健康与生态风险评价.pptVIP

健康与生态风险评价 Health and Risk Assessment Types Of Risk Assessment Human Health Risk Assessment - The characterization of the probability of potentially adverse(有害的) health effects from human exposures to environmental hazards. Ecological Risk Assessment – A process that estimates the likelihood of undesirable ecological effects occurring as a result of human activities. Problems With Risk Assessments A basic problem with both human and ecological risk assessments is the sparseness and uncertainty of the scientific data. Also - Variability within dose-response curves Extrapolation of animal data to humans Extrapolation from high-dose to low-dose effects(剂量效应) Four Steps To A Risk Assessment Document Hazard Identification Dose-Response Assessment Exposure Assessment Risk Characterization Hazard Identification Hazard identification involves gathering and evaluating toxicity(毒性) data on the types of health injury or disease that may be produced by a chemical and the conditions of exposure under which injury or disease is produced. The subset of chemicals selected for the study is termed “chemicals of potential concern”. Hazard Identification – Data Data from acute(急性的), subchronic, and chronic(慢性的) dose-response studies are used. a H.R.A. would have a priority ranking of studies that would involve humans and other mammals. an E.R.A. would use different species in different tropic levels; the test species selected are generally representative of naturally occurring species with practical considerations such as ease of culture, sensitivity, availability, and existing databases also involved. Dose-Response Assessment The dose-response assessment involves describing the quantitative relationship between the amount of exposure to a chemical and the extent of toxic injury or disease. The description is different for non-carcinogenic(致癌的) versus carcinogenic effects. Non-Carcinogenic Effects Allowable Daily Intake(日容许摄入量) - The US Food and Drug Administration, the Worl