Download Ch 15 _ 16 Risks _ Pests 2009

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Transcript
Chapter 15 & 16 Lecture
Risks and Pests
Hazard vs. Risk
• Hazard
• Anything that causes:
1. Injury, disease, or death to humans
2. Damage to property
3. Destruction of the environment
• Cultural hazard - a risk that a person chooses to
engage in
• Risk
 The probability of suffering (1, 2, or 3) as a result of a
hazard
• Perception
 What people think the risks are
Cost-Benefit Analysis
Risk Analysis
• Public policy is generated more by the perceived
risks of the public than through logic cost benefit
analysis.
• A cost-benefit analysis is a requirement for every
regulatory action for EPA
• Also is a means of deciding whether or not to
proceed with a given project.
• Common indoor air pollutants like: cigarette
smoking, asbestos, radon, and formaldehyde require
risk analysis
Cigarette Smoking
• Leading cause of cancer in U.S.
• Can cause cancer, lung disease, a bigger
risk of death in addition with other types of
air pollution.
• Highest health risk in U.S.
Cancer
• Proving that a chemical is a cause of cancer
is hard because a long time may elapse
between exposure and development of the
cancer
• If cancer risk from exposure to a chemical is
less than 1/1,000,000 then no EPA regulation
is needed.
• 25% of cancers can be traced to
environmental causes
Pesticides
• Integrated Pest Management (IPM) includes:
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adjusting environmental conditions
providing protection against pest damage
chemical pesticides
disease resistant varieties
crop rotation
biological controls
• Insecticides kill plants (* - not supposed to), mammals
(*), fish (*), & birds (*)
• A broad spectrum pesticide is effective towards many
types of pests (and us)
DDT
• DDT was not used for handling weeds but
has saved millions of lives by controlling
disease-causing pests
• The 1948 Nobel prize was awarded to
Paul Muller for discovering DDT
• DDT is a cheap, persistent, synthetic,
organic, compound & is subject to
biomagnifications in food chains
Determine toxicity for a chemical by
using a Dose-Response Curve
If the response is expected to be death,
what kind of organism should be tested?
Lethal dose at 50% = LD50
• The LD50 is a standardized measure for comparing
the toxicity of chemicals.
• The LD50 is the dose that kills half (50%) of the
animals tested in an experiment.
• LD50 tests result in the deaths of many laboratory
animals and the data are often controversial.
• Oral LD50 in rats for DDT is 87 mg/kg. So what
does that mean for humans?
• Threshold level of toxicity = The dose below which
no lethal effects are observed and/or above which the
lethal effects are apparent.
• Epidemiology is the study of the presence,
distribution and control of a diseases in a
population
• Morbidity is the incidence of disease in a
population
• Mortality is the incidence of death in a
population
Diseases
• Lyme disease can be transferred to
humans through a bite from an
infected tick (vector)
• Mosquitoes are the vector for
Malaria
– The protozoan of the genus
Plasmodium is the causative
agent of malaria
– DDT is great at killing
mosquitoes… should we use it?
• Lack of access to safe drinking water
is a major cause of disease
transmission in developing countries.
Acts
• The Federal Food, Drug, and Cosmetic Act (FFDCA)
is a piece of legislation that controls the safe amounts
of pesticide residues left on food eaten in the US
• Federal Insecticide Fungicide Rodenticide Act
(FIFRA) is a law that protects human and
environmental health from misuse of pesticides
• Food Quality Protection Act (FQPA) page 421 & 433