The survey of Zarin-Gol River water quality in Golestan Province using NSF-WQI and IRWQISC

Background and Aims : With regard to the presence of agricultural and recreational activities as well as Aqua culture (fish farming) industries around the Zarin-Gol River, the current study aimed to evaluate water quality of this river in terms of water quality indices. Materials and Methods: Regarding to the agricultural and livestock activities around the river, seasonal patterns of water quality indices (NSF-WQI and IRWQISC) were estimated using physic-chemical and biological parameters from 9 water quality monitoring stations. Sampling was done biweekly throughout summer and autumn. Measured parameters included fecal coliforms, biochemical oxygen demand, nitrate, dissolved oxygen, conductivity, chemical oxygen demand, phosphorus, turbidity, total hardness, pH and total solids. Because of the nature of the project, there were not ethical issues in this study. Results : The results of this study show that the WQI values in the samples from all stations were 54 to 61, based on both indices. NSF WQI index was moderate (70-50) and IRWQISC was also considered as moderate (55-45) and relatively good (55.1-70). Conclusions : Total solids, turbidity, nitrate, temperature, and fecal coliforms were the most affecting parameters. Furthermore, although the quality of river water was suitable for agriculture, it should be treated for drinking, based on the water quality index value. Keywords : water quality index, Zarin-Gol River, Golestan province, pollutant