1 We want to keep our eye on the polynuclear aromatic hydrocarbons, 



2 because those really should be the main focal point of any of these 



3 types of studies. Again, they range from the low part per billion in 



4 some of the coarse-grained areas to the two part per million total 



5 PAH's. We'll talk about that in a minute and what that means. 



6 In the depositional areas, the mud patch areas to the west of the 



7 study area, and then the slope and rise, again, sort of intermediate, 



8 but in the 100s of ppb that's fairly typical. So, high pollutant levels 



9 in the slope and mud patch areas. 



10 We'll be looking at some of this, but just in summary, the PAH 



11 compounds are generally—that we find in the whole system are generally 



12 of a non-fossil fuel origin. What I mean by that is they are basically 



13 a source of combustion of fossil fuels, more combustion processes, 



14 presumably on shore and then transported off shore. 



15 We'll see in the PAH composition that this conclusion arises from 



16 that. That this fossil -fuel index that we sort of invented several 



17 years ago to define the ratio of fossil fuels to total PAH's, are 



18 generally in the 20 to 50 range. It would be 100 if they were all 



19 petroleum material . 



20 So, 20 to 30 percent of PAH's generally can be ascribed to fossil, 



21 the vast majority of it is of a combustion origin. So that's the 



22 concentration overview. 



23 Through the Georges Bank benchmark program, especially, and to a 



24 less extent in the other studies, we have a reasonably good picture of 



25 the seasonal distributions of hydrocarbons. These are the conclusions 



26 and I'll back them up in the next few slides. 



27 In general, and I don't mean these as absolute, but on a gross 



28 level, defined by our sampling scheme and by the seasonality being four 



29 times a year, total hydrocarbons do not vary seasonally in the entire 



30 study area. 



31 The terrigenous plant material, and these are plant waxes which, 



32 for the most part, make up the large part of the hydrocarbon 



33 composition. These also did not vary seasonally. The implication here 



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