EPA in Illinois

Wedron Groundwater Site in Wedron, Illinois

Cleanup Status - Nov. 2016

Site Status Change - The Wedron site is being switched between EPA programs. It has been determined the major source of pollution is leakage from petroleum underground storage tanks. Under existing regulations, the Superfund Petroleum Exclusion applies and EPA Superfund can no longer expend additional resources at the site. The Superfund Petroleum Exclusion requires Superfund to defer to the EPA Resource Conservation and Recovery Act (RCRA) Underground Storage Tank program to address petroleum releases. Corrective action activities going forward will be handled under EPA’s RCRA Underground Storage Tank program.

Private Well Sampling – During the summer of 2016, three private wells were identified as having BTEX contamination. BTEX stands for petroleum-derived pollutants named benzene, toluene, ethylbenzene and xylene. One of the wells previously had detections, one of the wells was previously nondetect, and one of the wells was sampled for the first time. IEPA is suppling bottled water to one home that exceeded maximum contaminant levels (MCLs), and to another home below MCLs that had children present. Illinois EPA is leading the effort to get the homes being supplied with bottled water and a third home using carbon filtration, connected to a nearby deep replacement well that was installed by US EPA as part of the EPA Superfund removal action.

A recent private water well sampling event (21 wells total) took place in Wedron on Sept. 27. The LaSalle County Health Department assisted Illinois EPA in collecting the water samples, and Illinois EPA’s laboratory analyzed the samples. The Illinois Department of Public Health will interpret the results and prepare a letter for each property owner and/or occupant household to explain their specific results.

Wedron Monitoring Well Sampling - In October 2016, Illinois EPA sampled six monitoring wells in and around Wedron and one deep well installed by EPA to identify if contamination has reached these locations. The Illinois EPA laboratory analyzed the groundwater samples. The results were nondetect for all wells. “Groundwater” is an environmental term for underground supplies of fresh water.

Investigation report status – Final reports for groundwater and soil investigations by BP, Illinois Railway, Lockheed Martin, Technisand and Wedron Silica Co. have been completed and are available under Key Technical Documents. These investigations were completed as agreed through Administrative Orders on Consent (AOCs) with the companies. Since the investigations required under the AOCs have been completed, EPA is evaluating the AOCs for termination.

LUST Investigation – Illinois Railway submitted a revised Site Investigation Completion Report to Illinois EPA’s Leaking Underground Storage Tank Program in August 2016 for investigations of former UST areas on Illinois Railway property. Illinois EPA is currently reviewing the report.

Air monitoring – Wedron Silica completed a year-long ambient air monitoring study with U.S. EPA oversight. Data were compiled to estimate the annual average concentration of crystalline silica in the ambient air at both monitoring locations – one about three miles south of the Wedron Silica facility (South Monitor) and one directly north of the facility, near Wedron Silica’s main office (North Monitor). Because there is no regulatory standard for crystalline silica concentration in ambient air, the results were compared against a health-based criteria value of 3.0 µg/m³ (3.0 micrograms of crystalline silica per cubic meter of air). This value, as a long-term average, is the level at which several state and local health and environmental agencies have determined that long-term exposure (on the order of years) at or above could potentially cause adverse health effects.

At the North Monitor, the average crystalline silica concentration, which is the arithmetic mean of all samples collected over the duration of the study, was 1.45 µg/m³. Approximately 37 percent of samples had crystalline silica concentrations below the level that the laboratory method is capable of detecting and measuring, which is 0.3 µg/m³. These “nondetects” were assigned a value of 50 percent of the detection level (0.15 µg/m³) for the purposes of calculating the long-term average.

At the South Monitor, around 85 percent of the samples collected showed crystalline silica concentrations below the detection level. The remaining detectable-level samples were all at or below 0.69 µg/m³.

The data files are available under Air Monitoring Data.

Next steps – In July 2016, Illinois EPA hired a contractor to perform a pumping test of the lower aquifer in Wedron to better understand hydraulic properties of that underground water body. The pumping test results will help identify whether the uncontaminated lower aquifer will support additional new private wells and whether it is isolated from the upper aquifer. With this information in hand, Illinois EPA and EPA will work to identify remediation technologies and cleanup options. A report on the pump test results was received by IEPA on Oct. 7, 2016, and is currently under review.

Fact Sheet: Water Monitoring Reveals More Well Contamination (Nov. 2016)

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Site Description

In April 1982, several complaints of gasoline-type odors in Wedron residents’ private well water were received at the Illinois Department of Public Health. A groundwater investigation was started by the Illinois EPA. In 2009, benzene was detected in two private wells in Wedron (town of ~47 homes) at concentrations above the MCL of 5 ppb. In 2011, IEPA and IDPH sampled private wells in Wedron and found wells contaminated with BTEX constituents. The benzene detected in private wells exceeded the MCL, with levels as high as 2,800 ppb. Samples collected confirmed the presence of chemicals found in gasoline. IEPA referred the site to EPA in 2011. In 2014, EPA installed eight replacement drinking water wells pursuant to a CERCLA removal action. The wells were drilled into a lower uncontaminated aquifer (New Richmond Aquifer).

Additionally, investigations of several possible sources of pollution beyond a former gas station were completed. No additional major sources were found. The major source of pollution seems to be leakage from petroleum underground storage tanks. Therefore, the Superfund Petroleum Exclusion applies, and Superfund can no longer expend additional resources at the site. The Superfund Petroleum Exclusion requires Superfund to defer to the Resource Conservation and Recovery Act (RCRA) Underground Storage Tank program to address petroleum releases. Corrective action activities going forward, will be addressed under the RCRA Underground Storage Tank program.

In 2009, benzene was detected in two private wells in Wedron (town of 47 homes) at concentrations above the MCL of 5 ppb. In 2011, IEPA and IDPH sampled private wells in Wedron and found wells contaminated with BTEX constituents. The benzene detected in private wells exceeded the MCL, with levels as high as 2,800 ppb. IEPA referred the site to EPA in 2011. In 2014, EPA installed eight replacement drinking water wells pursuant to a CERCLA removal action. The wells were drilled into a lower uncontaminated aquifer (New Richmond Aquifer).

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