Determinación de los procesos hidrogeoquímicos participantes en la composición del agua de las fuentes de abastecimiento a pobladores de la delegación Iztapalapa, D.F., México

Abstract

The water supply issues for Basin of Mexico residents have been constant; recently they have increased in Iztapalapa because of the groundwater withdrawal. The most significant concentrations, obtained from 17 wells, were: Fe2+ (0.004 – 0.6 mg/L), Mn2+ (0.003 – 0.96 mg/L), Na+ (91 – 598 mg/L) and Cl- (59.5 – 372 mg/L), COD (3 – 63.8 mg/L) and specific conductivity (620 – 2503 μS/ cm), in addition with turbidity and bad odour. The following hydrogeochemical processes were determined: mixing between different groundwater flow components induced by heavy pumping, and brackish water of overlying aquitard, increasing of the ionic content of groundwater until the precipitation of minerals like carbonates, phosphates and silicates on supply network and turbidity of the water extracted. This was demonstrated by calculating saturation index with the software PHREEQC. Redox conditions are consequence of organic matter oxidation, and therefore sulfate reduction, denitrification and presence of gases such as CO2 and H2 S, the latter associated with corrosion in the drinking water network.