CHEMICAL COMPOSITION OF RIVERS AND LAKES 



G37 



Table 72. — Miscellaneous analyses, in parts per million, of South 

 American waters 



(Analyses A-C are from unpublished records of the Ministerio de Fomento y Obras 

 Fublicas of Peru. This Ministry has accumulated many partial analyses of lake 

 and river waters and many complete analyses of spring and well waters in addition 

 to the few presented here] 



i By calculation. 



A. Laguna Encantada, Peru, Jan. 11, 1957, analysis by E. Zapata VaUe and E. 

 Camet. 



B. Agua de Vitarte, Peru, Oct. 26, 1956, analysis by E. Arciniega and E. Camctt. 

 (May be ground water.) 



C. Agua de Puquio, Peru, June 10, 1952, analysis by E. Camet and E. Arciniega. 

 (May be ground water.) 



D. Lagoa Escondida, Estado de Mato Grosso, Brazil. Campos Paiva (1944, p. 

 47-48). 



E. Barima River above Eclipse Falls, British Guiana. Clarke (1924b, after Harrison 

 and Reid, 1913). 



F. Essequibo River above Wataputa Falls, British Guiana, Clarke (1924b, after 

 Harrison and Reid, 1913). 



G. Demerara River above Malalli FaUs, British Guiana, Clarke (1924b, after 

 Harrison and Reid, 1913). 



H. Courantyne River, British Guiana, Clarke (1924b, after Harrison and Reid, 

 1913). 



ions. The rivers of British Guiana are rather dilute and 

 remarkably high in silica. 



In addition to the analyses cited here there are more 

 of the same kind in Kyle (1897), and numerous analyses 

 lacking most or all of the major cations in Sioli (1950, 

 1951, 1953, 1955), Catalano (1927), Manoff (1939), and 

 Freise (1937). Derkosch and Loffler (1961) present 

 data for 9 cations and semiquantitative information 

 about trace elements in 25 Andean lakes. 



The best analyses for the Amazon system are recal- 

 culated from the previous edition of this book and pre- 

 sented in table 73. There are many recent analyses 

 of water from Amazonia, particularly in a number of 

 papers by Sioli (1950, 1951, 1953, 1955) but they lack 

 most or all of the major cations. It is remarkable 

 that the few scraps of data presented in table 73 should 

 have stood virtually alone for so long, not only as the 

 best information about the Amazon, but also as the best 

 for any large humid tropical river. They have, perforce, 

 figured largely in all global computations of hydro- 

 geochemistry, and they should be replaced by a more 

 nearly comprehensive series of data. 



No new data are available for the southern part of 

 South America nor is any work in progress. Pastore 

 and Huidoboro (1952) is said to contain partial analyses 



Table 73. — Analyses, in parts per million, of water from the 

 Amazon River and its tributaries 



[Analyses A-D are from Clarke (1924b)] 



i Computed from Ali03+Fe20a on the basis that Fej03 alone was present. 



The Amazon at Obidos. Mean of 2 analyses by F. Katzer, 1903. 

 The Amazon between the Narrows and Santarem. Analysis by P. F. Frank- 

 land. 

 The Tapajos. Analysis by F. Katzer, 1903. 

 The Xingu. Analysis by F. Katzer, 1903. 



of 37 waters of Argentina, but it has not been available 

 for consultation and may deal with wells and springs. 

 A selection of the old data is presented in table 74. 

 The generally high silica content of these waters is 

 their outstanding characteristic. 



Table 74. — Analyses, in parts per million, of water from rivers in 

 the southern part of South America 



[Analyses recalculated from Clarke (1924b)] 



A. Rio La Plata 5 miles above Buenos Aires. Analysis by J. J. Kyle, 1878. 



B. The Parana 5 miles above its entry into La Plata. Analysis by J. J. Kyle, 1878. 



C. The Uruguay midstream opposite Salto. Analysis by J. J. Kyle, 1878. 



D. Rio Primero, Argentina. 



E. Rio SaladiUo, Argentina. Analysis by A. Doering, 1883. 



F. Rio de Arias, Salto, Argentina. Analysis by M. Siewert, 1883. 



G. Rio de los Reyes, Jujuy, Argentina. Analysis by M. Siewert, 1883. 



GLOBAL COMPUTATIONS 



With the data for the composition of some of the 

 major rivers of the world at hand, it is possible to esti- 

 mate the mean composition of river water and the total 

 amount of chemical substance carried to the sea by the 

 rivers of the world. For this purpose it is necessary to 

 have some information about the area of the land sur- 

 face of the world and about the runoff of the various 

 rivers. The following computations have been based 

 principally on the discharge tables in a mimeographed 

 copy of the "Recommendation of the International 

 Association of Scientific Hydrology" which was accepted 

 by the Council of the Association and presented to the 

 delegates on September 13, 1957. The tables form the 

 basis for a resolution that a river-sampling net be set up 



