Chapter 17Human Health and Environmental Risks

•LD 50 Graphing

•Worm Lab

•Pollution within

•Notes ch 17

•Laws/ Risk analysis sheet

•Review

•Test

•Contagion/ medicine man

Three categories of human health risks

Physical- Env. natural disaster, UV light, radon

Biological- Disease

Chemical- Arsenic- DDT

Biological Risks Infectious diseases- those caused b y

infectious agents, known as pathogens.

Examples: pneumonia and venereal diseases

Chronic disease- slowly impairs the functioning of a person’s body.

Acute diseases- rapidly impair the functioning of a person’s body.

How would you categorize cancer? Ebola?

Leading Health Risk

What are some risks of chronic disease in developing countries/ low income?

What are some risks of chronic disease in developed countries/ high income?

Poverty is associated risks

As country becomes more

affluent…

Historical Diseases Plague:

Bacteria (Yesinia pestis) carried by fleas, then mice,

swollen glands, black spots and extreme pain, antibiotics are affective

Malaria:

protists (Plasmodium), Mosquito and human,

flulike symptoms, 350-500 mil contract, 1 mil die per year,

Middle East, sub-Saharan Africa, Asia, Central and South America, DDT

Tuberculosis:

Highly contagious bacteria ( Mycobacterium tuberculosis),

Lung tissue,

Cough into air where it can be transmitted for several hours, can be exposed and not suffer

Emergent Diseases (recently common) Many have jumped from animal to human

HIV/AIDS: 2006 discovered that virus came from genetically similar virus, chimpanzee, African nation Cameroon,

33 mil are infected

Ebola: Ebola hemorrhagic fever, 50 -89% of infected die in 2 weeks, fever, vomiting, internal and external bleeding

Mad Cow Disease: neurological disease, prions mutate to deadly versions, Bovine spongiform encephalopathy, Humans: vCJD or variant Creutzfeldt- Jacob disease

Difficult to kill through cooking

Bird Flu: H5N1 virus, has not been bad but has great potential

West Nile Virus: Birds to mosquito to human, crows, blue jays, robins,

Brain inflammation, kills very young, very old and immunocompromised

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

Answer the following questions in complete sentences

1.What are the three categories of risk for human health? Give an example of each

2.What is the difference between an acute and chronic disease?

3.What is the difference between historical and emergent diseases?

4.How can we combat disease in developing countries? Developed?

5.What is the impact on humans of each of the five major types of chemicals?

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 (sub-lethal)

Acute or chronic studies

Regulated by EPA

Epidemiology: study of human disease

Retrospective or prospective

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.

Factors that determine concentrations of chemicals organisms experience

•Routes of exposure

•Solubility

•Bioaccumulation

•Biomagnification

•Persistence

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

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.