(Portland, OR)  --  Health authority officials say soil testing done in Portland, after high levels of cadmium and arsenic were found in the air, show a low health risk for residents.  The Oregon Health Authority, the Department of Environmental Quality, and the Multnomah County Health Department announced the results yesterday, saying an analysis of soil samples in Southeast and North Portland shows a low risk for health problems.  Elevated levels of the toxic metals found in the air over Southeast Portland recently have been linked to glass factories operating in the area.  OHA officials say tests and data-analysis will continue.