Environmental Engineering Reference
In-Depth Information
the developing areas of the world. The major noncommunicable disease deaths
in the United States in 1988 were due to diseases of the heart, malignant neo-
plasms, cerebrovascular diseases, accidents, atheriosclerosis, diabetes mellitus,
and chronic liver disease and cirrhosis (accounting for 73 percent of all deaths).
An analysis of mortality due to noncommunicable diseases in five subregions
of the Americas in 1980 showed 75 percent of the total mortality attributed to
noncommunicable diseases in North America (United States and Canada); 60 per-
cent in Temperate South American countries (Argentina, Chile, and Uruguay);
57 percent in the Caribbean area (including Cuba, the Dominican Republic, and
Haiti); 45 percent in Tropical South America (including the Andean countries,
Brazil, French Guiana, Guyana, Paraguay, and Suriname); and 28 percent in
Continental Middle America (Central America, Mexico, and Panama). 117 The
mortality can be expected to shift more to noncommunicable causes in the devel-
oping countries as social and economic conditions improve and communicable
diseases are brought under control. Major diseases of developing countries are
gastrointestinal, schistosomiasis, malaria, trachoma, and malnutrition.
Treatment of the environment supplements treatment of the individual but
requires more effort and knowledge. The total environment is the most important
determinant of health . A review of more than 10 years of research conducted
in Buffalo, New York, showed that the overall death rate for people living in
heavily polluted areas was twice as high, and the death rates for tuberculosis
and stomach cancer three times as high, as the rates in less polluted areas. 118
Rene Dubos points out that “many of man's medical problems have their origin
in the biological and mental adaptive responses that allowed him earlier in life
to cope with environmental threats. All too often, the wisdom of the body is a
shortsighted wisdom.” 119
Whereas microbiological causes of most communicable diseases are known
and are under control or being brought under control in many parts of the world
(with some possible exceptions such as malaria and schistosomiasis), the phys-
iologic and toxicologic effects on human health of the presence or absence of
certain chemicals in air, water, and food in trace amounts have not yet been
clearly demonstrated. The cumulative body burden of all deleterious substances,
especially organic and inorganic chemicals, gaining access to the body must be
examined both individually and in combination. The synergistic, additive, and
neutralizing effects must be learned in order that the most effective preventive
measures may be applied. As noted earlier, chemicals contributed to 12 percent of
drinking water outbreaks during the period 1971 to 2002, which is greater than the
fraction attributed to viruses. 18 Some elements, such as fluorine for the control of
tooth decay, iodine to control goiter, and iron to control iron deficiency anemia,
have been recognized as being beneficial in proper amounts. But the action of
trace amounts ingested individually and in combination of the pollutants shown
in Figure 1.3 and other inorganic and organic chemicals is often insidious. Their
probable carcinogenic, mutagenic, and teratogenic effects are extended in time,
perhaps for 10, 20, or 30 years, to the point where direct causal relationships with
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