ROXBURY, NJ – The harmful algal blooms are back on Lake Hopatcong but scientists are already fighting back, starting in Landing Channel.

A recent test of the lake found concentrations of harmful algal blooms (HABs) that last summer would have prompted officials to consider closing public beaches and warning people to keep away from the water, said Lake Hopatcong Foundation Chairman Marty Kane.

However, because the state Department of Environmental Protection (DEP) recently revised the system it uses to warn about the health hazards of harmful algal blooms (HABs), the lake is still deemed safe and no beach closures are imminent, Kane said.

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He did not say where the increasing concentrations of HAB bacteria were found, and he did not know the numbers. Last summer, the DEP warned people to stay away from water once the cell counts of HAB Cyanobacteria reached 20,000 cells/ml, a level that many argued was too low to warrant the warnings.

Less Alarmist

Under the new system, confirmed Cyanobacteria cell counts of 20,000 to 40,000 cells/ml will yield a “watch” designation by the state. At that level, local health officials – not the state - will decide whether public beaches can remain open. The DEP will still advise people to “use caution during primary contact” with water and try to not ingest it or eat fish caught in it.

The HABs that ruined lake life last year first appeared on June 17 and lasted through the summer.

“If we were under last year’s rules, we’d be right at the borderline now,” Kane said on Friday. “We might soon be closing beaches.”

Scientists say HAB blooms are largely accelerated by the presence in lake water of phosphorous, a material that can come from stormwater runoff. Sunny, hot days and bouts of heavy rain, as were experienced last spring, play a part.

Handcuffing the HABs

This year, officials are trying to prevent the HABs from getting out of hand. In March, DEP Commissioner Catherine McCabe announced the award of $2.5 million in grants for nine demonstration projects around the state “that will implement and evaluate innovative technologies to mitigate and prevent harmful algal blooms.”

The Lake Hopatcong Commission received $500,000 to fund such projects and the first one will take place Monday in Landing Channel, the portion of Lake Hopatcong that juts into Roxbury.

Scientists from a company called Princeton Hydro will be spreading in the water “a phosphorus inactivating technology called Phoslock,” said Roxbury Public Works Director Rick Blood. The clay-based material acts to deactivate the nutrients feeding the bacteria, he said.

“This marks the first project to be implemented under the DEP HABs grant awarded to the Lake Hopatcong Commission in partnership with the Lake Hopatcong Foundation,” Blood said. “The purpose of this project, and all projects initiated under the grant, is to evaluate innovative technologies to control, prevent or mitigate HABs on Lake Hopatcong.”

Blood said the Landing Channel work is expected to take a week.

“Phoslock is applied as a slurry and sprayed from a boat,” he said. “The slurry will temporarily make the water appear turbid, but should disperse two to six hours after each treatment.”

According to Lake Hopatcong Commission Colleen Lyons Phoslock has no known negative health effects.

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