What is the difference between knowledge-based determination and TCLP-based determination?

• A. TCLP-based determination relies on laboratory testing; knowledge-based relies on information about the waste source
• B. Both rely on information about the waste source
• C. Knowledge-based relies on laboratory testing; TCLP relies on information about the waste source
• D. Knowledge-based relies on field measurements only

Answer: (A)

Knowledge-based determination relies on information about the waste source, processes, and materials handled to decide if the waste is hazardous, without performing a lab test. TCLP-based determination uses the Toxicity Characteristic Leaching Procedure in a laboratory to see if the waste leaches hazardous concentrations of constituents, providing objective evidence of toxicity. In practice, you use knowledge-based when you have solid process knowledge and can establish whether the waste is non-hazardous or hazardous based on sources and history; if that information isn’t enough or you need objective proof of toxicity, you perform TCLP testing. The other choices mix up which method depends on lab testing versus source information or imply field measurements only, which isn’t accurate.