EXH0744026684

5808 Lake Washington Blvd. NE, Suite 200 Kirkland, Washington 98033-7350 April 2001 556-2912-001 (01/61A) AR 026684 1. INTRODUCTION 1.1 BACKGROUND The Port of Seattle (POS) is conducting a water quality assessment to determine the feasibility of complying with state water quality standards after construction of the third runway at the Seattle- Tacoma International Airport (STIA). The POS is evaluating several options to provide a weight of evidence for compliance after the construction of the third runway, including best management practices (BMPs) and application of a water-effect ratio (WER) to determine a site-specific water quality standard for copper. A multiphase approach is being used to develop a WER for copper in Miller, Walker, and Des Moines Creeks. The first two phases, an initial toxicity screen to determine if the receiving waters were toxic to daphnids and two range finding bioassays to determine the approximate magnitude of the WERs, have been completed. The final phase, which has not been completed, includes the development of a site-specific water-effect ratio, which will be used to adjust the state water quality criterion (WQC) for copper. This memorandum summarizes the results from the screening level and range finding studies, with bioassay results _resented in Tables 2, 3, and 4 and Appendices A, B and C. 1.2 LABORATORY AND TEST METHODS The following section summarizes the testing procedures for bioassays conducted for the Port of Seattle. All testing was conducted by Parametrix's Environmental Toxicology Laboratory in - Kirk.land, Washington. 1.2,1 SAMPLE COLLECTION Samples were collected during qualifying…

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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 [...]