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Mercury in Onondaga Lake

- Background
- What is Mercury
- Mercury and Onondaga Lake
- Remediation Approaches
- References

Background of Onondaga Lake

Syracuse and Onondaga Lake Facts:

Onondaga Lake's dimensions are 4.6 miles in length by 1 mile in width, with an average depth of 35 feet. The maximum depth of the lake is 63 feet.

The major natural tributaries of Onondaga Lake are Nine Mile Creek and Onondaga Creek, which, when combined, account for approximately 70 percent of the water that flows into the lake each year. The Metropolitan Syracuse Sewage Treatment Plant, METRO, contributes about for 20 percent of the annual inflow. Ley Creek, Bloody Brook Harbor Brook, Sawmill Creek, Tributary 5A, and the East Flume contribute the other 10 percent of inflow. The lake only has one single outlet, which drains into the Seneca River.

On average, Syracuse receives more snow than any other large city in the United States. The city of Syracuse faces mild summers and cold winters. Onondaga Lake's temperatures reflect Syracuse's seasonal patterns, typically with highest temperatures in the month of July and lowest temperatures in January. The lake is ice-covered for the winter to spring period.

Original Use of Onondaga Lake:

Before the settlement of Europeans and the American Revolution, the Iroquois Confederacy was centrally located in the hills around Onondaga Lake. For the Iroquois and Onondaga Indians, Onondaga Lake was a very important waterway and cultural symbol. In the late 17th century, the Onondaga Indians introduced the French to salt springs on the shores of the lake. This led to commercial salt production on the lakeshore in 1793. The salt production attracted settlers to the Syracuse area, including mostly European settlers, Jesuit missionaries and French explorers. The lake offered salt, transportation, and other amenities to its settlers. The increase of population and industry caused an increase of pollution in the 19th and 20th centuries.

Pollution of Onondaga Lake:

With the Industrial Revolution, came pollution for Onondaga Lake. As the surrounding areas of the lake became populated, sewage was increasingly directly discharged into Onondaga Lake. This caused an excess amount of nutrients (phosphorus, nitrate and ammonia), bacteria and other harmful contaminants. Excess nutrients increase the production of algal growth, which depletes the amount of dissolved oxygen in the lake during the summer and fall. Fish depend on dissolved oxygen; therefore the fishery of the lake is negatively affected by this pollution.

The Solvay Process Company began to produce soda ash on the shores of Onondaga Lake in 1884. Throughout their production, the Solvay Company released 6 million pounds of salty wastes into Onondaga Lake. This waste was made up of chloride, sodium, and calcium. The lake's diversity of aquatic life and the amount of dissolved oxygen decreased due to the increase of salinity of the lake.

In 1921, the Allied Chemical and Dye Corporation, now the Honeywell Corporation, absorbed the Solvay Process Company. The Allied Company produced chlorine by a process, the chloralkali process, which utilized mercury cells. From 1946 to 1970, Allied discharged an estimated 165,000 pounds of mercury into Onondaga Lake. This mercury, along with the other pollutants, is still an existing problem for the lake.


Syracuse University
Department of Civil and Environmental Engineering

151 Link Hall
Syracuse, NY 13244
(315) 443-3434 (phone)
(315) 443-1243 (fax)