Frequent Questions

Skipping sections 7.1.4 – 7.1.4.4 in SW-846 Method 1311 based on previous extraction fluid determinations.

Can sections 7.1.4 – 7.1.4.4 (determining the type of extraction fluid) in Method 1311 be skipped if you have significant data showing the extraction fluid always used has been number 1 or 2 for a certain waste stream? We have a waste stream that always requires extraction fluid number 2 and were wondering if sections 7.1.4 – 7.1.4.4 could be skipped based on the previous extraction fluid determinations?

 

Method 1311 is a Method Defined Parameter (MDP) and must be followed exactly as described. However, there are situations where it may be inappropriate or wasteful to perform parts of the procedure. What you describe might be one of those situations. The best thing to do is to contact the RCRA regulator for the applicable site and get their permission to not check which fluid to use based on the historical precedent for your waste stream.

Two factors might have to be considered. Is the waste stream liable to change such that the other fluid might have to be chosen occasionally? Secondly, when performing 7.1.4-7.1.4.4 on the waste in question, is the measured pH in the vicinity of the pH 5.0 decision point? If it is not close to the decision point and the waste stream is stable, the wrong extraction fluid could not be chosen and the regulator may agree to let you skip steps 7.1.4-7.1.4.4.

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