Pollution History

Pollution History Timeline

Serious pollution problems in Onondaga Lake developed primarily as a result of sewage disposal and industrial discharges related to population growth and industrialization.

Population Growth and Industrialization Lead to Pollution

Solvay Process Company Facility and Erie Canal, early 1900s.

As Syracuse grew in the late 19th and the early 20th centuries, the lake's western shore became increasingly industrialized. Sewage disposal and industrial discharges into the lake also increased during this period, and as a result, the quality of the water began to suffer. Eventually, people stopped visiting Onondaga Lake for swimming and fishing, primarily because of the lake's degraded water quality. Over time, all of the lake's resorts and beaches closed. By World War II, the lake was mainly being used for the disposal of industrial and domestic wastes.

Sewage Disposal

Metro plant

Municipal wastewater (sewage) has been a major source of pollution to Onondaga Lake. Pollution problems associated with sewage include excessive levels of phosphorus, ammonia and nitrite, and bacteria and other harmful microorganisms in the Lake's water, as well as increased turbidity and reduced oxygen availability. For years, Syracuse dumped its sewage directly into the lake with little or no treatment. Steps were taken beginning in 1907 with the creation of the Syracuse Interceptor Sewer Board to address sewage related problems in Onondaga Creek and Harbor Brook. In 1960, Onondaga County established a sewer district and built Metro on the south shore of the lake. The County improved sewage treatment at Metro in 1979, and upgraded again in 1981. As a result, the water quality of Onondaga Lake has improved, but does not yet meet water quality standards.

Soda Ash Production

In 1884, the Solvay Process Company began production of soda ash on the Lakefront and nearby properties. Approximately 6 million pounds of salty wastes, made up of chloride, sodium, and calcium were discharged daily to Onondaga Lake from the Solvay Process soda ash facility before it closed. The discharge of salt and other wastes associated with the production of soda ash has had far-reaching impacts on Onondaga Lake and the adjoining Seneca River system. The lake's elevated salinity reduced the diversity of its aquatic life, and reduced dissolved oxygen levels. High concentrations of calcium discharged to the lake from soda ash production increased the calcium carbonate formation rate, resulting in excessive lake bottom accumulations. Allied Corporation (a successor to Solvay Process Company) closed the soda ash production facility in 1986; however, salty wastes are still entering Onondaga Lake from the Solvay waste beds located along Nine Mile Creek.

Chlorine Production and Mercury

In 1946, Allied Chemical and Dye Corporation (a successor to Solvay Process Company) began production of chlorine by the mercury cell process. As a result, mercury wastes were discharged directly into Onondaga Lake. The Allied facility discharged an estimated 165,000 pounds of mercury to Onondaga Lake between 1946 and 1970. Mercury loading was greatly reduced after 1970, and the Allied chlor-alkali plant was closed in 1977. However, scientists estimate that 7 million cubic yards of lake sediments remain contaminated with mercury, and mercury remains the contaminant of primary concern, because of its persistence in fish found in the lake.

Other Industrial Pollutants

In addition to soda ash and chlorine production, other industrial activities located on or near Onondaga Lake have contributed to a variety of industrial contaminants affecting the lake, including PCBs (polychlorinated biphenyls) and chlorinated benzene.

Tully Valley Mudboils and Sedimentation

Onondaga Lake suffers from excessive sedimentation, which is the settling of materials on the bottom of the lake. Some of this material comes from the Tully Valley mudboils located about 15 miles upstream from the mouth of Onondaga Creek. Mudboils are holes in the earth that discharge mud and soft sediments from underground. They are associated with groundwater flow under pressure. The occurrence of the mud boils have been attributed to AlliedSignal's (Honeywell) solution mining activities in the Tully Valley, although there is some disagreement over this contention.

Swimming and Fishing Bans

Pollution of the lake from municipal as well as industrial sources led to reduced use of the lake for recreation. By 1940, the lake was declared unsafe for swimming and by the 1970s, fishing was banned on the Lake.

1970s: Onondaga Lake Restoration Begins

The 1970s marked the beginning of the restoration of Onondaga Lake. Enactment and enforcement of various environmental laws including the Federal Clean Water Act in 1972 and the Resource Conservation and Recovery Act of 1976 and state and federal Superfund regulations, have brought about improvements in the lake. Scientific studies have been conducted relating to the impact of industrial wastes, combined sewer overflows and treated sewage wastes discharged to the lake. To learn more about the history of the lake restoration effort, see Addressing the Problem.

Onondaga Lake Today

A variety of cleanup efforts are underway today, and important progress has been made. Onondaga Lake water quality has improved significantly since the 1970s. Catch and release fishing was reinstated in 1986. To learn more about the Lake's current status see Pollution Status. To learn more about the cleanup efforts, see Cleaning Up Onondaga Lake.