Guidelines Establishing Test Procedures for the Analysis of Pollutants; Procedures for Detection and Quantitation

On March 12, 2003, EPA published a document in the Federal Register that proposed revisions to the regulations for the definition and procedure for EPA's method detection limit (MDL). The document also proposed to add to these regulations a definition of minimum level of quantitation (ML) and a procedure for developing it. The proposed rule requested comment on the revisions and additions. The MDL and ML are used to characterize the capabilities of analytical test procedures applied under the Clean Water Act (CWA). The proposed revisions were based on EPA's 2003 assessment of approaches to determining detection and quantitation capabilities of analytical methods. Today's document withdraws the proposed revisions. The proposed revisions were disfavored by the vast majority of commenters on the March 2003 proposed rule, and the Agency has determined that these proposed revisions do not represent the most effective way to address the public's and EPA's concerns regarding approaches to, and use of, detection and quantitation values. The Agency believes, preliminarily, that new approaches submitted in comments to the proposed rule might better address the issues EPA sought to address in its proposed revisions and that these new approaches warrant further consideration and refinement. Hence, EPA plans to work with stakeholders to evaluate one or more approaches to detection and quantitation that will satisfy the needs of programs, regulations, and initiatives at the Federal level for use of detection and quantitation procedures, and to revise its existing procedures, as appropriate.