Physicochemical and bacteriological study of water quality of wells in the Cuernavaca aquifer, Morelos

Abstract

The objects of the study were: to determine the bacteriological and physicochemical quality of the aquifer of Cuernavaca, Morelos, México; and to compare the water quality reported previously with the results of this study. Monthly samplings were carried out during a year, taking samples from ten wells and two springs, distributed as follow: 4 in the north area, 4 in the middle and 4 in the south. The samples were taken before the chlorine dispenser to define the natural conditions of the aquifer. Two bacteriological parameters and 12 physicochemical were determined. An analysis of discriminates was performance to know the variability of wells, and in according with it, the parameters were grouped in 3 functions that described the 98.28% of the variability. In according with Mahalanobis distances and the dispersion diagrams, it was observed that one well was separated (Ojo de agua), 2 were in one group (Zapata and Tezoyuca), and the rest were in other group. According to the hardness: 3 wells were moderately hard water, 3 hard and the others soft water, with predominatinceg of the carbonated hardness. Physicochemical parameter averages were lower of the maximum permissible limits of the NOM-127-SSA1-1994 for drinking water. All wells were bacteriological contaminated at least in a sampling. This may be due to the high and medium vulnerability of the materials of the aquifer in some zones, or a construction inadequate or a deficient protection of the wells. Nevertheless, the capacity of dilution of the aquifer has allowed maintaining the same quality of the groundwater of the Valley of Cuernavaca, although in some areas the anthropogenic contamination is evident.