Fact Sheet 1

Wayne Township, DuPage County , Illinois

Background

After testing was completed for roughly one thousand wells, two areas of contamination emerged. In one part of the county, there was a small area of contamination with methyl tertiary butyl ether (MTBE). This compound is added to gasoline to enhance the combustion process and allow the fuel to burn more cleanly. It is soluble in water and travels in groundwater whenever spilled or leaked. The concentrations discovered were not a health hazard, however. DCHD informed the well owners of the presence of the contaminant and gave advice about how to reduce exposure.

In Wayne Township, the well testing revealed vinyl chloride and cis-1,2 dichloroethene in a number of private wells in unincorporated areas along a north-south corridor parallel with Fair Oaks Road from just north of Army Trail Road (on the north) to North Avenue (on the south).

Are the chemicals that were found toxic?

Some VOCs can be toxic to humans at certain levels. In this case, vinyl chloride is the chemical of concern. It is considered toxic to humans at low levels and is a known human carcinogen.

What is vinyl chloride?

In its pure form, vinyl chloride is a colorless gas at room temperature and has a mild, sweet odor. It is a manufactured substance that does not occur naturally. Vinyl chloride is used to make polyvinyl chloride (PVC). PVC is used to make a variety of plastic products, including pipes, wire and cable coatings, and packaging materials.

Vinyl chloride can also be formed when other substances such as trichloroethylene (TCE) and tetrachloroethylene (PCE) – both common solvents - degrade or are broken down by bacteria in the environment. The groundwater contamination in Wayne Township is likely related to this type of contaminant degradation.

What level of vinyl chloride is considered safe in drinking water?

The maximum contaminant level (MCL), which is considered safe for public water supplies by U.S. EPA, is two parts per billion (ppb). To put this in perspective, a part per billion can be represented by one-half teaspoon of water in an Olympic sized pool (660,000 gallons). Public water supplies must routinely test for this contaminant among other VOCs and must meet federal standards.

What are the potential health effects from exposure to vinyl chloride?

Breathing vinyl chloride at high levels for long periods of time (as in the workplace) can result in permanent liver damage, immune reactions, nerve damage, and liver cancer.

At low level exposures, as with drinking or inhaling the low level vinyl chloride groundwater contamination in Wayne Township, there may be an increased risk of contracting cancer over one’s lifetime. Public health officials, therefore, advise using an alternative drinking water source where vinyl chloride is found in the groundwater in excess of the MCL. Another way to reduce exposure to airborne vinyl chloride is to limit time spent showering and to use an exhaust fan or keep a window open.

What happens to vinyl chloride when it enters the environment?

• Liquid vinyl chloride evaporates easily. Vinyl chloride in water or soil evaporates rapidly if it is near the surface.
• Vinyl chloride in the air breaks down in a few days to other substances, some of which can be harmful.
• Small amounts of vinyl chloride can dissolve in water.
• Concentrations decrease naturally over time in groundwater due to breakdown by bacteria and by mixing with clean water.

Vinyl chloride is unlikely to build up in plants or animals.

What specific areas are affected?

At the north end of the area, some private wells along Gerber Road just west of Fair Oaks Road are impacted by contamination, a few at levels greater than the MCL. A half mile to the south, in an unincorporated area with two short streets near Lies Road on the east side of Fair Oaks Road, numerous wells are impacted. Another half mile south a few wells tested positive for very low concentrations of vinyl chloride at the south end of the DuPage County Forest Preserve and just west of Fair Oaks Road.

What sort of notification has been made to owners of private wells?

DCHD sent notification letters to each private well owner whose well was tested, along with the analytical results from the tests. The Illinois Department of Public Health (IDPH) also sent letters and provided an interpretation of the results regarding health implications and advice on reducing exposure, if contaminants were found. The County has also held public informational meetings to discuss the contamination with area residents.

Is someone investigating the source of the vinyl chloride?

Yes. The Illinois EPA has been investigating potential sources for the contamination since early 2006. A report has been submitted to the Illinois EPA file as of June 8, 2006 for the first phase of the investigation performed. So far, a definitive source or sources of the contamination has not been identified.

In addition, Illinois EPA evaluated public water supply wells in the area, both ahead of (downgradient) and behind (upgradient) the groundwater flow direction (mainly toward the south) of the area of contaminated groundwater. The Bartlett municipal wells, which are in the deeper dolomite aquifer, upgradient from where contamination was found, currently do not show any VOC contamination like what was found in some private wells.

What types of potential sources were investigated?

Illinois EPA looked at businesses that typically would have used solvents in their processes. Some of the facilities evaluated - along Army Trail Road, for example - are currently enrolled in a cleanup program with Illinois EPA, so the Agency already had some information about those sites. Illinois EPA had little information about other facilities, so the Agency performed a historical records investigation and made one-on-one inquiries regarding what waste materials may have been spilled or leaked into the environment.

Mallard Lake Landfill has also been evaluated as a possible source, since many area citizens expressed concern about that site. Illinois EPA has many years of groundwater data from that site, and there is no evidence of contamination leaving the site that could affect downgradient wells. In addition, approximately 103 private wells downgradient of the landfill have recently been tested by the county, and none of the results show VOC contamination.

What is the next step?

In conjunction with information provided by DCHD inspectors, Illinois EPA is pursuing leads regarding potential sources of contamination upgradient from the observed contamination in private wells. Soil and groundwater data from White’s Septic Service, just north of the area of contamination, have been evaluated. Though soil and groundwater testing results at that site do not show contamination that would result in vinyl chloride in the downgradient private wells, Illinois EPA is investigating an area upgradient (north) of that site.

For more information:

A Fact Sheet about vinyl chloride is available on the Agency for Toxic Substances and Disease Registry at http://www.atsdr.cdc.gov/tfacts20.html.