PITTSFIELD, Mass. (NEWS10) — Local health officials are reminding the public that the health advisory issued on September 10, regarding a harmful cyanobacteria bloom in Pontoosuc Lake, is still in effect and continued caution is advised. Although results from the analysis of samples taken from the water column are within the acceptable range for all water activities, the presence of intermittent scum necessitates the continuation of the alert.

Public health officials in Pittsfield and the town of Lanesborough said they are continuing to monitor the levels of cyanobacteria and recommend that residents exercise caution when using the lake. The scum potentially has high levels of toxic bacteria and could produce adverse health effects on those swimming or with other close water contacts. The toxic scum accumulates on the downwind shore and therefore can come and go at any location.

Cyanobacteria are aquatic bacteria and are sometimes referred to as blue-green algae, despite being bacteria rather than algae. Recent test levels show that the bacteria in the water column below the surface is currently below the standard health-based threshold of 70,000 cells per milliliter which determines a public health risk. The problem is in the scum at the surface.

Since the visual presence of algae was first seen at Pontoosuc in early September, Pittsfield and Lanesborough officials, Friends of Pontoosuc Lake, and the state Department of Public Health have been monitoring water safety through routine monitoring and analysis.

Cyanobacteria levels in the current algae film covering most of the lake can potentially reach the toxicity threshold level and be harmful to humans, pets, and local wildlife. The health effects depend on the duration of the exposure. Skin contact can irritate the skin, eyes, nose, and throat, and cause inflammation of the respiratory tract. Swallowing contaminated water can lead to nausea, vomiting, abdominal pain, and diarrhea. In severe cases, the liver and nervous systems can be affected.

Algae blooms can change the water’s appearance from slightly discolored to resembling pea soup or thick paint. Blooms frequently appear blue or green but could be another color, such as brown or red.

A bloom’s toxicity cannot be determined visually. Algae blooms can also give the water a bad odor or taste.

Per recommendations from local boards of health, individuals and pets should not swim where the water is discolored or where foam or mats of algae are visible on the water’s surface. If you or your pets come in contact with the water, officials say you should rinse off with fresh water immediately. Call your doctor or veterinarian immediately if you or your pet experience any adverse health effects.

For more information, contact the Pittsfield Health Department at (413) 499-9411 or email health@cityofpittsfield.org. To learn more about harmful algae blooms, visit the Massachusetts Department of Public Health website.