چكيده انگليسي :
Abstract:
This study was conducted to determine water quality and sediment of Aras River based on environmental parameters, metals (Mo, Cu, As, Hg) and determine of heavy metals in fish species at four stations (From Julfa to 25km after Nourdos border) during four seasons from 2015 to 2016. All samples were carried out standard methods using titration and spectrophotometer instruments. Result showed that range of water and weather temperature, DO, BOD5, COD, EC, Turbidity, TA, CO2, pH, DIP, NH4/N, NO2/N, NO3/N and IRWQI were observed 200-24.00, 3.00-28.00 C, 8.90-15.01, 1.77-13.41, 2.00-86.00 mg/l, 1.00-1.34 ms/cm, 2.4-638.0 NTU, 116-247 mg/ CaCO3 l, 0.20-2.20 mg/l, 8.06-8.79, 0.026-0.195, 0.330-0.575, 0.005-0.026, 3.640-6.474 mg/l, and 31.10-48.02, respectively. Mean of whole parameters (TA, NO2- and NO3-) were significant between seasons and (p<0.05) but whole parameters were not significant between stations (p>0.05). Result showed that range of Mo, Cu, As, Hg in water and sediment were observed 0.10-23.01, 3.0-40.0, 0.02-0.81, 23.7-104.6 µg/l, 0.1-111.6, 17.5-482.5, 0.001-0.145, 46.8-303.6 µg/g.dw, respectively.As a conclusion, water quality of Aras River was classified in class III (moderate pollution) based on mean concentration of Cu and As concentration was observed less than threshold level. Water quality of Aras River was classified in class IV and II based on mean value of Hg and As, respectively. Maximum value of Mo and Cu at surface sediment was registered at stations 3 and 4 during all seasons which it is because of effluent of sewage from Mo, gold and other metals mines in Armenia country. Mean concentration of As at surface sediment was higher than standard value, but concentration of Hg was lower than threshold value. Bioaccumulation factor was also calculated for each species.The amount of Bioaccumulation factor for molybdenum is the highest and the arsenic metal has the lowest amount. The highest concentration of copper in Barbus lacerta with a mean of 13.6 ± 11.3 μg / g dry weight and for the molybdenum, Alburnoides bipunctatus had the highest mean concentration (11.7 ± 4.9) μg / g dry weight. The average concentration of mercury (13.1 ± 1.5 μg / kg dry weight) was highest in Alburnus alburnus. Regarding the arsenic element, as it was analyzed in a small number of specimens, the highest concentrations were recorded in Alburnoides bipunctatus . According to ANOVA, there is a significant difference between mean concentration of copper in different species (p <0.05) and the Duncan test has distinguished Alburnus alburnus from other species. As a conclusion, result showed that 61 percent of the total data indicates the quality of water was relatively bad, although about 31 percent of the total data (based on the quality of IRWQI) indicates the quality of water was "moderate level.This condition starting serious changes in water characteristics affected by environmental degradation, exposure to domestic and agricultural pollution.
