Bellingham drinking water shows rise in contaminants
Recent tests on town’s water supply show increased levels of chemicals; not an immediate health risk
BELLINGHAM – The town's water violated a drinking water standard set by the U.S. Environmental Protection Agency and contains a higher-than-allowed level of a contaminant called Total Trihalomethanes, or TTHMs, which are disinfection byproducts that occur when chlorine interacts with organic matter in the water.
The trihalomethanes levels do not pose an immediate health risk for drinking water customers, town offi- cials say. But according to the EPA, people who consume excess amounts of trihalomethanes over many years can develop health problems, including an increased risk of cancer.
“This is not an immediate risk. If it had been, you would have been notified right away,” the town's department of public works said in a statement on the town's web page. “However, pregnant women, infants, and women of childbearing age may be at increased risk and should seek advice from their health care providers if they have any con- cerns.”
According to DPW Director Donald DiMartino, the town is required to monitor the drinking water for TTHM levels on a quarterly basis (once every three months) at four specific locations in the distribution system. The results of this quarter’s sampling, which were received on Nov. 16, show that the system exceeds the standard or maximum contaminant level for TTHMs at three out of four locations in the northern part of town.
The standard for TTHMs is 80 parts per billion. The sampling con- ducted by the town showed TTHMs levels at 85 parts per billion at 79 Hartford Avenue; 90 parts per billion at 342 Hartford Avenue; and 88 parts per billion at 115 North Main St.
The fourth sample at 20 Cranberry Meadow showed TTHMs levels well below the standard at only 30 parts per billion.
DiMartino says TTHMs levels can vary depending on a number of factors including the amount of chlorine used, amount of organic material in water sources, temperature, water use, water storage, and season of the year. Control of TTHMs levels must be maintained while also applying appropriate levels of disinfectant in the water necessary to treat the water for contaminants and avoid bacterial issues.
“The town is working with the Massachusetts Department of Environmental Protection on evaluating operations, water quality and treatment plant performance with the intention of developing a corrective action plan to correct this issue,” said DiMartino, adding residents will be notified every three months
until the public water system is in compliance with the TTHMs standard.
DiMartino says a disinfection byproduct rule violation is completely new to the Bellingham Department of Public Works.
“We have been preforming routine quarterly testing for disinfection byproducts since 2011. We have experience slightly elevated results on a few occasions, but never at levels that triggered concern of a violation, until this summer,” he said. “As we are very inexperienced at addressing this problem, we will be leaning heavily on MassDEP and the professional engineers at Wright Pierce, our water treatment consultants, to help us resolve this matter.”
DiMartino says an action plan has yet to be drafted, but a meeting with MassDEP and Wright Pierce is scheduled to be held Dec. 10 to begin that process.
“We experienced elevated TTHMs numbers during our routine sample collection in August 2017, and while it is not unusual to have elevated numbers in August due to higher water temperatures, these were higher than typical summer readings,” DiMartino said. “The elevated readings did not trigger a violation; therefore, no notices were sent. However, we were required to complete an operation evaluation report.”
DiMartino said the department was “surprised” to see elevated results again in November.
“In the past only the summer time sample showed elevated results,” he said. “This is an indication that there may be some changes in the organic material in our raw water.”
DiMartino said two things became clear when compiling the operation evaluation report. The first is that sample collection locations and procedures need to be improved, and second, the department has very little data to help determine what if anything has changed in raw water quality.
“To resolve the first item we have started to install sampling stations which will allow us to collect samples that are a better indication of the water in our distribution system,” DiMartino said. “All disinfection byproduct sam- pling locations that yielded high readings had very long service lines. These customer’s taps are difficult to access and likely to yield samples that are not representative of the water in the distribution system. DPW sampling staff has also been briefed on the detail sampling procedure.”
The DPW has also expanded its sample collection and monitoring beyond basic requirements to hopefully build a usable database to analyze the cause of the issue, he said.
“The DPW staff has begun to perform some raw water sampling and we have collected samples for analysis by state certified lab that we hope will give us a better indication of the organic material in our raw water,” DiMartino said.
DiMartino says the age of the water in the system can cause elevated disinfectant byproduct results.
“We have contracted with an engineering firm to run a water system hydraulic model analysis that will give us an indication as to where water is not cycling through the water system,” he said. “The water age model should be completed before the end of December. The study should help us understand what is needed to keep water in the distribution system fresh and properly disinfected.”
The Hartford Avenue plant was constructed with capabilities to address elevated organic material in raw water, therefore, the town should have options within the treatment plants capabilities of the plant to address the issue, DiMartino said.
“We cannot stop chlorination of the water system; that would risk bacterial contamination,” he said. “But we can and do plan to make any modifications to the treatment process and distribution system necessary to get us back to compliance.”
The town remains the primary contact for all questions regarding the public water system. Any questions concerning sample results, status of projects, or public notice inquires should be directed to DiMartino at (508) 966-5816.
Residents who have health questions about exposure to TTHMs in drinking water you can contact the environmental toxicology program at the Massachusetts Department of Public Health at (617) 624-5757).