Is it possible that some of the chemicals were introduced into samples
accidentally either during sample collection or laboratory analysis?
It is unlikely that the concentrations reported in this report are not
representative of streams conditions because of an extensive quality
assurance program that was conducted as part of this study. The personnel
collecting these water samples have been extensively trained to collect
environmental samples for analyses of chemical compounds at extremely
low concentrations. This training ensures that the samples collected
were of the highest quality. As an added precaution, personal care items
(such as colognes, insect repellents, caffeinated products, and tobacco)
were not used by field personnel during and immediately before sample
collection and processing. A set of field duplicates and field blanks
were collected to act as a quality control check on the data. In addition,
an extensive laboratory quality assurance program was implemented for
this study (at least 1 laboratory spike and laboratory blank were analyzed
with each set of environmental samples). Finally, a comparison of results
for compounds that were measured by more than one analytical method
was used to evaluate further the validity of the results of this study.
