beaufort sea dispersant trial final results of the api

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Canadian Oil and Gas Lands Administration. Calgary, Alberta, Canada. Ottawa, Ontario, Canada. R. H. Goodman. Esso Resources Canada, Ltd. Calgary ...
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1987 OIL SPILL CONFERENCE

BEAUFORT SEA DISPERSANT TRIAL / . / . Swiss and N. Vanderkooy Dome Petroleum, Ltd. Calgary, Alberta, Canada

S. D. Gill Canadian Oil and Gas Lands Administration Ottawa, Ontario, Canada R. H. Goodman Esso Resources Canada, Ltd. Calgary, Alberta, Canada

In August 1986, in conjunction with the Canadian Offshore Aerial Application Task Force (COAATF) and the Beaufort Sea Oil Spill Cooperative, Dome Petroleum Limited conducted the Beaufort Sea Dispersant Trial, with the following objectives: • To determine the field effectiveness of aerially applied dispersants under Arctic conditions • To determine and test the operational parameters of "multi-hit" dispersant application • To define the logistics and cost requirements of a full-scale dispersant operation in the Arctic • To obtain a long-term (two days) record of oil slicks at sea, to determine their fate The trial was conducted at an offshore location approximately 40 km northwest of Tuktoyaktuk, Northwest Territories, Canada. Four slicks were created, each containing 2.5 m3 (15 bbl) of Alberta sweet mixed blend (ASMB) crude oil. One slick was left as an unsprayed control and the other three were treated with various amounts of British Petroleum's Enersperse 700 and Exxon's CRX-8. Effec-

tiveness was determined by using computer-enhanced infrared and ultraviolet detectors mounted in a remote-sensing aircraft and measuring the amount of oil left on the surface of the water after each spray pass. Results of the trial are presently being analyzed. However, initial conclusions can be drawn from preliminary data analyses as follows: • Successful completion of this trial has demonstrated that it is possible to conduct a full-scale, multi-hit dispersant operation using helicopters and slung buckets at remote locations in the Arctic. • Single applications of dispersant at dispersant/oil ratios of approximately 1:10 seem to be as effective as multi-hit applications, provided that the dispersant is given time (several hours) to work. • There was an obvious difference in the initial effectiveness of the two dispersants. However, after several hours, the amounts of oil dispersed by the two products were essentially the same. • Aged ASMB crude oil can be chemically dispersed even at relatively low temperatures (6° C) typical of the Beaufort Sea in summer.

FINAL RESULTS OF THE API TROPICS OIL SPILL AND DISPERSANT USE EXPERIMENTS IN PANAMA Thomas G. Ballou, Steven C. Hess, Charles D. Getter Research Planning Institute, Inc. 925 Gervais Street Columbia, South Carolina 29201

Anthony Knap, Richard Dodge, Thomas Sleeter Bermuda Biological Station Ferry Reach 1-15 Bermuda

This long-term experiment was designed to determine the intertidal/subtidal tradeoffs (if any) involved with using dispersants in shallow tropical waters. The experiment, conducted in Panama from 1983 to 1986, involved three treatment sites, each containing a coral reef, a seagrass bed, and a mangrove forest. Following treatment with dispersed oil, treatment with oil alone, or no treatment (reference), the sites were monitored for 18 months for short-term and long-term effects and recovery rates.

High concentrations of dispersed and undispersed oil were used to simulate a worst-case but realistic scenario. The results indicate differences in oil residence time in the intertidal zones at each spill site as well as effects on resident biota. To develop answers to the tradeoff question, we compared the long-term loss of intertidal wetlands (as seen at the oil-alone treatment site), with the short- and long-term effects on animal benthos in the subtidal seagrass and coral reef systems.