Record of Decision System (RODS)
SHEBOYGAN HARBOR & RIVER
|Site Name:||SHEBOYGAN HARBOR & RIVER|
|City & State:||SHEBOYGAN WI 53081|
|NPL Status:||Currently on the Final NPL|
|ROD Type:||Record of Decision|
The Sheboygan Harbor was constructed at the mouth of the Sheboygan River in the early 1920's. In 1954, the lower Sheboygan River, namely the channel upstream of the Eighth Street Bridge, was added as a portion of the Sheboygan Harbor for United States Army Corps of Engineers (USACE) maintenance dredging. Between 1956 and 1969, a total of 404,000 cubic yards of sediment were dredged downstream of the Eighth Street Bridge. The channel above Eighth Street has not been dredged since it was first dredged in 1956.
Prior to 1969, the USACE disposed of the dredged material from the Harbor in an authorized deep-water disposal area in Lake Michigan. However, there has been no dredging within the Sheboygan Harbor since the USEPA and the Wisconsin Department of Natural Resources (WDNR) determined that the sediment was unsuitable for open-water disposal. Sediment sampling done by the USACE in 1979 indicated moderate-to-high levels of lead, zinc, PCBs and chromium and moderate levels of arsenic present in sediment at all locations sampled. The USACE routinely removed lake sand from a sandbar that forms at the outer entrance of the Harbor. The USACE last dredged the Harbor mouth in the fall of 1991.
In June 1979, the USACE collected 11 sediment cores from the Harbor area ranging in depth from 1.5 to 9 feet. The USACE analyzed samples for lead, zinc, copper, chromium, and PCBs. The study revealed greater PCB and metal levels in the sediment of the Inner Harbor than in sediment from the Outer Harbor. In October 1979, the USACE collected a second round of samples consisting of 21 sediment cores. The USACE's analysis of these cores generally indicated an increase in PCB concentrations with the distance upstream from the Harbor and with the depth of the sediment. The Sheboygan River and Harbor are designated an Area of Concern by the International Joint Commission on the Great Lakes due to impairment of the beneficial uses of the waterway.
Examination of 98 sediment profile samples collected by the USACE from the Sheboygan Harbor from December 2 to 6, 1982, indicated the presence of PCBs in the surface sediment of the Harbor. The possibility that this sediment may be classified as regulated material (for PCBs and metals) has contributed to the impasse of implementing an acceptable maintenance dredging effort.
Tecumseh, a manufacturer of refrigeration and air conditioning compressors and gasoline engines, is located adjacent to the Sheboygan River in Sheboygan Falls. Tecumseh is considered a PRP because PCBs were found in sewer lines that lead to the River from Tecumseh and in hydraulic fluids used in Tecumseh Products Company's Diecast Division manufacturing processes. The contamination level is high in the sediments immediately surrounding the Tecumseh Plant, but decreases in concentration downstream. Tecumseh, prior to the issuance of regulations governing PCBs, used PCB-contaminated soils to construct a dike located along the river downstream of the Sheboygan Falls Dam. Tecumseh voluntarily excavated and replaced the dike following the USEPA's issuance of regulations governing PCBs in the late 1970's. Tecumseh undertook cleanup actions, but not before PCBs released into the Sheboygan River.
In 1978, the Wisconsin Department of Natural Resources (WDNR) conducted a survey that found numerous industries that discharge contaminants to the Sheboygan River. A handful had some level of PCB discharge to the river. A number of industries had heavy metals in their discharge. While heavy metals are an environmental concern, PCBs are a more significant problem and any PCB driven cleanup would address the heavy metals in the river.
In 1975 and 1976, the WDNR analyzed several industrial outfalls in the state for PCBs. From the WDNR files and the Thomas Industries response to an USEPA Request for Information in 1985, two outfalls from Thomas Industries, located in the area of concern, contained PCBs when analyzed by WNDR on two different dates. The discharge to the Sheboygan Wastewater Treatment Plant contained 35.0 parts per billion (ppb) PCBs on December 3, 1975 and 1000 ppb on March 25, 1976. An outfall to the Sheboygan River via a storm sewer contained 125 ppb PCBs on June 13, 1976. Another outfall to the Sheboygan River via a storm sewer contained 125 ppb PCBs on June 13, 1975 and 88 ppb on August 19, 1975.
Thomas Industries operated an aluminum die cast shop, which has been in operation at Plant #1 since the late 1950's. The machine shop operations consisted of milling, drilling, boring, and tapping of aluminum, steel, powder metal, cast iron, zinc and brass materials, and finishing and cleaning aluminum parts by acid wash, degreasing, vibratory and spindle finishing.
Kohler Company, located in Kohler, Wisconsin downstream of Sheboygan Falls, was found to have heavy metal discharges to the river above its permit limits in the 1970's. In addition, the Kohler Landfill Superfund site is located on the banks of the river adjacent to Kohler property. The State of Wisconsin is currently overseeing the closure of that facility. There were historic releases of heavy metals and PCBs from the landfill that are currently being addressed through the facility closure plan.
USEPA places the Sheboygan River and Harbor site on the National Priorities List (NPL) in 1986.
In 1989 and 1990, USEPA requested Tecumseh to conduct actions to remove about 5,000 cubic yards of contaminated sediment. This sediment was stored in two containment facilities at Tecumseh's Sheboygan Falls plant. In addition, approximately 1,200 square yards of highly contaminated sediment were capped or "armored" in place to prevent contaminants in the sediment from entering the river. Information developed during these activities is described in a document called an Alternative Specific Remedial Investigation (ASRI) report.
There are five separate sections that have separate selected alternatives, but for the ease of understanding which ones were used, they were all placed under the "Selected Alternative." The five sections include:
Upper River: Alternative 3-IV-A
The remedy for the Upper River removes a minimum of 88 percent of the remaining mass in the soft sediment deposits to achieve a soft sediment deposit Surface Weighted Average Concentration (SWAC) in the Upper River of 0.5 ppm or less. Removing 88 percent of the remaining PCB mass is likely to result in an overall Upper River SWAC of 0.5 ppm, or less, shortly after remediation because the average PCB concentration of 2.5 ppm for the hard sediments is likely overstated as it doesn't account for the actual spatial distribution of soft sediment in the hard sediment area.
The selected remedy for the Upper River is Alternative 3-IV-A, based on the SWAC and mass reduction approach. This approach removes an estimated 20,744 cubic yards of PCB-contaminated sediment containing 88 percent of the Upper River's remaining PCBs. Removal of 88 percent of the remaining PCBs in the Upper River will be required to achieve a PCB soft sediment deposit SWAC 0.5 ppm for the Upper River. Under this alternative, the areas capped/armored during ASRI/removal action activities will be removed, including Area 1. Sediment removal under this alternative requires five access points along the Upper River. Annual fish sampling will occur until fish consumption advisories are lifted. Sediment samples will be taken at least once every five years, after dredging is complete, to document natural processes and to ensure that over time the entire river will reach an average PCB sediment concentration of 0.5 ppm, or less, and that over time fish consumption advisories will be phased out.
Estimated Capital Cost: $30.6 million
Annual O & M Cost: $140,000 or $175,000
Duration of O & M: 30 years
Total Present Value (7% discount rate): $23.8 million
Estimated Time to Implement: 60 months
Middle River: Alternative 2: Characterization and Monitored Natural Processes for the Middle River
Due to the presence of PCB contamination and the dynamic nature of the river, this component of the river will be characterized to establish a baseline for evaluating natural process trends and tracking soft sediment concentrations toward soft sediment SWAC of 0.5 ppm for the Middle River over time. Within the last few years, high flow events may have significantly disturbed and redistributed soft sediment in the Middle River. In addition, contaminated sediment from the Upper River portion of the site may have migrated to the Middle River and with the identification of possible continuing sources near Tecumseh's Sheboygan Falls plant in the spring/summer of 1999, characterization of the Middle River may reveal areas of more highly contaminated sediment. If during baseline characterization PCB concentrations equal to or greater than 26 ppm are found, these soft sediment deposits will be removed as they would significantly impair the overall Middle River soft sediment SWAC from achieving a PCB concentration of 0.5 ppm, or less over time.
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