Oregon Agencies Seeking Hexavalent Chromium Source in Portland
The Department of Environmental Quality said its investigators continue to seek the source of the heavy metal selenium that has been, on average, elevated in southeast Portland's air since March 1.
Oregon state agencies including the Department of Environmental Quality (DEQ) are continuing to investigate the source of hexavalent chromium in the air in southeast Portland that has averaged higher than health-based targets since 24-hour monitoring began in early March, DEQ announced May 5. The latest air monitoring data show levels of the heavy metal selenium have returned to levels expected in urban environments; selenium levels had jumped after Bullseye Glass Co. in southeast Portland increased use of selenium in its manufacturing process beginning April 6, according to the agency.
"Still, the persistence of increased hexavalent chromium readings over time remains a concern to the Oregon Department of Environmental Quality and Oregon Health Authority, even as all metals collected by DEQ air monitors remain below Oregon 24-hour screening levels. Oregon 24-hour screening levels are short-term concentrations below which immediate health effects are not expected to occur," it reported.
The agency said its investigators continue to seek the source of the heavy metal that has been, on average, elevated in southeast Portland since March 1. The target concentration for hexavalent chromium is 0.08 nanograms per cubic meter of air (ng/m3) when compared to an annual average, but the 57-day average ranged between 0.0827 nanograms and 0.297 nanograms across the four monitoring locations surrounding Bullseye Glass. The company did not use chromium in glass production during that period. DEQ is looking at several potential sources, including a cement plant, rail yard, trucking facility, and two chrome-plating facilities, and have visited or are planning visits to those sites soon, and they are studying wind data and are planning to move air monitors to those areas in an attempt to triangulate the source.
Weekly air monitoring data from southeast and north Portland are reported each week by the interagency group that includes DEQ and OHA and published at http://SaferAir.Oregon.gov.