LIBERTY TOWNSHIP, N.J. (Warren County) — Mountain Lake remains under an advisory for blue-green algae despite signs that the spring bloom has largely subsided, according to the Mountain Lake Community Association.
The advisory remains in effect following the latest sampling by the New Jersey Department of Environmental Protection on June 16. Results released June 19 showed a cyanobacteria cell count of 14,125 cells per milliliter, well below the state’s threshold of 20,000 cells per milliliter for determining the presence of a harmful algae bloom.
However, toxin levels measured 2.19 micrograms per liter, slightly above the state’s advisory threshold of 2.0 micrograms per liter. As a result, the DEP has kept the advisory in place until further notice.
The toxin level was the lowest recorded this year, down from 4.74 micrograms per liter on May 19 and 3.32 micrograms per liter on June 2, according to the association.
The MLCA said it first observed signs of the bloom diminishing around June 6, when the lake’s appearance began shifting from brown and turbid to more typical conditions. The organization reported improvements in both water clarity and phycocyanin levels, a measurement of pigment associated with cyanobacteria.
Water clarity increased from 2.5 feet during much of the spring to 4 feet on June 8 and 6 feet on June 16, according to the association.
On June 19, the MLCA recorded a phycocyanin reading of 2 at a dock near the boat ramp, the lowest reading the group has measured this year. The association said the data indicates the bloom is continuing to fade.
Despite the improving conditions, officials noted the advisory remains in effect and the township cannot reopen the public beach until it is lifted.
The MLCA said it plans to contact the DEP next week regarding future sampling and will continue monitoring the lake and sharing updates as they become available.
