Oak Bluffs health officials closed Pay Beach to swimming Tuesday evening after water testing showed higher than allowable levels of harmful bacteria in the water.
Water samples taken Monday, July 9, on the popular stretch of town-owned beach along Sea View Avenue showed 163 colony forming units per 100 milliliters (cfu/100ml) of enterococci bacteria. State regulators require beaches closed if the level exceeds 104 cfu/100ml.
Pay Beach must remain closed until further water testing indicates the bacteria levels do not exceed the limits.
All other beaches in Oak Bluffs tested safe and remain open.
In past years, health officials in Oak Bluffs and other towns have been frustrated and puzzled at water testing results that required many Island beaches to be closed at the height of the summer season.
Oak Bluffs began weekly testing of town beaches on June 18. Tests on that day, and over the next two weeks, showed no “exceedences” at any of the six beaches tested.
On Monday, Pay Beach tested over the limits, but water samples taken a few yards down the beach at Inkwell Beach showed less than 10 cfu/100ml, essentially an undetectable amount of bacteria.
The Bureau of Environmental Health (BEH) posts beach water quality information on the Massachusetts Public Health Department website.
Enterococci are a group of bacterial species within the streptococcus genus, some of which (e.g. streptococcus faecalis) are typically found in human and animal intestines and are therefore present in sewage. These tests are also referred to as indicator organisms.
Any sample with a count greater than 104 cfu/100 ml qualifies as an exceedence, which requires that the beach be closed.
The BEH advises that swimming in polluted water can cause gastrointestinal symptoms such as nausea, vomiting, diarrhea, and abdominal pain, respiratory symptoms such as sore throat, cough, runny nose, and sneezing, eye and ear symptoms including irritation, earache, and itchiness, dermatological symptoms like skin rash and itching, and flu-like symptoms such as fever and chills.
Most of these symptoms are minor most of the time but can occasionally be more serious, especially in sensitive populations, like immuno-compromised children and the elderly.