor. As of June 1975, the National Cancer Institute had confirmed 27 cases of liver angiosarcoma among workers with a history of exposure to vinyl chloride, a major compound used in making plastics. Angiosarcoma of the liver is a rare form of cancer. An American Cancer Society survey re- corded only one case per 78,000 deaths. This indicates that workers exposed to vinyl chloride are 3,000 times more likely to develop this disease than the general public. The Department of Labor has adopted vinyl chloride exposure standards to protect workers within a plant and EPA has proposed standards to pro- tect the general public from atmos- pheric exposures that result from vapors being released by these plants. At a small plant manufacturing the pesticide Kepone, about 70 employees, out of a total workforce of 150 during 16 months of operation, were sickened with tremors, memory loss, nerve damage, blurred vision, erratic eye movements, chest pains and, in some cases, at least temporary ster- ility. Among the pollutants that attack workers are coal dust, asbestos fibers, lead particles, uranium radiation, chemical fumes, deafening noise, pesticides, and glass fibers. There is usually a long latency period—per- haps as much as 30 years—between the first exposure to dangerous en- vironmental pollutants and the oc- curence of disease. So it may be decades before we will know how much harm pollutants in the work- place are doing to the Nation's health. 13 ------- Pesticides Tn contrast to most other contami- •*• nants, pesticides are deliberately introduced into the environment as a killing agent to perform various beneficial functions. Improved agricultural production, control of dangerous insect-borne diseases such as malaria, and greater sanitation in homes and recreation areas are only a few of the many ways pesticides benefit human health. Widespread pesticide use has, however, also been accompanied by serious problems for man and his environment. It is presently known that many pesticides at various exposure levels will cause illness. Some highly toxic chemicals, such as parathion, can cause serious illness or even death if only one drop of the concentrated substances touches the skin. Reactions to pesticide exposure vary greatly. They include damage to the central nervous system, respiratory and digestive tracts, skin, eyes, mucous membranes, visceral organs, and the mind. Every year a number of persons are killed and still more are made seriously ill by pesticides. Improper application because of failure to follow instructions on pesticide labels or ignorance of pesticide hazards causes most of these incidents. While we are well aware of the immediate hazards, we do not know enough about the long-range effects on human health resulting from our increasingly widespread exposure to pesticides. Among the pesticide characteristics which contribute to this diffuse exposure are mobility, persistence, and bioaccumulation. Pesticides can be transported great distances by air and water. Measurable levels of DDT, for example, have been found in Antarctic penguins, although the animals have never been directly exposed to the compound. Some pesticides do not break down readily. Thus, they remain in the environment for very long periods and can move up the food chain through the process 14 ------- Radiation of bioaccumulation. In other words, minute quantities of chemicals absorbed by plankton and insects arc transferred, in constantly increasing concentrations, up the food chain to fish, birds, other higher animals and man. These chemicals are stored in body fat and tissues where they may remain for many years. Scientific experiments indicate that some pesticides have caused malformations in the developing embryos of test animals and that other pesticides may cause cancer in certain species. While there is no direct evidence linking pesticide residue to similar health effects in man, the potential for long-term effects on large numbers of people cannot be discounted. The nervous system — is it affected? Beyond the physical waste, environ- mental pollution may have a more profound effect on man: on mental health, for example. Most lead poison- ing causes behavioral difficulties, per- ceptual disabilities, and emotional instability. Mercury poisoning causes emotional instability, tremors, fatigue, dizziness, memory and speech diffi- culties, and headaches. Carbon mo- noxide poisoning causes apathy, psychological tiredness, headaches, temporal-spatial disonentation, re- tardation, and psychosis. Psychologi- cal impairment following exposure to pesticides has been discussed else- where, and a number of studies have linked excessive noise to higher mental hospital admissions as well as to other psychological disturbances. Tncrcasing man-made radiation also poses a danger to our health. The principal adverse effects that radiation can have on human health are genetic disturbances and cancer. Apparently, some body tissues are particularly vulnerable to irradiation, notably the blood-forming organs, thyroid, bone marrow, breast, lung and reproductive organs. The young, particularly, the unborn, are most susceptible to radiation damage. We all receive radiation from natural sources over which we have little control. Our remaining exposure comes from medical and dental X-ray machines; fallout from nuclear weapons testing; uranium mines, mills and fabrication plants; nuclear power generating and fuel-reprocessing installations; and various electronic devices. Many hospitals and laboratories commonly use radioactive isotopes in basic research and patient diagnosis and treatment. And construction materials with radioactive properties have been used for homes, schools, factories and other structures. In Tennessee, cement blocks arc often made of Conasauga shale, which contains high concentrations of thorium and in Florida blocks are sometimes made of phosphate rock, which contains high concentrations of radium. In buildings constructed of these materials, radioactive gases seep out of the blocks and accumulate in the ambient air. Granite, too, frequently emits gamma radiation. Despite this variety of sources, man's exposure to radiation thus far has been quite low. Nevertheless we know very little about the long-term effects of repeated exposure to radiation at low levels. One major hazard is 15 ------- damage to or alteration of human genes, since natural background radiation is believed to be one of the causes of natural mutation. It is generally accepted that any amount of radiation, however small, can cause damage to genetic cells and hence cause an indeterminate number of undesirable mutations. Such genetic damage is believed to be cumulative. Also, it is generally accepted that any increase in radiation exposure can cause increases in the frequency of many cancers. nvironmenta! Protection Agilicy V, Library outh Dearborn Street go, Illinois 60604 ------- Carginogens, Teratogens, ------- I ------- Carginogens, Teratogens, Mutagens These three terms have become more familiar to many Americans as we have become more aware of the perils of environmental pollution. Carcinogens arc substances that cause cancer. Teratogens cause birth defects. Mutagens cause hereditary changes thai may be passed from one generation to another Carcinogens The effect of carcinogens on human tissue (if exposure is sufficient) is generally irreversible. Incidences of cancer today may reflect an exposure many years ago. Similarly, carcino- genic contaminants added to the environment today may not reveal their damage until many years from now. Cancer is not one disease. It is at least one hundred diseases that in- volve derangement in body cells. Many cancers are self-inflicted by habits such as smoking, overeating, overdrinking and sunbathing. Carcinogens that produce cancer in experimental animals are found in low concentrations in food. Others, such as some air and water pollutants, certain pesticides and food additives, are everywhere. Not only are we ignorant of the carcinogenic potential of many substances repeatedly intro- duced into the environment, but we also do not know much about the synergistic effects of two or more carcinogens or even a single carcino- gen in combination with various pro- moting agents or other chemicals. It is not widely appreciated that a com- bination of pollutants can be more damaging than the sum of their separate effects. Many substances, which are not carcinogenic by them- selves, interact with other substances to promote the development of cancer. Cancer has been a major cause of death in the United States since 1900. In this century there has been an absolute increase in cancer deaths which cannot be explained as a re- sult of either the increase or aging of the population. On the average, cancer deaths have increased by about one percent per year since 1933. Cancer of the respiratory tract has shown the most rapid increase ever re- corded for a non-infectious disease,1800 percent during the past 40 years. And the death rate from lung cancer for urban residents is twice the rural rate, even after allowing for smoking habits. In the vast majority of cases, pollution in urban areas exceeds the levels in less populated regions. Numerous environmental pollutants are not only carcinogenic but tera- togenic and mutagenic as well. Tera- togens may cause monstrous deformi- ties. Congenital defects account for 14 percent of all infant deaths and are the third most common explana- tion for deaths in the newborn. Many substances induce abnormalties in a fetus at levels below those needed to make the mother ill. Methylmercury, for example, affects prenatal develop- ment; children born to mothers who have eaten food contaminated by it frequently exhibit a disorder resem- bling cerebral palsy. One of the most disquieting aspects of teratogens is that their potential for destruction has rarely been known in advance. X-rays, German measles, mercury, thalido- mide—all extracted costly tolls before their teratogenic features were recog- nized. Mutagens Mutagens result in transmissible changes that affect potential offspring. If a pollutant damages a cell while its capacity for division remains un- impaired, the result may be defects among future generations. Many chemicals which pollute the en- vironment are mutagenic in large doses. But we do not know whether these chemicals are mutagenic haz- ards at the levels they presently appear in the environment. ------- |