Establishment of Total Maximum Daily Loads (TMDLs) for Selected Pollutants at Various Segments of Wadi Al-fara’a

Total Maximum Daily Load (TMDL) is both a quantitative assessment of the pollution sources and the pollutant reductions needed to restore and protect water resources. In order to protect and restore impaired water bodies, the loads of pollutants that reach these water bodies need to be determined and controlled. To achieve this goal, the maximum amount of a pollutant that a water body can receive and still meet water quality standards (TMDL) should be determined. Al-fara'a catchment which is located in the Northeastern region of the West Bank, is affected by many point pollution sources such as industrial facilities, and medical centres, and non-point pollution sources such as cesspits. So three heavy metals TMDLs had been done for three segments of Wadi Al-fara'a, three toxic organics TMDLs and two pharmaceutical compounds TMDLs had been done for other two segments of WadiAl-fara'a by this research. The process of calculating and documenting the previous mentioned TMDLs involved a number of tasks, including characterizing the segments of Wadi Al-fara’a, selecting and setting water quality targets for the detected pollutants that will be relied upon in TMDLs calculations for them, then identifying point and non-point sources for the detected pollutants, calculating the loading capacity (TMDLs), and identifying source allocations for them. finally implementing these TMDLs. The analysis of the samples that were taken from the first sampling location which represent east Nablus wastewater. It has been shown, that in winter, the heavy metals concentrations increased in the water samples that were taken at this season compared with other seasons, due to the agricultural and urban runoff which represents another main source for heavy metals. It was concluded that Al-fara’a stream has poor self-purification for Copper. However, the results of Chromium, Zinc, Nickel and Lead indicate that the stream self- purification for these metals was satisfactory. The toxic organic Brommomethane which is a herbicide was detected at the tested locations at the stream, which indicates that it was still being used at the area as herbicide, in spite of the globally prohibition of using it. High loadsreductions are required to be implemented for the selected segments at Wadi Al-fara’a due to the great gap between the estimated TMDLs and the current loads for these pollutants that reach the wadi. The future East Nablus Wastewater Treatment Plant (ENWTP) will be the only point source to Wadi Al-fara'a for heavy metals, that it is not designated for a tertiary treatment, for that maximum limits (permits) for the detected heavy metals levels at the effluent of the prospective ENWTP were estimated as follows: 0.03 ppm for Copper, 0.065 ppm for Chromium, 0.01 ppm for Nickel, 0.032 ppm for Zinc, and 0.0002 ppm for Lead.