On May 3 (May 4 or 5 in case of bad weather) Crystal Lake will be treated with aluminum sulfate to help prevent harmful blooms of blue-green algae. It is the second part of the treatment, which was started in May 2020. According to Newton Environmental Engineer Maria Rose, “The dose was split in half to allow time for more watershed management and because the efficiency of treatment is improved by spreading it out over several years. The effect on the sediment should last more than a decade but the effect on the water column depends on ongoing inputs from the watershed.”
Maria further explains that “These products are used in purification of drinking water at water treatment plants. When added to water, they cause microscopic and even dissolved impurities to clump together into larger particles and settle. On the bottom, they continue to inactivate phosphorus, a key nutrient for algae. In concentrated form these products can be harmful but at the concentration achieved in the lake under the conditions of treatment there have been no harmful effects to people, pets, or aquatic life in over 20 years of applications in MA.”
