In Wisconsin the widespread use of the herbicide atrazine has led to the presence of
atrazine and it's metabolites in some groundwaters. One of the metabolites,
diaminoatrazine, is of particular interest because it is reported to pose a greater health
threat (to those drinking the water) than the other metabolites. Diaminoatrazine can be
measured by conventional gas chromatography techniques, but the test is time
consuming, expensive, and less robust than desirable. However, a new test for
diaminoatrazine, using enzyme linked immunosorbent assay (ELISA) technology, has
been commercially developed (although it is not yet on the market). The purpose of the
present study was to evaluate this new ELISA by comparing the results of split samples
analyzed by both the new ELISA and the conventional technique. Approximately 70
groundwater samples from Wisconsin wells, many of which were known by the
Wisconsin Department of Agriculture, Trade and Consumer Protection (DATCP) to be
contaminated by atrazine and atrazine metabolites, were collected and split. DATCP's
laboratory analyzed one set of the split samples using conventional extraction and
chromatographic analysis techniques. The other set of split samples were analyzed using
the new diaminoatrazine ELISA. This same set of samples was also analyzed by an
atrazine ELISA, a test that has been in use for about ten years. The results indicate that
while the new diaminoatrazine ELISA produces results that correlate with conventional
measurements, the ELISA produced results that were higher (usually about double) than
results obtained from the conventional technique. The higher results may relate to the
fact that atrazine (parent compound) can cross react (i.e., the new ELISA is not as
specific to diaminoatrazine as desired). The new diaminoatrazine atrazine ELISA
appears to be very sensitive, as it detected the presence of diaminoatrazine (or possibly
cross reactants) when the conventional technique was not able to detect it. Some samples
in which neither atrazine nor any of its metabolites could by detected by conventional gas
chromatography had detects using the diaminoatrazine ELISA. Interestingly, total
atrazine measured by the conventional GC technique (sum of the parent compound plus
all metabolites measured) gave similar results to the sum of the diaminoatrazine ELISA
and the older atrazine ELISA for the samples studied. Despite the fact that the new
diaminoatrazine ELISA does not produce the same results as conventional analyses, it
still could be a useful (and relatively inexpensive) test for determining waters that could
contain the diaminoatrazine metabolite (and thus pose an elevated drinking water health