State Update: Additional Sampling Locations and POETs (3/21/16)


March 21, 2016

Ongoing Well Sampling –The DEC, with our contractor Weston & Sampson, continues to sample additional drinking water wells in North Bennington.  Currently wells to be sampled include wells not sampled within the 1.5 mile area of concern, additional wells in the expanded area of concern along the following roads; Silk Road, Vail Road, Fairview Street, Orebed Road, Emmons Road, Harrington Road to Route 67W, and Rout 67W west of Harrington Road, wells already sampled that have PFOA detections less than 20 parts per trillion (ppt), and a limited number of wells which had non-detect PFOA concentrations where confirmation sampling is needed.  DEC samplers will reach out to the owners of these wells.  Samples will be collected from wells within these described areas for residents who have contacted the DEC.

Soil Sampling Soil sampling has been occurring over the past week and will continue this week.  The DEC approved the soil sampling screening plan which was proposed by Saint-Gobain’s contractor.  The sampling plan includes more than 100 samples at over 25 locations.  Results will be available in the coming weeks.   Soil samples were collected in eight different directions from the former Chemfab plant at varying distances to attempt to determine if soil contamination exists around the former plant and at locations where if there is any soil contamination it would be expected to be at its highest concentrations at these locations.  Once we get the results we will use this information to determine if additional sampling is required.  Individual residences are not being sampled at this time.   Soil sampling at the Hoosick Falls site in New York found very little PFOA contamination to the soils.

Point-of-entry Treatment Systems (POETs) –  POET installation has begun on any wells having PFOA above the 20 ppt standard. Once the POET has been installed system sampling will occur to ensure the filtration is performing as expected.  This sampling will begin on Wednesday.  POET sampling will be completed on an ongoing basis until all systems have been installed by Culligan.  Beyond this, POET sampling will be completed monthly for the first 3 months, and then evaluated to determine if the sampling frequency can be modified to something less than every month.  For the initial event (following installation) samples will be collected from the influent and effluent sampling ports for PFC analysis by Method 537, and from the effluent port only for Arsenic (Arsenic can be in the carbon filters but should quickly flush though the system if this is a problem) by standard methods.  Subsequent sampling will involve the collection of samples from the influent, midpoint and effluent sampling ports for PFCs.  If arsenic is below 10 ppb in the initial sample, its analysis will be curtailed.  If not, the system will be re-sampled to confirm arsenic levels have declined to below standards.  Culligan had some initial problems with arsenic in carbon, but has since purchased pre-washed carbon that should alleviate much of this problem.