CES CES Environmental Health & Toxicology 2 — Questions and Answers
Question 1: Which EPA framework is used to assess the risk that a contaminant in the environment poses to human health?
- NEPA Environmental Impact Assessment
- Risk Assessment Guidance for Superfund (RAGS) (Correct answer)
- Toxics Release Inventory (TRI)
- Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA)
Correct answer: Risk Assessment Guidance for Superfund (RAGS)
EPA's Risk Assessment Guidance for Superfund (RAGS) provides the standard framework for conducting human health risk assessments at Superfund and other contaminated sites.
Question 2: The four steps of the EPA human health risk assessment framework are, in order:
- Monitoring, modeling, mitigation, reporting
- Hazard identification, dose-response assessment, exposure assessment, risk characterization (Correct answer)
- Site investigation, sampling, analysis, cleanup
- Source identification, transport modeling, receptor analysis, remediation
Correct answer: Hazard identification, dose-response assessment, exposure assessment, risk characterization
The EPA's four-step risk assessment framework proceeds from hazard identification (what can cause harm) through dose-response and exposure assessment to risk characterization (quantifying risk).
Question 3: Which unit is used to express carcinogenic risk in EPA human health risk assessments for individual lifetime excess cancer risk?
- mg/kg/day
- Parts per million (ppm)
- Probability expressed as a dimensionless number (e.g., 1×10⁻⁶) (Correct answer)
- Hazard quotient (HQ)
Correct answer: Probability expressed as a dimensionless number (e.g., 1×10⁻⁶)
Carcinogenic risk is expressed as a dimensionless probability representing the incremental lifetime probability of developing cancer from exposure (e.g., 1×10⁻⁶ = 1 in a million).
Question 4: What is the Hazard Quotient (HQ) used for in non-carcinogenic risk assessment?
- To rank sites by contamination severity for Superfund listing
- To compare estimated exposure to a reference dose—values above 1 suggest potential concern (Correct answer)
- To calculate the monetary value of health damages from pollution
- To determine the lethal dose for 50% of a test population
Correct answer: To compare estimated exposure to a reference dose—values above 1 suggest potential concern
The Hazard Quotient is the ratio of estimated daily exposure to the reference dose (RfD); an HQ greater than 1 indicates that the exposure may exceed the level considered safe.
Question 5: Which class of persistent organic pollutants (POPs) was used historically as electrical insulators and is associated with endocrine disruption and carcinogenicity?
- Polycyclic aromatic hydrocarbons (PAHs)
- Polychlorinated biphenyls (PCBs) (Correct answer)
- Perfluoroalkyl substances (PFAS)
- Chlorinated solvents (TCE, PCE)
Correct answer: Polychlorinated biphenyls (PCBs)
PCBs were widely used as transformer fluids and electrical insulators until banned in 1979 under the Toxic Substances Control Act due to their persistence, bioaccumulation, and links to cancer and endocrine disruption.
Question 6: Which federal law authorizes EPA to require testing of industrial chemicals and to restrict those that pose unreasonable risks to human health or the environment?
- Resource Conservation and Recovery Act (RCRA)
- Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA)
- Toxic Substances Control Act (TSCA) (Correct answer)
- Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA)
Correct answer: Toxic Substances Control Act (TSCA)
TSCA, enacted in 1976 and significantly updated by the Frank R. Lautenberg Chemical Safety for the 21st Century Act in 2016, gives EPA authority to evaluate and regulate industrial chemicals.
CES CES Environmental Health & Toxicology 2
Which EPA framework is used to assess the risk that a contaminant in the environment poses to human health?