A REGULATORY APPROACH TO ATRAZINE MANAGEMENT - EVALUATION OF WISCONSIN GROUNDWATER PROTECTION STRATEGY

Atrazine, a corn herbicide, has been widely detected in surface (Ribau do 1993) and groundwater (Hallberg 1983). In response to atrazine cont amination of groundwater, Wisconsin has adopted the nation's most rest rictive atrazine management policy. This paper describes the rationale and structure of Wisconsin's atrazine regulatory framework and presen ts the results of an empirical assessment of that policy conducted dur ing the 1992 growing season. The nature of atrazine movement in and to groundwater makes direct observation of groundwater quality trends an impractical basis for policy, assessment. The impacts and efficacy of atrazine restrictions were evaluated through analysis of cropping sys tems data at the field level and farm management data at the whole-far m level. While the regulations did serve to reduce atrazine use, the o bserved response was largely limited to increased application of non-a trazine herbicides. Results indicate that 1992 groundwater protection benefits attributable to the regulatory program were small. 1993 restr ictions will provide greater protection to groundwater by requiring pr oducers to make more substantial changes in their use of atrazine. Des ignation of priority management areas (i.e., a zoning approach to pest icide restrictions) did provide additional protection to areas in the state with better recognized groundwater quality problems. Yet the zon ing approach caused significant confusion among farmers. The fact that restrictions have been phased in over several growing seasons offers an opportunity to minimize disruption associated with atrazine restric tions. Wisconsin's management of atrazine pollution will be instructiv e to states contemplating various groundwater protection measures as m andated by the U.S. Environmental Protection Agency (EPA) Groundwater Strategy.