Introduction:

Water is esential for life and, for this reason, it is considered as the most important natural resource to earth. The objective of this research was to evaluate the quality of drinking water used for the Ascension's inhabitants in Chihuahua, Mexico, in terms of physical-chemical-metals and microbiological analysis.

Method:

Water samples were collected in 10 sites of the city of Ascension in four season; spring, summer, autumn and winter. In each season five samples from each well that supply water to the community and five samples in houses were obtained. The first sampling was conducted in July 2011 (Summer), the second in September 2011 (Autumn), the third in December 2011 (winter) and the fourth in May 2012 (Spring); therefore, a total of 40 samples were collected. In these aliquots were estimated the following variables; potential hydrogen (pH), electrical conductivity (EC), temperature (T), dissolved oxygen (DO), turbidity (Tur), total dissolved solids (TDS), total coliforms (TC) and fecal coliforms (FC). In addition, the following metals were quantified; Al, As, B, Cd, Ca, Cu, Cr, Fe, Mg, Mn, Ni, Ag, Pb, K, Na, Se, Si and Zn. An Analysis of Variance (ANOVA) looking for season differences (Factor A), water source differences (Factor B) and their interaction (AxB) was performed. For the variables total coliforms and fecal coliforms the non-parametric test of Kruskal-Wallis was applied. In all cases it was considered a level of significance of 0.05 (α=0.05).

Results:

The results showed that about 80% of the water samples were positive for TC and FC and the Kruskal-Wallis test detected season´s differences (P<0.05). The variables pH and T were different due to season (P<0.05), for water source (P<0.05) and for the interaction (P<0.05). The DO was different for seasons (P<0.05) and no differences were noted for TDS and EC while Tur was undetected. The metals Be, Cd and Co were not detected and no statistical differences were noted for the elements As, Cr, Cu, Fe, Li, Ni, Pb, Sb, Se and Zn; Nevertheless, some concentrations of As, Cr, Fe, Ni, Se and Zn are higher than the permitted values established in national and international norms. The metals Ca, Mg, Mn and Sr were statistically different due to one factor or the interaction.

Discussion or Conclusion:

It is concluded that drinking water that is being consumed for the community of Ascension is contaminated with coliforms and some metals that potentially represent a health risk to the community.