Preliminary laboratory results have been received by the town from samples taken last week at Fresh Pond, and one finding, according to Town Engineer John Cronin, is “a problem.”
The amount of fecal coliform — bacteria found in the intestines of warm-blooded animals, including humans — was over the limit set by New York State Department of Health regulations, making the pond “unswimmable,” Mr. Cronin said.
Tests for another potentially dangerous substance, enterococcus, resulted in “lower than the ceiling value” for a dangerous condition, Mr. Cronin said.
The samples were taken by John Hallman, who has a commercial water testing business, on July 19 and sent to Long Island Analytical in Holbrook, which sent the results to Mr. Hallman on Monday.
Last week, after Vincent Novak and other residents of the area around Fresh Pond contacted the town’s Department of Public works reporting green scum on the shore, the town posted signs warning that swimming in Fresh Pond “may pose a risk to your health. Please refrain from swimming.”
After Mr. Cronin’s report to the board Tuesday, Supervisor Jim Dougherty thanked him and said, “Obviously we should keep those signs up.”
Mr. Cronin pointed out that according to state health department regulations, Fresh Pond “does not meet the definition of a bathing or swimming beach.”
There are other signs at the town landing off Lake Drive at the pond informing the public of the pond’s status, but swimmers, including small children, regularly ignore the notifications.
Fed by the local aquifer, the pond is what geologists call a kettlehole, dug out by the receding glacier of the last Ice Age.
Mr. Novak had alerted the New York State Department of Environmental Conservation (DEC) via email on July 12 that the pond was showing signs of blue-green algae blooms, which in turn could be “harmful algal blooms” (HAB).
According to the National Oceanic and Atmospheric Administration, the presence of HABs can produce “harmful effects on people, fish, shellfish, marine mammals and birds.”
Mr. Hallman said Monday that he had not taken samples for blue green algae testing.
Mr. Novak wrote that near the shore the pond had a “pea-soup green” color and that last month there was “green paint-like scum,” which had dissipated. Rebecca Gorney, a scientist with the DEC, responded to Mr. Novak’s email, replying that photos he had sent of the pond were “consistent with the appearance of cyanobacteria,” or blue-green algae.
Ms. Gorney said she was forwarding the information provided to colleagues in Suffolk County, and as of July 12, the DEC has listed Fresh Pond as having a “suspicious” algal bloom.
Concerns about the status of Fresh Pond got attention at Monday night’s meeting of the Water Advisory Committee from member Peter Grand, who lives in the area.
“We are testing for the wrong thing,” he told his colleagues, noting that the tests announced last week were for fecal coliform and enterococcus. But for Mr. Grand, the concern is what he called “an unknown hazard” caused by blue green algae.
Mr. Grand cited a 2013 report from Melville-based environmental engineers Nelson Pope & Voorhis that there were high levels of phosphates in Fresh Pond.
He suggested the committee look at the pros and cons of using alum to reduce phosphates in the water, noting that alum is neither an algaecide nor a pesticide, but “that doesn’t mean it’s not controversial.”
An internet search revealed questions about possible negative effect on fish and insects while indicating there was no detectable effect on people.
“It requires a lot more study,” Mr. Grand said.