Onondaga Lake Pollution

Onondaga Lake's present condition is the result of more than a century of domestic and industrial pollution.

A History of Pollution

Onondaga Lake is one of the most polluted lakes in the United States. The lake has a number of domestic and industrial pollution problems relating to population growth and industrialization in Syracuse over the last century. See Pollution History and the Pollution History Timeline to learn how Onondaga Lake's pollution problems developed.

Restoration Begins

Efforts to restore the health of Onondaga Lake began in the 1970s with the passage of the Clean Water Act. These efforts continued through the 1980s and 1990s. See Addressing the Problem to learn about historic restoration efforts.

Pollutants of Concern Today

The major sources of pollution in on Onondaga Lake are discussed under Pollutants and Sources. Major pollutants of concern can be divided into two main areas: those related to wastewater collection and treatment and those related to past industrial operations and uses.

Major pollution problems related to wastewater collection and treatment include:

1. High levels of phosphorus in the lake water,

 

2. High levels of ammonia and nitrite,

 

3. Bacterial contamination of the water after storm events.

Major pollution problems related to past industrial operations and uses include:

1. Contamination of the water by mercury and other toxic substances

 

2. High levels of salinity (salt) in the lake water.

Other pollution problems of concern include:

1. Excessive sedimentation, primarily from the Tully Valley Mudboils

 

2. Nonpoint source pollution generated in the lake's watershed.

Dissolved Oxygen

The presence of adequate levels of oxygen dissolved in the lake's water is essential to the health of Onondaga Lake's aquatic life. Oxygen levels are affected by some types of pollution, with severe impacts on fish and other aquatic life. To learn more about oxygen's role in the lake ecosystem, and how oxygen levels are affected by pollution, see The Importance of Oxygen.

The Pollution Problem Today

Despite serious challenges ahead, Onondaga Lake's water quality has improved significantly since the 1970s. Inputs for most pollutants have decreased substantially. To learn more about the current pollution levels, see Pollution Status.