Chemical characteristics of rainwater at a southeastern site of Brazil

Abstract

A total of 50 rainwater samples were analyzed in order to investigate trace elements in wet precipitation of Juiz de Fora City, during February, 2010 and February, 2011. Samples were analyzed for major cations (H3O+, Na+, NH4+, K+, Mg2+ and Ca2+) and anions (NO3−, SO42−, Cl− and HCO3−), hydrogen peroxide (H2O2), some trace metals (Cu2+, Zn2+, Cd2+ and Pb2+), as well as some other physicochemical aspects like pH, conductivity and redox potential. Rainwater pH mean was of 5.77 (±0.52). Cations and anions mean values ranged from 7.12 μEq L−1 (K+) to 39.6 μEq L−1 (Ca2+). Principal Component Analysis (PCA) with Varimax normalized rotation was performed, grouping the major analyzed cations and anions into different factors. Mg2+, K+, Ca2+ and HCO3− were assigned to soil contribution, Na+ and Cl− to sea–salt contribution and NO3−, SO42− and NH4+ to anthropogenic sources. Hydrogen peroxide average concentration was of 19.2 ± 17.5 μmol L−1 with higher values in summer and lower in spring and autumn, reverse case was observed for H3O+ levels. Zn2+ (7.31 ± 2.74) μg L−1 and Cu2+ (4.07 ± 0.74) μg L−1 were within the range of other studied areas, while Cd2+ and Pb2+ were below the detection limit.