TM15-02 Changes to National Water Quality Laboratory procedures used to establish and verify laboratory detection and reporting limits

This memorandum describes the implementation by the National Water Quality Laboratory
(NWQL) of selected components of ASTM International’s Standard Practice D6091-07 (ASTM
International, 2007) and supporting DQCALC software (Standard Practice D7510-10; ASTM
International, 2010) to determine and verify detection limits for selected NWQL methods annually. These ASTM standard practices, referred to as the DQCALC procedure in this memorandum, are being implemented as an alternative to the long-term method detection limit (LT– MDL) procedure previously used for many NWQL water methods (Childress and others, 1999).