Technical Report No. 4

ACUTE TOXICITY OF INTERTIDAL SEDIMENTS FROM PADILLA BAY, WASHINGTON, TO THE AMPHIPOD, RHEPOXYZNUS ABRONZUS

Douglas A. Bulthuis and Travis Shaw

November 1992

Bibliographic Citation
Bulthuis, Douglas A. and Travis Shaw. 1992. Acute toxicity of intertidal sediments from Padilla Bay, Washington, to the amphipod, Rhepoxynius abronius. Washington State Department of Ecology, Padilla Bay National Estuarine Research Reserve Technical Report No. 4, Mount Vernon, Washington. 37 pp.

Abstract
The acute toxicity of intertidal sediments at nineteen sites in Padilla Bay, Washington was determined for the amphipod, Rhepoxynius abronius. Mean survival of R. abronius ranged from 14 to 92 percent at sixteen sites scattered throughout Padilla Bay and ranged from 7 to 40 percent at three sites located near a former landfill. It is concluded that Padilla Bay is unlikely to be a good reference area for noncontaminated sediments because of the toxicity of the sediments to R. abronius at sites throughout Padilla Bay. There was no consistent pattern of toxicity among the 16 scattered sites that would indicate a point source contamination. It is suggested that the sea-surface microlayer may be a mechanism for concentrating contaminants in intertidal sediments and that intertidal sediments throughout Puget Sound may have higher sediment toxicities than adjacent subtidal sediments.