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EPA in Illinois

Wedron Groundwater Site in Wedron, Illinois

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Cleanup Status - Nov. 2016

Site Status Change -  The Wedron site has been 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 from underground storage tank systems. Corrective action activities going forward will be handled under EPA’s RCRA Underground Storage Tank program.

Private Well Sampling –During this summer, IEPA identified six homes connected to two separate deeper replacement wells (installed into the New Richmond aquifer in 1984) and two homes drawing water from the upper (shallow) aquifer as having benzene, toluene, ethylbenzene and xylene (BTEX) contamination. During July 2017, IEPA installed carbon filtration units in these eight homes to address the BTEX contamination. Recent sampling results indicate the carbon filtration systems are working properly. Groundwater is an environmental term for underground sources of fresh water. BTEX stands for petroleum-derived pollutants named benzene, toluene, ethylbenzene and xylene. The four contaminants often are found together.

During October 2017, U.S. EPA collected 27 groundwater samples from previously sampled residential wells in Wedron to better understand the current distribution of BTEX contaminants in groundwater. The Illinois Department of Health will interpret the results and prepare a letter for each property owner with their individual sampling results.

Wedron Monitoring Well Sampling - During October 2017, U.S. EPA collected groundwater samples from six previously installed monitoring wells in Wedron to better understand the current distribution of BTEX contaminants in groundwater.

Air monitoring

Wedron Silica completed an ambient air monitoring study with U.S. EPA oversight from February 2015 through March 2016. 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.

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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Contaminants at this Facility

Major contaminants of concern are benzene, toluene, ethylbenzene, and xylene (BTEX) in groundwater.

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Key Communication Documents

These are some of the key communication documents. More are included in the Superfund Records Collection for Wedron Groundwater Contamination.

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Key Technical Documents

These are some of the key technical and legal documents. More are included in the Superfund Records Collection for Wedron Groundwater Contamination.

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Past Site Superfund Updates

Site activities from July 2012 - Oct. 2015.

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