Determining "reliable detection limits" (RDLs) for environmental analyses.

It is generally accepted that the method detection limit or MDL (defined in 40 CFR 136, Appendix B) provides protection against false positives 99% of the time. This is correct, but only for the next single measurement performed after the MDL is determined. Subsequent measurements are not protected against false positives with the same degree of confidence, and there is no protection for false negatives. This paper provides a simple cost-effective approach for estimating the "reliable detection limit." Unlike the MDL, the statistic may be used for an indefinite number of future measurements and minimizes false negatives.