137 



Dr. Bolton. For instance, if you were to have a baseline of heavy 

 metal concentration of 50 to 100 parts per million (ppm), perhaps 

 in Baltimore Canyon or Georges Bank, you might typically find a 

 baseline of 300 or 400 ppm in some parts of the Gulf of Mexico. 

 These are purely hypothetical values. An increase of 5 to 10 ppm 

 would be significant in the first instance, and not significant in the 

 latter. The starting level of the contamination of the muds is much 

 higher. Whether all of the contamination in the gulf is from drill- 

 ing effluents is questionable; I certainly would not want to be held 

 to it. There is an awful lot of contamination in the Gulf of Mexico 

 coming from the Mississippi River which spreads across a good bit 

 of the northeastern gulf shelf. 



Mr. Wyatt. Have we shown damage from heavy metals, the 

 difference in the 3 to 400 parts per million? 



Dr. Bolton. There are a number of studies which could indicate 

 that the level of chromium and other heavy metals found certainly 

 could be a cause of concern. Chromium is one of the higher con- 

 stituent metals of drilling fluids. Cadmium is also found in higher 

 concentrations in the area, and that is a very toxic metal. 



Mr. Wyatt. That has shown up in shrimp, fish? 



Dr. Bolton. These references are from sediment studies. 



Mr. Wyatt. Well, what is the problem with those high concentra- 

 tions, I guess is what I am asking. 



Dr. Bolton. All right. Many fish and other organisms feed on 

 and in the benthos, in the muddy substrate. And if organisms are 

 living in that material and are benthic feeders, they may concen- 

 trate or at least accumulate a certain amount of heavy metals from 

 that sediment. Those organisms in turn can be eaten by other 

 organisms. So it is very possible to pass concentrations of heavy 

 metals through the food chain. The example used before of Mina- 

 mato Bay in Japan, with mercury contamination, is a good demon- 

 stration of this effect. 



Mr. Wyatt. You then from these basic studies of sediment have 

 detected a higher concentration of either cadmium or chromium in 

 shrimp from the Gulf of Mexico? 



Dr. Bolton. In the sediment. I am basing most of what I am 

 saying on sediment data. BLM's EIS on one of the gulf areas 

 specifically makes reference to the higher concentrations of heavy 

 metals 2 years after the location of the drilling rig. 



Mr. Wyatt. Of the what? 



Dr. Bolton. Of a rig in a sediment area. So I am really basing 

 my comments on the sediment concentrations. I am not that famil- 

 iar with the concentrations of the heavy metals in the organisms, 

 not so much because some of those measurements have not been 

 made, but in many cases because the measurements were made of 

 whole animals rather than of organs where metals might be con- 

 centrated. This approach results in an immediate dilution of the 

 concentrations of heavy metals. 



Mr. Studds. We will go around again if the gentleman has more 

 questions. I want to slip in, if I may, some questions that remain 

 here. 



Will the EPA discharge permits be submitted to the States for 

 consistency determinations under the Coastal Zone Management 

 Act? 



