ABT Environmental Toxicology 1 — Questions and Answers
Question 1: Which process describes the increasing concentration of a persistent toxin in successive trophic levels of a food chain?
- Bioaccumulation
- Biomagnification (Correct answer)
- Biotransformation
- Bioavailability
Correct answer: Biomagnification
Biomagnification refers to the progressive increase in concentration of a substance (e.g., methylmercury, DDT) as it moves up the food chain from prey to predator.
Question 2: The EPA's Superfund program (CERCLA) primarily addresses which environmental concern?
- Ambient air quality standards
- Cleanup of hazardous waste sites (Correct answer)
- Pesticide registration
- Drinking water disinfection
Correct answer: Cleanup of hazardous waste sites
CERCLA (Comprehensive Environmental Response, Compensation, and Liability Act) established the Superfund program to finance cleanup of uncontrolled hazardous waste sites.
Question 3: Polychlorinated biphenyls (PCBs) are classified as persistent organic pollutants primarily because they:
- Are highly water-soluble and rapidly excreted
- Resist environmental degradation and bioaccumulate in fat (Correct answer)
- React quickly with atmospheric ozone
- Have a short half-life in soil
Correct answer: Resist environmental degradation and bioaccumulate in fat
PCBs are highly lipophilic and resistant to biological and chemical degradation, leading to environmental persistence and bioaccumulation in fatty tissues.
Question 4: Which US regulation establishes Maximum Contaminant Levels (MCLs) for chemicals in public drinking water?
- Clean Air Act
- RCRA
- Safe Drinking Water Act (Correct answer)
- TSCA
Correct answer: Safe Drinking Water Act
The Safe Drinking Water Act (SDWA) authorizes the EPA to set MCLs, which are the legally enforceable maximum concentrations of contaminants allowed in public water supplies.
Question 5: Ground-level ozone is classified as a secondary pollutant because it is formed by:
- Direct emission from vehicle tailpipes
- Photochemical reactions between NOx and VOCs in sunlight (Correct answer)
- Industrial stack emissions of SO2
- Natural volcanic activity
Correct answer: Photochemical reactions between NOx and VOCs in sunlight
Ground-level ozone is a secondary pollutant formed when nitrogen oxides (NOx) and volatile organic compounds (VOCs) react in the presence of sunlight.
Question 6: Which environmental risk assessment step involves determining the relationship between dose and adverse health effect?
- Hazard identification
- Exposure assessment
- Dose-response assessment (Correct answer)
- Risk characterization
Correct answer: Dose-response assessment
Dose-response assessment evaluates the quantitative relationship between the level of exposure to a toxicant and the magnitude or frequency of the adverse health effect.
ABT Environmental Toxicology 1
Which process describes the increasing concentration of a persistent toxin in successive trophic levels of a food chain?