in the LWRV. By the 1991 growing season, atrazine was banned from use on all
irrigated fields, including those in the LWRV and in 1993 it could not be used anywhere
in the LWRV as well as other selected areas in the state.
2. Atrazine analysis
In 1990 only parent atrazine was being analyzed by The State Lab of Hygene. In
1991, 2 metabolites of atrazine, deethylatrazine and deisopropylatrazine, were added to
the analysis and included in total atrazine concentrations. By 1993, another metabolite,
diainoatrazine was added to the analysis.
3. Health standards for atrazine
In 1991 the PAL for atrazine was lowered from 0.35 ppb to 0.3 ppb and the ES
was lowered from 3.5 ppb to 3.0 ppb. These standards were to include metabolite
concentrations as numerical results became available.
Six monitoring wells were installed in April 1990 under a demonstration field site
at the Studnicka Brothers Farm in Grant Count-, near Muscoda. This site was chosen
because it was a demonstration 5si.te. for the UJW-E,-er s'on Nutrient and Pest
Management Program (NPM) which had been selected to show different manageAIent
practices for irrigated corn production on the sandy soils in the LWRV. In addition, the
Studnicka family had expressed concerns about the impacts of agriculture on
groundwater quality.