Onondaga's Water Pollution: How Much Remains?

Onondaga Lake, located in Central New York, has a long and painful history of pollution. For over a century, the lake received industrial and municipal sewage discharges, with human waste being dumped into the lake with little to no treatment. This led to high levels of ammonia and phosphorus, causing excessive algae growth and contaminating the water and sediment. While pollution control efforts and cleanup work have improved water quality and reduced toxicity levels, there is still work to be done to address the remaining pollution. The ongoing revitalization of Onondaga Lake is a complex process that involves various investigations, cleanup activities, and the coordination of multiple organizations.

Mercury pollution

Onondaga Lake, located in Central New York, has been a victim of poor waste management for over a century. The lake, which is roughly 4.5 miles long and 1 mile wide, has been severely degraded by industrial and domestic waste.

In 2002, a remedial investigation found that mercury contamination was still present throughout the lake, with the most elevated concentrations in the sediments of the Ninemile Creek delta and the southwestern portion of the lake. Methyl mercury, the form of mercury found in aquatic systems, is considered one of the most poisonous chemicals known. Even though mercury levels have been steadily declining, they are still too high for some groups to safely eat fish from the lake.

The cleanup efforts of Honeywell International, the successor of Allied Chemical, have been successful. Between 2009 and 2016, mercury levels in fish from Onondaga Lake fell by 70%. This has allowed for the revitalization of the lake and the return of fish populations. However, mercury is not the only toxin present, and until all the toxins are removed, the lake's ecosystem will continue to suffer.

Industrial and municipal sewage discharges

Onondaga Lake has been receiving industrial and municipal sewage discharges for over a century. The lake, which is located in Central New York, next to the city of Syracuse, covers 4.6 square miles and has an average depth of 35 feet. The lake's major tributaries are Nine Mile Creek and Onondaga Creek, which together account for about 70% of all the water that flows into the lake each year. The remaining 30% comes from other sources, including the Metropolitan Syracuse Wastewater Treatment Plant ("Metro"), which is the second-largest source of water for the lake.

The industrial and municipal sewage discharges have had a significant impact on the lake's water quality. In the late 1880s, industries began discharging waste, including mercury, salt processing residue, ammonia, organic compounds, and PCBs, into the lake, contaminating the water and sediment. This pollution led to a decline in the fish population, with species such as the American eel, Atlantic Salmon, and Whitefish disappearing. The pollution also limited recreational uses of the lake, as swimming and fishing were banned due to safety concerns.

The Metropolitan Syracuse Wastewater Treatment Plant has been working to reduce the amount of sewage discharge entering the lake. Upgrades to the facility have helped curb the algae-promoting nutrients like phosphorus and ammonia that were previously entering the lake. However, combined sewer overflows (CSOs) continue to release untreated sewage into tributaries that flow into the lake, contributing to pollution and generating concerns about bacteria.

In addition to the sewage discharges, Onondaga Lake also receives industrial discharges from various industries in the area. Honeywell International, Inc.'s predecessor companies, Solvay Process Company, Allied Chemical Corp., and AlliedSignal, Inc., have been identified as major industrial waste contributors. Other sources of contamination include the Metro facility, industrial facilities and landfills along Ley Creek, and the Crucible Materials Corporation. The lake has also been affected by stormwater runoff, which can carry pollutants from the surrounding areas into the lake.

Despite the ongoing challenges, recent cleanup efforts have shown promising results. Onondaga Lake is now the cleanest it has been in over a century, with improving water clarity and increasing plant and animal diversity. More than 65 species of fish have been documented in the lake, and it has once again become a destination for outdoor enthusiasts. These improvements would not have been possible without the dedication of federal, state, and local organizations, residents, and lake users who continue to work towards the revitalization of Onondaga Lake.

Algal blooms

Onondaga Lake, located in Central New York, has long been affected by pollution due to industrialization and urbanization in the region. The lake, which is sacred to the Haudenosaunee Confederacy, comprising the Seneca, Cayuga, Onondaga, Oneida, and Mohawk Nations, has been the subject of various clean-up efforts over the years.

One significant issue impacting the lake's ecosystem is algal blooms. These blooms occur due to high levels of ammonia and phosphates in the water, resulting from the dumping of sewage wastewater by the city of Syracuse. The excessive algae growth has far-reaching consequences. When the algae die, they are decomposed by bacteria, which consume large amounts of oxygen, leading to eutrophic and low-oxygen conditions in the lake. This oxygen depletion, or hypoxia, has detrimental effects on aquatic life, particularly cold-water fish that depend on well-oxygenated water to survive.

The presence of algal blooms in Onondaga Lake has been a persistent problem. In July 2024, harmful algal blooms were discovered in two popular Onondaga County beaches, Jamesville Beach and Gillie Lake. In response, the county's health department closed the beaches to swimming until the water was visually free of algae and water sampling confirmed the absence of toxins. This incident highlights the ongoing challenges posed by algal blooms in the lake, even with recent upgrades at Syracuse's main sewage facility, which have helped curb the influx of algae-promoting nutrients.

The impact of algal blooms extends beyond the immediate closure of recreational areas. The excessive algae growth and subsequent oxygen depletion have far-reaching ecological consequences. They inhibit plant and fish life, disrupting the delicate balance of the lake's ecosystem. This, in turn, affects the species that depend on these aquatic plants and fish for food and habitat. Furthermore, the toxins associated with algal blooms pose risks to humans, plants, and animals in and around the lake. These toxins, which include chemicals and chemical byproducts, can be dangerous to anyone who comes into contact with or consumes the water.

While the recent upgrades at the sewage facility have helped reduce the nutrients that contribute to algal blooms, combined sewer overflows (CSOs) continue to be a source of pollution. During heavy rain or melting snow, the sewers overflow, discharging a combination of runoff and sanitary sewage into tributaries that flow into Onondaga Lake. This untreated sewage contains high levels of phosphorus and ammonia, providing a continuous supply of nutrients that fuel the growth of algae. As a result, the problem of algal blooms in Onondaga Lake persists, despite the improvements in water quality and the resurgence of fish populations observed in recent years.

Sedimentation

Onondaga Lake, located in Central New York, has suffered from severe pollution due to industrial waste and sewage discharge. The lake, which is approximately 4.5 miles long and 1 mile wide, has been a site of environmental concern for decades. One of the major issues contributing to the lake's degradation is sedimentation.

The high levels of contamination in the sediments have far-reaching consequences for the lake's ecosystem. These toxins impact not only the water quality but also the plants, animals, and humans in and around the lake. The sediments at the bottom of the lake and its tributaries, such as Ley Creek, have been identified as requiring urgent remediation.

Efforts to address the sedimentation issue in Onondaga Lake have been ongoing. Between 2012 and 2014, approximately 2.2 million cubic yards of contaminated sediment were removed from the lake bottom and shoreline areas through dredging operations. This was followed by a capping process that utilized sand, activated carbon, siderite, and stone to cover 580 acres of the lake bed. The habitat restoration phase was completed in 2017, and the EPA has continued to monitor and review the site's progress.

The ongoing cleanup efforts at Onondaga Lake, including the remediation of contaminated sediments, have shown significant improvements. The lake is now the cleanest it has been in over a century, and plant and animal diversity is on the rise. However, there is still work to be done to address the legacy of pollution and restore the lake to its former glory.

Clean-up efforts

The Clean Water Act of 1973 was passed in a bid to improve the water quality of Onondaga Lake. However, it was not until several initiatives, including a 15-year multi-stage program completed in late 2017, that the lake finally reached the criteria required by the New York State Department of Environmental Conservation and the United States Environmental Protection Agency (EPA).

The EPA has identified 11 subsites of the Onondaga Lake site that require attention, including the lake bottom, GM-IFG, LCP Bridge Street, and Ley Creek PCB Dredgings. The New York State Department of Environmental Conservation is leading the investigation and selection of clean-up plans for all subsites except for Lower Ley Creek and the creek sediment and floodplain soil portion of the GM-IFG subsite.

In May 2024, the EPA approved the final design for addressing the contaminated floodplain soils and sediments at the Ley Creek Deferred Media portion of the GM-IFG subsite. The EPA provided $23 million in federal funding to begin the clean-up, with an additional $7 million coming from an Onondaga Lake site-related bankruptcy settlement. Construction is expected to start in spring 2025 and will take three to four years to complete.

Controlling the contamination migrating to Onondaga Lake from the various upland sites is an essential part of the overall cleanup of the lake. The Clean Water Act forced Metro, the Metropolitan Syracuse Wastewater Treatment Plant, to clear floating debris and eliminate harmful bacteria caused by sewage. They were also mandated to increase treatment to reduce ammonia and phosphorus deposits into the lake, which were then further oxidized and removed by 2005.

Upgrades at Syracuse's main sewage facility have helped curb the flow of algae-promoting nutrients like phosphorus and ammonia into the lake. However, these nutrients still enter the ecosystem from combined sewer overflows (CSOs) that discharge untreated sewage into tributaries that flow into the lake.

The Onondaga Nation has been instrumental in the clean-up efforts, invoking the legal system to reclaim stolen land rights with the express aim of restoring the land. In 2024, 1000 acres of land were returned to their stewardship, marking a significant milestone in the Onondaga Lake clean-up.

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