Environmental Problems, Their Causes, and Sustainability 1

hospitals stock large supplies of antibiotics and vaccinesfor treatment of common diseases, provide emergencyand hospital workers with detection systemsand protective gear, and alert doctors to the symptomsof the most common biological warfare agents.Comparative Risk AnalysisMost Serious Ecologicaland Health Problems19-5 RISK ANALYSISHow Can We Estimate Risks? Evaluate,Compare, DecideScientists have developed ways to evaluate andcompare risks, decide how much risk is acceptable,and find affordable ways to reduce them.Risk analysis involves identifying hazards and evaluatingtheir associated risks (risk assessment, Figure 19-2,left), ranking risks (comparative risk analysis), determiningoptions and making decisions about reducing oreliminating risks (risk management, Figure 19-2, right),and informing decision makers and the public aboutrisks (risk communication).Statistical probabilities based on past experience,animal testing and other tests, and epidemiologicalstudies are used to estimate risks from older technologiesand chemicals. To evaluate new technologies andproducts, risk evaluators use more uncertain statisticalprobabilities, based on models rather than actual experienceand testing.Figure 19-17 lists the results of a comparative riskanalysis, summarizing the greatest ecological and healthrisks identified by a panel of scientists acting as advisersto the U.S. Environmental Protection Agency (EPA).The greatest risks many people face today arerarely dramatic enough to make the daily news. Interms of the number of premature deaths per year (Figure19-18) and reduced life span, the greatest risk by faris poverty (Figure 19-19 (p. 430) and Figure 1-15, p. 17).Its high death toll is a result of malnutrition, increasedsusceptibility to normally nonfatal infectious diseases,and often fatal infectious diseases from lack of accessto a safe water supply.Thus the sharp reduction or elimination of povertywould do far more to improve longevity and human healththan any other measure. It would also greatly improvehuman rights, provide more people with income tostimulate economic development, and reduce environmentaldegradation and the threat of terrorism.Sharply reducing poverty is a win-win situation forpeople, economies, and the environment.After the health risks associated with poverty andgender, the greatest risks of premature death are mostlythe result of unhealthful choices that people makeabout their lifestyles—what I referred to early in thischapter as cultural hazards (Figures 19-18 and 19-19).By far the best ways to reduce one’s risk of prematuredeath and serious health problem are to avoidHigh-Risk Health Problems• Indoor air pollution• Outdoor air pollution• Worker exposure to industrialor farm chemicals• Pollutants in drinking water• Pesticide residues on food• Toxic chemicals in consumer productsHigh-Risk Ecological Problems• Global climate change• Stratospheric ozone depletion• Wildlife habitat alteration and destruction• Species extinction and loss of biodiversityMedium-Risk Ecological Problems• Acid deposition• Pesticides• Airborne toxic chemicals• Toxic chemicals, nutrients, andsediment in surface watersLow-Risk Ecological Problems• Oil spills• Groundwater pollution• Radioactive isotopes• Acid runoff to surface waters• Thermal pollutionFigure 19-17 Comparative risk analysis of the most seriousecological and health problems according to scientists actingas advisers to the U.S. Environmental Protection Agency.Risks under each category are not listed in rank order.(Science Advisory Board, Reducing Risks, Washington, D.C.:Environmental Protection Agency, 1990)smoking and exposure to smoke, lose excess weight, reduceconsumption of foods containing cholesterol andsaturated fats, eat a variety of fruits and vegetables, exerciseregularly, avoid alcohol or drink no more thantwo drinks a day, avoid excess sunlight (which agesskin and may cause skin cancer), and have only safe sex.How Can We Estimate Risks of UsingIncreasingly Complex Technology in OurLives? A Difficult TaskEstimating risks from using certain technologies isdifficult because of the unpredictability of humanbehavior, human error, and sabotage.The more complex a technological system and themore people needed to design and run it, the more difficultit is to estimate the risks. The overall reliability of428 CHAPTER 19 Risk, Toxicology, and Human Health