Study of Changes in Water Quality Index of Ziarat River in Gorgan at 2018

Water quality is an important factor that affects all aspects of eco-system and health food-to-business activities to the sustainability and health of the echo systemThis study was carried out with the aim of investigating the qualitative changes in the Ziarat River water.

Samples from the Ziarat River Station (5 stations) were sampled each year in 2018. Samples were transferred to the Golestan University of Medical Sciences in accordance with the standard conditions, along with ice. The parameters of nitrate, phosphorus, biochemical oxygen demand (BOD), chemical oxygen demand (COD), ammonium, total hardness and total Fecal coliform was measured according to standard method and the Water Quality Index (WQI) was calculated.

The results of the study, based on the WQI index, showed that the index for all stations was between 29.68 and 64.78, and in some of them the average was (50-70) and some stations had poor quality ( 50-25). The most effective parameter on the water quality of the river is the BOD parameter, and then it is the total solids, turbidity, phosphate, nitrate and total Fecal coliform.

The highest level of pollution in the terminal stations (4 and 5) due to more industrial activity is the entry of sewage and effluents into the river in Gorgan. Among the measured parameters of nitrogen and phosphorus as nutrients, if left unchecked, it poses a risk of eutrophication. Agricultural, livestock and recreational activities around the river affect the water quality of the river. So that a more appropriate quality was observed in the upstream stations. Considering that the Ziarat River is one of the most important sources of water supply needed in the agricultural and industrial sectors in Golestan province. Therefore, monitoring and control of pollutants entering this river is essential.