Resource Conservation and Recovery Act Guidance: U.S. Environmental Protection Agency Addresses SW-846 Holding Times

The United States Environmental Protection Agency (“EPA”) in a May 27th letter clarified how:

. . . holding times in the SW-846 Compendium, from sample collection to preparation and analysis, are interpreted, particularly for holding times greater than or equal to 7 days.

Gregory Sullivan, Acting Deputy Director of EPA’s Office of Resource Conservation and Recovery, was responding to a March 9th letter from Judy Morgan of the American Council of Independent Laboratories (“ACIL”).

EPA’s May 27th letter presented three initial points:

• The agency disagrees that the holding time guidelines/associated sample preservation recommendations in SW-846 are technically deficient
• The agency understands/agrees that inconsistent interpretations of evaluation of holding times across EPA programs can create inadvertent problems
• The agency agrees that inconsistent interpretations of how holding times are evaluated across EPA programs can lead to confusion for sample collectors, laboratories, and data users

EPA acknowledges that the primary purpose of establishing maximum holding times is to minimize changes to specific, measurable properties that were representative of the material at the time it was collected.

ACIL apparently stated in its letter that the concentration of many metals and organic chemicals can change more slowly in properly preserved materials and holding times on the order of days or months have been established for these tests. It is noted, however, that:

. . . some chemicals are identified in SW-846 as unstable or reactive over a short timeframe, and for projects where these chemicals are of particular interest, the best practice for obtaining representative measurements is to complete testing as soon as possible after samples are collected.

EPA notes that recommended holding times in Chapters 3 and 4 of SW-846 are identified as guidelines as opposed to agency requirements. The agency also notes that additional variables can affect chemical stability and need to be considered during project planning.

EPA states that the Office of Resource and Recovery has decided to clarify that the recommended holding times in SW-846 Chapter 3 (Table 3-2) and Chapter 4 (Table 4-1) greater than or equal to 7 days can be evaluated in the same units in which they are expressed. Consequently, the new guidance on sample holding times for the SW-846 program is:

Holding times for sample preparation and analysis greater than or equal to 7 days have been met if the sample is prepared or analyzed by the end of the last day or month of the specified maximum holding time. For example, a sample collected on a Tuesday is considered to have met a specified 7-day holding time as long as it is prepared or analyzed by the end of the day on the following Tuesday. A sample collected in January is considered to have met a specified 6 month holding time if it is prepared or analyzed before the end of July.

A copy of the letter can be downloaded here.