NORTH SALEM, N.Y.--Officials have been working since winter with the state Department of Environmental Conservation and the East of Hudson Watershed Corp. to lower the concentration of phosphorus in Peach Lake. The installation of filtration devices that reduce phosphorous is now complete.

The installation wrapped up about a month ago, town Supervisor Warren Lucas said, with just a few minor adjustments left to be completed.

According to the DEC, phosphorus is one of the leading causes of water pollution. 

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“Even if you live far from a water body, excess phosphorus from your lawn can wash off and pollute lakes and streams, harming fish and ruining boating and swimming,” the website reads. “More than 100 water bodies in New York State cannot be used for drinking, fishing or swimming because they contain too much phosphorus.”

Phosphorous in itself is an essential nutrient to aquatic plants at low levels, according to the DEC. However, an over-abundance of the element in freshwater bodies caused by run-off from lawns and septic systems causes excess algae. Not only is this hazardous to the lake’s ecosystems, according to the DEC, it can cause algae blooms leading to serious odor, taste and color issues” in drinking water.

“Excess phosphorus can cause eutrophic water conditions and increased carbon,” according to the DEC website. “This water, when mixed with chlorine, can result in the formation of ‘disinfection by-products’ or chemicals that are suspected of being carcinogenic and may cause the risk of early term miscarriages.”

Eutrophication is the reduction in dissolved oxygen in water bodies. As the lakeside properties near the 1.5-mile-long Peach Lake evolved over the years from vacation homes to permanent residences, the increase in storm water run-off from lawn fertilizers, which used to contain phosphorous, and septic tanks has raised its phosphorous levels, Lucas said.

Unlike other elements, which break down into gases and float away, phosphorous stays in a solid state, Lucas said, which means it never leaves the lake.

As the algae and seaweed grow and die off, the plants may sink to the bottom and decay, but the phosphorous remains. So silt continues to build at the bottom, and algae and seaweed continue to grow each summer. 

“Over a period of time, the lakes just fill up and what you have is a body of water that you can’t use any more,” Lucas said.

The DEC has regulations such at the Nutrient Run-off Law that put limits on the use of fertilizer/pesticide combination products that contain 0.67 percent phosphorus. The law applies to homeowners, landscapers and lawn care professionals, pesticide applicators, retailers, distributors and manufacturers of lawn fertilizers. There is no DEC regulation on the amount of phosphorous a lake or body of water can have.

Lucas said that the phosphorous levels are in flux; at certain times of the year, and from year to year, the levels vary.

Before the filters were installed, tests indicated levels in Peach Lake were about 32mcg/l. Lucas said he is hopeful the system will lower the phosphorus levels to about 20 micrograms per liter (20mcg/l). 
The eight filters, which were manufactured by Contech, are called “jellyfish” and are designed to remove sediment from the lake, Lucas explained.

Two of the filters are technically in the town of Southeast, but as the two municipalities both belong to the East of Hudson Watershed Corp., he said officials from Southeast have been very cooperative in working to lower the phosphorous levels in the shared lake.

In November, the Town Board voted to borrow $800,000 to design, purchase and install the eight units. The town will be reimbursed $450,000 by the DEC and $350,000 by the East of Hudson Watershed Corp., Lucas said.

Lucas said the phosphorus removal will take some time but will pay off in the end. Measures such as the jellyfish and installing filters in other areas that keep silt from entering the lake will contribute to the eventual lowering of the phosphorous levels of the lake, or at least containing them.

“I mean, it took it 100 years to get it to the point where it is,” Lucas said, putting the issue in perspective.