The town's environmental consultants, Drumlin LLC, will be giving a public presentation of their updated report on the Pine Tree Landfill at the Hampden Town Council meeting, Monday December 19th. The meeting starts at 7:00 p.m.
This is an update of their March 15, 2014 report, which stated despite "improving groundwater quality [a downward trend] in certain areas of the landfill..." according to the water quality table on page 4: out of 22 test wells, 10 show no trend or show an upward trendof contaminants: 7 no trend; 3 up; 12 down.
Page 6: "concentration of arsenic exhibited a 3-year increasing trend in 9 of 12 on-site locations where arsenic is analyzed."
In the updated report of November 21, 2016, they again state:
“Based on the water quality data collected at the site, these corrective actions appear to be improving the groundwater quality in certain areas around the landfill.”
While this may be true in some wells, according to the water quality table on p.4 on the new report, out of 22 landfill test wells, 14 show no trend or show an upward trend of contaminants:8 no trend; 6 up; 8 down. Of the 8 wells where the trend is down, 6only sometimes meet Groundwater Quality criteria [based on the only figures they give: on conductivity]; the other two wells where trends are down show ranges far above Groundwater Quality criteria, of the two Residential wells where data is given, one does not meet Water Quality standards; the other sometimes meets those standards, sometimes tests well above water quality standards.
On page 5:
Groundwater exceeds several MCL and/or MEG values for arsenic and sodium at off-site monitoring location DW-103..... However, at MW-916 arsenic exceeded the MCL or MEG value in all 2014 and the July and October 2015 sampling events. At MW-917, arsenic exceeded the MCL or MEG at 7 of 7 events. Secondary drinking water criteria of iron and manganese are also exceeded at MW-916 and MW-917.
On page 6:
There are also several locations noted in Table 1 where the rising trends have been observed. A review of data at these locations is discussed below.
MW03-802B, -803A, -803B: These monitoring wells are along the south side of the landfill and have generally shown elevated and increasing concentrations of specific conductivity and other parameters since the wells were installed in 2003. During 2012, PTL began operation of 2 gas extraction wells PTGW08-12 and -13 in the vicinity of the 802 and 803 wells. In response to the gas extraction, the methane concentrations in these wells have decreased, particularly in 2015, when an effort was made to extract landfill gas on a more consistent basis (see Section II). However the decrease in methane concentration in these wells has not resulted in a significant decrease in specific conductance, suggesting the potential for leachate migration in this area that is influencing the rising trend in these wells.
Question: Could leachate migration be caused by recirculating lechate to maximize methane production? If so, would it not make sense to discontinue recirculating lechate into the landfill?
Discussion of Arsenic in Groundwater.
The 2014 Annual Report identified that the concentration of arsenic exhibited a 3-year increasing trend in 9 of the 12 on-site locations where arsenic is analyzed. The increase was attributed to a combination of factors related to closure (e.g., completing the cover, decreasing recharge to the waste mass, etc.). During 2015, arsenic concentrations continued to increase in 4 wells, decreased in 2 wells and the rest of the wells remained in the same (elevated) range as was measured in 2014.
The report does conclude that:
the 2014 and 2015 data from off-site residential wells do not appear to indicate that the landfill is causing elevated arsenic concentrations off-site.
Water Quality Monitoring - 2016 to 2020.
PTL requested that they do less testing of their monitoring wells starting in 2016. It appears that DEP has accepted their request!
In March 2016, Sevee & Maher Engineers (SME) on behalf of PTL sent an e-mail to the MDEP with suggested changes to the on-going Environmental Monitoring Plan (EMP) for 2016 to 2020. The MDEP provided comments and the 2015 Annual Report included proposed changes to the Environmental Monitoring Plan. Table 1 above includes a comparison of the sampling regime from 2011 to 2015 versus 2016 to 2020. The primary changes are as follows.
Reducing the sampling from 3 times per year (spring summer and fall) to 2 times per year (spring and fall).
Reducing the sampling of dissolved methane to one time per year in monitoring wells;
Eliminating off-site well DW-111 (which has not been accessible during 2014 and 2015 sampling events) unless this well has not been sealed and would not be reused in the future.
Reducing the number of locations where leachate quality is sampled regularly from 7 to 2 (i.e., PDPS and LCS-3C, which have the largest flows). The remaining leachate flow locations will be each be sampled once during the 5 year period.
1. Were Hampden's landfill consultants consulted about the plan to do less testing
2. Was the Town of Hampden: Mayor/Town Council consulted?
3. In light of upward trends of contaminants over the last three years, (2014-2016), does it make sense to reduce the number of tests conducted to ascertian whether PTL's remediation plan is performing as needed?
Also of note:
Prior to 2010, methane concentrations in MW-916 and MW-917 exceeded 5,000 ug/L (p. 5)
State/Federal standards: Dissolved Methane must be below 700 ug/L
Concentrations have been reduced since the closing of the landfill.
1) was much of that methane prior to 2010 escaping into the surrounding air and neighborhoods?
2) what was the health risk to people living in the neighborhood of the landfill being exposed to, breathing in high levels of methane?
The report concludes:
There are several on-site locations that are close to or meet the corrective action criteria, compared to 2013 when no locations met these criteria.** However, groundwater in several wells south and southwest of the landfill has exhibited increasing concentration trends. Operation of the corrective action systems (groundwater extraction and external gas extraction) should be continued to maintain the improvement and PTL should be encouraged to look for opportunities to improve and enhance the correction action systems to accelerate the rate of improvement in the future.
**But data from 2014-2016, based on DEP data, shows trends where contaminates are either increasing or show no change.(my footnote).
Question: Should not DEP require PTL to take more aggressive corrective action, given that test results indicate contamination trends are increasing or not being reduced in the many of the landfill areas being tested?
If you have any questions or concerns about the report, this Monday is an opportunity to ask questions to the town's environmental consultants at the town council meeting.