ENV 1301 Lecture Notes - Lecture 12: Risk Management, Risk Assessment, Precautionary Principle
7 Apr 2016
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Document Summary
Found in water and air: chemicals can leach through the soil into groundwater, chemicals enter organisms through drinking or absorption, aquatic organisms are effective pollution. Some persist: can degrade quickly and become harmless. Or they may remain unaltered and persist for decades. Rates of degradation depends on the temperature, moisture, and sun exposure: persistent chemicals have the greatest potential for harm, break down products. May be more or less harmful then the original substance. Ddt degrades into dde, which is also highly persistent and toxic. Toxicants build up in animals tissues: biomagnification. Gets more concentrated: near extinction of peregime falcons, bald eagles and brown pelicans. Measures how much effect a toxicant produces at different doses: animal testing. The amount of toxicant the test animal receives. The type or magnitude of negative effects. The plot of the dose given against the response. Looks at lethal doses (ld 50) of effective doses (ed 50)
