UNIVERSITY PARK, Ill. (WLS) -- More than two weeks after water utility Aqua Illinois first issued a tap water "do not consume" advisory to all University Park residents, more than 40% of village homes and businesses sampled in the latest round of compliance testing still had lead concentrations above the EPA action level, according to new results released by the utility Monday.
Despite this prolonged water contamination, Aqua Illinois' latest weekly update pointed toward decreases in the maximum lead level and average lead level detected in the latest sampling (85.8% and 65.5% decreases respectively, according to Aqua Illinois) when compared to "Sample Group 1" results received on June 13, 2019.
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The utility's latest post-flushing samples (taken after letting the faucet run 2-3 minutes) show fewer than 10% of tested taps above the EPA action level, which it said is similar to last week's numbers. An Aqua Illinois spokeswoman clarified to ABC 7 that while the post-flushing tests included some of the compliance testing properties, "the post-flushing data also include other customer samples collected from other properties" that weren't sampled after 6 hours of stagnation.
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Further, ABC 7's initial review of the latest compliance testing results found an apparent slight decrease in the number of sampled properties with lead concentrations equal to or below the EPA action level of 15 ug/L. This was illustrated by a sloping green line across an Aqua Illinois chart.
When asked about this, Aqua Illinois' spokeswoman responded, "The 'slight dip' is not statistically significant given the variability of environmental samples. The percent of samples in the upper-level categories (>100 ug/L) is actually decreasing, which means the treatment is working as expected. As time progresses, we expect the number of <15 ug/L samples to increase. The new treatment will be observed in the upper-level categories first."
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