City Tracks Source of PCBs Discovered through Foss Waterway Monitoring
Since 2001, the City has monitored the stormwater system to protect water quality in the Thea Foss Waterway. The City tracks contaminants and eliminates them before they enter the waterway.
Recently, polychlorinated biphenyl (PCB) contamination was found in a residential area bordered by East 60th and East 65th streets between East I and East K streets. You can view the map of the affected areas. After extensive testing, the City traced the contamination to a crack sealant used in a road construction project in 1975.
The sealant believed to be the source of PCBs is contained under the roadway and in the storm drain catch basins. These catch basins are covered by heavy metal grates. The contamination is not accessible to the public. The City does not expect to find PCBs in the water supply or elsewhere in the neighborhood.
Regardless, the City is developing a plan to remove the contaminated material.
Information from Public Meeting November 20
Residents of the affected area attended a public meeting November 20 to learn more about the issue and ask questions. These materials were shown at the meeting:
What are PCBs?
PCBs are man-made chemicals that were widely used in construction materials and electrical products until they were banned in 1979. PCBs don't break down easily in the environment and may remain there for a very long time.
PCBs are ingested by fish and small organisms in water and accumulate in the food chain. So people who eat fish may be exposed to PCBs. PCBs can affect the health of people and animals if they build up in the body over a long period of time.
PCBs are considered legacy pollutants, meaning chemicals that remain in the environment long after they were first introduced. They typically weren't recognized as harmful when they were being used.
Additional Information on PCBs
How were PCBs discovered?
How much contamination did the City find?
The highest PCB reading was 260 parts per million (ppm), which came from a sample of the sealant collected inside a storm drain catch basin. The highest reading from dirt at street level was 24 ppm.
What does that mean? The Washington State Department of Ecology (Ecology) calls for cleanup at 1 ppm for residential properties. Cleanup levels for industrial properties are from 10 to 66 ppm. Ecology calculates the risk of 66 ppm on industrial property as one case of cancer per 100,000 workers, based on employees working 70-hour weeks, 50 weeks a year, for 30 years.
What are the next steps?
The City is working with the Department of Ecology and the Environmental Protection Agency to develop a plan to address the issue. The solution will likely involve removal of a portion of the street – along the edge of the street – so that the contaminated soils can be removed.
This work is tentatively planned for summer 2014, although factors such as budget and regulatory review timelines may affect the schedule.
Who can I contact for additional information?