CPWM Waste Characterization and Classification 5 — Questions and Answers
Question 1: Which of the following best describes the 'mixture rule' under RCRA?
- Any mixture of solid wastes is automatically hazardous
- A mixture of a listed hazardous waste with any solid waste is itself listed hazardous (Correct answer)
- Mixing two characteristic wastes creates a new waste code
- Dilution of hazardous waste with water is an approved treatment method
Correct answer: A mixture of a listed hazardous waste with any solid waste is itself listed hazardous
The Mixture Rule (40 CFR 261.3(a)(2)(iv)) states that mixing any amount of a listed hazardous waste with solid waste results in the entire mixture being classified as listed hazardous.
Question 2: What is the significance of a waste's 'hazardous constituent' concentration compared to its 'hazardous characteristic' threshold?
- Constituent concentrations determine generator category; characteristic thresholds set manifest requirements
- Characteristic thresholds trigger RCRA jurisdiction; constituent concentrations inform LDR treatment standards (Correct answer)
- Constituent concentrations apply only to K-listed wastes; characteristics apply to F-listed wastes
- Both thresholds are determined solely by TCLP testing
Correct answer: Characteristic thresholds trigger RCRA jurisdiction; constituent concentrations inform LDR treatment standards
Exceeding characteristic thresholds (e.g., TCLP limits) makes a waste hazardous under RCRA, while constituent concentrations in Appendix VIII are used to set LDR treatment standards for land disposal.
Question 3: Which waste classification applies to batteries, pesticides, mercury-containing equipment, and certain lamps under a streamlined RCRA management framework?
- F-listed wastes
- Universal wastes (40 CFR Part 273) (Correct answer)
- Characteristic D-wastes
- Conditionally exempt small quantity generator wastes
Correct answer: Universal wastes (40 CFR Part 273)
The Universal Waste Rule (40 CFR Part 273) establishes reduced management standards for widely generated hazardous wastes including batteries, pesticides, mercury lamps, and mercury-containing equipment.
Question 4: When characterizing an unknown waste, what is the recommended first step before conducting chemical analysis?
- Run TCLP on the waste immediately
- Review process knowledge and existing records to identify potential constituents (Correct answer)
- Apply all four RCRA characteristic tests simultaneously
- Assume the waste is hazardous and apply LQG standards
Correct answer: Review process knowledge and existing records to identify potential constituents
Process knowledge review—examining material safety data sheets, production records, and chemical inventories—is the first and most cost-effective step in unknown waste characterization.
Question 5: What distinguishes 'speculative accumulation' of recyclable materials from legitimate recycling under RCRA?
- Amount of material accumulated exceeds 90-day on-site storage limits
- Materials are accumulated without a reasonable expectation of timely recycling (Correct answer)
- Materials are stored in containers rather than tanks or piles
- Recyclables are mixed with non-recyclable solid waste
Correct answer: Materials are accumulated without a reasonable expectation of timely recycling
Speculative accumulation (40 CFR 261.1(c)(8)) occurs when recyclable materials are accumulated without a reasonable likelihood of recycling within one year, triggering RCRA waste management requirements.
Question 6: A waste exhibits a TCLP lead concentration of 6.0 mg/L. The regulatory threshold for lead is 5.0 mg/L. How should this waste be classified?
- Non-hazardous; the concentration is close to the threshold
- Hazardous waste with code D008 (toxicity characteristic for lead) (Correct answer)
- Acutely hazardous P-listed waste requiring special disposal
- Listed F-waste requiring LDR treatment before disposal
Correct answer: Hazardous waste with code D008 (toxicity characteristic for lead)
A TCLP lead result exceeding the 5.0 mg/L regulatory level (40 CFR 261.24) classifies the waste as D008, a toxicity characteristic hazardous waste for lead.
Question 7: Which federal law governs the cleanup of abandoned hazardous waste sites and uses waste characterization data to prioritize remediation?
- Resource Conservation and Recovery Act (RCRA)
- Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) (Correct answer)
- Clean Water Act (CWA)
- Toxic Substances Control Act (TSCA)
Correct answer: Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA)
CERCLA (Superfund) authorizes EPA to investigate and clean up abandoned hazardous waste sites, relying on waste characterization data to assess risk and prioritize remedial actions via the Hazard Ranking System.
CPWM Waste Characterization and Classification 5
Which of the following best describes the 'mixture rule' under RCRA?