Phase 3 Risk Characterization in EPA ecological risk assessment includes two major components: what are they?

• A. Risk estimation and risk description
• B. Hazard identification and exposure assessment
• C. Dose-response and exposure
• D. Risk management and risk communication

Answer: (A)

Phase 3 Risk Characterization brings together what we know about exposure and effects to describe the overall risk in a way that decision makers can use. The two components are risk estimation and risk description.

Risk estimation turns the exposure and toxicology information into quantitative numbers—like how big the risk is, using metrics such as risk estimates or hazard quotients, including any confidence intervals or uncertainties. This is the numerical part that shows the magnitude of potential effects.

Risk description translates those numbers into meaningful real‑world terms—identifying who or what is at risk, where and when the risk could occur, how severe the potential effects might be, and what uncertainties or data gaps affect confidence in the estimates. It’s the qualitative narrative that helps people understand the significance of the numbers.

The other options mix steps from earlier phases (hazard identification, exposure assessment, dose-response) or downstream activities (risk management, risk communication). Those are important, but they aren’t the two core pieces of Phase 3 itself.