III. RESULTS

     A. Research Areas

         This section presents the results of the Wisconsin study and answers
         the research questions around which the report is organized. We
         discuss programs in other states in the section titled Policy Areas.

         I. The extent of VOC contamination at Wisconsin landfills

             a. At how many landfills and in how many wells, leachate samples
                  and collection lysimeters did we find VOCs?

                  We sampled 20 municipal and 6 industrial landfills. The
                  industrial landfills consisted of four paper mill landfills,
                  one foundry landfill and one landfill accepting miscellaneous
                  industrial wastes (Table 1). Although none of the 26
                  landfills are licensed to accept hazardous waste, all
                  municipal waste streams contain household quantities of
                  hazardous waste that are exempt from existing EPA regulation
                  and contribute VOCs and other organic contaminants to the
                  landfill. In addition, older landfills may have accepted
                  hazardous wastes before the current regulations went into
                  effect in 1981.

                  Of the 26 landfills sampled, we detected VOCs in the
                  groundwater at 12 (Table 2). Of the 125 groundwater wells
                  sampled we detected VOCs in 29. We detected VOCs in leachate
                  at 18 of the 19 sampled landfills with leachate collection
                  systems. We sampled collection lysimeters at seven landfills
                  and detected VOCs in three.

              b. Which VOC parameters did we detect most frequently in
                  groundwater, leachate, and collection lysimeter samples?

                  Compounds were organized into chemical groups to show the
                  distribution of related compounds and breakdown products
                  (Table 3). The percentages are based on the number of
                  samples from each source (groundwater 26, leachate 19,
                  collection lysimeters 7). Tetrahydrofuran was most
                  frequently detected in collection lysimeter samples. It is
                  routinely found in glues used to seal the collection pipe to
                  the plastic membrane in the collection lysimeter. The 10
                  most frequently detected compounds in groundwater and the 10
                  most frequently detected compounds in leachate (12 compounds
                  total) are listed below:


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