Bài giảng Environmental Sciences - Chapter 15 & 16: Lecture Risks and Pests

Chapter 15 & 16 LectureRisks and Pests Hazard vs. RiskHazardAnything that causes:Injury, disease, or death to humansDamage to propertyDestruction of the environmentCultural hazard - a risk that a person chooses to engage inRisk The probability of suffering (1, 2, or 3) as a result of a hazardPerception What people think the risks areCost-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 analysisCigarette SmokingLeading 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.CancerProving that a chemical is a cause of cancer is hard because a long time may elapse between exposure and development of the cancerIf 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 causesPesticides Integrated Pest Management (IPM) includes: adjusting environmental conditions providing protection against pest damagechemical pesticidesdisease resistant varietiescrop rotationbiological controlsInsecticides kill plants (* - not supposed to), mammals (*), fish (*), & birds (*) A broad spectrum pesticide is effective towards many types of pests (and us)DDTDDT was not used for handling weeds but has saved millions of lives by controlling disease-causing pestsThe 1948 Nobel prize was awarded to Paul Muller for discovering DDTDDT is a cheap, persistent, synthetic, organic, compound & is subject to biomagnifications in food chainsDetermine toxicity for a chemical by using a Dose-Response CurveIf the response is expected to be death, what kind of organism should be tested?Lethal dose at 50% = LD50The 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 MalariaThe protozoan of the genus Plasmodium is the causative agent of malariaDDT 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. ActsThe 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 pesticidesFood Quality Protection Act (FQPA) page 421 & 433