Throughout the northeast and across the nation, state and local officials, health departments, and water utilities including Aquarion have focused their attention on a group of man-made chemicals called per- and polyfluoroalkyl substances (PFAS) that have been detected in drinking waters, including public and private water supplies, and bottled water. Some health officials indicate that consumer products, food, and cookware represent the largest exposure of PFAS to people. However, drinking water contaminated with PFAS can also be a source of exposure.
Although Massachusetts and federal health officials have not yet defined the maximum amount of these chemicals that they will allow to be present in drinking water, the Massachusetts Department of Environmental Protection (MassDEP) recommended in 2018 that the concentration of a group of PFAS compounds in drinking water not exceed 70 parts per trillion (ppt); this limit is referred to as an Office of Research and Standards Guideline (ORSG). On January 27, 2020, MassDEP updated the ORSG for drinking water to add an additional compound, PFDA, for a total of 6 PFAS compounds, and lowered the guideline to 20 ppt for the total sum of the concentrations of the 6 PFAS compounds.
To ensure the highest quality water for our customers, Aquarion voluntarily tested for PFAS chemicals in all of our water sources in 2019. These 2019 results and our latest water sample test results are shown below. Due to the number of water systems sampling for PFAS and the limited number of laboratories available for testing these compounds, the receipt of results from the laboratory can take upwards of 3 to 4 weeks from the sample date. Sites showing different results for the same date represent the results from different laboratories.
In October 2019 we voluntarily sampled water from all three of our water supply well locations in the Millbury system. The initial sampling results that we received from our laboratory on October 21, 2019 indicated that the level of PFAS found in our Oak Pond Well exceeded the original MassDEP guideline of 70 ppt. As a result, Aquarion immediately turned off the Oak Pond Well and consulted with MassDEP. Sample results from our two other water sources in Millbury (the Jacques Wells and the Millbury Avenue Well) showed levels of PFAS below the prior MassDEP ORSG guideline of 70 and new ORSG guideline of 20 ppt. These two water supply sources remain in service.
Aquarion performed additional monitoring in the Millbury distribution system in November 2019 and again in February 2020 to ensure that PFAS levels in our delivered water remained low while the Oak Pond source remained off-line. Test results confirmed that none of the 6 PFAS compounds covered by the Mass DEP guideline of 20 ppt were present in any of those samples, and that one additional PFAS compound was present at levels below 20 ppt. In March 2020 we tested source water in the two Jacques wells and after the treatment systems currently in place at the Jacques facility. This supplemental testing determined that there are low level PFAS concentrations present in both of the Jacques wells, and that our ion exchange treatment system is removing PFAS. On March 30th we completed our annual maintenance to our ion exchange treatment system to ensure the highest level of water quality delivered from the Jacques supply wells. Please refer to the data table below for test results from Millbury source water, treated water, and distribution system water.
In October 2019 we voluntarily sampled all three of our water supply well locations in the Oxford system. Sample results showed levels of PFAS below the MassDEP ORSG of 70 ppt, as well as below the 20 ppt ORSG from MassDEP.
In October 2019, we voluntarily sampled the water entering our distribution system including the Hingham Water Treatment Plant and Cohasset Interconnection. Sample results showed levels of PFAS below the MassDEP ORSG of 70 ppt, as well as below the 20 ppt ORSG from MassDEP.