TM14-01 Reduction in the use of sample-weight-based scaling of reporting levels for National Water Quality Laboratory methods for organics in solids and sediments

This memorandum describes changes to sample preparation procedures and resulting data reporting being implemented by the U.S. Geological Survey National Water Quality Laboratory for five methods that determine organic compounds in solids and sediments. These changes will reduce the use of sample-specific adjustment (scaling) of the reporting-level concentrations for these methods, simplifying the comparison of analytical results among samples. These actions were prompted by concerns expressed by data users trying to interpret scaled results. These changes will be effective for solids samples collected on or after October 1, 2014.