Congressional District # 07
PARSONS CHEMICAL WORKS, INC.EPA ID# MID980476907
Last Updated: January, 2012
The Parsons Chemical site is a six-acre site, located in Oneida Township west of Grand Ledge in northeastern Eaton county. Parsons mixed, manufactured, and packaged agricultural chemicals, including pesticides, herbicides, solvents, and mercury-based compounds from 1945 through 1979. Floor drains discharged into a septic tank and leach field which were ultimately discharged to a creek and then to the Grand River. Between 1979 and 1980, the State of Michigan collected sediment and soil samples from the creek and Grand Ledge ditch. The results revealed the presence of pesticides and elevated levels of heavy metals.
In 1980, ETM Enterprises, Inc. (ETM), a manufacturer of fiberglass parts, purchased the property. ETM conducted a limited study to find sources of the contamination. Following the study, ETM excavated, removed, and disposed of the septic tank and leach field. Through the mid-1980s, several soil sampling events took place, revealing elevated concentrations of mercury, arsenic, and chromium as well as pesticides, including dieldrin, chlordane, and DDT and its breakdown products.
In 1984, the site was included in the National Dioxin Study by the United States Environmental Protection Agency (EPA) who found various dioxins in sediments of the Grand Ledge ditch on plant property and in the sediment in the drainage tiles on and off the site. In 1985, the Michigan Department of Natural Resources fenced the dioxin-contaminated areas. About 11,000 people obtain their drinking water from three Grand Ledge municipal wells or private wells, located within three miles of the site. These wells were found not to be impacted by the site contamination.
Groundwater, surface water, soil, and sediment sampling was conducted by the state during the Remedial Investigation and Feasibility Study (RI/FS) which began in 1993. An RI is a study into the nature and extent of site contamination. An FS is a study of cleanup alternatives for the site. The primary focus of the RI/FS was a hydrogeological investigaion and the assessment of soil not previously investigated. The Baseline Risk Assessment, conducted to determine potential risk from contaminants at the site, determined that two of the inorganics detected were responsible for almost all of the potential human health risks if water from the monitoring wells is consumed. These two chemicals are manganese and zinc. The drinking water wells in the area are installed much deeper in the bedrock aquifer where potable water is available. Private water supply wells sampled during the RI showed no contamination.
This site is being addressed by the MDEQ with funding from the EPA.
Threats and Contaminants
Prior to clean up, sediments and soils contained: dioxin; heavy metals, including mercury, nickel, and arsenic; and pesticides, including DDT, dieldrin, and chlordane, at concentrations exceeding the applicable standards.
The only pesticide detected above standards in groundwater was dieldrin. Inorganic chemicals detected in monitoring wells above cleanup standards, included aluminum, arsenic, iron, lead, manganese, and zinc.
Residential wells have been sampled three times since 1993. No health-based standards for residential drinking water have been exceeded. A few inorganic chemicals were detected in residential wells at concentrations that were considered high enough to warrant monitoring. Manganese has an aesthetic standard of 50 parts per billion (ppb) under state law. This aesthetic standard was exceeded in some residential wells. While it does not pose a health threat, it may have other objectionable qualities such as staining or taste. Arsenic was detected in one well at a concentration close to the standard that was applicable in 1993. That standard has since been increased to 50 ppb which is significantly higher than the concentration detected in the well. Lead was detected in one residential well at a concentration of 3 ppb. The standard for lead in residential wells is 4 ppb.
Beginning in 1990, EPA and the State conducted the first of two non time-critical removal (NTCR) cleanup actions at the Parsons site. The first NTCR addressed 3,000 cubic yards of contaminated soils, identified prior to the RI. An innovative technology known as In-Situ Vitrification (ISV) melted the soil, destroying the pesticides and permanently binding the inorganic chemicals in the glass-like material that formed upon cooling. The NTCR was completed in 1995. An additional quantity of similarly contaminated soil was identified during the first NTCR but could not be addressed at that time due to contractural limitations. It was determined that a second NTCR would address the remaining soil. It was further decided that, if additional contaminated soil was identified during the RI, it would be addressed as part of the second NTCR rather than in the final cleanup action for the site.
The RI/FS was completed in late 1995, and a Proposed Plan, identifying the preferred cleanup alternative for the site, was issued in May 1996. The EPA issued a Record of Decision (ROD) in September 1997, documenting the rationale for the selected cleanup action at the site. The selected remedy includes long-term monitoring of private water supply wells and selected RI monitoring wells to determine whether site contaminants are migrating towards residential wells. The ROD further requires groundwater contaminant trend analysis to predict the likelihood of unacceptable groundwater degradation, and established specific threshold levels for dieldrin and arsenic. Finally, the ROD includes a contingency to connect residences to an alternate water supply (extension of the Grand Ledge municipal water supply system) if trend analysis indicates unacceptable groundwater degradation is occurring or if a threshold level is exceeded and confirmed by a second sample.
The second NTCR was conducted by EPA from late 1998 through the middle of 1999. Approximately 1,200 cubic yards of contaminated soil identified during the ISV project were excavated and removed. In addition, approximately 3,800 cubic yards of arsenic contaminated soil identified during the RI were removed across the highway from the Parsons property. This soil is believed to have been contaminated by site runoff.
The Remedial Design (RD) of the long term monitoring and trend analysis remedy began in September 1998. As part of the RD, a background investigation was performed in April 2000 to determine the concentrations of several inorganic chemicals present hydraulically upgradient of the site. This investigaion was done to determine what inorganic chemicals in groundwater, if any, could be attributed to the former Parsons site or whether they were naturally occuring. Results from this investigation revealed that manganese, aluminum, and zinc are all present at elevated concentrations in site monitoring wells. During the background study, it was discovered that the concentration of arsenic has increased in one off-site monitoring well, exceeding both the drinking water and Michigan's generic groundwater-to-surface interface criteria. No drinking water wells are impacted by this increase in arsenic. These results may be attributable to the activities associated with the second NTCR, since there was a great deal of excavation in the immediate vicinity of the well in question.
Data was evalutated and determined that no additional investigation was needed in the shallow groundwater formation down gradient of the site. The long term residential well monitoring program began in August 2003.
The first five-year review was completed in September 2003 and concluded the remedy was protective of human health and the environment in the short term. All immediate threats at the Site have been addressed. Long term protectiveness of human health and the environment will be verified through continued long term monitoring of the residential wells.
Sampling of monitoring wells at Parsons was conducted in October 2006 and the county health department completed their residential well sampling in July of 2006. These results were transmitted to the EPA in November of 2006 and the results showed no impacts of any contaminants above Safe Drinking Water Act Maximum Contaminant Limits (MCLs). Maximum Contaminant Limits are the highest level of a contaminant permitted in a public water supply well.
Michigan Department of Environmental Quality (MDEQ) is currently operating under a 2002 agreement with the EPA to conduct the cleanup actions at the site. Tasks include annual groundwater monitoring for heavy metals and dieldrin for up to 15 years (2002 through approximately 2017) until contamination is documented below criteria. (Dieldrin sampling is now dropped as no detections above Michigan regulatory standards were found in the 2002 through 2005 sampling events.) Tasks also include groundwater data trend analysis. It is expected that the metals contamination will naturally attenuate over time. The MDEQ will also develop a groundwater restriction for the site and for private wells located downgradient of the site. The trend data analysis will be evaluated during the next five-year review, which is scheduled to be completed by April 14, 2009.
The second five-year review for Site was signed in April 2009. This review found that the remedy at the Site is currently protective of human health and the environment, in the short term. Long-term protectiveness requires compliance with effective ICs. Compliance with effective ICs will be ensured through implementing ICs and through long-term stewardship.
The next five-year review will be due by April 2014.
ContactsRemedial Project Manager, U.S. EPA
lolita hill (email@example.com)
Community Involvement Coordinator, U.S. EPA
PARSONS CHEMICAL WORKS INC