IV-398 



The shoreline development creates problems similar to those 

 discussed under municipal and industrial waste sources. 



Mining from the estuary floor causes alteration of the estuarine 

 shape and water circulation characteristics. A secondary effect 

 is the turbidity problem associated with material removal. Mining 

 of sand and gravel from the estuarine floor is universal, while 

 oyster shell dredging in any great quantity is restricted to the 

 Gulf coast. These operations remove part of the estuarine floor 

 with a concomitant destruction of habitat and life. There are 

 also great amounts of suspended and settleable solids frequently 

 released into the water, from which they are redeposited in other 

 places. Phosphate mining, common in North Carolina and Florida, 

 may introduce nutrient phosphates and toxic fluorides into the 

 water. 



Extraction of minerals from sea or estuarine water is the third 

 type of mining activity. Minerals extracted include common salt, 

 magnesium oxide, magnesium metal and bromine. Available informa- 

 tion indicates that the pollutional impact of the water extraction 

 process is insignificant. 



The extent of estuarine mining activities is shown in Table IV. 2.8. 

 On a nationwide basis the sub-bottom mining industry is restricted 

 to the Gulf coast of Texas and Louisiana, and the coasts of 



