Fewer beach closures are expected this summer due to changes in state regulations governing swimming safety.
Under the new rules, water testing will still be done on a weekly basis at bathing areas across the Island, but samples will have to show high bacteria counts on two consecutive days before a beach is closed to swimming.
The state Department of Public Health voted last month to amend its regulations to prevent unnecessary beach closures when the water is actually clean.
The former rules, in place since 2001, required posted closings after a sample had indicated elevated bacteria levels. Testing methods require a 24-hour incubation period, so results are delayed one day. By that time, the source of the bacteria had likely disappeared from the swimming waters, health officials said this week.
“We can now redo a sample within the 24 hours and we don’t have to post that it was high,” said Marina Lent, the West Tisbury health inspector.
She said an isolated elevated bacterial count doesn’t mean very much in the ocean. “It’s a living system, it’s full of bacteria,” she said. “If you catch something in your jar it doesn’t mean you have contaminated waters.”
Maura Valley, assistant health agent in Tisbury, said her town has never recorded a repeated positive bacteria count. Elevated levels have always proven to be transient.
According to the DPH, about 80 per cent of elevated bacteria levels don’t last more than a day.
A high count has been recorded occasionally at Owen Little Way, a beach in Vineyard Haven, typically after high rains, Ms. Valley said. Though they knew there was probably no longer a problem with the beach, the board of health was forced to close it to swimming a day after the sample was collected, she said.
“For marine beaches, based on the past two years of data (2012 and 2013), DPH estimates that there will be approximately 240 fewer postings of marine beaches over the course of the season that would have otherwise occurred under our current regulations on a day that the beach water quality is actually clean,” wrote DPH spokesman Anne Roach in an emailed statement.
Beaches that have a history of more frequent high bacteria levels fall under the previous rules. An advisory must be posted at the beach as soon as a test comes back positive for elevated levels of bacteria.
These include Seth’s Pond in West Tisbury, a bathing area with repeated positive bacterial counts over the past four years.
The pond at Lucy Vincent Beach will be closed to bathing all summer, as it has become a primary bird hangout. In the last three years or so, high bacterial counts have been recorded at the pond.
“The pond is a very different system than the ocean,” Ms. Lent said.