Raining PCBs (image) University of Iowa Caption An University of Iowa study has found that people living in urban and rural areas have the same PCB levels in their blood. Researchers are trying to understand why. Credit Tim Schoon, University of Iowa Usage Restrictions None Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.