Environmental Toxicology Flashcards

Which process describes the increasing concentration of a persistent toxin in successive trophic levels of a food chain?

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.

The EPA's Superfund program (CERCLA) primarily addresses which environmental concern?

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.

Polychlorinated biphenyls (PCBs) are classified as persistent organic pollutants primarily because they:

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.

Which US regulation establishes Maximum Contaminant Levels (MCLs) for chemicals in public drinking water?

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.

Ground-level ozone is classified as a secondary pollutant because it is formed by:

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.

Which environmental risk assessment step involves determining the relationship between dose and adverse health effect?

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.