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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
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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?
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 • What are the three categories of risk for human health? Give an example of each • What is the difference between an acute and chronic disease? • What is the difference between historical and emergent diseases? • How can we combat disease in developing countries? Developed? • 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
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
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.