Influence of Industrial, Agricultural and Sewage Water Discharges on Eutrophication of Quttina Lake

The influence of human activities on water quality of Quttina lake (an important water resource in the middle region of Syria), has been evaluated and correlated with pollution source situated at lake banks; namely, phosphate fertilizer factory, agriculture and wastewater drainages. Surface and deep water samples from different sites in the lake have been collected and analyzed during the period of April to October 2009 to study the effects of pollution sources on Quttina lake eutrophication. Water quality parameters include temperature, pH, EC, Dissolved Oxygen (DO), Chemical Oxygen Demand (COD), Biological Oxygen Demand (BOD), ammonium, phosphate and nitrates ions, total nitrogen and total phosphorous. The results have shown that these parameters varied from one site to another, where the highest concentrations were found to be in those sites close to phosphate factory discharges and in the northern part of the lake. Moreover, seasonal variations in pollution parameters were clear, especially for ammonium, phosphate and nitrates ions in addition to oxygen parameters (DO, COD and BOD). Moreover, mean total phosphorus concentration in Quttina lake surface water varied between 0.51 mg/l and 2.2 mg/1, where the highest values were found to be near the phosphate fertilizer factory discharges in addition to sites close to wastewater and agriculture runoffs situated at the western side of the lake. In addition, N:P ratio varied between 1.1 and 22.9 during the sampling period; the natural ratio being 16:1. On the other hand, the parameter distribution with depth in two sites has been studied. The results have shown that there are no clear differences between the deep and surface samples, and this is due to lake shallow depth and water flow. Furthermore, positive relationships have been found between total phosphors and nitrogen and oxygen indicators (BOD and COD), which indicates the increase of organic pollution and the algal bloom.