TM01-03 Change in the Long-Term Method Detection Level and the Laboratory Report for Total Recoverable Phenol Analyses, because of Excessive Variability

The National Water Quality Laboratory (NWQL) analyzes water samples for Total Recoverable Phenols, parameter code 32730, lab code 2322. Quality-assurance programs at the NWQL indicate that the blanks for this method are subject to extensive variability, which occasionally produce apparent positive bias. The purpose of this memo is to describe the variability, discuss NWQL actions to compensate for the blank variability, and to report the possible effects on the data base.