Journal of health research in community

Introduction and Purpose: Population growth and the pollution caused by discharge of sewage, waste leachate and surface runoff has caused water contamination. Zoning river water quality is the first and most important step in managing quality of water resources; because it clarifies the process of change in pollution, according to the time and place. Water health quality evaluation of the Cheshmeh Gerdoo river is of great importance, since it is a drinking-water supply and pollutants have been discharged into this river. 
Methods: In this study, sampling from six stations was performed, during three months. Then, water-quality parameters, i.e., dissolved oxygen (DO), biological oxygen demand (BOD), fecal coliform, NO3, PO4, TS, turbidity, temperature and pH were examined along the river. The data were analyzed using NSFWQI quality indices.
Results: In this study, the lowest DO quantity was equal to 6.4 mg/l at station 6 and the maximum amount was equal to 8.5 mg/l at station 1. Other parameters showed an increasing trend. In accordance with our results, NSFWQI index was calculated at the best and worst cases to be 54.85 and 39.19, respectively. Thus, the water-quality index in the upper part of the river, at station 1, was in the “average” category, and at the stations 4, 5 and 6 it was in the “bad” category.
Conclusion: Raise in the levels of fecal coliform and BOD, from the beginning to the end of the river, indicated an increase in pollution. This problem might be caused by discharge of untreated sewage, since the river passes through rural and urban areas. Moreover, the increase in the levels of NO3 and PO4 can be resulted from pollution with agricultural effluents. Also, increase of TS and turbidity can be related to absence of suspended solids deposited along the river.