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Mercury contamination in Lake Onondaga – Part 3

Posted by Betsey Seibel on Apr 1, 2015 11:20:00 AM

The Resurgence of Onodaga Lake - Part 2

BlueReservoir_3950130lowresThis is part three of the Onondaga Lake story. In part two, we outlined what happened once rescue efforts started in the 1970s with new laws and standards that helped to drive change in and around the lake. In this post, we want to focus on what happened after Onondaga Lake was declared a Superfund site in December 1994, and after the signing of an historic agreement in 1998 among the county and various government entities that helped reduce phosphorus and ammonium discharges from the city’s waste treatment plant. It was shortly after this agreement that the water quality started to improve, giving the community a reason for optimism.

Despite the improving water quality, much needed to be done to clean up Onondaga Lake and give it back to the community as a true recreational resource. When it was declared a Superfund site, 12 areas in and around the lake were identified for cleanup. Each of these locations had a remediation strategy. In 2005, New York State Department of Environmental Conservation (DEC) and the U.S. Environmental Protection Agency issued the Onondaga Lake Cleanup Plan, and in December 2006, Honeywell, owner of the industrial sites around the lake, entered a Consent Decree with the DEC to implement the remediation plan.

Part of the plan included the dredging of an estimated 2.65 million cubic yards of sediment from the lake bottom in water 0-30 feet and using an isolation capping over 425 acres of the area. In water greater than 30 feet in depth, a thin layer cap would be installed over an estimated 154 acres.

According to the DEC website:

“The most highly contaminated materials will be treated and/or disposed at an off-site permitted landfill. The balance of the dredged sediment will be placed in one or more Sediment Consolidation Areas (SCA) constructed on one of Honeywell's Solvay wastebeds, which historically received process wastes from Honeywell's former operations."

“The estimated cost to implement the remedy is approximately $451 million.[i] Additional projects around the lake bring the cost of the cleanup to nearly $1 billion.

On July 31, 2012, Honeywell began dredging and capping the lake of contaminated sediments.  In November 2014, the dredging was complete; one year ahead of schedule. The completion marked a major milestone in the overall restoration project with additional habitat and capping projects running through the end of 2016.

Since the cleanup efforts began, the lake has experienced significant improvements, including:

  • Phosphorus discharges to Onondaga Lake from the sewage treatment plant reduced by approximately 86% between 1993 and 2009. Phosphorus levels in the upper waters are in the best condition in over 100 years.
  • Chloride concentrations have decreased from 1800 milligrams per liter in 1985 to 450 milligrams per liter in 2009.
  • Methylmercury levels in the water have decreased 95 percent while mercury levels in small mouth bass have decreased from 2.5 ppm to 1.0 ppm.
  • Planted 1.1 million plants, shrubs and trees, helping to restore 37 acres of wetlands by September 2014.
  • Since 2000 aquatic plant coverage in Onondaga Lake has increased from 85 to 387 acres.
  • More than 110 species of fish, birds and mammals have returned to the wetland and nearby areas, including 56 documented fish species and bald eagles.
  • In 2008, the North American Fishing Club named Onondaga Lake one of the top 10 bass fishing destinations in the United States.

Onondaga Lake, once considered the most polluted lake in America, is on its way back to becoming the proud centerpiece of the community. Despite all of the abuse it has absorbed for more than a century, Onondaga Lake is a symbol of resiliency and an example of what can be accomplished when science and technology work together with nature. 

Teledyne Leeman Labs and their sister company Teledyne Tekmar's analytical instruments are used to test water for mercury and Volatile Organic Compounds (VOCs). For more information on these instruments, be sure to visit the products pages

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