7 CHAPTER 2 Environmental Change and Health 2.1 OUR CHANGING ENVIRONMENT The environment, which sustains the life of all living organisms, can also be a profound source of ill health. As mentioned in the previous chapter, increasing industrialization, expanding technology and economics, coupled with growing world population in recent decades have radically changed, and are still changing, our environment. These changes have profound impacts on the health and well-being of living organisms. Some of the adverse effects we have experienced in recent years include increasing air pollution, acid rain, global warming, destruction of the ozone layer by CFCs, mounting waste, and others. In a rare departure from its tradition of naming a “Man of the Year,” Time magazine designated “Endangered Earth” as “Planet of the Year” for 1988. The January 2, 1989, issue of the magazine was dedicated to this theme. On the front pages of several articles in the issue are these words: “What On EARTH Are We Doing?” 1 One of the most pressing problems we face today is the release of large quantities of a variety of chemicals into the environment. This leads to air, water, and soil pollution, and food contamination. Furthermore, the release of these chemicals is not limited to areas adjacent to point sources such as industrial facilities. Rather, the chemicals can be transferred to distant areas and regions where they may elicit detrimental effects on living organisms. While environmental pollution has been a major concern in the U.S. and the world for several decades, there has been an increasing awareness concerning the impacts of air and water pollution and disposal of toxic wastes on public health. The extent to which air pollution affects public health is shown by many air pollution-related episodes throughout the world. One of the most widely known episodes is the 4000 “excess deaths” that occurred in London in 1952. Similar but less serious air pollution- related injuries also occurred in Los Angeles, New York, and several other major cities, although the air pollutants involved were often different from one another. LA4154/frame/C02 Page 7 Wednesday, May 17, 2000 3:35 PM © 2001 by CRC Press LLC 8 ENVIRONMENTAL TOXICOLOGY Human diseases and casualty arising from water pollution attracted much atten- tion throughout the world following the incidences of “Minamata disease” and “itai- itai-byo” or “Ouch-ouch disease.” The Minamata disease was caused by eating fish and shellfish laden with highly toxic methylmercury, while the itai-itai-byo was mainly attributed to consumption of rice contaminated with high levels of cadmium (Cd). In addition to affecting human health directly, water pollution also threatens aquatic life, particularly fish. For instance, in the early 1960s millions of fish in the lower Mississippi River died from the effects of chlorinated organic pesticides, particularly endrin. In the early 1970s, contamination of fish with DDT and PCBs (polychlorinated biphenyls) caused an abrupt halt to commercial salmon fishing in the upper Great Lakes. Also, around the middle of 1960s, New York City’s Hudson River was found to be dying as a result of severe water pollution. The sources of the pollution were found to be raw sewage dumped into the river by the city; discharge of large quantities of paint from an industrial plant; oil dumping from the Penn Central Railroad; and discharge of water at elevated temperatures from a nuclear power plant. 2 There is reason to be encouraged, however. In 1966 several fishermen formed the Hudson River Fishermen’s Association. Mainly because of their effort and that of others who joined subsequently, much improvement has been made. Beginning in 1968 scores of polluters were forced to spend millions of dollars remediating the Hudson. The by-product of these actions has been one of the greatest environmental success stories of the century. Today the Hudson produces more fish per acre than most other major estuaries of the North Atlantic. Fish and fishermen, boaters, swimmers have returned to the river. 2 Another major concern is the possible deleterious effect of an increasing number of toxic synthetic chemicals discharged into the environment. In the U.S., an assess- ment of the extent and severity of contamination is further complicated by the nearly exponential growth of the synthetic organic chemistry industry since the early 1940s. About 70,000 chemicals are estimated to be in common industrial and commercial use in the U.S., and this number continues to grow by about 1000 new compounds every year. 3 Only a limited number of ecological assessments on the bulk of the chemicals on the market or those introduced each year have been undertaken. The human health effect of many of these chemicals, particularly over long periods of time at low exposure levels, is not known. One of the most widely known episodes related to disposal of hazardous wastes is that of Love Canal. It was an abandoned canal bed near Niagara Falls, New York. In the1940s and 1950s, Hooker Chemical & Plastics Corp. dumped 23,000 tons of chemical wastes into the Love Canal landfill. 4 After the canal was filled and covered with earth, the land was transferred to the city of Niagara Falls. Homes and a school were then built on the edge of the old canal. The area of covered chemicals became a playground. In 1968, Occidental Chemical (OxyChem) purchased Hooker Chemi- cal. In 1977, black oily fluids oozed from the ground in the canal’s vicinity. The fluids were subsequently identified as a potent mixture of chlorinated hydrocarbons. Chil- dren attending the school showed unusual health problems, such as skin rashes, chemical burns, and severe physiological and nervous disorders. Furthermore, an unusually high number of miscarriages and birth defects was noted. A lawsuit amount- LA4154/frame/C02 Page 8 Wednesday, May 17, 2000 3:35 PM © 2001 by CRC Press LLC ENVIRONMENTAL CHANGE AND HEALTH 9 ing to nearly $3 billion in health claims was then filed against the city of Niagara Falls. Eventually, the state purchased and demolished about 100 homes in the area and state officials evacuated 500 houses in 1978. Federal and state crews cleaned up the landfill and surrounding contaminated areas. Litigation followed between New York State and the company against each other. Finally, in 1994 OxyChem and the state agreed to settle their conflicting claims stemming from the incidence.* 2.2 OUR CHANGING DISEASE PATTERN Associated with the changes in our environment are the changing pattern and distribution of diseases or health effects. For instance, at the turn of the century pneumonia and tuberculosis were the two leading causes of death in most countries, including the United States. Because of improved sanitation and public health mea- sures, coupled with advancements in medical sciences and technology, tuberculosis and many other contagious diseases have largely been eradicated. In place of these relatively straightforward illnesses, however, are diseases that have multiple causes, i.e., chronic cardiovascular–respiratory diseases and malignant neoplasms or can- cers. As shown in Table 2.1, since about 1950 these diseases have become the leading causes of death in the United States. Importantly, five of the ten leading causes of death in the U.S. are considered environmentally related. They include heart diseases, cancer, chronic obstructive pulmonary diseases, chronic liver disease, and cirrhosis (Table 2.1). A similar pattern is also evident in many other countries, including the developing world. In Brazil, for example, infectious diseases caused 39 to 60% of all deaths, depending on the region of the country, in 1940. But by 1980 these diseases accounted for only 3 to 16% of deaths. On the other hand, cardiovascular diseases accounted for only 9 to 13% of mortality in 1940 but rose to 20 to 38% in 1980. 5 What are the reasons for these changes? Scientists agree that environmental pollution affects all living organisms including humans. Many human diseases are traceable to substances in the air, water, and the foods we consume. Some of the industrial agents released into the general environment are regarded as carcinogenic (cancer-causing) as well. We will explore this to some extent in the next section. 2.3 EXAMPLES OF ENVIRONMENTAL DISEASES Many diseases have long been related to occupation. The British doctor, P. Pott, is widely recognized as the scientist who, in 1775, first pointed out the direct connection between occupational exposure and the risk of a specific cancer, i.e., chimney sweeps and cancer of the scrotum. 6 Miners, stone cutters, and lens grinders often developed respiratory disease from inhaling large quantities of dust. Many hatters suffered brain damage as a result of absorbing highly toxic mercury vapors * Note: Remediation of the land took place and in April 1992 resettlement of the area started. By 1994, nearly 70% of the 280 available houses had been sold. Some 30% of the purchasers had lived in the area before the evacuation. 4 LA4154/frame/C02 Page 9 Wednesday, May 17, 2000 3:35 PM © 2001 by CRC Press LLC 10 ENVIRONMENTAL TOXICOLOGY Table 2.1 Changing Causes of Death in the U.S. Between 1900 and 1995 Year 1900 1950 1995 Rank % Rank % Rank % 1 Pneumonia-influenza bronchitis 14.4 a 1 Disease of heart 36.6 a 1 Disease of heart* 27.4 a 2 Tuberculosis 11.3 2 Malignant neoplasm 14.9 2 Maligant neoplasm* 25.8 3 Diarrhea & enteritis 8.1 3 Cerebrovascular diseases 10.6 3 Unintentional injuries* 6.0 4 Heart disease 8.0 4 Accidents 6.8 4 Cerebrovascular diseases* 5.3 5 Bright’s disease (chronic nephritis) 4.7 5 Pneumonia & influenza 3.1 5 Chronic obstructive pulmonary diseases* 4.1 6 Accidents 4.5 6 Diabetes mellitus 1.7 6 HIV infection 3.1 7 Congestion & brain hemorrhage 4.2 7 Suicide 1.3 7 Pneumonia & influenza 2.6 8 Diseases of early infancy 4.2 8 Chronic liver disease & cirrhosis 1.0 8 Suicide 2.2 9 Cancer & other malignant tumors 3.7 9 Homicide & legal intervention 0.6 9 Homicide & legal inter vention 1.8 10 Diphtheria 2.3 10 Chronic obstructive pulmonary disease 0.5 10 Chronic liver disease & cirrhosis* 1.5 a Percent of total deaths. * Diseases that are considered environmentally related. From National Center for Health Statistics, Health United States, 1996–97 and Injury Chartbook, USDHHS. DHHS Publication No. (PHS)97-1232, July, 1997. LA4154/frame/C02 Page 10 Wednesday, May 17, 2000 3:35 PM © 2001 by CRC Press LLC ENVIRONMENTAL CHANGE AND HEALTH 11 from mercurials (chemical compounds containing mercury) used in making felt. Asphalt, coal tar, pitch workers, textile dyers, and shoe and leather workers are suspected of having an increased risk of developing bladder cancer because of their association with coal products and aromatic amines. However, in the past several decades, environmental diseases have spread beyond those in a few specialized occupations. Among the most serious are: cancer, respi- ratory diseases, birth defects, heavy-metal poisoning, and injury to the reproductive system. These are briefly examined below: 2.3.1 Cancer Studies show that nearly 30% of the total mortality in several industrialized countries is due to cancer. 7 Cancer incidence and mortality in most of these countries have been consistently increasing. Moreover, this trend is independent of the aging of the population. Several hypotheses have been advanced to explain the causes of the observed increases. Major causes that were suggested include lifestyle, personal habits, and diet. However, these hypotheses have overlooked the role of environ- mental changes caused by industrial activities. As mentioned above, in the last 100 years, and particularly since WWII, industrial development has been expanding at an accelerating rate. This has resulted in release of a large number and quantity of chemicals into the environment, polluting the air, water, and soil, and potentially contaminating the food we consume. Many researchers have long recognized that a close association exists between industrial activities and cancer incidences and cancer death rates. The U.S. has one of the world’s highest incidences of cancer associated with environmental pollution. Cancer is now second only to heart disease as a cause of death in the U.S. Moreover, until recently the rate of cancer death had been increasing steadily (Table 2.1; Figure 2.1). The actual number of deaths from cancer, however, is still rising. For example, 416,509 Americans died of cancer in 1980. The figure increased to 505,322 in 1990, and in 1995 it was 538,455. 8 According to the American Cancer Society’s estimate, the toll for 1999 was about 563,100 — more than 1500 people a day. 9 The northeast region of the United States is known to be a highly industrialized and polluted area. This region is known also to have a particularly high incidence of cancer. Studies done by the National Cancer Institute indicate that areas where iron and lead smelters are located have high rates of lung cancer. Similarly, areas with industrial plants manufacturing soaps, rubber, chemicals, and printing inks have high rates of bladder and liver cancer. A recent New York Department of Health study has found that Nassau County women living within 1 km of a chemical, petroleum, rubber, or plastics facility were 60% more likely to develop postmeno- pausal breast cancer than were those who lived in other parts of the country. 10 An alarming trend associated with cancer is its increasing incidence rate among children in the United States. Although the reasons for the increase remain unclear, many experts suspect that it may be partly due to growing exposure to new chemicals in the environment. According to the National Cancer Institute, the rate of increase has risen to nearly 1% a year. Over a few decades, that has meant striking double-digit LA4154/frame/C02 Page 11 Wednesday, May 17, 2000 3:35 PM © 2001 by CRC Press LLC 12 ENVIRONMENTAL TOXICOLOGY increases. Some experts in the field estimate that a newborn child today faces a risk of about 1 in 600 of contracting cancer by age 10. In the United States, cancer is diagnosed each year in an estimated 8000 children below the age of 15. Although cancer kills fewer children than accidents do, it is the most common of fatal child- hood disease, accounting for about 10% of all deaths in childhood. Concern over the relationship between pesticides and various illnesses and death has drawn much attention. An example is chlorinated hydrocarbon-based pesticides and dioxin. Accidents during the manufacture of 2,4,5-T (2,4,5-trichlorophenoxy acetic acid) and polychlorinated phenol derivatives have caused acute dioxin poi- soning of plant workers and populations in several countries. In Vietnam, 2,4,5-T and related dioxin-contaminated defoliants were used exten- sively from 1961 to 1969. Among the major toxic effects attributed to dioxins is liver cancer. Between 1956 and 1961 (the year in which spraying of the herbicides began), 159 cases of primary hepatic cancers were recorded among 5492 cancers in the Hanoi area, while between 1962 and 1968, 791 primary hepatic cancers were observed in a total of 7911 cancers. This represented a more than threefold increase in the proportion of primary cancer of the liver. 11 2.3.2 Birth Defects In a person’s life span, the period of greatest susceptibility to exogenous injury is during the early stages of morphogenesis. It is estimated that approximately 3% of all live births in the United States have significant birth defects. 12 This represents Figure 2.1 Percent changes in deaths of total cancer and respiratory system cancer in the United States between 1950 and 1995. Percent changes were calculated based on 1950 figures (as 100%) for both total cancer and respiratory system cancer. <HDU 3HUFHQW 7RWDOFDQFHU 5 HV S V\V WHP FDQFHU LA4154/frame/C02 Page 12 Wednesday, May 17, 2000 3:35 PM © 2001 by CRC Press LLC ENVIRONMENTAL CHANGE AND HEALTH 13 about 100,000 congenital anomalies in a total of 3 million live births annually. Intrauterine growth retardation can be caused by a number of agents, including hypoxia, drugs, X-ray irradiation, maternal endocrine and nutritional factors, and environmental chemicals. Many chemical species are known to be teratogenic, i.e., capable of causing birth defects. The chemicals include various organic solvents, pesticides, dioxins, several heavy metals such as Pb, Cd, Hg, and others. Many human epidemiological data support the claim that environmental chemicals are an important factor responsible for inducing teratogenicity. For example, in an earlier study by the Ohio Department of Health, it was found that women in three commu- nities with PVC (polyvinylchloride) plants bore more children with birth defects and other malformations than women in other communities in the state. 2.3.3 Reproductive Damage Recent studies have shown that a variety of toxicants can induce detrimental effects on reproductive systems in animals and humans. For instance, reproductive damage in seagulls and other wildlife presented some of the first clues about the adverse effects of DDT. 13 Organochlorines have also been implicated in impaired reproductive success in fish populations of the Baltic and North Seas. 14,15 These compounds also adversely affect the health and reproduction of seals. 16-18 More recently, reproductive anomalies in wildlife have sparked concern about the ability of a number of chemicals to cause ill effects by disrupting the body’s normal hormonal system. An increasing number of chemicals are now known to have such action. Examples include organochlorines such as PCBs, dioxins, as well as DDT; pesticides such as carbamates (e.g., aldicarb, carbofuran), triazines (e.g., atrazine and simazine [herbicides]), and pyrethroids, (see Chapters 3 and 12); heavy metals such as Cd, Pb, and Hg; organobrominate compounds, and others. The reproductive toxicity of the pesticide DBCP (2,2-dibromo-3-chloropropane) became clear in the late 1970s and early 1980s when male farm workers in the banana- growing region of Costa Rica were found to be sterile. By the mid-1990s, nearly 1500 male workers had been diagnosed with sterility from exposure to DBCP. 19 2.3.4 Respiratory Diseases Many epidemiological and animal studies have shown that airborne pollutants are commonly found in the urban environment in concentrations high enough to adversely affect the lungs. 20,21 During the last four decades, chronic bronchitis, emphysema, and lung cancer have become major public health problems in the United States and other major industrialized countries. In the United States, although heart disease has been known as the number 1 killer for several decades, death rates for the disease have been decreasing steadily since about 1950 (Table 2.1). By contrast, the rates of cancer death (the number 2 killer in the U.S.) continued to increase steadily until 1993, when the increase diminished. 8 Overall annual increase in cancer death rates is more than 1%. Cancer death rates involving the respiratory system, however, increased dramatically LA4154/frame/C02 Page 13 Wednesday, May 17, 2000 3:35 PM © 2001 by CRC Press LLC 14 ENVIRONMENTAL TOXICOLOGY between 1950 and 1990. Using the 1950 rate as a basis for comparison, there was a 120% increase in 1970, and in 1990, the increase jumped to 223%. Significant increases continued until 1993, when they began to diminish (Table 2.2 and Figure 2.1). Although the reasons for the differences are not entirely clear, many scientists consider that the observed results may be attributed, to a large extent, to environ- mental pollution. In Japan, the level of air pollution has markedly decreased since the early 1970s, but the number of patients with respiratory disease due to air pollution has increased. Between the late 1950s and 1960s, a large number of patients in Japan suffered from chronic obstructive lung diseases, such as chronic bronchitis, bronchial asthma, and emphysema. Studies showed that during this period, there were many chronic bron- chitis patients in Yokohama and Kawasaki, two highly industrialized cities near Tokyo, that were heavily polluted with SO 2 and soot. Researchers in Japan concluded that the SO 2 pollution caused acute respiratory diseases and aggravated the conditions of patients already suffering from respiratory disease. One of these respiratory conditions was even referred to as “Yokohama and Kawasaki Asthma.” 22 2.3.5 Heavy Metal-Induced Diseases Following the Industrial Revolution, the production of heavy metals, such as copper (Cu), lead (Pb), and zinc (Zn), increased dramatically. Between 1850 and 1990, production of these three metals rose nearly tenfold, with concomitant increases in the emissions of various metals, including Pb, Cd, Hg, and nickel (Ni). 23 Another toxic element is arsenic (As). In limited geographic areas some of these metals and nonmetallic elements accumulate to excessive levels because of industrial pollution and have produced major outbreaks of chronic illness in humans. Some highlights of these follow. Although chronic Pb poisoning has plagued humans at least since the time of the ancient empires, the importance of Pb as an environmental pollutant has received wide-spread attention only in recent decades. In ancient Rome, Pb in pipes and in Table 2.2 Comparison of Death Rates for Total and Respiratory System Cancers in the U.S. Between 1950 and 1995 Age-Adjusted Cancer Deaths per 100,000 Populations Year Total Cancer Percent Increase Cancer of Respiratory System Percent Increase 1950 125.4 a — 12.8 a — 1960 125.8 0.3 19.2 50 1970 129.8 3.5 28.4 122 1980 132.8 5.9 36.4 184 1990 135.0 7.6 41.4 223 1995 129.9 3.5 39.7 210 a The rate of 1950 was used as basis of comparison. From National Center for Health Statistics, Health United States, 1996–97 and Injury Chartbook, USDHHS. DHHS Publication No. (PHS)97-1232, July, 1997. LA4154/frame/C02 Page 14 Wednesday, May 17, 2000 3:35 PM © 2001 by CRC Press LLC ENVIRONMENTAL CHANGE AND HEALTH 15 drinking and cooking vessels was a major source of excessive intake. Even today, Pb contamination in water supplies occurs in some communities. Lead pipes in older plumbing and soldered pipe joints can contaminate drinking water, especially “soft” water. However, the Pb in smoke from burning trash and coal and, until recently, automobile exhausts is probably even more hazardous, since it is inhaled or ingested as a contaminant of foods, after settling on vegetation. Lead paint in older homes is even more dangerous, because small children often ingest paint from woodwork, plaster, floors, and furniture. It is not surprising, therefore, that as many as 25 to 30% of American children living in urban areas may be suffering “subclinical” Pb poisoning. 24 The most prominent adverse effects of Pb involve the nervous system, the hematopoietic system (an organic system of the body, consisting of the blood and the structures that function in its production), and the kidneys. As mentioned previously, one of the most serious outbreaks of anthropogenic poisoning of the industrial age is the epidemic of mercury (Hg) poisoning, now known as “Minamata disease.” This illness occurred in Minamata Bay, Japan, in 1953, and the highest incidence was found to be among fishermen and their fami- lies. 25 Later, when it was observed that household cats and sea birds were being affected, attention turned to fish and shellfish as etiologic factors. This in turn led to the study of the water of Minamata Bay and to the identification of Hg in a factory effluent as the cause of the disease. The study concluded that the fish consumed by victims contained high levels of toxic methylmercury. When ingested, methylmer- cury can cause permanent damage to the brain and kidney, loss of vision, and disturbed cerebral function. Ultimately, coma and death follow in severe cases. The discovery of gold in Serra Pelada in the Amazon in 1979 touched off a great flow of migrants into that area in the 1980s. Many of these were in search of gold. There are potentially serious health effects from high levels of metallic Hg exposure during gold mining. Mercury is used to bind the gold, and the resultant amalgam is heated at high temperatures with a blow torch to separate the gold from the Hg. This vaporized Hg gradually accumulates in the aquatic food chain. In contrast to the Hg poisoning in Minamata, where a single industrial source polluted one local fishing area, in the Amazon region thousands of Hg sources pollute the waters. Brazilian mining agencies estimated that 300,000 miners had been distributed among 1800 gold fields in the Amazon in the early 1990s. By 1996, some 3000 tons of Hg had been released into the environment, compared to the 200 to 600 tons dumped into Minamata Bay. 5 Another outbreak of chronic illness called “itai-itai byo” or “ouch-ouch disease” occurred along the Jintsu River in northern Japan in the mid-1950s. Victims of this disorder suffered severe bone pains. Eventually, the victims’ softened bones disin- tegrated even under slight pressure, leading to multiple fractures. Death also occurred, and this was attributed to kidney failure that developed during the course of the disease. Extensive research ultimately identified the culprit as cadmium (Cd) in rice grown near a Pb and Zn mining facility. Effluent from the mine, combined with Cd-laden fumes, had polluted the rice paddy. In addition to its effect on bones, Cd is also a nephrotoxin and it can cause hypertension. A more detailed discussion of heavy metals is presented in Chapter 12. LA4154/frame/C02 Page 15 Wednesday, May 17, 2000 3:35 PM © 2001 by CRC Press LLC 16 ENVIRONMENTAL TOXICOLOGY 2.4 REFERENCES AND SUGGESTED READINGS 1. Time , Endangered Earth, January 2, 1989, 26. 2. Kennedy, R.F., Jr., The river reborn, Life , September, 1999, 65. 3. U.S. Environmental Protection Agency (U.S. EPA), Handbook. Ground Water , EPA/625/6-87/016, 1987, 212. 4. Kirschner, E., Love Canal settlement, Chem. & Eng. News , June 27, 1994, 4. 5. Moran, E.F. and Fleming-Moran, M., Global environmental change: the health and environmental implications in Brazil and the Amazon basin, Environ. Sci ., 4(Suppl.), S025, 1996. 6. Cole, P. and Goldman, M.B., in Persons at High Risk of Cancer. An Approach to Cancer Etiology and Control , Fraumeni, J.F. Jr., Ed., Academic Press, New York, 1975, 167. 7. Maltoni, C. and Selikoff, I.J., Preface, in Living in a Chemical World , Maltoni, C. and Selikoff, I.J., Eds., Ann. N. Y. Acad. Sci ., New York, 1988, xv. 8. National Center for Health Statistics, Health United States, 1996–97 and Injury Chartbook , USDHHS. DHHS Publication No. (PHS)97-1232, July, 1997. 9. American Cancer Society, Cancer Facts & Figures — 1999 , 1999, 4. 10. American Chemical Society, Chem. & Eng. News , April 18, 1994, 13. 11. Lapporte, J.R., Effect of dioxin exposure, Lancet , 1, 1049, 1977. 12. Kalter, H. and Warkany, J., Congenital malformations. Etiologic factors and their role in prevention, N. Engl. J. Med ., 308, 424, 1983. 13. U.S. Environmental Protection Agency (U.S. EPA). Special Report on Environmental Endocrine Disruption: An Effects Assessment and Analysis , 1997, 72. 14. Von Westernhagen, H. et al., Bioaccumulating substances and reproductive success in Baltic flounder, Platichthys flesus , Aquat. Toxicol ., 1, 85, 1981. 15. Barnthouse, L.W., Suter, G.W., and Rosen, A.E., Risks of toxic contaminants to exploited fish populations: influence of life history, data uncertainty and exploitation intensity, Environ. Toxicol. Chem ., 9, 297, 1990. 16. Reijinders, P.J.H., Reproductive failure in common seals feeding on fish from polluted coastal waters, Nature (Lond.), 324, 456, 1986. 17. Morris, R.J. et al., Metals and organochlorines in dolphins and porpoises of Cardigan Bay, West Wales, Mar. Pollu. Bull ., 20, 512, 1989. 18. Johnston, P.A. et al., Pollution of UK estuaries: historical and current problems, Sci. Total Environ ., 106, 55, 1991. 19. Thrupp, L.A., Sterilization of workers from pesticide exposure: the causes and con- sequences of DBCP-induced damage in Costa Rica and beyond , Internat. J. Health Services , 21, 734, 1991. 20. WHO, Health Hazards of the Human Environment. World Health Organization, Geneva. 1972. 21. Fennelly, P.F., The origin and influence of airborne particulates, Amer. Scient ., 64, 46, 1976. 22. Murakami, M., Environmental health surveillance system for monitoring air pollution, Environ. Sci ., 4, 1, 1996. 23. Nriagu, J.O., History of global metal pollution, Science , 272, 223, 1996. 24. Waldron, H.A., The blood lead level threshold, Arch. Environ. Health , 29, 271, 1974. 25. Kondo, T., Studies on the origin of the causative agent of Minamata disease. 4. Synthesis of methyl(methylthio) mercury, J. Pharmaceut. Soc. Japan , 84, 137, 1964. LA4154/frame/C02 Page 16 Wednesday, May 17, 2000 3:35 PM © 2001 by CRC Press LLC [...]...LA4154/frame/C 02 Page 17 Wednesday, May 17, 20 00 3:35 PM ENVIRONMENTAL CHANGE AND HEALTH 17 2. 5 REVIEW QUESTIONS 1 2 3 4 5 6 7 8 9 10 11 12 Briefly explain the air pollution episode that occurred in London in 19 52 What is “Minamata disease”? What does “itai-itai-byo” or “ouch-ouch disease” refer to? Explain the differences in water quality in New... U.S between 1900 and 1950? Name five of the leading causes of death in the U.S that are considered environmentally related What is the recent trend in the incidence rate of children’s cancer in the United States? What does “teratogenic” mean? Name three chemicals that are teratogenic Briefly explain how environmental chemicals may be associated with the reproductive system Explain the differences between... associated with the reproductive system Explain the differences between the total cancer death rate and that of respiratory system cancer in the U.S between 1950 and 1990 What environmental problem exists in gold mining in the Amazon Basin? © 20 01 by CRC Press LLC . 125 .4 a — 12. 8 a — 1960 125 .8 0.3 19 .2 50 1970 129 .8 3.5 28 .4 122 1980 1 32. 8 5.9 36.4 184 1990 135.0 7.6 41.4 22 3 1995 129 .9 3.5 39.7 21 0 a The rate of 1950 was used as basis of comparison. From. 1996. 23 . Nriagu, J.O., History of global metal pollution, Science , 27 2, 22 3, 1996. 24 . Waldron, H.A., The blood lead level threshold, Arch. Environ. Health , 29 , 27 1, 1974. 25 . Kondo,. Chartbook, USDHHS. DHHS Publication No. (PHS)9 7-1 23 2, July, 1997. LA4154/frame/C 02 Page 10 Wednesday, May 17, 20 00 3:35 PM © 20 01 by CRC Press LLC ENVIRONMENTAL CHANGE AND HEALTH 11 from mercurials