Study of the organic pollution in euphrates river, southern of Iraq Al-Fanharawi Ali Abdulhamza1, Al-Jasimee Ahmed Sabah2 1Department of Environment & Pollution, College of Science, Al-Muthana University, Al-Muthana, Iraq 2Department of Biology, College of Science, Al-Qadisiyah University, Al-Qadisiyah, Iraq Online published on 9 January, 2019. Abstract Water pollution is one of the main problems that cause harm to man and his environment. In order to evaluate the quality of our inland water and the extent of its contamination with organic matter, this study was conducted. Water samples were collected monthly from six selected stations on Euphrates river, three of them in Nasiriya city are Al-Sindinawiya, Al-Fadhliya and Souk Al-Shuyuk district. The other three were in Abu Al-Shulan, Al-Medana city center and Qurna district for the period from October 2017 to May 2018. Samples collected in 500 ml polyethylene bottles. The biological oxygen demand (BOD) was determined by the BOD Sensor after calibration and processing. The results of the study showed that the values of BOD5 had recorded the highest concentration in the first site of the study and amounted 47.5 mg/l either the lowest value was recorded in the fourth site (4.87) mg/l, as well as the values in the other four stations were 6 in S2, 7.12 mg/l in S3, 7.62 in S5, and 6.75 mg/l in S6, respectively. The values of BOD5 during the months of the study ranged from 2 to 54 mg/l as lowest and highest value during the months of March 2018 and May 2018, respectively. The river water classified according to Hynes scale as doubtful clean in the fourth station, bad in the second, third, fifth and sixth stations, and very bad at the first station. In general, all study sites assessed as very bad (13.31) mg/l. Statistically, there were significant differences between the values of the BOD5 between stations at the probability level (p ≤ 0.05), these significant differences not showed between the months. Top Keywords Organic pollution, BOD5, Euphrates river, Iraq. Top |