Water quality assessment in the Sufi-Chay river (NW-Iran) using diatoms as bio-indicators

This study can be considered as the first case study on the rivers of Azerbaijan, Iran, which tries to analyze the Sufi-Chay river using diatoms, water chemistry and biological factors. The Sufi-Chay river is located in the region of Azerbaijan (northwestern Iran). In order to study of diatoms, a number of rocks from different areas of the riverbed were collected and then rubbed in some river water. After that, the solution transferred to the bottles and then tansferred to laboratory. In the next step, the solutions were digested with hydrogen peroxide and put it on the heater for one and a half hours and boil it (Hot H۲O۲ method). Then pick up the solutions from the heater and place at room temperature to cool. Then add some HCl to the solution and put it again on the heater and boil for fifteen minutes. After this time, add the residual solution of distilled water to wash the acids in the solution, this wash continues for three days and every ۲۴ hours. After washing, put a few drops of the solution on the cover slip to dry completely. In the next step, after drying, we fix the cover slip on the slide using Naphrax glue. Then, we start studying the slides under microscope. The study showed that Nitzschia palea, Nizschia amphibia, Diatoma vulgaris were dominant during spring, summer and winter whilst Navicula tripunctata, Gomphonema parvulum were dominant in autumn. Ecological evaluation of the river by using diatom community showed that the upstream of the river had high quality of water whilst downstream had low quality.

کلیدواژه ها:

Rivers ، Sufi-Chay ، Diatoms ، Water quality.