High enterococcus bacteria levels remain a consistent problem at East Creek at Lake Montauk — and the cause a continuing mystery — as reported in the latest water quality update from Concerned Citizens of Montauk for the week of July 18.
Jaime LeDuc, program support specialist at C.C.O.M., which monitors and tests for entero levels, could only speculate that East Creek's elevated entero level — 2,489 MPN/ml (most probable number per millimeter) — "might have something to do with septic systems that need to be upgraded."
East Creek led the entero pack this week, seeing a slight dropoff from last week's 2,755 MPN/ml, and was one of four test sites out of 32 with high bacteria levels, according to the C.C.O.M. survey. Tuthill Pond in Montauk came in at 932, which Ms. LeDuc said was likely due to an enhanced presence of bird droppings.
The outflow area in Accabonac Harbor east of the Old Stone culvert in Amagansett has also registered consistently high bacteria levels, and this week came in at 1,553 MPN/ml (up from 309 last week), while the culvert at Northwest Creek had an entero level of 724. Anything higher than 104 MPN/ml presents a potential health risk to humans.
It's not surprising to see high bacteria levels in culverts, said Ms. LeDuc, especially after a rainfall. "It's unfortunately the norm," she said. Levels can also spike after king tides or when water temperatures rise in the summer.
Still, an absence of big rains in recent weeks has also played out in the weekly report, where most test sites had entero levels of 20 or below. The boat ramp at Fort Pond in Montauk was the lone test site with a medium bacteria level, at 51 MPN/ml. "When we do start to see higher numbers, it's usually because of rain," said Ms. LeDuc.
Citizens can do their part to keep the entero risk at bay, said Ms. LeDuc, who noted that C.C.O.M. has "consistently tried to get people to upgrade their septic systems, and to not use nutrients or pesticides on their lawns. And never swim near outfall areas after it rains."
The testing crew at C.C.O.M also monitors local waters for the presence of blue-green algae, which can produce toxic cynobacteria blooms. Two test sites at Fort Pond in Montauk — on Industrial Road and at the boat ramp — registered slightly higher than last week, but continued to indicate a low risk for a toxic bloom, which can be especially dangerous to dogs who may lick themselves dry after a swim, said Ms. LeDuc.
Ms. LeDuc noted that C.C.O.M. expects to see an increase in blue-green algae levels as the summer grinds on, "but we don't know if it's going to rise to the level of toxic."