The Shrewsbury Water Department participated in two rounds of sampling for hexavalent chromium, known as Chromium – 6, as part of an evaluation study required by the EPA for all water systems serving 10,000 or more residents. This was done in the basic time period of 2013-2015. Our finished water and distribution samples ranged from 3.4 – 4.1ppb, (parts per billion). There is presently no federal or state level for hexavalent chromium other than total chromium, at a level of 100ppb. Total chromium consists of the more natural occurring trivalent chromium, (Chromium -3), and hexavalent chromium, (Chromium – 6).
As a result of a news story from the Environmental Working Group, Harwich at 20ppb along with Danvers at 4.4ppb and Shrewsbury at 4.1 ppb, were identified as the three highest in the state. Harwich has subsequently identified their problem as new stainless steel piping in their treatment plant. This report raised our concern as to the accuracy of our results and in turn, Shrewsbury resampled our finished water, along with each individual well. Our local state certified laboratory ran the tests for hexavalent chromium and all of the samples came back as non-detected, which were reported in that format on the website. After discussion with the laboratory, their detection limits were set too high and they were not able to record the lower levels that we had requested. Subsequently, we resampled all our sources again and sent them to what is considered the premier laboratory in the country for hexavalent chromium analysis, Eurofins Analytical. Our finished water showed a result of 3.2ppb, consistent with past analysis. We wanted to see whether the problem originated from within in our treatment process or from the individual wells. Two of our wells, Home Farm 6-4 and 6-3, showed levels higher than expected, which is the cause of our finished water results.
Hexavalent chromium is used in the metal plating industry, as well as in anti-corrosion products, paints, plastics and the welding of stainless steel, among other uses. Since there are industries using some of these processes in close proximity to our wells, we have contacted them to conduct ground water analysis along their property to determine if any hexavalent chromium is entering our well area from that direction. It appears to be a narrow area affected, as another well less than 50 feet away is not affected to this point.
Even though at this time there is not a federal or state limit for hexavalent chromium, our goal is to stay as close to zero as possible. The only state in the country to have a limit for hexavalent chromium is California, with a standard of 10ppb as of April 2014. With the EPA gathering data on this substance, it is quite possible the California limit of 10ppb will be the national standard. Below are our results from the 10/26/2016 testing;
Finished Water – 3.2ppb Home Farm 6-4 – 9.0ppb
Home Farm 6-1 – 0.17ppb Lambert’s 3-3 – 0.17ppb
Home Farm 6-2 – 0.14ppb Lambert’s 3-2 – 0.13ppb
Home Farm 6-3 – 6.7ppb Sewell #4 – 0.10ppb
On Tuesday, November 15, 2016, at 7:15 PM, Robert Tozeski Superintendent of Water and Sewer will be reporting to the Board of Selectmen on this matter and will provide any additional information that becomes available.
Questions may be directed to the Water Department at 508-841-8506.