1 particles and moving the contaminants that are associated with them into 



2 the sediment column. 



3 Not only do we find that the plutonium shows this sort of a trend. 



4 I'd like to illustrate that lead-210, which has a little different 



5 introduction, lead-210 is a naturally occurring isotope, it hasn't been 



6 pulsed in as a result of man's activity. It has a major source from the 



7 atmosphere, but it also has a source from the decay of radon-226 and 



8 seawater. 



9 It shows in inventory and in profile a very similar shape and 



10 magnitude as the plutonium. That is that the inventories of lead-210 



11 are about two and a half times greater than they are in the continental 



12 slope sample, and that the depth of penetration of lead-210, which has a 



13 half life of 22.3 years, is far greater than you can expect without 



14 invoking significant biological reworking in this particular area. 



15 Let me close by showing you a map that shows the inventories of 



16 lead-210 in the areas where I've had a chance to measure it. You find 



17 it on Georges Bank. Page said clearly that it was an erosional area, 



18 and you can see that in the coarse sediments of Georges Bank there, 



19 there is essentially no excess lead-210 in one particular sample in very 



20 coarse-grained sediments. 



21 In the mud patch, so-called, the anomalous area of fine-grained 



22 sediments that exists on the continental shelf, south of the islands, we 



23 finda significant amount of lead-210. In the canyon axis, however, in 



24 Lydonia Canyon, we have the highest value that we've measured anywhere 



25 on the east coast. 



26 I think this argues for the fact that there is a potential for the 



27 accumulation of contaminants in the axis of this particular canyon, on 



28 the basis of some of the sedimentary processes that we've documented in 



29 other phases of our program. 



30 Thanks a lot. 



31 DR. MACIOLEK: Any questions for Mike? I have one, of course. 



32 You showed us some information from 550 meters from the North Atlantic 



33 study, did you look at the pattern at 2,100 meters, the slope/canyon 



34 comparison there; station 8 in the canyon? 



69 



