ETX 135 MIDTERM ANSWER_KEY_Word03 - ETX 135 Midterm ETX 135...

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ETX 135 Midterm ETX 135 MIDTERM EXAM 2010 The midterm is worth 30% of the course grade. The midterm is worth 200 points. Provide your answers in a Blue Book. No notes or books can be consulted during the exam. 1. What is the definition of health risk assessment, and what is health risk assessment used for? (10) Definition: Health risk assessment is the characterization of the potential adverse health effects of human exposure to environmental chemicals. Alternative Definition: Health risk assessment is a characterization of hazard from exposure to chemicals involving understanding of toxicity of the chemical(s), exposure, and characteristics of the exposed populations. Used for: To assist society/decision makers to weigh possible harms with possible benefits To determine possible harms from exposure For risk managers to use in making risk management decisions to control exposures . 2. Name and describe the steps taken in the risk assessment process. Explain the objective of each step. (20 points) Hazard Identification: The process of determining what adverse effects are caused by exposure to an agent, based on human epidemiology, animal toxicology and other relevant data. (Sometimes includes looking for what chemical when you have observed an adverse response. More often know what chemical people are being exposed to and looking for what potential adverse effects could result from exposure.) Dose-Response Assessment : Quantifying the relationship between the exposure or dose of a chemical and the adverse effect or response Exposure Assessment: Quantifying the amount of exposure humans receive from various media (air, water, soil, food, etc). (involves characterizing population exposure and sometimes subsets of the population.) Risk Characterization: Combining the first three steps into a coherent picture describing the risks of exposure to the chemical(s). Includes discussion of major uncertainties. 3. What is the definition of an adverse effect as defined by U.S.EPA? (8 points) “A biochemical change, functional impairment, or pathologic lesion that affects the performance of the whole organism, or reduces an organism’s ability to respond to an additional environmental challenge” 4. What are the Bradford Hill Criteria used for? Explain at least two of the criteria (other than temporality)? (8 points) The Bradford Hill criteria are used in a weight-of-evidence analysis as guidance in evaluating a data base to determine whether exposure to an agent (e.g., a chemical) causes an effect (e.g., an adverse health effect). Needed to have two of these described in your response: Biological plausibility – Is there information which leads to a conclusion that the effect seen makes sense from a biological perspective? Supporting data that the effect seen from exposure to a chemical is reasonable based on what we know about the biology of the 1
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ETX 135 Midterm organ system and the toxicity of the chemical increases the confidence in a cause and effect
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ETX 135 MIDTERM ANSWER_KEY_Word03 - ETX 135 Midterm ETX 135...

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