Congressional District # 05
BAY CITY MIDDLEGROUNDSEPA ID# MID981092935
Last Updated: March, 2012
The Bay City Middleground Landfill site (BCML) is an inactive landfill and dredged sediment disposal area. The site is located on the western portion of Middleground Island, which lies between the Saginaw River east and west channels, in Bay City, Michigan. Hotchkiss (Formerly Cass) Avenue borders the site to the south, Evergreen Drive to the east, City of Bay recreation fields to the north and the Saginaw west channel to the west.
The site is approximately 43 acres in size and includes a mounded landfill (Mounded Area), a capped center refuse consolidation area (located between the Mounded Area and the former Dredge Disposal Area), and a former engineered trench (located between Mounded Area and the capped refuse consolidation area). The former Dredge Disposal Area, located to the north, was created when the U.S. Army Corps of Engineers deposited Saginaw River and Saginaw Bay dredge spoil in the vicinity of the site. The site is fenced along the northern, southern, and eastern sides and partially fenced along the western perimeter. The gates are locked, restricting access to the site. Approximately 58,900 people live within a 4-mile radius of the site.
The site was owned and previously operated by Bay City. The landfill accepted wood, concrete, construction and demolition debris, municipal and household wastes, and industrial wastes. The sediments in some areas of the Saginaw River and Bay have been found to be contaminated with a variety of hazardous substances, including pesticides and polychlorinated biphenyls (PCBs).
The site is being addressed through federal and state actions.
Threats and Contaminants
Hazardous substances from the site have contaminated the groundwater and surface water. Contaminants found at the site at elevated concentrations include solvents, benzene, toluene, ethylbenzene, xylenes, polynucleic aromatics, phthalates, PCBs, pesticides, and heavy metals. Results of the Remedial Investigations (RI) conducted between 1997 and 2002 revealed that PCBs and zinc were present in certain groundwater surface water (GSI) interface monitoring wells, located along the western edge of the site, adjacent to Saginaw River. The RI also revealed that no horizontal migration of volatile organic compounds (VOCs), and semi-volatile organic compounds (SVOCs) or PCBs were observed at the site.
The City of Bay City purchased the site in the early 1950s. The filling began around 1956. According to Michigan Department of Natural Resources (MDNR), during the late 1950s and 1960s, the basic method of operation was to excavate and fill trenches. These trenches were excavated below the water table, then filled with refuse and covered.
A letter from the Michigan Department of Public Health (MDPH) dated 1968 addressed to the Bay City Manager noted that during a site inspection, liquid industrial wastes were being disposed of at the landfill.
Around 1971, the open trench method of disposal was discontinued. Between 1971 and 1974, Bay City placed a 5-foot thick clay cap over the areas where the trench method of refuse disposal was utilized. Following placement of the clay cap, filling operations continued in the southern area of the site.
After 1974, the landfill was operated as an area-type landfill, where refuse was placed within berms, compacted and periodically covered with soil. Eventually, the site was converted to a mounded landfill.
Bay City ceased operation of the landfill during August 1984, after it was ordered to close by MDNR because it did not meet the Michigan Act 641 requirement.
During August 1986, Bay City and MDNR reached a consent agreement that addressed final closure and monitoring of the landfill. In 1987, a clay cap of at least 2 feet thick was constructed over the Mounded Area, and a leachate collection system was installed along the perimeter of the landfill slope.
The MDNR performed a hydrogeological investigation between 1986 and 1987 to evaluate the baseline hydrogeologic information for the site, and to identify shallow and deep groundwater flow areas in addition to characterizing leachate potentially existing in the landfill. The investigation indicated groundwater mounding within the landfill area and a general northerly groundwater flow. The results of the chemical analysis identified several VOCs and inorganic constituents in several groundwater samples and shallow groundwater at the perimeter of the site.
Phase I Initial RI activities were conducted in 1989/1990. A total of 900 gallons of PCB-containing liquid were recovered during the development of one of the recovery wells.
In 1999, completed the Interim Remedial Action (IRA) at Monitoring Area Well 8 (MW-8 Area). The IRA (grouting and sheetpile containment) successfully isolated PCB-containing materials in the MW-8 Area.
An RI was conducted by the PRP Group to identify and delineate contaminants at the site. A Draft RI Report was submitted to the MDEQ in August 1998. Following the receipt of the review comments, additional work was conducted as an Addendum to the Draft RI Report. The RI Report was approved by MDEQ in a August 2000.
Additional investigation activities were developed through discussions between the PRP Group and MDEQ, and were proposed in the Additional Feasibility Study (FS) Investigation Activities Work Plan, dated August 2001. Work plan results indicated that zinc concentrations exceeded the zinc criteria of 1.1 mg/l (unfiltered) and 0.238 mg/l (flitered). Total PCBS were also detected above Criteria.
In May 30, 2003, completed a groundwater funnel and gate system IRA that addressed PCBs in the groundwater at the GSI-7 Area.
In November 2003, gas evaluation was conducted within the mounded area of the landfill. A more detailed mercury vapor analysis was conducted in September 2004. It was concluded that the existing landfill gas venting system was adequate and that mercury was not an issue in landfill gas emissions at the site.
To supplement the Remedial Action Plan (RAP), additional groundwater sampling activities at the GSI were conducted based on discussions between the PRP Group and MDEQ on October 27, 2004. Evaluation of data concluded that the detected concentration of barium, zinc, ammonia, and total dissolved solids (TDS) are above generic GSI values at some wells, but it was anticipated that the mixing zone criteria would be established at the site and that the results would be less than the mixing zone based criteria.
In September 2004, completed a groundwater funnel and gate system IRA that addressed PCBs in the groundwater at the GSI-8 Area.
Sampling events were conducted in 2005, 2006, and 2007 to confirm the groundwater concentrations were in compliance with applicable criteria and to assess ammonia in groundwater at the site. All of the GSI wells sampled during these sampling events exhibited concentrations that were less that the calculated total ammonia value protective of the final acute value (FAV) GSI. Hydraulic conductivity investigation activities were also conducted July 8, 2005 to further evaluate and verify hydraulic conductivity along the western side of the site. The groundwater flow rate discharging from the site to the west channel was estimated to be 20,950 gallons per day (gpd).
The PRPs continued semi-annual sampling events in accordance with the Groundwater Monitoring Plan, dated May 2009 and the Remedial Action Plan.
ContactsRemedial Project Manager, U.S. EPA
nabil fayoumi (firstname.lastname@example.org)
Community Involvement Coordinator, U.S. EPA