Notes
Email dated August 10, 2000 from Kate Rhoads to Kelly Whiting transmitting a Word document (POS-Cu.doc) containing technical comments on copper (Cu) levels in stormwater runoff from Seattle-Tacoma International Airport (STIA) runways. AR017903-017904. Comments address total recoverable (TR) copper median concentration of 37 ug/l versus the dissolved fraction surface water acute toxicity standard of 4 ug/l (assuming hardness of 24), TSS levels, NPDES permit Whole Effluent Toxicity (WET) testing using daphnia and Flathead minnows, dissolved Cu concentrations of 13 ug/l in WET test stormwater, WAC 173-205, salmonid toxicity concerns, and comparison data from NUPR and freeway stormwater. Raises questions about whether additional stormwater treatment for metals removal is warranted and whether salmonids should have been used as WET test species given copper’s greater toxicity to salmonids and salmon habitat in receiving waters.