Mixed Deck — All CES Topics Flashcards

Under the Clean Water Act Section 404 program, which agency issues permits for discharge of dredged or fill material into waters of the United States?

Answer: U.S. Army Corps of Engineers

The U.S. Army Corps of Engineers administers the Section 404 permit program for discharges of dredged or fill material into waters of the United States.

What is leachate?

Answer: Liquid produced from waste decomposition

Leachate is a liquid that forms when water percolates through waste materials, dissolving and carrying various contaminants. It is commonly associated with landfills, where rainwater or moisture within the waste mixes with decomposing refuse. Leachate is highly contaminated and must be carefully collected and treated to prevent soil and groundwater pollution.

Which term describes the minimum concentration of a substance that can be reliably reported with a defined level of confidence using a specific analytical method, typically set at 5–10× the MDL?

Answer: Practical quantitation limit (PQL)

The practical quantitation limit (PQL) is an operationally defined reporting threshold, typically 5–10 times the MDL, at which reliable quantitation with acceptable precision and accuracy is achievable.

Which waste management technique involves the high-temperature oxidation of hazardous organic wastes, achieving >99.99% destruction efficiency for certain compounds?

Answer: Incineration

Incineration at high temperatures (>1200°C) achieves destruction and removal efficiencies (DRE) of at least 99.99% for principal organic hazardous constituents (POHCs).

Which law governs hazardous waste management in the U.S.?

Answer: Resource Conservation and Recovery Act (RCRA)

The Resource Conservation and Recovery Act (RCRA) is the principal federal law in the U.S. governing the disposal of solid waste and hazardous waste. RCRA provides a comprehensive framework for managing hazardous waste from its generation to its final disposal ("cradle-to-grave"), including requirements for treatment, storage, and transportation. It also promotes resource recovery and waste minimization.

A real estate development company plans to build a new subdivision. The project requires filling in a portion of a federally protected wetland to construct an access road. Which federal law will primarily require the company to obtain a permit for this specific activity?

Answer: Clean Water Act (CWA) Section 404

Section 404 of the Clean Water Act establishes a program to regulate the discharge of dredged or fill material into waters of the United States, which includes wetlands. Therefore, placing fill material in a wetland for road construction would require a Section 404 permit.

Which greenhouse gas has the highest global warming potential (GWP) over a 100-year timeframe among those regulated under the Kyoto Protocol?

Answer: Sulfur hexafluoride (SF6)

Sulfur hexafluoride (SF6) has a GWP of approximately 23,500 over 100 years, making it the most potent of the six Kyoto Protocol greenhouse gases.

Which in-situ remediation technology is most appropriate for a LNAPL gasoline plume in a shallow unconfined aquifer?

Answer: Dual-phase extraction (soil vapor extraction combined with groundwater pump-and-treat)

Dual-phase extraction removes both vapor-phase VOCs from the vadose zone via SVE and liquid-phase LNAPL/dissolved-phase hydrocarbons via simultaneous groundwater extraction, making it highly effective for fuel hydrocarbons near the water table.

What is a nonattainment area under the Clean Air Act?

Answer: A geographic area that does not meet one or more NAAQS for a criteria pollutant

EPA designates nonattainment areas when monitoring data shows that ambient air quality fails to meet NAAQS for one or more criteria pollutants. These areas must develop plans to achieve compliance.

In a Tier 1 ERA screening, a hazard quotient (HQ) > 1.0 indicates:

Answer: The exposure estimate exceeds the effects benchmark, warranting further evaluation

HQ > 1.0 signals that estimated exposure exceeds the protective benchmark and triggers higher-tier assessment, but does not confirm actual harm.

What is 'bioremediation' in the context of hazardous waste site cleanup?

Answer: Use of microorganisms to degrade contaminants in place

Bioremediation uses naturally occurring or introduced microorganisms to metabolize and break down hazardous contaminants.

The concept of 'first flush' in stormwater management refers to which phenomenon?

Answer: Disproportionately high pollutant concentrations in early stormwater runoff

The first flush effect describes the phenomenon where the initial portion of stormwater runoff carries the highest concentrations of accumulated pollutants from impervious surfaces.

What practice supports sustainable forestry?

Answer: Selective logging with replanting

Sustainable forestry practices aim to manage forests for long-term ecological, economic, and social benefits. Selective logging, where only certain trees are harvested while others are left to grow, combined with active replanting efforts, is a key practice. This approach minimizes disruption to the forest ecosystem, maintains biodiversity, prevents soil erosion, and ensures a continuous supply of timber resources for future generations.

A company wants to claim 'carbon neutrality.' Which combination of actions is required?

Answer: Measuring all material emissions, reducing them as much as feasible, and offsetting remaining emissions

Carbon neutrality requires a complete GHG inventory, maximum feasible emission reductions, and high-quality offsets to neutralize any remaining emissions.

What is the difference between point source and nonpoint source water pollution?

Answer: Point sources discharge from identifiable locations (pipes, outfalls); nonpoint sources come from diffuse areas (runoff, atmospheric deposition)

Point sources have discrete, identifiable discharge locations (factory pipes, sewage outfalls) regulated by NPDES permits. Nonpoint sources are diffuse (agricultural runoff, urban stormwater) and are harder to regulate.

In a TCLP (Toxicity Characteristic Leaching Procedure) test, what does the procedure simulate?

Answer: Leaching of contaminants in a municipal landfill environment

TCLP simulates leaching conditions in a co-disposal municipal solid waste landfill to determine if a waste exhibits the toxicity characteristic.

In the design of a modern hazardous waste landfill, a leachate collection system is a critical component required by RCRA regulations. What is the maximum allowable depth of leachate that can accumulate over the liner system?

Answer: 30 cm (1 foot)

According to EPA regulations under RCRA (40 CFR 264.301), the leachate collection and removal system must be designed, constructed, and operated to ensure that the leachate depth over the liner does not exceed 30 cm (one foot). This requirement is to minimize the hydraulic head on the liner, reducing the potential for leaks.

Which of the following is a common method for managing solid waste?

Answer: Recycling

Recycling is a common and effective method for managing solid waste by converting waste materials into new products. This process reduces the need for virgin raw materials, conserves energy, and decreases the amount of waste sent to landfills or incinerators. It is a key component of sustainable waste management strategies, promoting resource efficiency and environmental protection.

Enhanced in situ bioremediation (EISB) of chlorinated solvents in groundwater most commonly involves:

Answer: Adding electron donors (e.g., emulsified vegetable oil) to stimulate anaerobic reductive dechlorination

EISB for chlorinated solvents typically injects electron donors such as emulsified vegetable oil, molasses, or lactate to create reducing conditions that promote microbial reductive dechlorination.

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?

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.