Congressional District # 15
NOVACO INDUSTRIESEPA ID# MID084566900
Last Updated: November, 2012
The 2.6-acre Novaco Industries (Novaco) Superfund site is located at the intersection of Summerfield and Piehl Roads in Temperance, Monroe County, Michigan, which is about 50 miles south of Detroit and about 5 miles north of Toledo, Ohio. The now-dissolved Novaco Industries was a tool and die manufacturing and repair facility. In June 1979, a tank of chromic acid used for Novaco's plating operations developed a leak and an unknown quantity was spilled into the ground. Later that year hexavalent chromium was detected in both the facility's water supply well and in a nearby Veterans of Foreign Wars (VFW) Post well. Within a year of the spill, chromium was detected in a water sample from a residential well located to the west of the VFW building. Approximately 85 residences and businesses are located within one-half mile of the site.
EPA proposed the Novaco site for listing on the Superfund National Priorities List (NPL) in December 1982 and the site was listed on the NPL in September 1983.
Site ResponsibilityThe Novaco Industries Superfund site was addressed through state and federal actions.
Threats and Contaminants
In the 1980s, groundwater samples from the shallow aquifer under and near the Novaco site contained low levels of hexavalent chromium. Chromium contamination was not found in monitoring wells or in residential wells that were screened in (drew their water from) a deeper aquifer. Ingestion of contaminated groundwater was found to be the only potential health risk at the site. Hexavalent chromium is a potential carcinogen (cancer-causing agent).
Testing conducted during the 1990s, however, showed that the level of chromium contamination had dropped below federal drinking water standards and that the site no longer posed a potential health risk.
The contaminated VFW and residential wells were replaced with deeper wells in a limestine aquifer. Meanwhile, in mid-to-late 1979, Novaco Industries undertook a groundwater pump-and-treat remedy to reduce chromium levels in the groundwater due to the spill. About 122,000 gallons of water were reportedly pumped from the old VFW and the Novaco supply wells, treated on site using a chemical reduction process, and then discharged into a ditch along Piehl Road. However, not all chromium contamination was removed. Monitoring conducted by the Michigan Department of Natural Resources (MDNR) and the Monroe County Health Department from 1979-1981 did not show further residential well contamination and the chromium concentrations in the wells that were monitored generally declined during the period. However, hexavalent chromium levels were measured at up to 940,000 micrograms/liter (ug/l) or 940,000 "parts per billion" (ppb) during this time. In contrast, the federal Safe Drinking Water Act maximum contaminant level (MCL) for chromium is 50 ppb.
EPA conducted a remedial investigation at the Novaco site after the site was listed on the NPL and found that hexavalent chromium ("Cr+6") levels in the groundwater were high enough to warrant the selection of a groundwater pump-and-treat remedy in a 1986 Record of Decision (ROD). The selected remedial action consisted of a network of pumping wells to be drilled into the contaminant plume with extracted water to be pumped to a treatment plant that would electrochemically reduce the hexavalent chromium to less-soluble trivalent chromium ("Cr+3"), which could then be filtered out of the treated water stream. The last treatment step would be to run the filtered water through an ion exchange polishing step before discharging the cleaned water into nearby Indian Creek. The groundwater pump-and-treat action was targeted to run for about four years.
However, as sampling was conducted during a pump test during the remedial design phase, chromium levels were found to have dropped sharply. Studies indicated that hexavalent chromium is somewhat unique among metallic solutions, because although it is normally quite soluble in water, Cr+6 can undergo transformation into the less soluble and less toxic Cr+3 if the surrounding soils contain organic matter or forms of iron which can be oxidized by Cr+6 (which is then reduced to Cr+3). These types of reactions may have contributed to the sharp decrease in hexavalent chromium levels in groundwater at the Novaco site. Chromium in the trivalent state (Cr+3) is less soluble and tends to bind to soil particles and does not exhibit the same level of toxicity as hexavalent chromium.
Due to the changed conditions, EPA issued a ROD Amendment in 1991 for the Novaco site that changed the active cleanup remedy selected in 1986 to only groundwater monitoring. The ROD Amendment called for five years of monitoring and stated that if chromium levels were below levels of concern after five years, then "No Further Action" would be warranted.
EPA established the groundwater monitoring network and began sampling for the five-year period in February 1993. During the first year, samples were collected quarterly and all results were below detection levels. After that time, sampling frequency was reduced to semiannually. The final sampling event was conducted in August 1997. From 1988 to 1992, none of the groundwater samples collected had contained chromium at levels above the 50 ppb MCL and, between 1993 and 1997, all samples were "non-detect" for chromium. Therefore, groundwater monitoring was considered complete.
Work to dismantle the groundwater monitoring network in accordance with procedures established by the Michigan Department of Environmental Quality (MDEQ) was completed in December 1997. In 1998, EPA deleted the site from the NPL.
ContactsRemedial Project Manager, U.S. EPA
mary tierney (firstname.lastname@example.org)
Community Involvement Coordinator, U.S. EPA