Pulsed Exposure Toxicity Testing: Method Development and Initial Evaluation for Stormwater Compliance
Technical Report,01 Jul 2017,01 Jul 2018
Naval Information Warfare Center Pacific San Diego United States
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This report describes a preliminary research effort to modify whole effluent toxicity WET testing protocols designed for continuous flow discharges for application to episodic andor ephemeral discharges such as those associated with storm water runoff. The effort was undertaken in response to a Naval Base San Diego industrial stormwater National Pollutant Discharge Elimination System NPDES permit R9-2013-0064 condition that allows the Navy to assess and propose alternative testing parameters. The research was conducted for Naval Base San Diego by environmental toxicologists at the Navys Information Warfare Center Pacific NIWC Pacific. The technical approach taken was to modify the WET testing method to simulate a range of exposure conditions found at the end-of-pipe. The test conditions matrix included acute and chronic endpoints with commonly used test organisms copper, zinc, and a combination of the two toxicants at various concentrations found to cause toxicity under standard WET testing and short-term exposure conditions representing the 50th, 75th, and 95th percentile historical rainfall durations observed in San Diego over the past 55 years. The initial testing culminated in its application to multiple stormwater samples collected from Naval Base San Diego outfalls during a single rain event in March 2016. All testing was conducted concurrently with standard test method durations for comparison.