Chapter 17 Human Health and Environmental Risks

Objectives Identify the three major categories of human health risks List the major historical and emerging infectious diseases Name the five major types of toxic chemical s Distinguish between does-response studies, retrospective studies, and prospective studies Describe th efactors that help determine the chemical concentrations that organisms experience Explain the factors that go into a risk analysis and distinguish between the two major philosophies of chemical regulation

Human Health and Environmental Risks: Citizen Scientist List 3 reasons why the city population of Old Diamond in Norco, Louisiana, is comprised mostly of lower-income African Americans. Describe the accidents that occurred in 1973 and 1988 List effects of each accident. Describe the actions Margie Richards took to help the people of Old Diamond EPA: Bucket Brigade: 2002: 2007: Are there any Shell Oil chemical plants or oil refineries near Los Angeles? Where? Should action be taken as Margie Richards did for the people of Old Diamond?

Three categories of human health risks physical biological chemical

Biological Risks Infectious diseases- those caused b y infectious agents, known as pathogens. Examples: pneumonia and venereal diseases

Biological Risks Chronic disease- slowly impairs the functioning of a person’s body. Acute diseases- rapidly impair the functioning of a person’s body.

Historical Diseases RiskCauseEffectTreatment Plague Malaria TB Plague Malaria Tuberculosis

Emergent Diseases RiskCauseEffectTreatment HIV/AIDS Ebola Mad Cow Disease Bird Flu West Nile Virus HIV/AIDS Ebola Mad Cow Disease Bird Flu West Nile Virus

Chemical Risks Neurotoxins- chemicals that disrupt the nervous system Carcinogens- chemicals that cause cancer Teratogens- chemicals that interfere with the normal development of embryos or fetuses Allergens- chemicals that cause allergic reactions Endocrine disruptors- chemicals that interfere with the normal functioning of hormones in an animal’s body

Chemical Risks TypeExample of Chemicals (Use Table 17- 1) Sources of Chemicals (Use Table 17- 1) Effects of Chemicals (Use Table 17- 1) Neurotoxins Carcinogens Teratogens Allergens Endocrine Disruptors Neurotoxins- chemicals that disrupt the nervous system Carcinogens- chemicals that cause cancer Teratogens- chemicals that interfere with the normal development of embryos or fetuses Allergens- chemicals that cause allergic reactions Endocrine disruptors- chemicals that interfere with the normal functioning of hormones in an animal’s body

Dose-Response Studies LD50- lethal dose that kills 50% of the individuals ED50- effective dose that causes 50% of the animals to display the harmful but nonlethal effect

Synergistic interactions- when two risks come together and cause more harm that one would. For example, the health impact of a carcinogen such as asbestos can be much higher if an individual also smokes tobacco.

Routes of Exposure

Bioaccumulation bioaccumulation- an increased concentration of a chemical within an organism over time

Biomagnification Biomagnification- the increase in a chemical concentration in animal tissues as the chemical moves up the food chain.

Persistence Persistence- how long a chemical remains in the environment

Risk Analysis

Personalizing Risk 1 in a 1,000,000 chance Airplane, swimming 1 in a 100,000 chance Skydiving 1 in a 10,000 chance White water kayaking 1 in a 1,000 chance Motorcycle Racing 1 in a 100 chance Annual Racing the Grand Prix Circuit 1 in a 10 chance Climbing the Himalayas As it turns out, most people are willing to take risks up to and including one in a thousand. The participation rate drops off rapidly for risks greater than one in a thousand. Surprisingly, you will find people who are willing to participate in high-risk activities where the odds are one in a hundred and even one in ten of dying. (No wonder it is so difficult to control deadly STD’s)

Qualitative Risk Assessment Making a judgment of the relative risks of various decisions Probability- the statistical likelihood of an event occurring and the probability of that event causing harm

Quantitative Risk Assessment The approach to conducting a quantitative risk assessment is: Risk= probability of being exposed to a hazard X probability of being harmed if exposed

Stockholm Convention In 2001, a group of 127 nations gathered in Stockholm, Sweden, to reach an agreement on restricting the global use of some chemicals 12 chemicals were to be banned, phased out, or reduced These include DDT, PCBs, and certain chemicals that are by-products of manufacturing processes.

Measuring Your Impact How Does Risk Affect Your Life Expectancy? An interesting way of examining risky behaviors is to determine how different behaviors reduce your life expectancy. Using U.S. government statistics, we know that the life expectancy for men is 75.6 years and the life expectancy for women is 80.8 years.

a. If you choose to smoke, the loss of life expectancy will be 6.6 years for the average man and 3.9 years for the average woman. What is the life expectancy for men and women who smoke? b. Alcoholism leads to a 12-year decline in life expectancy in both sexes. What would your life expectancy be if you were an alcoholic man who also smoked? c. Being overweight causes a loss of 36 days of life expectancy for every pound that you are overweight. If you become 20 pounds overweight, by how many years will your life expectancy be reduced? d. Based on the above numbers, what is the life expectancy of an alcoholic woman who smokes and is 20 pounds overweight?

c.