Chapter 15 & 16 LectureRisks and Pests

Hazard vs. Risk• Hazard• Anything that causes:

1. Injury, disease, or death to humans2. Damage to property3. 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 AnalysisRisk 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: – 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