Oak Bluffs Water Has Chlorine Boost
By CHRIS BURRELL
The tap water in Oak Bluffs has tested clean for a week now, but the chlorine added to combat bacteria levels detected early last month has left town water tasting and smelling like a swimming pool.
"The chlorine is very strong, and it's not pleasant," resident Selena Roman told the Gazette yesterday. "We typically drink tap water, and we're not drinking it now. It's horrible."
"When you flush the toilet, you can smell the chlorine, and when you're in the shower, you feel like you're in a Chlorox vapor," said resident Marney Toole.
Most of the 4,000 residents of Oak Bluffs rely on the public water supply.
Oak Bluffs water officials say they started to chlorinate the water last month at a rate of two parts per million when routine tests found coliform bacteria, including levels of e coli. The water district samples water at 18 sites across town.
Early last month, five sites tested positive for coliform, said water superintendent Deacon Perrotta. Follow-up tests three days later found three sites showing coliform levels.
The bacteria is benign unless people are suffering from some immune deficiency, said Mr. Perrotta.
Water officials have no hard evidence to suggest a source for the bacteria and e coli, but they suspect that the bacteria found last month is not coming from the public wells, but rather from inside the water mains themselves.
"We get so much usage and flow in the summer that the extra water in the interior of the main knocks off stuff built up in there and creates a bacteria," said Oak Bluffs water commissioner Michael deBettencourt.
But coliform levels remained a stubborn presence for much of last month. Subsequent tests found the bacteria at two sites, one supplying the Martha's Vineyard Hospital and the other at Farm Neck Golf Club.
Mr. Perrotta notified the hospital, asking if anyone had reported illnesses or reactions such as diarrhea that could be attributed to ingesting contaminated water. There were no such reports.
Then, on August 23, results from another resampling found bacteria in 15 of the 18 sites. "We had a ton of hits," said Mr. Perrotta.
He was also growing suspicious of the results. Water officials were pumping chlorine into the system at a rate of two parts per million but they were seeing substantial residual levels of chlorine.
"When you're carrying a chlorine residual of over one million parts per million, the tests aren't correct," he said.
The point is that the residual chlorine levels should be markedly lower if they have attacked any bacteria, Mr. Perrotta explained.
Last week, water officials tested all 18 sites again, and they came back clean. But chlorination will continue for most of this month with the dosage gradually lessening each week.
Mr. Perrotta said the chlorine will be added this week at a rate of 1.5 parts per million and then one part per million the following week.
Mr. Perrotta, who also serves as water superintendent in Tisbury, said public water supplies on the Island are not typically disinfected, but when tests warrant chlorination, the more effective procedure is to taper off the additive gradually, not abruptly.