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EARLY WARNING MARINE WATER SUPPLY PROTECTION STRATEGY: THE THREAT OF OIL SPILL (PETROLEUM HYDROCARBON) CONTAMINATION
Citation:
Young, D R., D T. Specht, AND R J. Ozretich. EARLY WARNING MARINE WATER SUPPLY PROTECTION STRATEGY: THE THREAT OF OIL SPILL (PETROLEUM HYDROCARBON) CONTAMINATION. Presented at Pacific Estuarine Research Society, Tacoma, WA, May 18-19, 2001.
Description:
Oil spills resulting from the twice-grounded freighter New Carissa on the Central Oregon coast in the spring of 1999 caused substantial concern regarding potential petroleum hydrocarbon (PHC) contamination of Coos Bay, Alsea Bay and Yaquina Bay estuaries and resident seawater facilities. Of prime concern were the circulating seawater systems of marine research institutions and major aquaria - in the absence of data concerning concentrations of PHC in intake pump systems, the decision was made or considered to shut down the pumps and truck salt water from a known uncontaminated remote source, while drastically curtailing throughput, imperiling research projects and/or aquaria stock. To satisfy the urgent need for more immediate data in Yaquina Bay estuary, a simple, rapid water monitoring program was devised and established at the Hatfield Marine Science Center to provide sufficient warning of threatening levels of PHC in seawater adjacent to or entering intake pump systems. This program included 1) walking adjacent beaches at high tide in search of tar balls, patches or sheens; 2) continuous pumping of subsurface seawater from just below seawater pump intake ports to a small, baffled aquarium tank designed to trap and retain both negatively-buoyant materials such as tar balls, and floatables such as oil slicks; and 3) collection of subsurface, near-surface and surface slick water samples for rapid analyses of PHC levels quantified as marine diesel equivalents (MDE). The latter step employed a Turner Designs? Model 10 fluorometer equipped with oil-sensitive optical filters and excitation lamp. A reference sample of marine diesel was obtained from a local marina fueling station, and dissolved in isopropyl alcohol as the interim primary standard; sand-filtered seawater obtained from the institution circulation system prior to appearance of spill material was used as a fluorescence blank. The average (2 + 2 g/L) and maximum (`10 g/L) subsurface water concentrations of MDE observed were well below reported thresholds of aquatic toxicity. In comparison, near-surface water collected from the fishing fleet anchorage directly across Yaquina Bay averaged about 20 g/L MDE. Similar results were obtained from the monitoring of two subsequent oil spill episodes in the Yaquina Bay estuary, demonstrating the usefulness of this simple approach in making decisions regarding the costly interdiction of circulating seawater at marine research facilities and aquaria.