Lead levels drop, but hexavalent chromium persists in SE Portland
Slight increase in cadmium still below 24-hour screening levels
Levels of lead monitored for the period ending May 11 show that levels in the air decreased following spikes detected in monitors on May 9 and 10 that were likely connected to Bullseye Glass Co. in southeast Portland.
Results of monitoring on May 11 showed lead levels have returned to those seen in previous months of monitoring, and are well below the 24-hour screening level—the short-term concentration above which immediate negative health effects could occur.
Hexavalent chromium levels are still averaging above 12-month health goals, known as ambient benchmark concentrations. Investigators at the Oregon Department of Environmental Quality continue to seek the source of these emissions.
Levels of cadmium in the air at the Children’s Creative Learning Center (CCLC) in southeast Portland showed an increase on three days—May 6, 9 and 10—during the monitoring period, but did not exceed the 24-hour screening level. The increase caused the average cadmium level to go above the long-term health-based goals. State officials will continue to watch these levels.
“We are investigating several aspects of how Bullseye operates, including its production processes, maintenance procedures and raw material handling, to better understand what the cause of these cadmium and hexavalent chromium readings may be,” said Keith Johnson, manager with DEQ's Northwest Region.
Concentrations below short-term health risk levels
Arsenic continues to average above long-term health based goals. Both the increased cadmium and arsenic averages, however, remain well below the Oregon 24-hour screening level, and for arsenic, is consistent with levels that would typically be found in urban environments.
During the past week, lead levels have dropped from a high of 669 nanograms per cubic meter of air (ng/m3) to 65 ng/m3, which is below the threshold at which lead would pose any immediate risk to people.
10-week averages for metals
The following table lists the 10-week average concentrations compared with what’s expected in urban environments (urban background), and the health-based target (ambient benchmark):
Comparison values for metals in air are posted online. http://public.health.oregon.gov/HealthyEnvironments/TrackingAssessment/EnvironmentalHealthAssessment/Documents/metals/comparison-values-metals-in-air.pdf
The air monitor at CCLC is one of five monitoring devices, operating 24 hours a day, that DEQ placed around southeast Portland near Bullseye to measure levels of heavy metals in the air. There is also one air monitor near Uroboros Glass in north Portland.
DEQ continues its search for the source of hexavalent chromium readings that have stayed elevated since March 1. The agency has visited several industrial sites, including a cement plant, rail yard, trucking facility and chrome-plating facilities near the southeast Portland air monitoring locations.
Bullseye is just one potential source of the higher hexavalent chromium, although it has not used the metal in glass production since mid-February.
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 SaferAir.Oregon.gov. For information about the Cleaner Air Oregon initiative to align industrial air toxics regulations with human health, visit CleanerAir.Oregon.gov.
DEQ reaches agreement with Uroboros Glass
DEQ on Wednesday executed a Mutual Agreement and Final Order (MAO) with Uroboros that requires the glass-maker to take additional steps to limit its emissions of certain hazardous air pollutants (HAPs) including metals. The MAO was prompted by the U.S. Environmental Protection Agency’s determination that the company operates furnaces that are subject to regulation under federal air quality rules.
Contacts:
Jennifer Flynt, Oregon DEQ 503-730-5924, flynt.jennifer@deq.state.or.us
Jonathan Modie, OHA Public Health 971-246-9139
PHD.Communications@state.or.us
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