Tests conducted twice last week at the south end of Lake Montauk by the Suffolk County Department of Health Services revealed a brief but heavy influx of enterococcus bacteria following heavy rain, but an almost total absence of the potentially harmful pollutant two days later.
Reached yesterday morning, East Hampton Town Supervisor Bill Wilkinson said the test results “speak for a retention pond in that area. In the meantime, the south end should be closed to bathing for a time after heavy rains. We will benefit from the new data.”
The tests were made at the suggestion of Supervisor Wilkinson following an Aug. 10 discussion of the lake’s overall health by members of the Lake Montauk Watershed Advisory Committee. Tests by the Health Department to see if the water at the popular spot known as South Beach was fit for swimming had not been made since 2005.
That was the year the town decided to remove a lifeguard from the beach. Health Department protocol does not require testing at unguarded beaches. The Health Department agreed to Mr. Wilkinson’s request, however.
In accordance with the recommendations of the federal Environmental Protection Agency, and with requirements of the state’s sanitary code for bathing beaches, the county uses enterococci as indicator organisms for marine beaches. The E. coli bacteria are used as indicator organisms to test for shellfish contamination and for bathing at freshwater beaches. Both types of organisms are associated with human sewage.
The tolerance for enterococcus (an intestinal flora) is 104 colony-forming units per 100 milliliters of water. The tests conducted on three locations at the south end of Lake Montauk on Aug. 16, immediately after the heavy rains of the previous two days, showed levels greater than 800, 892, and 800 c.f.u. per 100 milliliters respectively. The test conducted near the area used for bathing measured 800 c.f.u. per 100 milliliters.
The same locations — one at the bathing area, the other two near streams entering the lake on either side — were tested again two days later. The results showed a dramatic drop in enterococcus bacteria, to 4 c.f.u. per 100 milliliters in all three test sites. R.D.