EXH1084041138

issolved and particulate forms of copper waste treatment systems. are common trace contaminants in storm • Laboratory studies, field surveys, and water runoff and wastewater. In the dissolved effects ratio procedures conducted by regula- state, copper appears in various forms, ran_ng tory authorities and independent researchers from the cupric ion to numerous organic-inor- since 1976 verify that copper rapidly binds with ganic complexes. The ionic form of copper is organic and inorganic matter during biologica_ toxic at very low concentrations, while corn- waste treatment, making it unavailable to inter- plexed copper is basically nontoxic. RegulatoD' act biologically (nonbmavailabte) and thus non- agencies have long known about this "Jekyll and toxic to aquatic life. Hyde _ behavior, but the standard permitting • All EPA and state agency field studies con- approach has been to assume that all dissolved firm that copper in biologically treated effluents copper is present in the most toxic form. which is not toxic to Daphnia, the sensitive species is rarely accurate because the ionic form is high- used to establish the tederal copper criteria. ly reactive, readily forming nontoxic complexes. These studies demoastrate that biologically treat- Laboratory-derived numerical water quality ed effluents eliminate copper toxiciD' with significant criteria tor copper, developed by the U.$. Envi- additional complexang capabiliW m reserve. Copper ronmental Protection Agency (EPA) in 1984 and typically discharged (40 to 200 u_) by publicly updated in 1993, assume that the toxic form o! owned treatment works (POTWs) should pose no dissolved copper exists in biologically…

Open full document

Upcoming Events

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 [...]