What are the preservation requirements for the leachates in Method 1311?
As noted in Secs. 6.3 and 6.4 of Method 1311 (the Toxicity Characteristic Leaching Procedure), chemical preservatives shall not be added to samples before leaching. However, the samples may be refrigerated, unless refrigeration will result in irreversible physical changes to the waste.
According to Sec. 6.6, once leached, the portion of the leachate for the metals analyses must be acidified with nitric acid to a pH < 2, unless precipitation occurs, in which case, consult Sec. 7.2.14 of the method for instructions.
The portions of the leachate to be analyzed for the organics must be preserved as described in the individual determinative methods. For volatiles, there is generally no need for further acidification, since the leachate is already at a pH below 7, which should retard any biological activity in the leachate. The portions of the leachate for volatiles, semivolatiles, and herbicides analyses must be stored with minimal headspace at 4° C.
Other Category: Holding Time & Preservation