the survey as planned. Appendix V contains a description of the sampling 

 locations in the general area covered by the oil slick from the Avgo Mer- 

 chant. In summary, it was assumed by URI that the most likely/ to show sig- 

 nificant quantities of oil would be: areas 



(1) Areas covered by the slick for the longest period of time. 



(2) Shallow areas. 



(3) Areas covered by the slick when the sea state was high. 



In addition, the remainder of the area covered by the slick (deeper areas and 

 areas covered when the sea state was calm) would also be sampled. Two 

 areas, designated "A" and "B" in Figure 3-5, were determined to have been 

 covered by heavy oil concentrations for at least 6 days. Area A includes the 

 site of the Argo Merchant. Area B is the area where the slick stalled for 6 

 days before moving eastward. URI investigators randomly selected 30 stations 

 within the two areas: 6 in area A, and 24 in area B. In addition to these 

 30 stations, URI chose 3 stations in shallow areas (designated "C") ; 3 that 

 were covered by a heavy concentration of oil during high sea states ("D") ; 2 

 that coincided with Endeavor cruise 002 stations 1 and 2 ("E") ; and 2 sta- 

 tions located between areas A and B ("F"). 



Appendix V lists the positions of all the above stations, except those 

 designated "G," which were chosen by the chief scientist during Endeavor 

 cruise 004. And it is at two of these stations, G-42 and G-43, that oil has 

 been determined up to date, as well as at stations A-40 and D-36 (figure 3- 

 6). 



Screening Procedures 



Sediment samples are being screened by two methods : thin-layer chroma- 

 tography, and ultraviolet fluorescence. Selected samples are then forwarded 

 to the NOAA National Analytical Facility in Seattle for GC-MS analysis. 



The ultraviolet fluorescence procedure developed by Gordon and Krisa 

 (1974) is being used on both the water column and sediment samples to deter- 

 mine if substantial quantities of oil are present. The thin-layer chromato- 

 graphic method was developed by Mississippi State University under contract 

 to the U.S. Coast Guard. 



Thin-layer chromatographic screening of sediments . A measured volume of 

 sediment (5 cubic centimeters) is extracted with 2 milliliters of spectro- 

 quallty hexane by stirring the slurry for 1 minute. The hexane is then de- 

 canted into a 5-milliliter vial and reduced in volume to 0.5 milliliter by 

 gentle warming over a hot plate. Twenty-five microliters of the concentrated 

 hexane extract is spotted on the active side of type 5A chromatographic paper 

 strip approximately 1.5 centimeters above the bottom edge. The spot is 

 allowed to dry thoroughly and then developed in a mixture of 35% petroleum 

 ether and 65% benzene for 45 to 60 seconds. The chromatographic strip is 

 allowed to dry and viewed under ultraviolet light. The presence of a blue 

 fluorescent spot is indicative of the presence of oil. The greater the 

 intensity of the fluorescence, the greater the quantity of oil. The minimum 



