Zoning of Boron contamination under influence of hot spring in the northwest of Lake Urmia, Iran

Groundwater is one of the main sources of drinking and agricultural water in the Salmas Plain in northwest of the Lake Urmia basin. Recently, boron contamination was reported in the down-plain. Boron (B) is an essential micronutrient for human health and plant growth, however high concentration (more than 1.5 mg/l) of boron is very detrimental to agriculture and human health. The present study examined the major water bodies which possibly contribute to boron contamination by identifying the origin of boron contents in the study area. A total of 42 groundwater and surface water samples were collected. The spatial distribution of boron contents showed that contamination occurred mainly in the south where thermal and mineral springs are dominant. An anomalous concentration of boron (more than 400 mg/l) was found at Abgarm thermal springs which discharge directly into the surface waters. The contamination spread over the central and east areas. This is because contamination moves through the faults. The high concentration of boron in this region may be attributed to the rock-water interaction.