The Effect of Utilizing Microbiological Parameters on Water Quality Index Values Implemented at Wadi Al-Arab Dam Reservoir, North-Jordan.

The aims of this study are to investigate the effect of using microbiological parameters, particularly Escherichia coli on water quality index values that has been implemented at Wadi Al-Arab Dam Reservoir (WADR) in Northern Jordan and to evaluate its water suitability for domestic purposes. For these purposes, the study period from January 2009 through December 2014, one sample on a monthly basis was used in the calculation of WQI. Firstly, computed the WQI for the seventy two samples that were analyzed for different physico-chemical parameters such as pH, Electrical Conductivity, Total Dissolved Solids, Total Suspended Solids, ions of Sodium, Potassium, Calcium, Magnesium, Chloride, Sulfate, Bicarbonate, Ammonium, Nitrite and Nitrate in various seasons (winter, spring, summer and autumn). Secondly, performing the previous calculations taking into account the Escherichia coli (species of bacteria) counts. The analyzed results (by WQI method) have been used to depicting water quality for the two approaches. Based on physico-chemical parameters, the calculated values for WQI over the 6-year study period from 2009 to 2014 were 83.4, 80.6, 59.33, 78.0, 89.3, and 85.4, respectively. On the other hand, the WQI values were 41.7, 40.1, 43.5, 44.2, 51.0 and 44.7, respectively, as a result of incorporated microbiological parameters in WQI calculations that significantly contribute to decrease the WQI values over the 6-year study period. The analysis shows that the water quality rank of the (WADR) is varies from good to marginal based on physico-chemical parameters only, and from poor to marginal based on physico-chemical and microbiological parameters. In comparison with the World Health Organization (WHO) and Jordanian Standards (JS 286:2008). The results signify that the (WADR) is not polluted based on the physical and chemical characteristics of water. However, from microbiological perspective the water is not safe for domestic use and needs further treatment