Water from the Timok river in Serbia : estimation of its suitability for arable soil irrigation

This paper presents the results of analysis of the content of hazardous and harmful substances in the water for irrigation, sampled during the vegetation season 2012/2013 in the basin of the Timok River, from Knjaževac to Visočni hill (Mokranja). The investigation was carried out in three cycles of monitoring on 17 selected sites, which gravitate on the an arable soil that was irrigated. During the mentioned period in the water samples it was determined the values of pH (potentiometrically), ECw (conductiometrically), TDS (gravimetrically); determination of the content of trace elements and heavy metals Cr, Ni, Pb, Cu, Zn, Cd, B, As and Fe was done according to ICP methodology, using ICAP 6300 ICP optical emission spectrometer; heavy metal Hg was determined by a flame atomic adsorption analyzer SensAA Dual. The content of trace elements and heavy metals in the samples of water is generally below the maximum allowable concentration (MAC), except in one sample, during the first cycle of sampling, where it was recorded increased Cu content, exceeding the recommended limits (0.2509 mg l-1 ). One water sample from the Timok River, sampled in the second cycle of monitoring, showed a slight increase in the Ni content above the recommended limits (0.124 mg l-1 ). Since the location of this sample was also in the vicinity of the village, the assumption is that it is caused by an anthropogenic activity. Based on the obtained data of the content of hazardous and harmful substances in the water for irrigation of the Timok River, it can be concluded that the water is usable for irrigation of agricultural crops and soils, with frequent quality checks during the summer months