An analyst may use any method given in Standard Methods for a particular constituent when the results are reported to determine compliance with NPDES limits.

An analyst may use any method given in Standard Methods for a particular constituent when the results are reported to determine compliance with NPDES limits.

• A. True
• B. False
• C. Only methods published in the last decade
• D. Only methods with no interferences

Answer: (B)

Regulatory reporting for NPDES limits requires using methods that are approved for compliance determination. Standard Methods is a broad reference with many methods, but not every method it lists is approved for regulatory reporting. The permit and regulations (such as 40 CFR Part 136 or state equivalents) specify which methods are acceptable for determining compliance. Factors like interference, sample type, hold times, calibration, QA/QC, and method detection limits all matter, and some Standard Methods may be outdated or not sanctioned for enforcement data. So you can’t rely on “any method found in Standard Methods” to determine compliance; you must use EPA-approved (or state-approved) methods listed as acceptable for the specific parameter.

Regulatory reporting for NPDES limits requires using methods that are approved for compliance determination. Standard Methods is a broad reference with many methods, but not every method it lists is approved for regulatory reporting. The permit and regulations (such as 40 CFR Part 136 or state equivalents) specify which methods are acceptable for determining compliance. Factors like interference, sample type, hold times, calibration, QA/QC, and method detection limits all matter, and some Standard Methods may be outdated or not sanctioned for enforcement data. So you can’t rely on “any method found in Standard Methods” to determine compliance; you must use EPA-approved (or state-approved) methods listed as acceptable for the specific parameter.