How good are the new laboratory methods used to measure the 95 chemicals
in this study?
There are two major advantages that this activity has over many other
method development activities. First, these research methods were developed
as part of a national-scale field assessment that provided an opportunity
to analyze samples from a wide range of hydrologic sources across the
Nation. This provided the ability to test method reliability for a wide
range of water types. Second, 5 methods were developed concurrently
as part of this study, and 15 of the 95 chemicals actually were measured
by more than one laboratory using more than one method. This provided
the added opportunity to make direct comparisons of performance of multiple
methods for the same chemical in the same sample. In addition, a rigorous
Quality Assurance/Quality Control (QA/QC) plan was implemented as part
of the each laboratory method, as well as a field QA/QC plan. Data on
these QA/QC plans are available and provide the best evaluation of the
performance of these methods.
