Abstract
The objective of this study was to investigate concentrations, compositions of PAHs and to study physical and chemical water characteristic in Tigris River. This study was conducted during July 2017 to April 2018. The results showed that twelve PAHs compounds were detected in water and sediment of the river and the highest concentrations of these compounds were founded in sediment samples. Concentrations of PAHs in water samples have a ranged between (0.36µg. l-1) in wet season to (0.53µg.l-1) in dry season, while the sediment sample have a ranged between (633.23µg.kg-1) in wet season to (778.28µg.kg-1) in dry season. The origin of PAHs in water and sediment were pyrogenic depending on the ratios of Phenanthene/Anthracene, Anthacene/ (Anthacene + Phenanthene), low molecular weight/high molecular weight. According of these results, it can be concluded that the Tigris River is polluted with the PAHs, and anthropogenic activities with the largest impact on the water health and quality of the river.
Highlights
The main Iraqi resources (Tigris and Euphrates) were suffered from the decline of their annual flow, many factors impact of this situation such as dam construction in neighboring countries and the impact of global climate change (4,6)
The results of Electrical conductivity (EC) showed that there is increased in dry season compared to wet season, that might be due to increase the temperature in dry season, which cause raising in EC values, that’s agreed with results reported by Hassan et al (41) and Talib et al(77), in addition to decreased river water levels in these months, there were no clear differences between sites Salinity (S‰) The results showed that the minimum value of S‰ was recorded 0.33 ‰ in August, October2017 and April 2018, and the maximum value was 0.57 ‰ in November 2017, with mean value 0.42 ‰
The increasing value of salinity in dry season was due to the Lake Tharthar is affected on increasing salinity of Tigris River water When water levels of the River were decreasing, water has been added from Lake, which characterized with high salinity (70), and from drainage of lands around the river (81), there is no variations between sites just a bit (80)
Summary
The main Iraqi resources (Tigris and Euphrates) were suffered from the decline of their annual flow, many factors impact of this situation such as dam construction in neighboring countries and the impact of global climate change (4,6). The maximum discharge of the Tigris River before the construction of dams for the period 1931-1960 reached 1.207m3/s. In 1980 the annual river flow reached 715m3/s This decline was continuing and fell to[522] m3/s-1 at Baghdad city after 2000 (5). The PAHs in aquatic environment were originate from two sources the first one was pyrogenic which are produced from incomplete combustion of coal, oil, and gas, garbage, or other organic substances like tobacco or charbroiled meat (32,34, 58). PAHs origin can be evaluated from different indices like ratio of Phenanthrene/ Anthracene, Benzo[a] anthracene/(Chrysene+Benzo[a]anthracene),Fl uoranthene/ (Fluoranthene+ Pyrene), and low molecular weight/high molecular weight (67). The origin of PAHs for both water and sediments are pyrogenic origin, according to the results of the ratios (P/Ant >10, Ant/(Ant + P) 1, while the results of P/Ant 0.1,
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
