Environmental Engineering Reference
In-Depth Information
3. Nonmetallic inorganics: arsenic and asbestos, for example, are carcinogens.
4. Biological contaminants such as aflatoxins and pathogenic microorganisms;
animal and human drugs such as diethylstilbestrol (DES) and other syn-
thetic hormones; and food additives such as red dye No. 2.
Evaluation of the toxicity of existing and new chemicals on workers, users, and
the environment and their release for use represent a monumental task, as already
noted. Monitoring the total effect of a chemical pollutant on humans requires
environmental monitoring and medical surveillance to determine exposure and
the amount absorbed by the body. The sophisticated analytical equipment avail-
able can detect chemical contaminants in the parts-per-billion or parts-per-trillion
range. However, mere detection does not mean that the chemical substance is
automatically toxic or hazardous. But detection does alert the observer to trends
and the possible need for preventive measures. Short-term testing of chemicals,
such as the microbial Ames test, is valuable to screen inexpensively for car-
cinogens and mutagens. The Ames test determines the mutagenic potential of a
chemical based on the mutation rate of bacteria that are exposed to the chemi-
cal. However, positive results suggest the need for further testing, and negative
results do not establish the safety of the agent. Other tests use mammalian cell
cultures and cell transformation to determine mutagenicity.
Prevention and Control
Prevention of the major causes of death, such as diseases of the heart, malignant
neoplasms, cerebrovascular disease, accidents, and other noninfectious chronic
and degenerative diseases, should now receive high priority. Prevention calls for
control of the source, mode of transmission, and/or susceptibles as appropriate.
The prevention and control of environmental pollutants generally involves the
following:
1.
Eliminate or control the pollutant at the source
. Minimize or prevent pro-
duction and sale; substitute nontoxic or less toxic chemical; materials and
process control and changes; recover and reuse; waste treatment, separation,
concentration, incineration, detoxification, and neutralization.
2.
Intercept the travel or transmission of the pollutant
. Control air and water
pollution and prevent leachate travel.
3.
Protect humans to eliminate or minimize the effects of the pollutant
.This
includes water treatment, air conditioning, land-use planning, and occupa-
tional protection.
At the same time the air, sources of drinking water, food, aquatic plants, fish
and other wildlife, surface runoff, leachates, precipitation, surface waters, and
humans should be monitored. Biosensor technology can assist in determining
exposure to pollutants, however for the foreseeable future, epidemiological stud-
ies collecting blood and other biological specimens, astute clinical observation,
