For more than 15 years, Stephen Clark has been directing and participating in research and testing in the areas of aquatic ecotoxicology and environmental chemistry. Stephen’s recent emphasis for his Ph.D. dissertation research has been on the effects of contaminants on aquatic organism at the cellular/biochemical level (e.g., "biomarkers"). Stephen has also been actively involved in the development of sediment toxicity testing approaches, including sediment-water interface testing, as well as the development of toxicity identification evaluation (TIE) methods for algae. Stephen’s professional and academic research has included extensive experience with a suite of established EPA and ASTM aquatic and sediment toxicity tests, ranging from freshwater, estuarine and marine organisms. Stephen is also expert in regulatory aspects of aquatic ecotoxicology, and has contributed in the preparation and implementation of Management and/or Monitoring Plans for San Francisco Bay, the Pacific Coast, Monterey Bay, and the Sacramento River Watershed.

Stephen’s project management includes a leadership role, from conception and design of the experimental approach, client representation to regulatory authorities, analysis of results, and finally, reporting of the results to the concerned parties. Selected projects that involved a leadership role by Stephen include:

	development and implementation of aquatic TIEs for ambient waters;
	evaluation of sediment, elutriate, and pore water toxicity in a variety of sloughs and estuaries throughout the west coast of the U.S.;
	evaluation of petroleum related toxicity to a native California fish species;
	toxicity testing of agricultural runoff to native California fish and invertebrate species;
	development of new marine and estuarine bioassay tests for sediment and ambient waters;
	NPDES toxicity testing for municipal and industrial dischargers;
	assessment of surface water runoff toxicity in urban and agricultural dominated regions.

Stephen Clark can be reached at (707) 207-7766 (telephone) or by email at slclark@pacificecorisk.com.