TM94-07 Description and use by districts of Laboratory QC sample information in organic determinations

This memo describes the laboratory quality-control (QC) sample information available for district use in interpreting the results of determinations of organic substances in environmental samples. The general quality-assurance (QA) practices for analytical activities used by the National Water Quality Laboratory (NWQL) are outlined in Pritt and Raese (1992). Friedman and Erdmann (1982) describe more general QA practices for chemical and biological analyses of water and sediment samples. This memo provides more specific information about the type, purpose, and frequency of laboratory QC samples in organic analyses, and it provides some examples of their use by districts in interpreting results of environmental samples.