Assessing Sirwan River Water Quality based on a single-factor assessment and comprehensive pollution index methods

In this paper, single-factor assessment methods and comprehensive pollution index were chosen to evaluate the Sirwan River water quality situation. The mean physicochemical values of dissolved oxygen, total dissolved solids, turbidity, color, major cations, and anions ranged from 7.77 ± 0.55 to 7.80 ± 0.18 mg L-1; 472.83 ± 23.97 to 478.83 ± 24.23 mg L-1; 8.13 ± 8.28 to 14.61 ± 15.76 NTU; 14.15 ± 5.76 to 25.07 ± 17.19 Hazen; Calcium from 62.19 ± 2.05 to 64.06 ± 1.72 mg L-1; Magnesium 21.20 ± 2.01 to 21.74 ± 1.47 mg L-1; Sodium 17.68 ± 2.79 to 22.44 ± 2.76 mg L-1; Potassium 2.50 ± 0.22 to 2.64 ± 0.18 mg L-1; Bicarbonate 284.76 ± 5.43 to 289.80 ± 5.87 mg L-1; Chloride 18.10 ± 6.71 to 18.69 ± 7.82 mg L-1; Sulfate 59.70 ± 3.23 to 67.67 ± 3.01 mg L-1; and Nitrate 3.06 ± 02.90 to 3.85 ± 1.34 mg L-1, during the study, respectively. Using the single-factor assessment approach, it was determined that the concentration of total dissolved solids was observed at (S5), turbidity and color at (S4, S5, and S6), and bicarbonate exceeded the standard at all sites. During the study, the comprehensive water pollution index rates changed from 0.49 to 0.87 with a mean of 0.62 ± 0.16 and from 0.44 to 1.12 with a mean of 0.74 ± 0.30. According to the estimation results of both methods there was a slight to moderately polluted water class at all sites of the studied river.