1 AFTERNOON SESSION 



2 (2:10 p.m.) 

 3 



4 DR. AURAND: So, dealing with the concept of impacting agents and 



5 conclusions, Jerry, can we go ahead and write down what you would think 



6 maybe would be the main points? You can just talk and I will write. 



7 DR. NEFF: Obviously, the impact-causing agents, let's assume the 



8 scenario of a drilling rig, an exploratory rig about a kilometer from 



9 one of the canyons, which I think is the most reasonable scenario. 



10 The two areas of concern are drilling muds and drill cuttings. In 



11 that situation, you would get, presumably finer fractions of the mud 



12 into the canyonhead or into the canyon, depending on where. That is 



13 your major impact-causing agency associated with any exploration 



14 activity. 



15 There is a remote possibility of oil spills, but the likelihood of 



16 an oil spill during an exploration is not terribly greater than the 



17 likelihood of an oil spill at any other time, I guess. There's not a 



18 lot of oil . 



19 DR. AURAND: Actually, it's less, according to the statistics. 



20 DR. AYERS: How about biological impacts, say, a kilometer away? 



21 DR. NEFF: That's what I was getting to next. If you have mud and 



22 cuttings presumably falling through the water column and diluting, 



23 fractionating, so basically what you have is mud solids and some 



24 cuttings accumulating on the bottom of the canyon, that could affect 



25 local fauna through burial or chemical toxicity. 



26 Available data, which is fairly substantial, would indicate that 



27 the chemical toxicity problem is probably very minor. There is just not 



28 much left in the solid fraction by the time it has gotten away that 



29 could cause any problems. 



30 In terms of metal , bio-accumulation, contamination, tainting, 



31 whatever you want to call it, is obviously the other concern. Of the 



32 metals in drilling, probably only chromium, lead, and zinc are 



33 potentially toxic if they were accumulated by the animal. To my 



34 knowledge, barium to tissues is not toxic when ingested. That would be 



260 



