EXH1300052334

During a twelve month period in 1998-99, the Port of Seattle characterized the whole effluent toxicity (WET) of stormwater samples from four outfalls at Seattle-Tacoma International Airport (STIA.) This testing was conducted in accordance with USEPA and Washington State guidelines and the Port's individual NPDES stormwater permit for the airport. The WET tests used two aquatic organisms, a water flea (Daphniapulex.) and the fathead minnow (Pimephales promelas.) All eight test results for two of the outfalls met the Washington State Department of Ecology performance standards for survival for each organism. These two outfalls drain 79% (200 ha, 492 ac) of the airfield runways and taxiways. Nine often test results for a third outfall, that drains 60 hectares (149 acres) of mostly access roadways and the terminal and cargo building rooftops, also met the performance standards. In contrast, seven of nine WET results for a fourth outfall that drains 6 hectares (14 acres) of rooftops and roadways were below the performance standards and led to a subsequent source tracing investigation. Supplemental sampling and analysis, including metals chelation with EDTA indicated that zinc was the most likely source of toxicity in samples from this fourth outfall. Further investigations revealed that about 0.8 hectare (2 acres) of zinc-galvanized metal rooftop on two air cargo buildings was the principal source of the zinc, where typically 50% or more was in the dissolved form. Synthetic runoff samples obtained by spraying domestic water on the metal rooftops also exhibited toxicity and considerable zinc, while the raw…

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PSCAA Advisory Council Meeting Agenda
Add to CalendarMWednesday Mar 11, 9:00am - 11:35am
1904 3rd Avenue, Suite 105, Seattle, WA 98101
Call to order – Roll Call – Quorum Established – Land Acknowledgement We would like to acknowledge that our Agency operates in four present-day counties, which are the traditional lands of the Coast Salish people, past and present. This acknowledgement does not take the place of authentic relationships with indigenous communities in our jurisdiction and [...]