Updated 12:30 pm, Thursday
The West Tisbury board of health telephoned The Times Thursday and said that Uncle Seth’s pond is open for swimming.
West Tisbury health agent John Powers Wednesday closed Uncle Seth’s Pond, after the latest water test results showed that bacteria levels were above the state standard.
Mr. Powers said water tests taken Monday revealed enterococci bacteria counts of 229 colony forming units per 100 milliliters (cfu/ml). The state standard is 61 for fresh water.
In salt water, the accepted level of enterococci for a single sample is 104 colony forming units per 100 milliliters.
Mr. Powers said he would continue testing and alert the public when the popular fresh water pond may be reopened to swimming.
The news remained good for Lambert’s Cove Beach, closed several times last month. Mr. Powers said test results remained clean.
As for a probable cause for the elevated bacteria levels, Mr. Powers said it could be a combination of factors including heavy rains. Ocean beaches are subject to a variety of influences, he said, that include runoff, currents, and wind direction.
West Tisbury health officials closed six public and private beaches on July 7 and again on July 13, after the results of water quality tests showed high levels of enterococci bacteria, above the state standard for safe swimming.
According to the Massachusetts Department of Environmental Protection (DEP), enterococci bacteria are an indicator organism that may mean water is contaminated by fecal coliform bacteria.
High levels of enterococcus can cause skin irritation, vomiting, or diarrhea.
The Bureau of Environmental Health (BEH) posts beach water quality information on the Massachusetts Public Health Department website.