35 



I have given in this table also a column showing the toxicity of 

 these various heavy metals. The ratio of the rate of supply to the 

 toxicity gives the volume of water that would be raised by an annual 

 increment of the amount presented as the toxic level by the rate of 

 addition which is presented under the term "rate of mobilization." 



This is in metric units, and perhaps it is worth bringing this in 

 ^perspective in terms of what they mean in common language. 



The units 10 to the 12th litei-s per year is really the number of cubic 

 kilometers of seawater that would be raised to the toxic level of 

 concentration. 



I might also point out, which is not emphasized in the table, that 

 the value given for mercury is very nearly the value naturally present 

 in the seawater. Many others are present at much lower concentra- 

 tions than these toxic levels. 



To further put these numbers into perspective, one can compute 

 the area of the oceean's surface which would be contaminated to this 

 degree with a point source of release. 



Taking the mixed depth of the ocean as 100 meters the release of 

 mercury by the combustion of fossil fuel would contaminat a surface 

 area of 160,000 square kilometers to a dapth of 100 meters. This is 

 equi\-alent to 61,500 square miles, and for interest, I looked up the 

 area, the land area of the State of Washington — Senator Mangnuson, 

 the chairman of the committee, might l3e interested in this — and 

 this 61,000 square miles is about equal to the land area of the State of 

 Washino-ton. It is almost twice the area of the State of South Carolina, 

 represented by you, Mr. Chairman. 



It is clear "that we are not talking about an insignificant problem 

 from mercury, which is the most serious hazard in this regard, and 

 even for some of the other metals there are considerable volumes or 

 areas of the ocean which might well be contaminated by the release 

 of these elements in the world that man is adding to the natural cycle. 



In terms of the chlorinated hydrocarbons, one of our problems is 

 that we do not know the rate at which these decompose in seawater 

 as yet. Woodwell has made estimates that it would take over 20 years 

 to remove 90 percent of the DDT which is at present in the ocean, and 

 I have also quoted some data in the text on the amount of DDT and 

 of PCB's which have recently been found in organisms living in the 

 open sea many, many miles from shore. 



Again, the units here are given in metric terms, but they correspond 

 to parts per billion, rather than the parts per million that we were 

 talking about earlier. 



I would like to also state that there are many new synthetic organic 

 chemicals that are being made each year, including other pesticides, 

 detergents, and pharmaceuticals, and 'these are reaching the environ- 

 ment with impacts which are virtually unknown. 



I think we can skip now to a diagram that I have presented 



Senator Hollings. Before you get to that diagram, doctor, on sul- 

 furic acid, have you got work on that? We had the threat of an ocean 

 dump far out at sea. It was a great thing, acccording to a lot of scien- 

 tists. In fact, they were saying that the fish got brighter and brighter, 

 and they almost had you believe that we ought to put it in there, but 

 w^hen they said it did not contaminate, and you put some in a glass of 

 water and asked them to drink it, they would not. 



