Frequently Asked Questions
MCL = maximum contaminant level
OUs = Operable Units
ppb = parts per billion
ROD = Record of Decision
Table of Contents
Prepared May 2013
1. How many wells has EPA sampled? How many homes have wells that exceed the Maximum Contaminant Level for benzene?
EPA has tested 43 private wells in Wedron. Seven exceed the Maximum Contaminant Level, or MCL, for benzene of 5 parts per billion, while two were just below that level. We are providing bottled water for these nine homes, and have installed temporary whole-house treatment units.
2. What does EPA plan to do to help people with contaminated wells?
From our November 16, 2012, Action Memo (PDF) (20pp, 1.4MB):
First, we will continue to provide bottled water to residents with contaminated wells until we put an alternative water source in place.
Second, we will continue to provide temporary whole-house treatment units until we choose a long-term option.
Third, we will evaluate three options:
Option 1 – install whole-house treatment units that remove volatile organic compounds, or VOCs. We will maintain those units for one year, and then property owners must maintain them.
Option 2 – drill a shared semi-private deep well that is double-cased to prevent contamination.
Option 3 – tie affected homes into new semi-private deep wells outside the ground-water plume area.
Fourth, we will put one of these three options in place.
Fifth, if we connect homes to new semi-private deep wells, we will close the contaminated wells according to state and local well abandonment procedures.
3. Who pays for maintenance?
Property owners would be responsible for maintenance of whole-house treatment units after one year. If EPA connects residences to a new semi-private deep well, they should create a legal agreement that covers maintenance issues and fees. They should consider paying into an association fund to maintain the well, the pump and the water main, as well as to pay for sampling the well.
4. How long will it be before the EPA provides an alternative water supply to homes with well water contamination?
Once any required legal agreements are done, we expect to complete the project in 90-120 days.
5. Can there be legal problems among the residents connected to a shared well?
Yes. So we recommend residents create a legal agreement to handle maintenance and set up ways to resolve disagreements. This should be done before we install the shared well.
6. Will it make a difference to other non-contaminated wells if a new well is built for the nine affected homes?
We may find contaminated drinking water in the future at additional homes close to the plume, so we’re evaluating what to do if that happens. Our November 16, 2012 Action Memo says we intend to cover the cost of additional ground-water sampling and provide alternative water supply to as many as 10 additional homes if needed.
7. If there is a possibility more homes may have their wells contaminated, couldn’t EPA provide more homes – besides the nine mentioned – access to a new communal well?
We have funds to provide alternative water only to residents with wells that show contamination above or near the MCL. We’re evaluating what we might do to provide an alternative water supply to residents whose wells become contaminated in the future.
8. After the nine affected homes get an alternative water supply, will EPA test the water in those wells and in the rest of the community?
EPA has sampled the whole-house filters to make sure they are working properly, and results show they are. If the semi-private well is installed, we will sample the well on installation and for the first year. The residents will be responsible for annual sampling after that.
9. How does benzene affect plumbing, water heaters and water softeners? If my well water has benzene, will I need to replace my home’s plumbing and water heater?
We installed carbon filter units in homes with contaminated wells. Granular carbon in combination with packed tower aeration has proven effective for removing benzene from water to below the MCL. Each homeowner will have to decide for themselves whether to replace any plumbing.
10. How is the carbon in whole-house treatment units disposed of? Is it considered hazardous waste?
Once they have been used, some carbon filters may require hazardous waste handling and disposal. We have reviewed carbon filter handling and disposal requirements with residents who have treatment units.
11. What happened before when there were contaminated wells in Wedron?
Wedron has a history of contamination in drinking water dating back to 1982. The Illinois Environmental Protection Agency and the Illinois Department of Public Health did an investigation from 1982-1985 and determined that seven private wells and a well at the former Martin Marietta Corp. facility were contaminated with VOCs and high levels of benzene. In 1985, the Illinois Commerce Commission installed two new semi-private deep wells on the former Martin Marietta property near the existing Wedron Silica technical center, and seven residences were hooked up to the wells.
12. Are there any problems with the wells installed in 1985?
Neither of the wells installed in 1985 are contaminated.
13. What is the cause of the contamination? Will EPA address the cause?
In July and August 2012, EPA and Illinois EPA conducted an investigation to find possible sources of contamination and define the extent of the ground-water contamination plume. We found several possible sources but there may be more. Current and former owners and operators of Wedron businesses may be responsible, including gas stations, fueling operations, farm supply businesses, laboratories, sand mining operations and railroad transport. We are still working to have the responsible parties conduct additional investigation on their properties to make sure we find all possible sources of the contamination.
14. How deep is the benzene plume? What area does it cover? Is it moving?
Our July 2012 investigation found high benzene levels in soil samples above the first layer of sandstone, which is commonly found at 20-23 feet below the surface. We found contamination in some wells drilled 140 feet or less in the plume area. Wells 180 feet deep or deeper have not shown contamination. We will oversee a voluntary ground-water study by Fairmount Minerals Ltd. to gather additional information. We have maps showing the plume and have shown the maps (PDF) (9pp, 3MB) at public meetings. The plume can move as a result of pumping, and depending on the elevation of the bedrock and ground water.
15. Are there other environmental concerns in Wedron?
As part of its investigation, EPA will do samples for vapor intrusion of soil gas outside Wedron homes. If warranted, we will also check for vapor intrusion under basement concrete slabs, in crawl spaces and inside homes. (See EPA’s Vapor Intrusion fact sheet (2pp 253KB)) During the 1982-1985 investigation, Illinois EPA and Illinois DPH found soil vapors on the former Martin Marietta scale house property, now owned by Wedron Silica Co. We found VOC contamination in soil during the 2012 study on the right-of-way adjacent to the Hoxsey property and on property owned by the railroad.
16. How can wells that draw water from the same aquifer show different levels of benzene?
Many factors can cause different benzene levels at wells that draw from the same aquifer, including the well casing, the depth and what geologic formation the well is drawing water from. Shallow wells within the plume generally are showing contamination while deeper wells are not.
17. Why doesn’t EPA use federal funds to clean up the ground water now?
Our policy is to follow “the polluter pays” model for cleaning up contamination, and we will follow that model to secure funding for cleaning up the contamination in Wedron. Also, sites that only have petroleum product contamination do not qualify for certain types of long-term cleanup funding under the Superfund program. What we’ve found so far shows the contamination came from petroleum products, so we’re looking to other regulatory authorities – such as the Safe Drinking Water Act – to secure funding from potentially responsible parties and ultimately put a long-term solution in place. We are still investigating possible contamination from non-petroleum products.
18. What is EPA doing to clean up the contamination?
Some of our work is short-term:
- Installing whole-house treatment units in homes with well contamination and possibly connecting those homes to new semi-private deep wells.
- Conducting vapor intrusion studies.
- Working with Illinois EPA on additional soil investigation on the Hoxsey property.
- Overseeing Fairmount Minerals Ltd.’s voluntary ground-water study.
While other actions are long-term:
- Identifying long-term solutions to provide alternative water to all Wedron residents.
- Identifying all parties with potential responsibility for the contamination.
- Working to secure funding from responsible parties so we can ultimately put a long-term solution in place.