IV-408 



(Figure IV. 5. 25) or as subtle and invisible as the pathogenic 

 organisms which may accompany it. 



Table IV. 5. 11 lists some estuarine systems with severely degraded 

 water quality. While not exhaustive, this list shows the extent of 

 water quality degradation in many of the estuarine systems of the 

 United States, and it gives a general appreciation of the kinds of 

 water quality damage that now exist. The data in this table show 

 only that water quality degradation exists in the estuarine systems 

 listed. In many cases the data available are not sufficient to 

 determine specific sources of the pollution or how to correct 1t. 



DAMAGE TO ESTUARINE ECOSYSTEMS 



Pollutional damage to estuarine ecosystems may be sudden and dramatic 

 as fish or other aquatic life forms suddenly dying, or 1t may be so 

 gradual as not to be noticed for many years. 



Fish kills such as those shown in Figure IV. 5. 26 are readily 

 apparent even to the casual observer; their causes are sometimes 

 not so easy to determine. Industrial wastes appear to be respon- 

 sible for the majority of fish kills in 1966, the last year for 

 which data are available, with food processing being the most 

 common industrial activity responsible. The estuarine brackish 

 and salt waters, however, had less than one percent of the fish 

 casualties reported; probably one reason is the enormous volumes of 

 waters available for dilution of waste discharges. (IV-5-11) 



