Cleanup: Industrial Chemicals
Adapted from USEPA, NPL Site Narrative for Onondaga Lake, Federal Register Notice: Dec 16, 1994.
Onondaga Lake was placed on the National Priorities List (NPL) in the mid-1990s. The site is located in the City of Syracuse and in the towns of Salina, Geddes, and Camillus. The Site comprises the Lake itself, its tributaries, and the upland hazardous waste sites that have contributed or are contributing contamination to the Lake (sub-sites).
Sub-sites include Honeywell LCP Bridge Street, Honeywell Semet Residue Ponds, Honeywell Wastebed B/Harbor Brook, Honeywell Willis Avenue, the Town of Salina Landfill, General Motors-former Inland Fisher Guide facility, Ley Creek Deferred Media, the GM-Ley Creek Dredgings, and Geddes Brook/Nine Mile Creek.
Onondaga Lake received surface water discharges from various industrial processes as well as municipal wastewater treatment plants. The industrial facilities —mostly located on the west shore of Onondaga lake and many now owned by Honeywell—manufactured numerous organic and inorganic chemicals. The Willis Avenue plant and LCP's Bridge Street plant, used a mercury cell process to produce chlorine, sodium hydroxide, and potassium hydroxide. Each plant discharged aqueous waste streams containing mercury as part of normal operations.
Other waste sources include the Solvay Waste Beds containing by-products generated from soda ash production and Semet Residue Ponds containing wastes generated from acid washing of light oil.
Several consent orders have been signed between Honeywell and NYSDEC related to the Solvay Waste Beds, the Semet Residue Ponds, and groundwater contamination at the location of the Willis Avenue Plant. In early 1992, Honeywell's predecessor (Allied-Signal) and NYSDEC signed a consent decree to perform a remedial investigation/feasibility study (RI/FS) to determine the type and extent of contamination at Onondaga Lake and to identify alternatives for remedial action.Adapted from NYSDEC. Onondaga Lake Proposed Plan, Executive Summary. Nov 2004.
Honeywell with NYSDEC oversight conducted field and laboratory investigations in 1992, 1993, 1994, 1995, 1999, and 2000. NYSDEC conducted a supplemental lake water investigation in December 2001 and supplemental wetland sampling in May 2002.The following were the key findings of the remedial investigation:
- Mercury contamination is found throughout the lake with the most elevated concentrations detected in sediments in the Ninemile Creek delta and in the sediments and wastes present in the southwestern portion of the lake.
- Much of the contamination in the southwest portion of the lake is in an 84-acre area known as the In-Lake Waste Deposit (ILWD). The ILWD was formed primarily through the deposition of calcium carbonate and other wastes resulting from discharges from Honeywell’s former operations. The volume of the ILWD is estimated to be more than 4 million cubic yards.
- Other contaminants present in Onondaga Lake sediments include benzene, toluene, ethylbenzene, and xylenes (BTEX), chlorinated benzenes, polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and polychlorinated dioxins and furans. These contaminants are primarily found in the southwestern portion of Onondaga Lake, including the ILWD. Elevated concentrations of some contaminants in certain locations in the southwestern portion of Onondaga Lake extend to a depth of at least 25 feet in lake sediments.
- Current and historic sources of contaminants to Onondaga Lake are evaluated in the remedial investigation. For example, ongoing transport of contaminants to the lake via groundwater has been documented for several contaminants, including naphthalene (from the Wastebed B/Harbor Brook site), chlorobenzene and dichlorobenzenes (from the Willis Avenue site), and all four BTEX compounds (from the Willis Avenue, Semet Residue Ponds, and Wastebed B/Harbor Brook sites). It is likely that the plumes of pure phase product that lie beneath some of these sites are a source of contaminants in groundwater, and may also be contributing product directly into the lake.
- Onondaga Lake fish have elevated contaminant levels, and eating these fish would result in potential health risks.
- Contamination in the lake presents risks to all trophic levels of the Onondaga Lake ecosystem.
The results of the remedial investigation were used during the feasibility study in the development and evaluation of possible remedial alternatives for Onondaga Lake. The goals selected for this site are to achieve the following, to the extent practicable:
- Applicable and appropriate sediment effect concentrations for chemical parameters of interest and the bioaccumulation-based sediment quality value for mercury by reducing, containing, or controlling chemical parameters of interest in profundal (deep) and littoral (the lake where water depths range from 0 to 30 feet) sediments.
- Chemical parameters of interest concentrations in fish tissue that are protective of humans and wildlife that consume fish.
- Surface water quality standards associated with chemical parameters of interest.
The proposed remedy (referred to as Alternative 4) would remediate all areas of the lake where the surface sediments exceed the cleanup criteria. These cleanup criteria were developed to address acute risks in Onondaga Lake.
|Sediment Management Units,
Onondaga Lake ROD
SMU 1 - In-Lake Waste Deposit (ILWD)
SMU 2 - Causeway
SMU 3 - Wastebeds 1 through 8
SMU 4 - Mouth of Ninemile Creek
SMU 5 - Northern Shore
SMU 6 - Ley Creek to 700 ft south of Onondaga Creek
SMU 7 - 700 ft South of Onondaga Creek to the ILWD
SMU 8 - Profundal Area
During the feasibility study, Onondaga Lake was separated into eight areas or sediment management units (SMUs) for ease of evaluating alternatives in different portions of the lake. The proposed remedy includes:
- SMUs 1-7, dredging prior to capping to a depth that prevents a loss of lake surface area (ensures that any cap is submerged), minimizes erosive forces on the cap, and optimizes habitat, as well as ensuring cap effectiveness, removal of nonaqueous phase liquids (NAPLs), and reduced concentrations of chemical parameters of interest in select SMUs.
- In SMU 8, phased thin-layer capping, the performance of an oxygenation pilot study followed by full-scale implementation (if supported by the pilot study), and monitored natural recovery.
The proposed remedy is estimated to include the dredging of up to an estimated 2,653,000 cubic yards of sediment from the littoral zone with most of the dredging being performed in SMU-1 (the ILWD) and SMU-2. It would also include the use of isolation capping over an estimated 425 acres of the littoral zone (within SMUs 1 to 7). An estimated 154 acres of the profundal zone in SMU 8 would receive a thin layer cap.
Other highlights of the proposed remedy:
- Optimize habitat areas where dredging/capping would occur.
- Enhance habitat along an estimated 1.5 mi of shoreline (SMU 3) and over approximately 23 acres (SMU 5) to stabilize calcite deposits and oncolites and promote submerged macrophyte growth.
- Segregate the most highly contaminated materials (such as pure-phase chemicals segregated during the dredging/handling process) by treating and/or disposing them at an off-site permitted facility. Place the balance of the dredged sediment in a Sediment Consolidation Area that would be constructed on one of Honeywell’s Solvay wastebeds that historically received process wastes from Honeywell’s former operations.The containment area would include, at a minimum, the installation of a liner, a cap, and a leachate collection and treatment system.
- Treat water generated by the dredging and sediment handling processes to meet NYSDEC discharge limits.
- Continue existing institutional controls on fish consumption, as necessary, and implement other institutional controls (for example, prohibit unauthorized dredging in capped areas) as needed to ensure long-term effectiveness of the remedy.
- Implement a long-term operation, maintenance, and monitoring program to detect the effectiveness of the remedy, ensure that the remedy remains effective, and include any additional action that might be necessary to maintain remedy effectiveness (for example, cap repair).
Remediation of the Onondaga Lake subsite would need to be coordinated with upland remedial activities. The control of contamination migrating to the Lake from the various upland sites (Willis Avenue site, Semet Residue Ponds, Wastebed B/Harbor Brook, LCP/Bridge Street, and Geddes Brook/Ninemile Creek) is an integral part of the overall cleanup of Onondaga Lake. To prevent the recontamination of lake sediments, active sources of contamination to a given portion of the Lake would need to be shut-off before performing cleanup activities in that area of the Lake.
Therefore, the timing of remedial activities in Onondaga Lake would need to be coordinated with the remedial work that would be performed as part of the interim and final remedies at these upland sites.
The remedial construction (dredging and capping) components of this preferred remedy are estimated to take approximately 4 years. This does not include the time it would take to design the remedy which would also take approximately 3 years. Design and construction activities at several of the upland areas would be ongoing while design of the lake remedy was underway.
The estimated present worth cost (2004) to implement the remedy is approximately $451 million. The cost to construct the remedy is estimated to be $414 million, and the estimated average annual operation and maintenance cost is $3 million.