Hydrogeochemical examination of Van Plain surface and groundwaters

In this study, it is aimed to determine hydrogeochemical structure of surface and groundwater in Van Plain, and to evaluate it in terms of usage. For this purpose, totally 50 surface and groundwater samples have been taken for in-situ measurement and laboratory analysis. Additionally, trace element analysis has been done in rock samples that taken from 10 localities. Van Plain waters which are of mostly represented by Ca+Mg-HCO3 character that have T, pH and EC25 values varying between 9.35-27.74 °C, 6.57-8.30 ve 316-2570 µS/cm, respectively. Consequently, the chemical structure of the groundwater in Van Plain is controlled by water-rock interaction processes. The 18O-D isotope values of the groundwater are between Global and Mediterranean meteoric water lines, which indicating that they are meteoric origin. The anthropogenic contamination was detected above the limit values for nitrogen compounds in a few surface water sampling points, but no significant problem was determined in groundwater. The trace element contents, except for arsenic and vanadium, of Van Plain waters are generally below the limit values. The arsenic value was observed between 0.6 ppb and 9.47 ppb at the 19 sampling points, while it was observed (10.29-168.10 ppb) at 31 sampling points that above the limit value (10 ppb) foreseen by the standards. The vanadium in the water ranges between 1.82 ppb and 24.74 ppb and it was observed above the limit value of 15.0 ppb at 9 sampling points. The arsenic and vanadium values in the rocks at the study area and its surroundings observed between 0.01-33.1 ppm and 0.1-139.1 ppm, respectively. The high concentrations of geogenic heavy metal pollution at both surface and groundwater were especially observed at the central and northern parts of the plain.