1 The other thing I have done just to give a handle on the magnitude 



2 of the concentrations that we measure is compare it to average shale, 



3 this is world average shales, fine-grained sediments, which I like to 



4 assume is a commodity that is not impacted by anthropogenic inputs. 



5 So, this is non-contaminated sediments, if you compare it and it's 



6 about the same, you can assume that the sediments are not highly 



7 contaminated. If you were to plot data from Boston Harbor against 



8 average shale, you'd find that the histogram goes off the scale to the 



9 top. 



10 We plot average shale as an enrichment factor, we assign a value 



11 of one to that value. You can see two things, first of all the 



12 histograms for the other metals, cadmium, chromium, copper, and lead, 



13 are not dramatically higher than what we find for average shales. 



14 I can point out, however, that lead is the only metal that we 



15 found on the continental slope at all which has an enrichment in the 



16 surface sediment compared to deeper levels. That story is a consistent 



17 one all along the East coast in fine-grained sediments. 



18 I think the argument stands that this is a reflection of the use 



19 of [inaudible] lead in gasoline making its way to the marine environment 



20 and showing up in the surfaces of some of these cores. 



21 The other important point from this diagram is that in each case, 



22 for these particular metals, in fact, I should say for only these 



23 metals, the 12 we analyzed, we find a consistent pattern of cadmium 



24 being higher in the canyon axis than on the continental slope, similar 



25 for each of the four metals. 



26 So, on the basis of these very low levels of metals, we still can 



27 see a consistent increase in the canyon axis where increased scavenging 



28 is expected than on the continental slope. 



29 I would like to get into the last line of evidence that suggests 



30 there is greater scavenging in the canyon axis than on the continental 



31 slope, and this comes from just a very small amount of data, two cores, 



32 taken from about 630 meters in Lydonia Canyon and on the open 



33 continental slope some distance to the west. 



67 



