Site-specific marine water-quality criterion for cyanide

A site-specific marine water-quality criterion for cyanide was developed fo r Puget Sound, Washington, USA. The U.S. Environmental Protection Agency (U .S. EPA) national cyanide water-quality criterion is driven by toxicity dat a for the eastern rock crab, Cancer irroratus, a species not resident to th e U.S. western coast (West Coast). The reported LC50 for C. irroratus is si x times lower than any other marine species tested. Cyanide acute toxicity tests were conducted using first stage zoeae of all four species of Cancer spp. resident to Puget Sound to develop a site-specific criterion for this water body. Testing with Puget Sound Cancer spp. reveals sensitivities 24 t imes less, on average, than C. irroratus. Recalculation of the Puget Sound water-quality criterion for cyanide, by substituting the new Cancer spp. da ta for the C. irroratus data, results in water-quality criterion protecting marine life against acute and chronic toxicity of 9.4 and 2.9 mug/L cyanid e, compared to the U.S. EPA national value of 1.0 mug/L for both acute and chronic toxicity.