Town of
Nassau
Dewey Loeffel Landfill Cleanup

Dewey Loeffel Landfill Cleanup

Click here for updates and files from 2017.

 

Click here for updates and files from 2016. 

 

 


EPA Update on Loeffel - February 15, 2018

Subject: Dewey Loeffel Landfill Superfund Site: Recent and Upcoming Field Work

 

Below is a summary of upcoming field work that is anticipated to occur outside of the landfill property itself, as well as some other notable upcoming or recently completed site activities.

  • Landfill/Groundwater Investigation:
  •  
    • As part of the investigation of shallow groundwater, the installation of 38 shallow wells at 19 locations both inside and outside of the landfill was completed in May 2017. Consistent with the approved investigation work plan, the locations and depths of these new wells were selected based upon the results of the direct-sensing investigation and the discrete groundwater and soil sampling conducted in 2016. Hydraulic conductivity testing, which measures how readily groundwater flows in the surrounding aquifer, was performed in the new shallow wells in summer 2017. The first groundwater sampling event for the new wells was completed in October 2017. Samples of non-aqueous phase liquid (NAPL) were collected in November 2017 and December 2017. The near-continuous water level monitoring program began in October 2017 and is scheduled to continue into spring 2018. In accordance with the approved work plan, the first temporary shutdown and start-up of several extraction wells was conducted from February 2-5, 2018 in order to further evaluate the interaction between the extraction wells and water levels at and near the landfill. As a result, the flow rate of groundwater to the treatment plant was reduced during this time period. A second shutdown/startup monitoring event is tentatively scheduled for early March 2018. The schedule for this shutdown/startup monitoring event is subject to change based on precipitation and it is anticipated to be approximately 72 hours in duration.
    • As part of the investigation of deep bedrock groundwater, three new deep bedrock boreholes were installed between December 2016 and February 2017. Several different sampling and testing activities were completed in the three bedrock boreholes between March 2017 and August 2017 (see previous updates for details). The three boreholes were converted into multi-level monitoring wells in November 2017 and are scheduled to be sampled in spring 2018 to help determine the nature and extent of deep groundwater impacts.
    • As part of the investigations of both shallow and deep groundwater, monthly water level measurements were collected in May 2017-February 2018 for the new and existing monitoring wells, as well as for three surface water staff gauges located in Valley Stream. Water level measurements are scheduled to be collected at these locations again in March 2018.
  • Drainageways Investigation:
  •  
    • No field work is expected in the next month.
  • Removal Action for Tributary T11A:
  •  
    • In accordance with the approved sampling and analysis plan, soil and sediment samples were collected from 175 locations in November 2017 and an additional 62 locations in January 2018. The results of the January 2018 sampling are under EPA review and will be summarized in a Data Summary Report along with the results of the November 2017 sampling.
  • Monitoring and Other Activities:
  •  
    • The next residential well monitoring event is scheduled for May 2018 and will include residential wells monitored on a quarterly and semi-annual basis.
  • Some of the abovementioned activities may be visible along roadways, such as Mead Road, Central Nassau Road and Curtis Hill Road.

 


EPA UPDATE: January 17, 2018
 

Below is a summary of the upcoming field work that is anticipated to occur outside of the landfill property itself, as well as some other notable upcoming or recently completed site activities.

  • Landfill/Groundwater Investigation:
    • As part of the investigation of shallow groundwater, the installation of 38 shallow wells at 19 locations both inside and outside of the landfill was completed in May 2017. Consistent with the approved investigation work plan, the locations and depths of these new wells were selected based upon the results of the direct-sensing investigation and the discrete groundwater and soil sampling conducted in 2016. Hydraulic conductivity testing, which measures how readily groundwater flows in the surrounding aquifer, was performed in the new shallow wells in summer 2017. The first groundwater sampling event for the new wells was completed in October 2017. Samples of non-aqueous phase liquid (NAPL) were collected in November 2017 and December 2017. The near-continuous water level monitoring program began in October 2017 and is scheduled to continue into spring 2018. In accordance with the approved work plan, the temporary shutdown and start-up of several extraction wells is scheduled for the week of January 26, 2018 in order to further evaluate the interaction between the extraction wells and water levels at and near the landfill. The schedule for this shutdown/startup monitoring event is subject to change based on precipitation and it is anticipated to be approximately 72 hours in duration. As a result, the flow rate of groundwater to the treatment plant will be reduced during this event. A second shutdown/startup monitoring event is tentatively scheduled for mid-February 2018.
    • As part of the investigation of deep bedrock groundwater, three new deep bedrock boreholes were installed between December 2016 and February 2017. Several different sampling and testing activities were completed in the three bedrock boreholes between March 2017 and August 2017 (see previous updates for details). The three boreholes were converted into multi-level monitoring wells in November 2017 and are scheduled to be sampled in spring 2018 to help determine the nature and extent of deep groundwater impacts.
    • As part of the investigations of both shallow and deep groundwater, monthly water level measurements were collected in May 2017-January 2018 for the new and existing monitoring wells, as well as for three surface water staff gauges located in Valley Stream. Water level measurements are scheduled to be collected at these locations again in February 2018.
  • Drainageways Investigation:
    • No field work is expected in the next month.
  • Removal Action for Tributary T11A:
    • In accordance with the approved sampling and analysis plan, soil and sediment samples were collected from approximately 175 locations in the tributary in November 2017. The results of the November 2017 sampling were received in December 2017. The collection of an additional 62 soil and sediment samples is scheduled to be completed during the week of January 15, 2018 to further delineate PCBs in the tributary. Following the receipt of the analytical data, a Data Summary Report will be submitted summarizing the results of both sampling events.
  • Monitoring and Other Activities:
    • The next residential well monitoring event is scheduled for February 2018 and will include residential wells monitored on a quarterly basis.
  • Some of the abovementioned activities may be visible along roadways, such as Mead Road, Central Nassau Road and Curtis Hill Road.