Hidroquímica dos rios Curuá, Caxiuanã e Baía de Caxiuanã, Melgaço - Pará

Abstract

This research discusses the hydrochemistry of Curuá, Caxiuanã Rivers and Caxiuanã bay waters in order to demonstrate the influence of short-term climatic variables (precipitation and temperature) on the chemical composition of these water bodies. Samples were collected monthly between January 2006 and December 2010, from five sampling points. The following parameters were analyzed: major cations and anions; silicon, iron and aluminum, breathing rate, dissolved organic and inorganic carbon, free CO2, methane and suspended material. The results do not showed significant variability of the physic-chemical and chemical constituents (T, pH, electrical conductivity, cations, anions, breathing rate, organic and inorganic carbon dissolved free CO2, methane and suspended material) for Curuá, Caxiuanã River and also in the Caxiuanã bay over the study time. Only the dissolved organic carbon, showed a direct relationship with rainfall. The Piper diagram enables classify the waters of the region Caxiuanã as sodic calc-magnesian-chlorinated. As the studied area is one region without anthropogenic influence, the lack of variations during the study period, suggests an equilibrium system.