Investigation of physicochemical properties of water in downstream areas of selected dams in Aras catchment and water quality assessment (Case study: Aras catchment in the border area of Iran and Armenia)

The aim of this study was to evaluate the physicochemical properties of downstream water of Aras river dams. Sampling was performed from early 2018-2019 in selected stations. Heavy metals were measured by atomic absorption spectrometry. Nitrate, nitrite and total dissolved solids concentrations were also measured by spectrophotometer. Concentrations of Ca, Na and K were measured with a Flame Photometer and the rest were measured with specialized devices. The results showed that the lowest electrical conductivity in the measured samples was 0.789 and the highest was 4.346 µs/cm, which basically indicates the high limit of soil and water for irrigation of plants. On the other hand, total solids with 1211 ppm indicate a moderate limit for salinity. Also; regarding pH, the average recorded for the study area is 8.17, which is within the national permissible and standard range of the world health organization. Nitrate and nitrite are both above the permissible and standard range. Potassium is within the permitted and standard range. Calcium, according to the average obtained in the study area (64 ppm) can be said that this parameter is within the allowable and standard range. In the case of lead (0.09 ppb), it can be said that this parameter is within the allowable and standard range. In the case of cadmium (0.8 ppb), it can be said that this parameter is within the allowable and standard range, 3 parameters nitrate, nitrite and TDS have an average higher than the national standard.