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Update 4

Update #4: Crestwood Public Water Supply

Bedrock Groundwater Sample Results

October 9, 2009

Village of Crestwood, Cook County

The volatile organic compound (VOC) sample results from the Illinois EPA’s recently installed bedrock monitoring well indicate vinyl chloride contamination of the bedrock groundwater between Playfield Cleaners and the former Crestwood PWS well, as predicted by the Illinois EPA’s groundwater flow modeling results. The VOC samples were collected from the bedrock monitoring well on September 17, 2009. Illinois EPA experts believe these data implicate the Playfield Cleaners property as the source of contamination of the former Crestwood PWS Well #1.

Two groundwater samples were taken from the monitoring well drilled 49 feet deep, 15 feet into bedrock. The monitoring well is located approximately halfway between the suspected contamination source area, Playfield Cleaners, and the former PWS well. The monitoring well site and depth were chosen in an effort to intercept contaminated groundwater that our modeling had indicated would have been drawn toward the PWS well during its operation. The concentration of vinyl chloride found in the bedrock’s groundwater between 39 and 49 feet below ground surface averaged 55.7 parts per billion (ppb), ten times the concentration Illinois EPA found in the PWS well 3 years ago (5.4 ppb). Please review the Bedrock Monitoring Well Installation and Sampling Report which includes the sampling results.

These sample results have been shared with the Illinois Department of Public Health (IDPH) for health-based interpretation. Because both shallow groundwater and bedrock groundwater flow to the north-northeast, toward the Cal-Sag Channel, contaminants in the groundwater will also move in this direction. There are no known private drinking water wells in the area, consequently, no public health hazard from exposure by drinking this water is believed to exist. Because there are also no homes in the path of groundwater flow, the Illinois EPA and IDPH conclude that there is not a public health hazard for exposure through vapor intrusion into homes. We also would not expect children at the playground to be exposed to vapors from the groundwater contamination.

If I have any questions, where can I find more information?

This Crestwood fact sheet update, previous updates, and environmental investigation results, may be found at the web site link above. Paper copies of this fact sheet are also available at the Crestwood Public Library. Any further updates from the Illinois EPA concerning Crestwood will also be posted at this web site.

Residents with questions for Illinois EPA should contact: Mara McGinnis (phone 217-524-3288; e-mail to: Mara .McGinnis@illinois .gov )

Residents with specific health-related questions or concerns about private wells should contact: Tom Baughman (phone 630-293-6800; e-mail to: Tom .Baughman@illinois .gov )