(This post is the fourth in a series describing the Site Investigation activities that are taking place or will be in the areas around the Saint-Gobain facility.)
Testing completed in 2017 indicated the presence of PFAS in stormwater generated at the Saint-Gobain facility and in samples collected from nearby surface water bodies. Saint-Gobain is completing additional testing in 2018, with the objectives of identifying the source of PFAS and evaluating the trends in PFAS concentrations in stormwater and surface water over time. These data are needed so that solutions can be put in place to address this ongoing release of PFAS.
Sampling has been and will be completed during periods of dry weather and during periods of rainfall, making it challenging to predict when the sampling may occur. NHDES has received data from two of the six sampling rounds planned for 2018: 1) samples were collected in May during a dry period with no rainfall; and 2) samples were collected in June during a wet period with rainfall of greater than ¼ inch. A summary of the data is shown below.
More information can be found at the following links:
- Data tables and lab reports for the May sampling: http://www4.des.state.nh.us/IISProxy/IISProxy.dll?ContentId=4720752
- Data tables and lab reports for the June sampling: http://www4.des.state.nh.us/IISProxy/IISProxy.dll?ContentId=4724406
- Map showing the sampling locations (see page 36): http://www4.des.state.nh.us/IISProxy/IISProxy.dll?ContentId=4707076
- Additional description of the work being completed and NHDES’ comments on the proposed scope of work:
Maximum Concentrations Detected (ng/L or ppt) in Samples Collected in May and June 2018
|Sample Location||PFOA||PFOS||Total PFAS (includes PFOA + PFOS)|
|Stormwater Piping Network||7,600||1,100||18,566 (16 compounds)|
|Stormwater Outfall||2,200||140||4,257 (34 compounds)|
|Merrimack River (near the Stormwater Outfall)||220||35||600 (34 compounds)|
|Dumpling Brook (near the mouth of the Merrimack River)||650||48||1,299 (16 compounds)|
|Unnamed Brook A (unnamed brook north of the facility, which does not appear to be accessed for recreational purposes)||1,200||20||1,653 (34 compounds)|
In addition to PFOA and PFOS, other PFAS were detected in stormwater and surface water samples, including, but not limited to shorter-chain PFAS (similar to PFOA, but with fewer carbons), and “precursor” compounds that have been shown in previous studies to break down in the environment into PFOA and/or PFOS.
Currently, NHDES does not have surface water quality standards for PFAS. However, a new state law directs NHDES to develop a plan by January 1, 2020, which includes a schedule and cost estimates, for establishing surface water quality standards for PFOA, PFOS, perfluorononanoic acid (PFNA), and perfluorohexanesulfonic acid (PFHxS).
A summary of the sampling results and NHDES’ response to these results can be found in NHDES’ August 28, 2018 comment letter: http://www4.des.state.nh.us/IISProxy/IISProxy.dll?ContentId=4734828
 Interstate Technology Regulatory Council, March 2018, Naming Conventions and Physical and Chemical Properties of Per- and Polyfluoroalkyl Substances (PFAS): https://pfas-1.itrcweb.org/wp-content/uploads/2018/03/pfas_fact_sheet_naming_conventions__3_16_18.pdf