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12-07-2021 11:16am
DWWD's November 18th Testing for TTHM in Drinking Water Shows Mixed Bag: Concentrations Above and Below Maximum Contaminant Level
Darlene Cancell
Editor
In an update from Dedham-Westwood Water District that was posted today on the Town of Westwood's Twitter account, DWWD has provided results of its November 18 ,2021 water testing for total trihalomethanes (TTHMs) and the results are a mixed bag.
Image is a chart taken from Dedham-Westwood Water District's December 3, 2021 update, as posted by the Town of Westwood on its Twitter account.DWWD states that the samples taken so far are "not an indication that we are no longer in violation of the maximum contaminant level for TTHM." Monitoring for compliance of TTHMs in drinking water is conducted over the course of a year.
The November 18th sampling measurements show lower levels of TTHM in four locations and higher levels in two locations. The tank samples with lower TTHM were Fox Hill 1 and Fox Hill 2. Distribution system samples at Far Reach Pump Station and Dedham Medical Associates also yielded lower concentrations of TTHM than in past measurements. However, higher levels of TTHM were recorded in tank samples for Sandy Valley and Stoughton Road. The Stoughton Road sample (72.6 parts per billion), though higher, remains under the maximum contaminant level allowed for TTHM of 80 ppb.
DWWD's update, titled, "Total Trihalomethanes (TTHM) MCL Violation Update: 12/03/2021" also reiterates much same information that had been provided by DWWD's new Executive Director Blake Lukis at the Westwood Select Board Meeting of November 15, 2021 and a DWWD customer notice dated November 4, 2021.
The December update highlights DWWD's ongoing mitigation measures. DWWD has engaged the services of Weston & Sampson, an environmental and engineering consulting firm, to research the cause of the elevated TTHMs. It has increased the blended and supplemental water supply from the Massachusetts Water Resource Authority to reduce TTHM in the water supply. It has also increased sampling, testing, and monitoring of TTHM.
DWWD's December update also states in more concrete terms that additional equipment for plant, tanks, and the distribution system are now included in DWWD's 2022 capital plan. The idea of looping dead ends to reduce stagnant water in the current distribution system had been discussed as a possibility at Select Board's November 15th meeting. Time will tell if the improvements to plant and the distribution system are implemented and whether the new additions help prevent an exceedance of TTHM from recurring.
A video of the November Select Board meeting with the new DWWD Executive Director is available from Westwood Media Center here.
Pictured below are the three pages of the December 3, 2021 update from DWWD on the TTHM violation.
