Assessment of the Organic Pollution in Sawa Lake

Abstract One of the primary issues that harms both man and his environment is water pollution. This study was carried out to assess the level of organic pollutants in Sawa lake water. Water Sampling collected from October 2021 to February 2022, monthly, samples taken from three different sites. Biological oxygen demand (BOD 5 ) measured by the BOD Sensor after calibration and processing, and some related environmental parameters were also measured. The results showed that BOD 5 values ranged between (5.9-7.6) mg/l, higher value was 12.5 mg/l recorded in S1 and S2 during February, and lower concentration (3 mg/l) recorded in S2 during November. The value of BOD 5 in all periods of study was 6.67 mg/l. The findings of the statistical analysis showed that there were significant differences between the sites and months (p≤ 0.05). Monthly changes in the physicochemical properties of lake water and the autochthonous organic matter may be a reason for increasing the concentration of organic content, in addition to the wastes that arrives from near area. According to the Hynes classification, the river water in all sites classified as doubtful to bad. Negative significant correlations were founds between BOD5 and DO (r= -0.75) and positive significant correlations between BOD5, EC and nitrate (r= 0.54, r=0.42), respectively.