Panda, a Border Collie sniffer dog, checks out samples at the Dogs Against Cancer and For Life Foundation in Hungary. Barnabas Honeczy/AP hide caption

itoggle caption Barnabas Honeczy/AP

Some scientists doubt the findings of a report that suggests widespread chromium contamination of drinking water. Elena Elisseeva/iStockphoto.com hide caption

itoggle caption Elena Elisseeva/iStockphoto.com

Army Captain William Krueger studies CT scans at the National Naval Medical Center in Bethesda, Md. CWO4 SETH ROSSMAN/NAVY VISUAL NEWS SERVICE hide caption

itoggle caption CWO4 SETH ROSSMAN/NAVY VISUAL NEWS SERVICE