Chapter 17Human 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

Risk Cause Effect Treatment

Plague

Malaria

TB

PlagueMalariaTuberculosis

Emergent Diseases

Risk Cause Effect Treatment

HIV/AIDS

Ebola

Mad Cow Disease

Bird Flu

West Nile Virus

HIV/AIDSEbolaMad Cow DiseaseBird FluWest 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

Type Example 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 systemCarcinogens- chemicals that cause cancerTeratogens- chemicals that interfere with the normal development of embryos or fetusesAllergens- chemicals that cause allergic reactionsEndocrine 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 chanceAirplane, swimming

1 in a 100,000 chanceSkydiving

1 in a 10,000 chanceWhite water kayaking

1 in a 1,000 chanceMotorcycle Racing

1 in a 100 chanceAnnual Racing the Grand Prix Circuit

1 in a 10 chanceClimbing 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.