by a consideration of regional geology. For example, brines are not likely to be 

 found in New England, but chloride from sea water is found in streams and 

 ground-water reservoirs or aquifers near the coast. Unless extensive intrusion is 

 caused by human activities such as excavations or ground-water removal, the 

 latter is significant only in a fairly narrow coastal strip. 



Saline water in sedimentary rocks may also emerge in springs at the surface of 

 the earth. Depending on original depth, such water may be warm or hot. Also, 

 springs associated with volcanoes or recent volcanic activity may contain 

 chloride. It is beyond the scope of this paper to discuss whether this chloride 

 actually comes from the depths of the earth or is recycled sea salt. As with the 

 cases discussed above, the likely presence of such sources is best determined 

 from geological considerations. 



SOURCES ASSOCIATED WITH MAN 



The Minerals Yearbook for 1971 1? gives the following breakdown of salt used 

 in the United States in 1970: road deicing salt - 23 percent; food and 

 food-related uses — 17 percent; water softeners - 5.6 percent; and all other uses, 

 mainly industrial — 54.4 percent. A detailed source-by-source discussion would 

 become lengthy and confusing, so the approach will be to aggregate sources into 

 major categories of sewage and septic tank effluents, industrial effluents, and 

 road deicing salt. The sources associated with man are more homogeneous in 

 distribution than are the natural sources, hence they are as important in New 

 Hampshire as elsewhere. 



Ordinary Sewage and Septic Tank Effluents 



Contributions of chloride from human wastes undoubtedly vary with climatic 

 and other factors, but a reasonable value is that each human being contributes 

 about five to nine grams of chloride in excreta per day 1^17 which is equivalent 

 to four to seven pounds per capita per year. Kitchen and normal commercial and 

 manufacturing wastes contribute on the order of 14 pounds per capita per year, 

 and this combines with the human excreta value for a rule-of-thumb value of 20 

 pounds per capita per year contribution of chloride from these sources. ^^ In 

 general, the chloride level in effluents is raised some 40 to 80 mg/£. over the 

 basic value in the effluent-bearing water. 



15 I. U.S. BUREAU OF MINES, MINERALS YEARBOOK, 1971, METALS, MINERALS, 

 AND FUELS 1031-1041 (1973). 



16c. N. SAWYER & P. L. McCARTY, CHEMISTRY FOR SANITARY ENGINEERS 378 

 (2nd ed. 1967). 



17 G. M. FAIR, J. C. GEYER, & M. C. MORRIS, WATER SUPPLY AND WASTE WATER 

 DISPOSAL 549 (1954). 



18 O'Connor & Mueller, A water quality model of chlorides w Great Lakes, Proceedings 

 American Society of Civil Engineers 96, No. SA4, 955-975, 1970. 



