Researchers Collecting Samples (IMAGE) University of Minnesota Caption Researchers collected samples and took chemical measurements of the sediment from San Francisco Bay to try to find the source of contaminants. Credit University of Minnesota, College of Science and Engineering Usage Restrictions with credit to the University of Minnesota, College of Science and Engineering License Licensed content 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.