evaluation of the water quality pollution indices for groundwater resources of ghahavand plain, hamadan province, western iran

background: due to the increasing pollution of water resources, this study was carried out for evaluation of water quality pollution indices for monitoring of heavy metals (as, zn, pb and cu) contamination in ghahavand plain, hamadan province, western iran during spring and summer 2012. methods: totally, 20 ground water wells were chosen randomly. the samples were filtered (0.45 μm) and maintained cool in polyethylene bottles. samples were taken for the analysis of metals, the former was acidified with hno3 to ph lower than 2. metal concentrations were determined using icp-oes. results: the mean values of contamination index (cd), heavy metal pollution index (hpi) and heavy metal evaluation index (hei) in samples for spring season were -2.27, 9.01 and 1.73 respectively and in samples for summer season were -1.95, 8.69 and 2.04 respectively. it indicates low contamination levels. comparing the mean concentrations of the evaluated metals with who permissible limits showed a significant difference (p<0.05). conclusion: the mean concentrations of the metals were significantly lower than the permissible limits. although the heavy metal pollution of the ground water in ghahavand plain is lower than who permissible limits, but severe precautions consideration such as manage the use of agricultural inputs, prevention of use of wastewater and sewage sludge in agriculture, control of overuse of organic fertilizers and establishment of pollutant industries are recommended in this area.