Avaliação da qualidade da água de área úmida localizada na Bacia do Rio Corumbataí (SP) - Brasil

Water quality assessment of wetland located in the Corumbataí River Basin (SP) - Brazil

Abstract

Isolated topographic depressions located in interfluves that accumulate rainwater and have a high water table are environments of high hydrological and hydrochemical relevance. The objective of this research was to evaluate the hydrochemistry of a geographically isolated wetland (GIW) surrounded by sugarcane crops, located in the Corumbataí River Basin, through laboratory analysis. Four monitoring wells (P) were installed in the GIW, water samples were collected bimonthly and the water table and physical and chemical parameters were measured (in situ). The waters presented high values ​​of Ce and HCO₃^- even during rainy periods. Concentrations of PO₄^3-, SO₄^2-, Cl^-, NO₃^-, CO₃^2-, HCO₃^-, Na⁺, Ca²⁺, K⁺ were found, especially in P4 in September/2021. These elements do not belong to the essential constituents of the minerals of the Rio Claro Formation, which supports the GIW, and can be found in the composition of fertilizers (PO₄^3-, NO₃^-, Cl^-) and soil conditioners (SO₄^2-, CO₃^2-), some associated with the cations K⁺, Ca²⁺ and Mg⁺² or as disintegrants of fertilizer granules(NaHCO₃). The PCA analysis indicated that P2 and P4 are possibly the most impacted and rainwater may be the main element of chemical control of the GIW waters.