Laboratory Analysis, Transfer of Custody and Transportation to Laboratory

1. Laboratory Analysis, Transfer of Custody and Transportation to Laboratory John Wondolleck, CDM October 12, 2010

2. Laboratory Analysis • Detection limits • Cleanup to background translates to very low chemical concentrations for some parameters • A key constraint is the ability of a laboratory to “see” concentrations at low levels • Rural residential risk based screening levels have not been developed, • Laboratories were asked to propose detection limits that were 2 orders of magnitude below the suburban residential risk based screening levels

3. Proposals from Laboratories • Initially laboratories were asked to provide information that described for each analysis their capability to detect as low as possible • After the initial responses, CDM asked the laboratories to respond with their potential contractual detection limits

4. Why was there such a wide variation in the responses from the laboratories? • Most Method Detection Limits (MDLs) are laboratory specific and developed per procedures in 40CFR • EPA’s SW-846 and other method publishers do not provide specific MDLs for the analytes, they do in some cases provide a quantification limit that is achievable if the method is followed as written • The MDLs on the table were provided by five laboratories in their response to CDM’s solicitation • Also included is a “typical” MDL observed by CDM chemists based on experience with labs