Risk Analysis and Mitigation Flashcards
7 cards from real CES practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Risk Analysis and Mitigation flashcards as text
In a quantitative risk assessment, what does the term 'probability of exceedance' refer to?
Answer: The probability that an exposure level will exceed a defined threshold within a given period
Probability of exceedance describes the likelihood that a given magnitude of hazard or exposure concentration will be exceeded over a specified time period.
Which exposure pathway is typically evaluated when a receptor is a child living near a contaminated soil site?
Answer: Incidental ingestion of contaminated soil
Children are particularly susceptible to incidental soil ingestion (hand-to-mouth behavior), making this the primary evaluated pathway in residential soil exposure scenarios.
What is the primary purpose of a sensitivity analysis in environmental risk assessment?
Answer: To identify which input variables most influence the final risk estimate
Sensitivity analysis identifies which uncertain input parameters (e.g., exposure frequency, body weight) contribute most to variability in the overall risk estimate.
Under EPA's Superfund risk assessment framework, what cancer risk level is generally considered the upper bound of the acceptable risk range?
Answer: 1 in 10,000 (10⁻⁴)
EPA's acceptable cancer risk range for Superfund is 10⁻⁶ to 10⁻⁴, with 10⁻⁴ being the upper bound that generally triggers remedial action.
Which of the following best describes 'institutional controls' as a risk mitigation strategy?
Answer: Legal and administrative measures that limit land use or human exposure
Institutional controls are non-engineered legal mechanisms (deed restrictions, zoning ordinances) that reduce exposure by limiting land use or activities at contaminated sites.
What is a Reference Dose (RfD) used for in human health risk assessment?
Answer: Evaluating non-cancer hazard from daily oral exposure over a lifetime
The Reference Dose (RfD) is an EPA-derived estimate of a daily oral exposure level that is unlikely to cause non-cancer adverse effects over a lifetime, used to calculate the Hazard Quotient.
A site has a Hazard Index (HI) of 3.5 for a single contaminant acting on the nervous system. What does this indicate?
Answer: Non-cancer health effects may occur and further evaluation is warranted
An HI greater than 1 indicates that non-cancer adverse effects may be possible, with higher values suggesting greater potential for harm, warranting further assessment or remediation.