Story By Matthew Hendrickson
March 25, 2009 – For a half-century, cars and trucks used leaded gasoline, spewing potentially toxic pollution into the air. Leaded gas was banned in the 1970s, but a troubling question lingers: Has pollution from leaded gas tainted our soil, especially near major highways?
To test our theory, we collected soil samples from playgrounds in three parks in Oak Park, a Chicago suburb. Cutting through Oak Park is U.S. 290, also known as the Eisenhower Expressway, one of the nation’s busiest roads.
One soil sample was from Barrie Park, which overlooks the highway. Another was from Longfellow School Park, a quarter-mile away; a third from Grove Park, about one mile away.
We then sent the samples to the city of Chicago’s childhood lead-prevention program for testing. The results: All were positive, though under levels authorities say should cause concern.
The highest reading – 200 parts per million – was from the sample found at the park overlooking the expressway. The sample furthest from the highway had the lowest lead level.
While the findings seem to lend support to the theory that decades-old highway exhaust is still affecting neighborhoods, the lead found could have also come from lead paint or other sources.
Tony Amato, supervisor of the lead-prevention program and the official who oversaw our testing, said all three test results were low. He said lead levels need to be at least 400 ppm at playgrounds and 1,000 ppm elsewhere to sound alarms.
But he acknowledged there is no safe level of lead in soil, and that in Chicago, inspectors rarely test soil for lead – only a few times a year.
Moreover, he said, little can be done if troubling amounts are found.
“Unless we are prepared to scrape off the top layer of the earth, we won’t get rid of (lead),” he said.
Still, for many parents of children who play in these parks, any positive result can be worrisome.