We detected VOCs in groundwater at all three of the retarder
         or combined retarder and natural attenuation sites we
         sampled. Leachate taken from the lined portion of landfill
         #2637 contained VOCs.

         Of the four natural attenuation landfills we sampled, three
         had detectable levels of VOCs in groundwater. The fourth
         landfill (#057) contained no VOCs in groundwater, had one of
         the smallest waste volumes, and is one of the oldest
         landfills sampled.

    c.   Was there a difference in VOC contamination between municipal
         and industrial landfills?

         Of the six industrial waste landfills sampled, we detected
         VOCs in groundwater at only one landfill, a recycling paper
         mill. Industrial leachates were tested-at three paper mill
         landfills, one foundry landfill and one landfill accepting
         miscellaneous industrial waste. In leachate from landfill
         #2873, containing paper mill waste, we detected only a low
         concentration of toluene (Table 8). In leachate from
         landfill #2488, containing paper mill waste, we detected only
         toluene and ethylbenzene.   In leachate from landfill #2695,
         containing recycling paper mill waste, we detected a wide
         range of volatile organics similar to those detected in
         municipal leachates. In leachate from landfill #1940, a
         landfill accepting miscellaneous industrial waste, we
         detected fewer parameters and a lower concentration of
         parameters than leachate from other sampled municipal
         landfills. In leachate from landfill #2974, containing
         foundry waste, we detected no VOCs.

         VOCs were detected in collection lysimeter samples at
         industrial sites. Solvents used during construction,
         however, are probably responsible for at least some of the
         VOCs found in the collection lysimeter samples.

3. The relationship between VOCs and indicator parameters

    a. Are inorganic parameters elevated where VOCs are detected?

        For each well where VOCs were detected, we compared indicator
        parameters with VOCs (Table 11). Chloride is used to
        indicate when contamination may be occurring because it is
        not easily attenuated and often moves at the front of an
        advancing leachate plume. Despite this, in almost all cases
        where we detected VOCs in groundwater, chloride
        concentrations were at background levels. Although well
        MW-29 at landfill #2680 had elevated levels of VOCs, it did
        not have chloride concentrations above background. Even


- 14 -