264 



These tables show industrial water use for the coastal States, not 

 for the coastal counties only, but nearly all wastes discharged into 

 the waters of these States ultimately reach estuarine waters. Only 

 4,000 of the more than 200,000 manufacturing plants in the coastal 

 States account for 97 percent of the total liquid wastes discharged. 

 Of the nearly 22 billion gallons of industrial wastes discharged daily, 

 only 29 percent receive any waste treatment. The Pacific Southwest 

 biophysical region has the greatest percentage of industrial wastes 

 treated, while the North Atlantic biophysical region has the least. 



Of the major water use industries shown in table IV.5.8. the petro- 

 leum and coal products industries have the highest percentage of 

 wastes treated and the chemical industries have the least. These five 

 industrial groupings are responsible for 76 percent of the total volume 

 of industrial wastes discharged in the coastal States. 



The primary metals and petroleum and coal products industries are 

 centralized in the Middle Atlantic, Gulf, Pacific Southwest, and 

 Pacific Northwest regions, but the other major water use industries 

 are distributed throughout all regions. The kinds of wastes associated 

 with food, paper, and chemical manufactures are therefore universal 

 problems, while the other major industrial waste types concern only 

 particular estuarine environments. 



This discussion considers only the volumes of wastes either treated 

 or not treated; it does not consider the level of treatment provided. 

 Some industrial wastes, including those from all major water use 

 industries, require extensive treatment before disposal to the environ- 

 ment. Others do not require anything other than settling and clari- 

 fication. The percentages of wastes treated, however, do give an idea 

 of relative concern for the environment expressed in action by the 

 industrial and institutional communities. 



Desalination operations and the ever-growing nuclear power facili- 

 ties are new kinds of industry representing potential environmental 

 problems. Salt water conversion plants remove dissolved materials 

 from water to make it fit for municipal consumption and industrial 

 process use. In the case of sea water, where salt concentrations are as 

 high as 33,000 mg/1, the purification of each million gallons of water 

 results in a waste containing almost 300 pounds of impure salts. Nu- 

 clear operations present a completely different problem — ^that of pro- 

 tecting the environment from exposure to harmful ionizing radiatlion. 

 Since environmental exposure must be held to a minimum, careful 

 control and monitoring of existing and potential radiological waste 

 sources are essential. 



DREDGING AND FILLING 



Intensification of use of the estuarine zone has resulted in many 

 artificial changes being made in its physical structure. Shoreline areas 

 have been filled to create more land area for residential and commer- 

 cial use ; channels have been dredged and maintained to permit safer 

 and better navigation; harbor facilities have been dredged; bridges 

 and causeways have been built. All of these activities have impact on 

 the coastal zone ecosystem, but the activities having the most impact 

 on water quality are dredging and filling. The potential for pollution 

 of the system exists in both filling and dredging; both can introduce 

 foreign materials into the water, destroy aquatic habitat, and alter 



