Chapter 17 Human 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, 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, % 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.