Evaluation of Gas Origin in Water Wells in the Bahar Plain, North of Hamedan City, Iran

The Bahar great plain is located in north of the Hamedan city. Bahar, Lalejin, and Famenin cities are also situated in this plain. In the vicinities of these cities especially in the eastern parts of the plain, lots of water wells are dugout with very bad taste and smell in waters. Greate amount of HCO3-, CO2, SO2 gases are exhalative from these wells. Acids formed from reaction of these gases and water, erode well instruments. Gases are stated to have hydrothermal origin according to several studies. The result of this research does not support this hypothesis.