Water pollution occurs when harmful substances, often from human activities, contaminate bodies of water such as lakes, rivers, and oceans. These contaminants degrade water quality, negatively impacting their uses and the ecosystems they support. The broad impact of water pollution extends to both environmental health and human well-being, affecting aquatic life and potentially leading to health risks through consumption or contact.
Identifying the Most Polluted Lake
Onondaga Lake, located in Central New York adjacent to Syracuse, has historically been considered one of the most polluted lakes in the United States. This 4.6-square-mile lake has endured over a century of severe contamination. Pollution began as early as the late 1800s, leading to a ban on ice harvesting in 1901, swimming in 1940, and fishing in 1970 due to toxic contamination.
Primary Sources of Contamination
Onondaga Lake’s contamination stems primarily from three sources: industrial discharges, municipal wastewater, and polluted runoff. From 1946 to 1970, Allied Chemical and Dye Corporation discharged approximately 165,000 pounds of mercury into the lake. This industrial waste also included polychlorinated biphenyls (PCBs), pesticides, creosotes, heavy metals like lead and cobalt, polycyclic aromatic hydrocarbons (PAHs), and chlorinated benzenes, which settled into the lake’s sediments.
Municipal wastewater from the Metropolitan Syracuse Wastewater Treatment Plant introduced significant amounts of ammonia and phosphorus into the lake. These nutrients fueled excessive algal blooms and decreased oxygen levels. Additionally, combined sewer overflows (CSOs) during heavy rainfall events released untreated sewage and stormwater directly into the lake’s tributaries, introducing bacteria and other pollutants. Stormwater runoff from the surrounding watershed also contributes pollutants such as sediment, road salt, fertilizers, pesticides, and animal waste.
Ecological and Health Consequences
The extensive pollution of Onondaga Lake has had severe ecological impacts, altering its aquatic ecosystem. High levels of ammonia and phosphorus from sewage led to widespread algal blooms, depleting dissolved oxygen for aquatic life. Industrial contaminants, particularly mercury, have accumulated in the lake’s sediments and bioaccumulated in the food web, resulting in elevated toxic contaminants in fish.
Methylmercury, a highly toxic form of mercury, can cause liver issues, deformities, and gill damage in aquatic wildlife. For humans, consuming contaminated fish poses significant health risks, as methylmercury is a neurotoxin that can lead to neurological disorders and developmental issues, particularly in children and developing fetuses.
Ongoing Restoration Efforts
Significant efforts have been undertaken to restore Onondaga Lake since its designation as a federal Superfund site in 1994. Remediation strategies involve preventing contaminant migration, removing contaminated material, and capping designated areas. Large-scale dredging projects have removed millions of cubic yards of contaminated sediment, followed by capping to isolate remaining pollutants.
Improvements to the Metropolitan Syracuse Wastewater Treatment Plant, including advanced treatment for ammonia and phosphorus, have substantially reduced nutrient loading and improved water clarity. Regulatory bodies like the New York State Department of Environmental Conservation (NYSDEC) and the U.S. Environmental Protection Agency (EPA) oversee these efforts, which also include habitat restoration. Community involvement plays a role in habitat creation and monitoring, contributing to the lake’s ongoing revitalization.