34 



Senator Holijngs. This is in ^ood support of the Toxic Substances 

 Act. This committee has just reported it out — it has not come out 

 actually, but the committee voted last week and it will be reported 

 out and considered by the Senate, no doubt, in the next 2 or 3 weeks. 



Dr. Ketchum. Very good. I think it is an important aspect of this 

 whole problem. 



You then summarize exactly the same type of material, the heavy 

 metals, the chlorinated hydrocarbons, the oil pollution in the sea, all 

 of which are both produced in large quantities, are toxic, and all of 

 which are persistent in the marine environment. 



Domestic pollution is somewhat different insofar as it is essentially 

 a natural product of human metabolism. This can be decomposed in 

 the marine environment. 



Senator Hollixgs. What about that sludg( we were talking about a 

 little bit earlier? For example, when we put in sewage disposal and 

 treatment facilities at the city of Charleston, and as a result, have 

 been able to open up about a $60 million area of oyster beds that had 

 been closed since 1926. 



What I am saying is that we hav^e taken care of the sludge. 



Dr. Ketchum. Sewage treatment plants are aimed at reducing the 

 total organic effluent. Much of this is decomposed in the treatment, 

 and some accumulates in the sludge, and this sludge must also be dis- 

 posed of in some way with proper treatment. Provided it does not in- 

 clude toxic materials from industrial wastes, it can be used as a soil 

 conditioner, as landfill. 



It is rather a poor fertilizer, but it can be beefed up with the addi- 

 tion of certain chemicals and make it into a fertilizing material and 

 returned to the land, which after all, is where the major share of our 

 food comes from, and it is this recycling to the land which should be 

 our objective. 



We also have considerable problems in the disposal of solid wastes 

 and the problems of the persistent plastic materials which are becom- 

 ing more and more common in our usage today. 



That has already been mentioned by Dr. Martin. 



I would like to make a few comments on the term "toxicity," how- 

 ever, because this is a difficult word to define and it is not always well 

 understood. 



Any substance on earth is toxic if the concentration is great enough 

 in the wrong environment. ¥ov example, a characteristic of the marine 

 environment is the salt content of the water, but most marine organ- 

 isms can survive only within a narrow range of salinitv. Estuarine 

 organisms may not be able to survive in the open sea where the salinity 

 is hiijher. Many other examples can be given. 



Our concern, our gi-eatest concern, is witli those materials which are 

 toxic or lethal in concentration in the range of parts per million or less. 



I would like to refer to the table I inti-oduced and it appears in my 

 testimony. It is an efl^ort to put some quantitative evaluation on the 

 various heavy metals that are toxic and ai-e critical in terms of being 

 produced in large quantities and reaching the enviromnent in consid- 

 erable quantities. 



Many of these metals are present in coal and oil and when these 

 materials are burned, they are released to the atmosphere and ulti- 

 mately return either to the soil or to the oceans. 



