All water samples were either immediately frozen, or were extracted with 

 hexane aboard ship (on the later Endeavov cruises) in order to stabilize any 

 hydrocarbons contained within against bacterial degradation. Frozen samples 

 were transported, using a completely documented chain of custody, by G. 

 Heimerdinger, NOAA Liaison at Woods Hole Oceanographic Institution, to the 

 USCG R&D Center at Groton, Connecticut. The water samples were then extracted 

 and prescreened for petroleum hydrocarbons (PHC) by R. Jadamec of the Center. 



A Chemical Analysis Committee, formed at a meeting at Woods Hole, Jan- 

 uary 3-4, 1977, is monitoring the continuing analyses of all water samples. 



Ultra-violet fluorescence screening of water samples 



By this procedure, one liter of sample is extracted twice, using 10- 

 milliliter portions of spectroquality hexane. The two hexane extracts are 

 combined and then analyzed by synchronous scanning ultraviolet fluorescence. 

 The excitation and emission monochromators are initially set at 255 and 280 

 nanometers, respectively. The continuous excitation-emission spectrum is 

 recorded until final settings of 475 and 500 nanometers on the excitation and 

 emission monochromators, respectively, are obtained. The resulting flu- 

 orescence spectrum reveals the distribution of the polyaromatic rings present 

 in the sample. Comparison of the sample spectrum with that of the reference 

 oil spectrum, obtained at various concentration levels, will indicate the 

 relative concentration of oil present in the sample. The sample taken from 

 surface slick by Gait and Mattson on December 19 is being used as the refer- 

 ence oil. 



The screening of water column samples is still in progress. Analyses of 

 samples collected by the USCGC's Bittersweet, Evergreen, and Vigilant di- 

 rectly beneath the slick indicate very low levels of PHC concentration. All 

 water samples analyzed indicate an absence of high-molecular-weight polyaro- 

 matic hydrocarbons at various depths beneath and around the slick from Decem- 

 ber 20 through December 31. The absence of 4- and 5-ring polyaromatic com- 

 pounds in the water makes it difficult to use the whole oil as a concentra- 

 tion standard. As a temporary compromise, the 2- and 3-ring portion of the 

 whole oil spectrum was employed as the concentration reference. The error 

 this introduces is one of slightly overestimating the amount of oil present 

 in the water column samples. Using this method of calibration, as well as 

 calibrating against the API "pool" No. 2 fuel oil (available from the Biology 

 Department, Texas A&M University), the highest petroleum hydrocarbon (PHC) 

 concentrations measured were approximately 250 parts per billion. These were 

 found in samples taken beneath the slick by the USCGC's Vigilant and Bitter- 

 sweet. Samples on these cruises were taken at two depths ranging from 1 to 

 10 feet below the surface. It is in the deeper of the two samples that the 

 highest concentrations were found according to R. Jadamec. It is the con- 

 sensus of the chemical analysis committee that the oil observed in the water 

 samples is actually the "cutter stock," which represents about 20% of the 

 cargo oil. An effort is being made by P. Fricke of WHOI to obtain an authen- 

 tic sample of this "cutter stock." When a sample is obtained, the water 

 column samples will be corrected to it as a new standard. 



75 



