A Contribution to the Hydrochemistry and Water Typology of the Amazon River and Its Tributaries

Abstract

The geological diversity of the Amazon Basin, as well as the pluvial regime, influences the characteristics of the waters. To know the water types of the rivers of the Amazon basin, 288 superficial water samples were collected, 94 of them along the Amazon River and 194 in their tributaries, from March 2009 to September 2012. The physical, chemical, and physicochemical properties were analyzed. Rivers with pH between 6.5 and 7.6 and electrical conductivity (40.00 - 80.00 μS cm-1) are water bodies that are influenced by the Andean region (e.g., the Amazon River and some of its right bank tributaries). On the other hand, the rivers with pH in the range of 3.5 to 5.5 and conductivity <30.00 μS cm-1, which are Amazon River’s left bank tributaries, reflect the characteristics of the Guiana Shield. The rivers with pH (6.0 to 7.0), low ionic charge, and conductivity <40.0 μS cm-1, such as the lower Amazon River’s right bank tributaries (Tapajos and Xingu) which are influenced by the Central Brazilian Shield, and also the middle/upper Amazon River’s right bank tributaries (Tefé, Coari and Jutaí).

The physical-chemical characteristics of surface waters in the management of quality in clearwater rivers in the Brazilian Amazon

“…Other studies of different types of Amazonian rivers found similar results. Rodrigues- Filho et al (2015) found DO below 5.0 mg/L in some stretches of the Xingu River, as did Silva et al (2019), who found DO concentrations below 6.0 mg/L for the Negro and Trombetas Rivers, and below 5.0 mg/L for the Nhamundá I River. Silva et al (2013) studied several parts of the Amazon River and found DO concentrations below 5.0 mg/L.…”

“…Wasserman et al (2019) found pH below 6.0 for most Amazonian rivers of different types. Silva et al (2019) found values below 5 in the Urubu River. Rios-Villamizar et al (2020) found pH below 5 in blackwater rivers, and below 6 in clearwater rivers, which were classified as acidic and not in accordance with Resolution 357/05.…”

Hydrochemical Classification of Amazonian Rivers: A Systematic Review and Meta-Analysis

“…From literature (RÍOS-VILLAMIZAR, 2013;RÍOS-VILLAMIZAR et al, 2014, 2016, 2020a, 2020bSILVA et al, 2019) we collected data available on hydrochemistry of rivers and streams (Figure 1 and Appendix). For that purpose the web sites of Science Direct, Google Scholar, Springer Link and Scielo, among others, were consulted.…”