1 But when you put it in water, the chromium is introduced as six 



2 sometimes. It is a question of what form it is in, but anyway, the six 



3 tends to be reduced to three because of the organic material in the 



4 water. 



5 Even though the geochemists will tell you that six is the stable 



6 phase, you can't get the three back to six very easily because of the 



7 slow kinetics and the fact that the three binds very tightly to 



8 particles, so basically, what settles on the bottom is three and that is 



9 quite insoluble. 



10 DR. RAY: Certainly, I think it is worth knowing that even at high 



11 levels in the laboratory where we test for chromium effects, you still 



12 can't come up with a good correlation between chromium uptake and levels 



13 and toxicity. So far, that's been the case. 



14 DR. NEFF: It is a tricky metal to work with, because of the 



15 multiple variances. 



16 DR. RAY: Jerry, do you also want to comment on the produced water 



17 question? 



18 DR. NEFF: On the produced water situation, assuming that it was 



19 discharged from the platform, and that is only one of several options 



20 available, the produced water is usually a saline brine, at least as 



21 concentrated as seawater. The salts are the same salts as in 



22 seawater--sodium, chloride, iron, magnesium, and calcium. 



23 The main potentially impact-causing agents are hydrocarbons--low 



24 molecular weight hydrocarbons--aromatics, benzene, and several metals. 



25 Strangely enough, it is almost the same suite of metals, but they are in 



26 a more mobile form. We don't know what the species are, but they are 



27 potentially ionic metals. 



28 The ones most likely to be high are zinc, copper, sometimes lead, 



29 so those are probably the bad actors. You rarely get high levels of 



30 cadmium and mercury. High is several -fold higher than seawater. The 



31 benchmark is the seawater, because that is what you are dumping stuff 



32 into--the seawater. 



33 My criterion for what metals are elevated is a thousand-fold above 



34 ambient level seawater. Those are the kinds of metals--barium, too. 



262 



