Tests determine coliform bacteria in base water Published Jan. 5, 2015 By 66th Medical Squadron Bioenvironmental Engineering HANSCOM AIR FORCE BASE, Mass. -- The base water system recently violated a drinking water standard. Although this incident is not an emergency, as customers, base personnel have a right to know what happened, what personnel should do, and what base civil engineers are doing to correct this situation. Officials collected 15 samples in November to test for the presence of coliform bacteria. Of those, two samples showed the presence of total coliform bacteria. The standard is that no more than one sample per month may do so. Additionally, all samples were collected on one date during November. Public water systems that use surface water and serve more than 4,900 people must conduct more than one sampling round in a month so that potential bacteria problems can be identified more quickly. What should I do? People do not need to boil water or take other corrective actions. However, if residents have specific health concerns, consult a physician. People with severely compromised immune systems, infants, and some elderly may be at increased risk. These people should seek advice about drinking water from their health care providers. General guidelines on ways to lessen the risk of infection by microbes are available from the Environmental Protection Agency's Safe Drinking Water Hotline at 1-800-426-4791. What does this mean? This is not an emergency. If it had been, residents would have been notified immediately. Coliform bacteria are generally not harmful themselves. Coliforms are bacteria which are naturally present in the environment and are used as an indicator that other potentially-harmful bacteria may be present. Coliforms were found in more samples than allowed and this was a warning of potential problems. Usually, coliforms are a sign that there could be a problem with the system's treatment or distribution system, such as pipes. When civil engineers detect coliform bacteria in a sample, follow-up tests are done to see if other bacteria of greater concern, such as fecal coliform or E. coli, are present. No other bacteria were found in subsequent testing. The frequency of sample does not affect the water quality, and did not attribute to the total coliform violation. Officials have adjusted the sampling frequency to meet the requirement. What happened? What is being done? Upon notification, the CE officials flushed the water lines and Bioenvironmental Engineering returned to the sites, and resampled. Coliform bacteria were detected in the resample. Upon notification of the second coliform-positive result, Civil Engineering and Bioenvironmental Engineering returned to the site, let the water run from the faucets and resampled, which included taking additional samples upstream and downstream. Coliform bacteria were not detected in any resamples. Additionally, the Bioenvironmental Engineering sampling plan has been adjusted to collect samples at regular time intervals throughout the month to meet the sample collection interval requirements. Hanscom Air Force Base receives water from the Massachusetts Water Resources Authority, MWRA, via the Town of Lexington. The presence of coliform bacteria is an issue seen most often in that late summer and throughout the fall with the warmer water temperatures during this time of year. The Air Force Civil Engineer Center has funded three projects at Hanscom to replace aging water lines around the base at multiple locations. This process decreases tuberculation, reduces areas that can harbor bacteria, and increases flow capacity throughout the distribution system so that follow-up flushing is more effective. Although the coliform bacteria may still be present, the levels are expected to decrease significantly due to this work. Base officials are committed to ensuring customers are supplied with quality drinking water and continuous monitoring by Bioenvironmental Engineering to ensure the quality of the water remains high. For further information, please contact Master Sgt. Jalayne Powers at 781-225-6366. Please share this information with all the other people who drink this water, especially those who may not have received this notice directly. Residents can do this by posting this notice in a public place or distributing copies by hand or mail.