Electrochemical attributes of water from Cerrado wetlands (Veredas), Triângulo Mineiro region, Brazil

Abstract

Veredas are wetlands typically found in the Brazilian Cerrado playing important environmental functions. The hydromorphic conditions control important processes and reactions occurring in these environments. The objective of this study was to assess the pH, redox potential (Eh), and electrolytic conductivity (EC) of water from five veredas located in the Triângulo Mineiro region, nearby Uberlândia and Uberaba, Minas Gerais State, Brazil. The pH and EC of water samples (in triplicate) collected in different positions (upper, middle and bottom) of the selected wetlands were monitored monthly from September 2014 to September 2015. Eh was monitored in an incubation experiment using soil samples from the superficial layer (0-20 cm) and subsurface layer (40-70 cm) of the middle position of two of the selected veredas. In general, pH ranged from 3.4 to 6.5 throughout the year. For EC, the values ranged from 1.0 to 67.0 µS cm-1. Most of the year, pH was between 4.2 and 5.1 and EC was around 9.0 µS cm-1. Under laboratory conditions, Eh decreased from oxidic conditions to suboxidic (reduced) conditions. There were no significant differences between the wetlands and soil layers regarding the variation of Eh.