Estimation of coliform contamination rate and impact of environmental factor on bacterial quality of tube well water supplies in Khorramdarreh County, Iran

Abstract

In this study, the presence of fecal coliforms in tube wells of Khorramdarreh County, Iran, and impact of environmental factors on quantity and quality of these organisms were evaluated. In a cross-sectional survey, 76 tube well water samples from March to September 2010 were tested to determine presence of fecal coliforms, by measuring the most probable number (MPN), and identification of three enteric bacteria namely, Escherichia coli, Klebsiella sp. and Salmonella sp. Out of 76 wells, 24 (31.57%) and 25 (32.89%) wells showed presence of fecal coliforms, during rainy and dry seasons, respectively. In contrast to seasonal changes, depth of the wells showed significant correlation with type of isolated bacterial indices (P = 0.0005). On the other hand, depth of the well and seasonal variations did not show any significant correlation with fecal coliform contamination rate. The level of bacterial contamination of tube wells, in terms of presence of fecal coliforms is alarming. This was only an indicative study, and therefore, appropriate studies are required to determine the extent, risk factors and nature of the problem.

Keywords: Fecal coliforms, tube well, E.coli, Klebsiella sp., Salmonella sp.