Published in the September 1, 2015 edition
By MARK SARDELLA
WAKEFIELD — A recent test conducted of algae samples from Lake Quannapowitt by a professional water testing laboratory showed alarmingly high levels of microcystin, a toxin associated with blue-green algae. Microcystin is produced during algal blooms and is considered the most toxic form of over 80 known toxic variants.
Town Engineer Michael Collins, who chairs the Lake Quannapowitt Water Quality Committee, told the committee last night that tests of a sample taken on Aug. 20 showed microcystin levels of 2,020 parts per million, 145 times higher than the 14 parts per million limit recommended by state guidelines. The study was conducted by GreenWater Laboratories/Cyano Lab, a laboratory in Palatka, Fla. with a strict focus on cyanobacteria/algae and the toxins they produce.
“The microcystin level greatly exceeds the Massachusetts guidance level for microcystins,” Mark T. Aubel, Ph.D. of GreenWater Laboratories wrote in his report to the town.
Collins noted that algae bloom samples from the same area tested by local scientist Douglas Heath (also a member of the Lake Committee) over a period of six years have come back a 5 parts per million or less. Collins said that Heath’s method of sampling and location has been the same every time. Heath also collected the Aug. 20 sample sent to GreenWater Laboratories for testing.
“Now a certified laboratory does it and it comes back at 2,020,” Collins said. “I’m concerned about cyanobacteria in the Lake.
Other members of the committee questioned the fact that the samples had been collected near the outfall at the head of the Lake, where the algae blooms tend to collect.
“We’re skewing the results,” member Denis Cloherty said. “We’re going down to the scum collection part of the Lake.” A few hundred feet away, a Colonel Connelly Park, Cloherty maintained, “the water is much clearer. It’s not indicative of the Lake.”
But Collins explained that test was for the toxicity level of the cyanobacteria, not the amount of bacteria.
“We know that back in 2013 the entire Lake was full of algae,” Collins said. “It wasn’t one corner. It was throughout the Lake.”
Committee member James Murphy told Cloherty that it didn’t really matter where the sample was taken from because the level of microcystin from the recent professional lab results was dangerously high.
Cloherty maintained that if the barrier to the outflow at the head of the Lake were simply lowered, the algae blooms that collect in that area would flow out of the Lake.
“If we allowed it to flow downstream, we wouldn’t have it in the Lake,” Cloherty insisted. “Why is that so complicated?”
Committee member Steve Breton pointed out that all kinds of “wet activities” including stand up paddle boarding have been going on in the Lake all summer with no reports of anyone getting sick. He did admit that his dog had recently gotten sick after drinking some water from the Lake but couldn’t say for sure if there was a connection.
Breton raised an issue that Cloherty has raised in the past related to re-opening the flow of several Reading brooks into the Lake as a way to flush the algae blooms out. Breton wondered if somehow treating the water from those brooks before it enters the Lake might make it a more feasible solution.
But Collins again argued that restoring flow from those brooks at the Reading end of the Lake would do little to improve conditions of the Lake as a whole, especially at the southern end.
The committee discussed recent dissolved oxygen tests conducted in the Lake. Low levels of dissolved oxygen have been seen in the Lake at times at certain depths. Low oxygen levels have been associated with the ability of cyanobacteria to survive at the expense of more desirable micro-organisms.
The subject again turned SolarBees, the solar-powered water circulators that sit on the surface and pull water from the bottom of a lake and circulate it out to the sides, creating a more consistent level of aeration. Collins and committee member Frank J. Luciani, Jr. have indicated a willingness to give the SolarBees a try.
“SolarBees give you a more uniform water column,” said Luciani.
It has been estimated that it would take about 13 of the units to handle Lake Quannapowitt. Each unit costs about $50,000 but they can be leased with an option to purchase.
But Breton wasn’t convinced, saying that no one has been able to show how the mechanisms improve lake conditions.
Luciani said that the SolarBees have been used successfully in over 300 lakes in North America. Collins challenged anyone to provide an example where the units have been deployed correctly and haven’t worked in controlling algae problems.
Collins called SolarBees “an interesting natural problem solver.” He invited members of the committee to join him next week on a field trip to Santuit Pond in Mashpee to look at a SolarBee installation.
Collins maintained that creating a treatment system to reduce the amount of phosphorus entering the Lake from the watershed to a sufficient degree to control the cyanobacteria would cost millions of dollars and would be cost prohibitive. He said that he had yet to see an example where such a watershed treatment approach had “turned a lake around.”
Collins said that town officials would be meeting today to discuss the laboratory findings of high levels of microcystin toxin in the algae samples from the Lake. Collins noted that microcystins are hepatotoxic (able to cause serious damage to the liver) and have even been implicated in ALS.