Published in the August 4, 2015 edition
By MARK SARDELLA
WAKEFIELD — While acknowledging the need to pursue a watershed-wide, long-term nutrient management plan, Town Engineer Michael Collins and some other members of the Lake Quannapowitt Water Quality Committee appear to be leaning toward a more immediate “in-lake” solution to the cyanobacteria (aka blue-green algae) that has plagued the Lake for years.
That in-lake solution could take the form of “SolarBee” water circulators that aerate the water. Collins views the SolarBees as a “natural approach” as opposed to other in-lake solutions such as chemical treatments.
Collins warned the Lake Committee last night that introducing chemicals that are not naturally occurring can tend to also produce unforeseen adverse consequences.
In recent years, Lake Quannapowitt has taken on a pea soup green color by the end of summer as a result of the proliferation of the cyanobacteria. While the aesthetic consequences can be easily seen, based on its research, the Lake Committee now regards the bacteria as a potential serious health hazard.
“The data shows that you don’t want cyanobacteria in your water,” Collins said.
Member Leonard Malvone has done some in-depth research into the dangers of cyanobacteria on behalf of the Committee. While not an emergency at this moment, Malvone cautioned that the cyanobacteria “can become a public health hazard.” The bacteria produces neurotoxins, which he said can even aerosolize and have a cumulative health effect.
These toxins can be toxic and dangerous to humans as well as other animals and marine life in general. Several cases of human poisoning have been documented. Malvone cited studies suggesting that significant exposure to high levels of some species of cyanobacteria producing toxins can cause amyotrophic lateral sclerosis (ALS, also known as Lou Gehrig’s Disease).
“You have to do something in the Lake to eliminate the cyanobacteria,” Collins reiterated.
Collins and Committee member Frank J. Luciani Jr. are inclined to give the SolarBees a try. Collins said that SolarBees have been used in more than 300 water bodies in the United States and Canada. He said that every community using SolarBees that the Committee has contacted reports success in controlling the cyanobacteria.
Other committee members have expressed concerns over the SolarBees aesthetic impact on the Lake and their potential to present obstacles to boaters. But Luciani said that when some members went to view a SolarBee installation at a lake in Mashpee, the units were not easily visible from shore.
The SolarBee circulators sit about three feet out of the water and are supported by floats along the sides. Each unit is anchored to the bottom to keep it in position. A unit will impact the circulation of water to a range of about 600-700 feet.
Collins said that the SolarBees can be leased for $10,000 annually per unit. The lease fees can be applied toward purchase. Initially, it was believed that as few as seven units could take care of the Lake but other estimates have suggested that a higher number may be needed.
Collins and Luciani said that beneficial effects of SolarBees in reducing the cyanobacteria are typically seen in the first year.
Committee members discussed the idea that an in-lake solution to the cyanobacteria problem, whether SolarBees or something else, would not preclude a longer term nutrient management approach with respect to the watershed surrounding the Lake.
Since phosphates fuel the growth of cyanobacteria, a nutrient management approach would include reducing the amount of phosphates entering the Lake via storm drains and runoff. It could also include the planting of “riparian zones” around the Lake, which can serve as natural biofilters.
Collins said that the town will be required to address the nutrient management issue under the federally mandated National Pollutant Discharge Elimination (NPDES) program.
Committee member Jim Murphy reviewed some of the results of his most recent tests of the Lake water for phosphates and dissolved oxygen. Low levels of dissolved oxygen are often associated with an overabundance of cyanobacteria.
Committee member Dennis Cloherty continued to insist that restoring flow into the Lake from several Reading brooks would provide a low cost solution by fostering sufficient water turnover to clean the Lake.
Collins remained skeptical, maintaining that those brooks would also add their own phosphates to the Lake.
The Lake Committee is expected to deliver a progress report to the Board of Selectmen on Monday, Sept. 14.