Microbial Contamination and the Effect of Some Physicochemical Parameters on the Presence of Microbial Contaminants in Drinking Water in Kuhdasht, Iran

Microbial contamination in water is often related to human feces. This research was conducted to investigate the microbial contamination of drinking water and some parameters affecting this contamination in the city of Kuhdasht.

In this cross-sectional study, a total of 132 water samples were collected. The presence of total and fecal coliforms was evaluated by the Enzymatic Assay method. Heterotrophic plate count (HPC), residual chlorine, turbidity, pH, and temperature were also measured according to standard methods. The Correlation between parameters was evaluated by the Spearman test using SPSS-20 software.

The results showed that total coliform was present in 6.8% and fecal coliform in 6% of the samples. The mean HPC, chlorine, turbidity, and pH were respectively 31.71 CFU/ml, 0.38 mg/l, 0.58 NTU, and 7.52. Correlation coefficients between T.Coli, E.Coli, and HPC with residual chlorine were -0.235, -0.175, and -0.142 and with turbidity were -0.010, 0.005 and 0.013, respectively. Turbidity, pH, and HPC were desirable in 100% of the samples, but residual chlorine was undesirable in 33%.

The results show, the effect of residual chlorine and turbidity on the presence of microbial contaminants in drinking water. In areas with higher chlorine, less microbial contamination was observed, and conversely, in areas with higher turbidity, less residual chlorine was observed, resulting in more microbial contamination. Therefore, control of residual chlorine level and turbidity in drinking water is very important.