Written by Carol Frank Thursday, 04 April 2013 00:00
Decisions affecting the sustainability of our water supply will be made in the coming months and it is a time for the public and community leaders to better understand the issues at hand to insure that the big picture is in clear focus and our water supply is protected.
It has been over a decade since the issue of the plume of contamination flowing from the old defense plant, Unisys Corporation, in Lake Success was on the public radar. In 2002, Lockheed Martin, the responsible party, and the New York State Department of Conservation sought public support to “fast track” the clean-up of the plume which was traveling quietly, but steadily in the underground aquifer in a north, northwesterly direction with a leading edge that was directly under the Great Neck South School complex at a depth of approximately 400 feet.
The contamination, mostly volatile organic compounds, is a hodgepodge of multi-syllabic chemicals, trihloraethene, tetrachloroethene, 1,2-dichloroethene and Freon 113, all of which must be removed before water can be safe to drink.
The parties were seeking permission from the school district to install an extraction well at the school’s maintenance facility which would take water from the aquifer and pipe it to another nearby site to clean the water and to re-inject the cleaned water back into the aquifer. After a number of community meetings to fully explain the procedures and safeguards to the public, permission was granted by the school district.
This was considered an interim solution to the problem and in 2004 this system for cleanup was constructed and went into operation.
The leading edge of contamination has now traveled north of the Long Island Expressway, but south of Northern Boulevard and covers an area of approximately 900 acres according to Gary Cambre, spokesperson for Lockheed Martin. Plumes of contamination in an aquifer typically move about one foot a day.
As a part of a more permanent solution, Lockheed’s engineers have proposed various approaches for cleanup to the DEC and a public hearing on the matter will be held, probably in April. The agency will make the final decision about which option is the most feasible.
At a recent Village Officials Association meeting, Gregory Graziano, superintendent of the Water Authority of Great Neck North, spoke about the authority’s concerns about various approaches proposed. In a nutshell, he believes that some of the proposals to remediate the plume from Unisys may inadvertently and unintentionally increase the rate of saltwater intrusion into wells on the peninsula.
His arguments were bolstered by Bill Merklin, vice president of Dvirka and Bartilucci, an engineering firm, who explained the science of salt water intrusion. Ground water pumping can reduce freshwater flow toward coastal discharge areas and cause saltwater to be drawn toward the freshwater zones of the aquifer. Saltwater intrusion decreases freshwater storage in the aquifers, and, in extreme cases, can result in the abandonment of supply wells. Wells toward the northern tip of the peninsula have already succumbed to salt water intrusion and are not part of Great Neck’s water supply. The authority takes pains to regulate pumping patterns to avoid disrupting the aquifer flow that pushes outward toward the bays and the Sound by rotating well usage and using some just in the summertime when demand rises. But in spite of these efforts, the authority is seeing a trend toward higher salt levels in certain wells.
The authority installed wells off the peninsula on Community Drive as a fail-safe measure for safe drinking water in 1999. Those wells are already impacted by the moving plume and it was discovered after they began pumping during their start-up phase that salt water levels were suddenly increasing in a well to the north. Engineer Merklin said, “It’s not often that data is so clear ... it became very clear that the pumping was drawing salt water toward Community Drive.”
Addressing a question about salt water intrusion, Lockheed Martin spokesperson Cambre wrote the following emailed answer: “The NYSDEC did not identify the salt water intrusion potential as an item requiring evaluation in the feasibility study; however, in response to a water authority request, Lockheed Martin’s consultants did evaluate the potential for increased salt water intrusion under the Lockheed Martin recommended remedy and found that the potential for increasing salt water intrusion would be insignificant. This evaluation did not address any saltwater intrusion that may already be occurring as a part of normal water supply pumping, but it did show that additional pumping for the purpose of groundwater remediation will not change current conditions.”
State Senator Jack Martins suggested that Great Neck leaders and water purveyors should have a unified approach and solution to put forth to the DEC and Lockheed Martin regarding this important issue.
Many other plumes are being investigated and followed in Great Neck. On Great Neck Road a plume is coming from an Amoco station and Mayflower Cleaners. There are several plumes on Steamboat Road, one from ExxonMobil, another from Friendly Taxi, one from Pristine Cleaners and another from Doray. Stanton Cleaners on Cuttermill Road has a pump and treat facility onsite and was an EPA superfund site.
According to Graziano, it could be worse. He said: “We are lucky that we do not have big problems with pesticides and nitrate pollution in the groundwater as elsewhere in Nassau County.”
And he added that residents should understand that all of the water that comes through their taps is safe, exceeding New York State standards for drinking water and has been tested and cleaned if necessary. Graziano concluded, “We have made a commitment to guard our water supply, not just for now, but for the future.”
As Senator Martins said, “The aquifer here in Great Neck is made more fragile because it is surrounded by salt water ...”