Investigation of Pollution of Water Resources and Pollution Zoning in the Saroq Watershed (West Azerbaijan Province)

Arsenic is a toxic element with environmental and health risks. The aim of this study is to investigate and monitor arsenic concentration level of pollution and its concentration zoning in the water resources of Saroq watershed. In this study, 45 samples from wells, springs and river were collected in two stages (filtered samples in the first step and bulk samples in the second step). The position of sampling points was determined based on expert judgment and random method. Anions were analyzed by gas chromatography and metals were analyzed by ICP-MS. The overall results indicated that water was polluted by arsenic in some areas. Evaluation of the origin and zoning maps of arsenic in water revealed that the source of pollution is both anthropogenic and geogenic resources. Most of the geogenic sources are located in the north-east and east of the area on the alteration zones and is resulted from Quaternary volcanic rocks forming source of the hot springs in the study area. Mining activities are the most important cause of pollution in the downstream area of the mines in the north of area, thus, it can be said that anthropogenic origin is a major cause of pollution. Transfering and re-deposition of arsenic in the study area is controlled by the solution- deposition and absorb- disposal reactions, which is controlled by Eh and pH. Transporting and re-deposition of arsenic is done by oxy-hydroxides of this element. In general, except for the northern and north-western parts, in most parts of the studied area, the level of pollution is not that much high so by considering appropriate management there will not be much pollution problem in the area.