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Temporal variability of selected dissolved elements in the lower Orinoco River, Venezuela
Author(s) -
Mora Abrahan,
Alfonso Juan A.,
Sánchez Luzmila,
Calzadilla Malvis,
Silva Soraya,
LaBrecque John J.,
Azócar José A.
Publication year - 2008
Publication title -
hydrological processes
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.222
H-Index - 161
eISSN - 1099-1085
pISSN - 0885-6087
DOI - 10.1002/hyp.7159
Subject(s) - alkalinity , weathering , evaporite , tributary , dissolved organic carbon , carbonate , environmental chemistry , total dissolved solids , precipitation , geology , chemistry , mineralogy , hydrology (agriculture) , environmental science , sedimentary rock , geochemistry , physics , cartography , geotechnical engineering , organic chemistry , environmental engineering , meteorology , geography
Monthly analyses of pH, conductance, alkalinity, total suspended solids, dissolved major cations (Na, K, Ca and Mg), and selected dissolved trace elements (Fe, Al, Mn, Cu, Zn and Cr) were conducted on waters of the lower Orinoco River from February 2004 to May 2006. The data show strong seasonal variability. Major cations had maximum concentrations at low water, and were correlated with pH, conductance and alkalinity because of the tributaries coming from the Andean zones, where the weathering of evaporites and carbonate shales controls water chemistry. K concentrations did not show any relation with evaporite weathering, probably because large amounts of K come from the Guayana Shield rivers as a consequence of feldspar weathering. The concentrations of dissolved Fe, Mn and Cu were highest during the high water stage. Concentrations of the elements K, Cr, Zn and Cu are correlated with each other but not with dissolved Fe and Al, which probably are complexed with humic and fulvic substances. Mn concentrations did not show relationships with other variables. Inter‐annual variability of dissolved elements is explained by temporal changes in precipitation. Copyright © 2008 John Wiley & Sons, Ltd.