1 The data that I'd like to show you today really is concentrated 



2 on just one of them, just in Lydonia Canyon. I wish there was more data 



3 on some of the others, because they're all a little different as both 



4 Page and Brad have alluded already. 



5 I'd like to deal with the issue of pollutant scavenging in Lydonia 



6 Canyon. There are four lines of evidence that make me think that the 



7 potential for pollutant scavenging is greater in Lydonia Canyon than it 



8 is on the adjacent continental slope or on the adjacent continental 



9 shelf. 



10 The lines of evidence that I'll be discussing, the intensity and 



11 the frequency of sediment resuspension, which is much greater in the 



12 canyons.... Let me diverge and stop for a moment and just say that the 



13 reason that's important is the observation that the availability of 



14 fine-grained particles and the surfaces of those particles in absorbing 



15 contaminants from sea water has been well -documented. 



16 So, if you have a mechanism that puts absorbers into the water 



17 column to remove pollutants, those pollutants then may be carried by the 



18 fine-grained materials and they may control the transport. 



19 The second line of evidence that I'll be discussing are some 



20 recent rates of accumulation that we've measured in piston cores in the 



21 area. Then I'd like to show you some trace-metal data from surface 



22 sediments that suggest that the canyon axis is, indeed, an area of 



23 preferential deposition of contaminants, 



24 Finally, and perhaps the most compelling evidence, is the 



25 distribution of radioactive isotopes plutonium and lead-210, both which 



26 can be considered as analogues for contaminants--for sediment and 



27 reactive contaminants in sea water. I'll show you that there are 



28 inventories in the canyon axis that are greater than in areas outside 



29 the canyon. 



30 First let's talk about sediment traps and the flux of resuspended 



31 sediment. This diagram shows the different types of sediment traps that 



32 we used during the Lydonia Canyon experiment that Brad summarized 



33 earlier. 



60 



