PITTSFIELD — A green film on Pontoosuc Lake sparked new concerns over the weekend about cyanobacteria levels in its waters.
Lee Hauge, harbor master for the lake, said Tuesday that he sampled water for testing on Monday after discovering discoloration in the water. Results should be in later this week.
This latest concern follows a scare in July that prompted health officials to close the lake. Hauge said samples since then "have not been alarming," but the lake showed more of a greenish color in recent days than it had earlier in the summer.
"The appearance this week was worse than we've seen before," he said.
Cyanobacteria levels in the lake have been tested five times so far this summer, he said — twice in July, twice in August and once this month. He said the highest-level sample came from the first sampling event in July.
Bacteria levels reaching 70,000 cells per milliliter trigger a public health risk, the city has said, while the lake's highest sample yielded 11,000 cells of cyanobacteria.
Health Director Gina Armstrong confirmed via email that test results are pending.
"Monitoring and testing has been on going since late July and water samples were sent to the lab again today," she said.
The Lakes and Ponds Association of Western Massachusetts, of which Hauge is the president, will host a symposium on the emerging cyanobacteria threat on Oct. 5 at Zion Lutheran Church.
Amanda Drane can be contacted at adrane@berkshireeagle.com, @amandadrane on Twitter, and 413-496-6296.