Perchlorates in the Illinois Environment

Perchlorate is an inorganic compound that can affect human health by disrupting thyroid function. It is used in explosives, pyrotechnics, rockets, missiles, fireworks, road flares, and other items. In Illinois, potential perchlorate sources include activities at active or former federal facilities (Illinois was the nation’s leading producer of ammunition during World War II), manufacturing facilities, mining, construction, and miscellaneous uses such as fireworks displays and water treatment plants. We assessed perchlorate impacts at current and potential drinking water sources in the study areas of ten sites in Illinois: six federal facilities and four manufacturing sites. We identified the public water supplies (surface water and groundwater) used by the communities in the study areas and demonstrated that they were not currently impacted by perchlorate contamination. We identified private wells in the study areas and collected samples representative of different aquifers. We also identified surface water bodies that may be recharging groundwater in each study area and collected samples from streams flowing at the time of sample collection. Existing data (including well records, geology, hydrology, and analytical data generated by other investigations) were reviewed for each site. The samples were analyzed for perchlorate using EPA Method 314.1. Perchlorate was not detected at or above the quantitation limit of 2.0 μg/L in any of the samples that we collected.