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Lecture 10 Risk assessment.pdf Flashcards
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Lecture 10 Risk assessment.pdf Flashcards
Lecture 10 Risk assessment.pdf Flashcards
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1
Question
What is risk in the context of risk assessment?
Answer
Risk is the possibility or probability of suffering harm from a hazard.
2
Question
What does the risk paradigm in risk assessment involve?
Answer
The risk paradigm includes contaminants, receptors, exposure pathways, and the assessment of risk.
3
Question
Why is risk assessment considered important in regulatory science?
Answer
Risk assessment is essential as it may require action even without full scientific understanding of a hazard, setting default procedures to bridge gaps in scientific knowledge.
4
Question
What are the phases involved in Environmental Sites Assessment for Risk Assessment?
Answer
The phases include Phase I - Assessment, Phase II - Characterization, Phase III - Remediation, and Phase IV - Management Verification.
5
Question
What does Risk Assessment Verification involve in Environmental Sites Assessment?
Answer
Verification includes sampling to confirm estimates, management plan development, and a technical scientific assessment of risks.
6
Question
What are the benefits of risk assessment according to the Natural Research Council?
Answer
- Helps rank contribution to overall risk - Helps identify risks that are easily reduced or eliminated - Helps clarify what is known and not known about the situation - Provides quantitative information for decision-making
7
Question
What are some applications of risk assessment mentioned in the text?
Answer
- Health Canada regulations for foods and drugs - Canada Council of Ministers of the Environment - National Contaminated Sites Program - Canada Wide Environmental Standards - Ontario Ministry of Environment - Site-specific cleanup guidelines for contaminated soils - CEPA (Canadian Environmental Protection Agency)
8
Question
What are the stages of risk assessment outlined in the text?
Answer
1. Problem Definition 2. Identify Contaminant 3. Receptor Analysis 4. Pathways Analyses 5. Exposure Assessment 6. Toxicity Assessment 7. Risk Characterization 8. Uncertainties 9. Critique
9
Question
What stages were part of the Risk Assessment Framework in the past?
Answer
- Problem Definition - Contaminant Screening - Receptor Screening - Pathway Analysis - Conceptual Exposure Model - Exposure Assessment - Toxicity Assessment - Risk Characterization - Qualitative Stage - Quantitative Stage
10
Question
What factors are considered in the Problem Definition stage of risk assessment?
Answer
- Purpose - Management goals - Policy context - Audience - Hazard definition - Receptors - Level of funding
11
Question
Identify Contaminant
Answer
Single compounds or complex mixtures with a few compounds driving toxicity. Found in contaminated soil, air pollution, or other sources of exposure.
12
Question
Receptor Analysis
Answer
Involves studying organism species or groups exposed to stressors. A scenario is defined for the average person, considering age, gender, and other factors. Sensitive subpopulations, like children, are of recent interest. Exposure length, latency for cancer, and routes of exposure are defined.
13
Question
Pathways Analyses
Answer
This step determines the environmental fate leading to exposure of the receptor. Routes of exposure are evaluated, and the amount of exposure is quantified using methods like DOSE, measurements, and modeling.
14
Question
Exposure Assessment (1)
Answer
Involves quantifying exposure from multiple routes like air, water, soil, sediments, diet, and others.
15
Question
Exposure Assessment (2)
Answer
The exposure (g of chemical/day) is calculated as Concentration x Intake Rate for ingestion, inhalation, and dermal contact. Total exposure is the sum of exposure from food, air, and dermal contact.
16
Question
What does EDI stand for in exposure assessment?
Answer
Estimated Daily Intake
17
Question
What is the formula to estimate dose for each exposure medium?
Answer
EDI = IR x C x B x EF x ED / BW
18
Question
What does IR represent in the dose estimation formula?
Answer
Intake rate (m3 air/day or kg food/day)
19
Question
What does C represent in the dose estimation formula?
Answer
Chemical concentration (mg/m3 air or mg/kg food)
20
Question
What does B represent in the dose estimation formula?
Answer
Bioavailability factor (fraction of chemical available for uptake in organism)
21
Question
What does EF represent in the dose estimation formula?
Answer
Exposure frequency (days/year)
22
Question
What does ED represent in the dose estimation formula?
Answer
Exposure duration (days)
23
Question
What does BW represent in the dose estimation formula?
Answer
Body weight (kg)
24
Question
What is the exposure factor formula in the context of EESA10?
Answer
Exposure factor = 3 d/week x 52 weeks/year x 4 years
25
Question
What are the components of total EDI in exposure assessment?
Answer
Total EDI = EDI food + EDI air + EDI dermal
26
Question
What is a fundamental assumption in chemical risk assessment regarding noncancer effects?
Answer
Noncancer effects have thresholds
27
Question
What is the main difference in risk assessment approach between carcinogenic and non-carcinogenic effects?
Answer
Carcinogenicity has no threshold, while noncancer effects have thresholds
28
Question
What are the key steps in the assessment of noncarcinogenic hazards?
Answer
1. Exposure assessment to measure or estimate dose in mg/kg/day 2. Hazard identification to establish a range of noncancer effects and select one as the basis
29
Question
What is the process for determining dose-response relationship in non-carcinogenic hazard assessment?
Answer
Conduct a chronic rodent bioassay to determine the NOAEL (No Observed Adverse Effect Level) and LOAEL (Lowest Observed Adverse Effect Level) from the graph.
30
Question
How is the reference dose (RfD) derived in non-carcinogenic hazard assessment?
Answer
The RfD is derived from the rodent NOAEL or LOAEL by dividing it by uncertainty factors to make it lower and more protective.