Transcript Chapter 17_lecture

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
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Biological- Disease

Chemical- Arsenic- DDT
Biological Risks

Infectious diseases- those caused b y infectious
agents, known as pathogens.
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Examples: pneumonia and venereal diseases
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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

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Plague:

Bacteria (Yesinia pestis) carried by fleas, then mice,

swollen glands, black spots and extreme pain, antibiotics are affective
Malaria:
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protists (Plasmodium), Mosquito and human,
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flulike symptoms, 350-500 mil contract, 1 mil die per year,
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Middle East, sub-Saharan Africa, Asia, Central and South America, DDT
Tuberculosis:
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Highly contagious bacteria ( Mycobacterium tuberculosis),
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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
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Ebola: Ebola hemorrhagic fever, 50 -89% of infected die in 2 weeks,
fever, vomiting, internal and external bleeding
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Mad Cow Disease: neurological disease, prions mutate to deadly
versions, Bovine spongiform encephalopathy, Humans: vCJD or
variant Creutzfeldt- Jacob disease
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Difficult to kill through cooking
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Bird Flu: H5N1 virus, has not been bad but has great potential
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West Nile Virus: Birds to mosquito to human, crows, blue jays, robins,
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Brain inflammation, kills very young, very old and
immunocompromised
Chemical Risks
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Neurotoxins- chemicals that disrupt the nervous system
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Carcinogens- chemicals that cause cancer
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Teratogens- chemicals that interfere with the normal
development of embryos or fetuses
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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
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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 (sublethal)
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Acute or chronic studies
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Regulated by EPA
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Epidemiology: study of human disease
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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
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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
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Probability- the statistical likelihood of an event
occurring and the probability of that event causing
harm
Quantitative Risk Assessment
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The approach to conducting a quantitative risk
assessment is:
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Risk= probability of being exposed to a hazard X
probability of being harmed if exposed
Stockholm Convention
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In 2001, a group of 127 nations gathered in Stockholm,
Sweden, to reach an agreement on restricting the
global use of some chemicals
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12 chemicals were to be banned, phased out, or
reduced
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These include DDT, PCBs, and certain chemicals that
are by-products of manufacturing processes.