High bacteria counts lead to more beach closures, swimming alerts

By Melissa M. Werthmann and Sarah N. Mattero, Globe Correspondents

On such a hot and humid day, some Massachusetts residents won’t find relief at the beach.

Several beaches are closed today or have issued warnings to swimmers after tests revealed high bacteria counts, according to state agencies.

All four sections of Wollaston Beach in Quincy were given red flags, and the highest levels of bacteria were found at Sachem Street.

Wollaston Beach Manager Patrick Millerick said a blue flag means the water is safe and has normal conditions. A red flag means there is a safety concern, such as high bacteria.

“You can go in if you want, but we would advise not to,” Millerick said.

He said high bacteria is common after heavy rain and that beach staff plan to retest the water later today.

SJ Port, a spokeswoman for the Massachusetts Department of Conservation and Recreation, said Wollaston beach has four testing sites along its narrow waterfront that can produce different readings, based on tide turnover.

A red flag warning was issued at Belair Beach in Hingham, after bacteria registered at the highest counts since 2003.

Briarwood Beach and Forbes Beach in Wareham, which closed Thursday, will remain closed until officials retest the water Aug. 8. White Beach and Tuck’s Point Beach in Manchester-by-the-Sea and Grace Olivers Beach in Marblehead are also closed today.

Nauset Light Beach in Eastham and Marconi Beach in Wellfleet remain closed to swimming from bacteria. Nantucket and New Bedford have reopened all of their beaches after receiving desirable results from testing.

Port said that some Bay State beaches can have chronic issues with bacteria counts and are affected by population, location, and nearby facilities. Port said a densely populated area with an older sewer system would likely have higher bacteria levels than a rural area with a new sewer system. She said nearby construction sites or dog parks can also prove problematic for water conditions, because rain runoff will carry bacteria into the ocean.

Port said water quality is tested weekly, and even daily at beaches during peak summer sessions. But when rainfall amounts to over half an inch, some beaches are automatically posted with red flags, she said.

“We do test, but we also ... post those beaches because historically we know they have runoff issues,” she said.

Port reminded swimmers that unless bacteria levels are abnormally high, healthy people are not likely to get sick from going in the water. Young children and those with chronic illness should be more cautious, she said.

“We don’t close the beaches because you have a constitutional right to the oceanfront,” Port said. “But you are taking your health in your own hands if you swim at a posted beach.”