The UI study technique involved collecting 66 soil samples near Cedar Rapids streets on August 25, 2008 -- about 70 days after the flood. About 94 percent of the sampling sites were located inside the estimated flood area, and researchers concentrated on sampling sites south of Cedar Lake and west of the Cedar River. The total sampling area covered almost 4 square miles. Each sample involved collecting approximately 2 pounds of soil from a 5-inch-deep site using a trowel. The soil samples were placed in labeled, plastic Ziplock freezer bags and brought to the UI, where they were refrigerated prior to being analyzed -- using gas chromatography, mass spectrometry for chlordanes, and tandem mass spectrometry for PCBs.
Hornbuckle says that residents of Cedar Rapids and other cities should know that these chemicals are widely present in urban soils. She adds that we don't know the source of the PCBs found in Cedar Rapids soils, but that chlordane is probably present because homeowners used the insecticide to kill termites and that the original contamination probably occurred more than 30 years ago.
"Both these chemicals are now banned from production and sale, but are still in our environment because they are nearly nonbiodegradable," she says. "It is my opinion that we should not use chemicals that are so persistent in any household activity, but it is difficult for the average homeowner to know how to judge this. This data is not, but should be, provided on the containers of all the products we purchase."
Manufactured from about 1930 until being banned in the 1970s due to their toxicity and persistence
|Contact: Jennifer Brown|
University of Iowa Health Care