APPENDIX B -
Landfill Monitoring Data in Massachusetts

In response to an EPA request for information on mercury releases from non-hazardous waste landfills, the Division of Solid Waste Management (MADEP DSWM, 1994) has conducted a review of the available data on the following six solid waste landfills:

These landfills were selected based upon the broad spectrum of waste that was accepted at each facility and the amount of data that was available at the Boston office at this time of the study. The data reviewed included sampling of groundwater monitoring wells, surface water, private wells and leachate samples. One round of soil sampling (Randolph) and one round of landfill leachate seeps (Greenfield) were also examined. Data from this analysis is summarized below and examples of the actual data are attached; the complete data set can be obtained from the MADEP Division of Solid Waste Management.

The majority of the samples were analyzed for dissolved mercury using EPA Method 245.1 Cold Vapor Technique. Out of 53 sampling rounds and 592 individual samples there were a total of seven (7) exceedances of the MCL for mercury (0.002 mg/l). Five of the exceedances were found at the Plainville Landfill and two were found at the Peabody NESWC Landfill. The vast majority of samples showed that mercury contents were below the detection limits of the methods of analyses used.

At the Plainville Landfill, all the exceedances of the MCL were detected in leachate samples which are collected by the landfills groundwater protection system; none were detected in groundwater. The values reported as exceedances of the MCL for mercury at the Plainville Landfill ranged between 0.003 mg/l and 0.2 mg/l.

At the Peabody Landfill, one exceedance of the MCL was detected in six samples collected from a groundwater diversion manhole (0.003 mg/l). The other exceedance was detected in one of seventeen samples from private wells near the landfill. The private well showing the exceedance (0.006 mg/l) is located cross-gradient from the landfill and it is unlikely that the mercury in the well can be attributed to contamination from the landfill. Sampling of six other private wells in the same general area showed that the mercury content was below the detection limits for the testing method used. However, the analysis for samples from private wells near the Peabody Landfill in 1988 had a detection limit of 0.005 mg/l, which is above the MCL for mercury. Therefore, mercury levels above the MCL of 0.002 mg/l but below the detection limit 0.005 mg/l could not be discerned.

Based on the limited data reviewed for these facilities, it is clear that mercury is capable of being leached from municipal solid waste (e.g. Plainville leachate data). However, the groundwater data shows no indication that mercury has moved beyond site boundaries at the landfills examined. Future contamination of groundwater, especially at unlined landfills may occur.

EXAMPLE OF RESULTS OF TWO LANDFILLS ASSESSED

Abbreviations used in this section:

RANDOLPH:

PLAINVILLE:

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Questions or Comments?
C. Mark Smith MA DEP Office of Research and Standards email: C.Mark.Smith@state.ma.us