Environmental Investigations of Onondaga Lake

Onondaga Lake Barge Drill Rig
There have been numerous investigations done on Onondaga Lake and within the surrounding watershed of the lake. These investigations have resulted in the United States Environmental Protecting Agency (US EPA) proposing the lake for listing on the NPL list (NPL). The NPL is defined as the EPA's list of the most serious uncontrolled or abandoned hazardous waste sites in the United States. The NPL is updated on a regular basis. Since Onondaga Lake was proposed for listing on the NPL, the EPA and the New York State Department of Environmental Conservation have entered into a cooperative agreement to produce a comprehensive investigation, including a site wide risk assessment, of the site. The results of this investigation are summarized in the following paragraphs.

The investigation has determined that the site is contaminated with many chemicals. These chemicals include; mercury, petroleum hydrocarbons (fuel products), chlorinated solvents and polychlorinated biphenyls (PCB's). The potential sources of some of the contaminants include; the former 'Oil City'-petroleum storage facilities that were located along Onondaga creek, several former Allied Chemical facilities (now Honeywell), the Semet tar beds (an Allied Chemical waste facility) that are along the lake's southwest-shore, Ninemile Creek (and associated waste beds located along its shores), and METRO (the Metropolitan Wastewater Treatment Plant, Onondaga County). In addition, historically large discharges of sediment from Onondaga Creek are associated with geologically unusual 'mud boils' which occur in the upper watershed of the creek (in the southern Tully valley). These mud boils have been the center of research by the  U.S. Geological Survey (USGS).

By reviewing the data collected the lake has been determined a public health hazard. The NYS Department of Health (DOH) issued an advisory recommending that no fish be eaten from Onondaga Lake. This is because fish from the site are contaminated with mercury and PCB's which have a high risk of adverse health effects. It has also been determined that fecal bacteria contamination of the lake still continues to be a problem. The presence of fecal bacteria is an indicator of the presence of other microorganisms that may be disease causing. Fecal contamination poses a potential health hazard to recreational users, especially swimmers. Since swimming in the lake has been prohibited since 1940, this contact is currently limited. However, some people do still swim in the lake. Since recreational activities at the lake are the primary route of exposure to site-related contaminants, it is difficult to estimate the total number of people exposed. However, it was estimated that 216,682 people are potentially exposed to site-related contaminants. This estimate was based on totaling the entire populations of the towns of Salina and Geddes, and the City of Syracuse, which border Onondaga Lake to the south and west (based on the 1990 census).

Several remedial investigations (& feasibility studies; RI/FS) have been completed to date in and around Onondaga Lake as part of the Onondaga Lake cleanup.  That work has lead to the NYSDEC in finalizing a cleanup plan for Onondaga Lake.  The decision to agree to this plan is referred to as a 'record of decision' (ROD) and was agreed to in 2005. The elements of the plan include dregging a portion of the lake bottom, 'capping' part of the lake bottom with sediment, and building a barrier wall along the southwest shore of the lake.  However, significant amounts of contaminants (including mercury) are proposed to be left on lake bottom with the completion of the cleanup plan (a more complete listing of the work to be completed can be found at this  NYSDEC website).  A summary of recent work on the lake cleanup is available through the Atlantic States Legal Foundation.  Further information on the status of the lake can be found at the Onondaga Lake Partnership, the NYS Department of Environmental Conservation (for Onondaga Lake), and at the U.S. Environmental Protection Agency for the site.

Solvay Waste Beds

waste beds 3
Primarily CaCl waste eroding along the western shore of Onondaga Lake, produce strongly alkaline conditions locally

Waste Bed Berm
CaCl waste located on the waste bed hills between Onondaga Lake & the State Fair grounds 

Waste Bed Piles
Eroded waste beds along the western shore of Onondaga Lake, note: the wooden piles marking the location of former support walls for the waste beds 

Onondaga Lake Superfund Sites

Onondaga Lake Superfund
Locations of NPL listed sites in the watershed of Onondaga Lake (click to launch larger image in new window) 

Tully Mud Boils

Mudboil 1
Located in the southern watershed of Onondaga Creek, mudboils produce large quantities of sediment which decrease the clarity of Onondaga Creek 

Mudboil 2
Recent photo of the mud boils 

Note: we appreciate the use of three of the above images; of the drilling barge on Onondaga Lake, of the mapping of NPL sites around the lake, and of the Tully mudboil (b/w) from the Onondaga Lake Partnership and the U.S.Geological Survey, respectively.


For more on the environmental cleanup of Onondaga Lake, consider taking a course in the ETG program at Onondaga Community College. Review some of the courses available at

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