One Quincy beach and one Braintree beach remain closed to swimming, while two Scituate beaches have been closed to swimming this week after tests showed high bacteria counts in the water.
Testers look for enterococci bacteria, which are found in the intestines of animals and humans, and sometimes in fecal matter.
“High levels of enterococci at the beach indicate the waters may also contain other disease-causing microbes that are present in sewage but are more difficult to detect,” said the Woods Hole Oceanographic Institution’s website.
As a result, beaches that receive readings higher than 104 colony forming units per 100 milliliters of water are closed to swimming.
This week, several beaches remain over the threshold for safe bacteria levels, and as a result the public is advised to avoid swimming in the water.
According to reports from the Bureau of Environmental Health, Chikatawbot Beach in Quincy has been closed since Aug. 16 after tests taken on Aug. 15 showed levels of 862 cfu/100 ml.
Follow up tests taken the next day showed 121 cfu/100 ml of water and closed the beach for the weekend.
The beach has been retested today, but if the geometric mean of the last five samples is above 35, then the beach will remain closed to swimming.
Like in Quincy, Smith Beach in Braintree has been closed to swimming since Aug. 15. Testing taken on Aug. 14 showed 272 cfu/100 ml. Testing typically occurs on Tuesday, but no updates for this week were yet available.
Additionally in Scituate, Minot Beach was closed to swimming on Wednesday after tests from Tuesday showed 144 cfu/100 ml. of bacteria in the water.
Egypt Beach, too, was closed to swimming after tests showed bacteria levels of 175 cfu/100 ml. All other Scituate beaches remain open.
Closed Scituate beaches were resampled on Wednesday, and results will be available Thursday afternoon.
Typically, tidal changes help clear out the bacteria from the beach. If test results return to normal by Thursday, the beaches will be open to swimming for the weekend.
Beaches are tested weekly from June through Labor Day.
For more information on beach closings, visit here.