Environmental Science: Toward a Sustainable Future Richard T. Wright Chapter 15 Environmental Hazards and Human Health PPT by Clark E. Adams

Environmental Hazards and Human Health Links between human health and the environment Pathways of risk Risk assessment

Some Definitions Environment: combination of physical, chemical, and biological factors Hazard: anything that can cause injury, death, disease, damage to personal/public property, or deterioration or destruction of environmental components Risk: probability of suffering a loss as a result of exposure to a hazard

Links between Human Health and the Environment The picture of health Environmental hazards

The Picture of Health: Some Terms Morbidity: incidence of disease in a population Mortality: incidence of death in a population Epidemiology: study of presence, distribution, and control of disease in a population

Causes of Human Mortality

Environmental Hazards Cultural Biological Physical Chemical

Cultural Hazards Consequence of choice Risky behavior To what cultural hazards do college students commonly subject themselves?

Deaths from Various Cultural Hazards

Biological Hazards Pathogenic bacteria Fungi Viruses Protozoans Worms

Global Map of Tuberculosis, 2001

Infectious Diseases More prevalent in, but not exclusive to, developing countries Contamination of food and water Lack of resources for sanitation Lack of education Ideal climates for transmission of vector-borne diseases like malaria

Malarial Parasite Life Cycle

Physical Hazards Natural disasters, e.g., tornadoes, floods, hurricanes, and wildfires Avoidance of risk important in prevention, e.g., building homes in floodplains, and living on the coast Climate change: consequences of elevated greenhouse gases

Chemical Hazards Result of industrialization Exposure through ingestion, inhalation, absorption through skin May be direct use or accidental Many chemicals are toxic at low levels

Chemical Hazards 74 chemicals are known to be carcinogenic (Table 15-2) Environmental carcinogens initiate mutations in DNA; several mutations lead to a malignancy

Pathways of Risk The risk of being poor The cultural risk of tobacco use Risk and infectious diseases Toxic risk pathways

The Risk of Being Poor One major pathway for hazards is poverty No money for health insurance Higher probability of exposure to environmental hazards

The 10 Leading Global Risk Factors Fig. 15-9 here

Environmental Health Factors contributing to the environmental health of a nation include: Education Nutrition Commitment from government More equitable distribution of wealth

The Cultural Risk of Tobacco Use

Regulation of Smoking Warning labels Smoke-free zones in public places FDA regulations Lawsuits against the tobacco industry

Risk and Infectious Diseases One major pathway of risk is contamination of food and water Inadequate hygiene Inferior sewage treatment

Control of Infectious Disease Genome sequencing of the Anopheles mosquito Bed nets Change in land use practices: wetland development New effective antimalarial drugs

Worldwide Distribution of Malaria

Toxic Risk Pathways Categories of impact of airborne pollutants Chronic: effect takes place over a period of years Acute: life-threatening reaction within a period of hours or days Carcinogenic: pollutants initiate cellular change leading to cancer

Indoor Air Pollution: Developed Countries Hazardous fumes from home products Well-insulated buildings Long exposure to indoor air

Indoor Air Pollution: Developing Countries Results from burning biofuels (wood, dung) inside homes Acute respiratory infections in children Chronic lung diseases Lung cancer Birth-related problems

Risk Assessment Environmental risk assessment by the EPA Public-health risk assessment Risk management Risk perception

Definition of Risk Assessment The process of evaluating the risks associated with a particular hazard before taking some action in which the particular hazard is present

Loss of Life Expectancy from Various Risks: Top Five (see Fig. 15-16) Alcoholic Poverty Smoking – male Poor social connections Heart disease

Loss of Life Expectancy from Various Risks

Environmental Risk Assessment by the EPA Hazard assessment (What chemicals cause cancer?) Dose-response assessment (How much?) Exposure assessment (How long?) Risk characterization (How many will die?)

Public-Health Risk Assessment Potential global impact High likelihood of causality Modifiability Availability of data (see Table 15-4)

Risk Management Usually involves: Cost–benefit analysis Risk–benefit analysis Public preferences

Risk Perception: Hazard vs. Outrage Hazard: expresses primarily a concern for fatalities only

Risk Perception: Hazard vs. Outrage Outrage includes: Lack of familiarity with technology Extent to which the risk is voluntary Public impressions of hazards Overselling safety Morality Control Fairness

Risk Assessment/Management Some suggest we use distributive justice in making decisions about risk Ethical process of making certain that everyone receives proper consideration Should reduce environmental racism/injustice

Risk Assessment/Management Not a perfect system Precautionary principle Lack of certainty should not be used as a reason for preventing environmental degradation/hazards

End of Chapter 15