Iran is located within the dry and semi dry regions, thus almost 90% of the required water is secured through the use of ground waters. This study was undertaken to evaluation of water quality pollution indices for heavy metals (As, Zn, Pb, Cd, Cr, Cu and Mn) contamination analysis in Razan Plain in 2012.
Materials and Methods
Totally, 20 ground water wells were chosen randomly. After preparation of samples for the analysis of cations in the labratory, elements (As, Zn, Pb, Cd, Cr, Cu and Mn) concentration were determined using ICP-OES. Also three documented methods evaluated in this study are the contamination index (Cd), the Heavy metal Pollution Index (HPI) and the Heavy metal Evaluation Index (HEI).
The results showed that mean values of Cd, HPI and HEI for spring season were -2.96, 45.47 and 4.04 respectively and for summer season were -3.54, 45.07 and 3.59 respectively and indicates low contamination levels. Also, comparing the mean concentrations of the evaluated metals with WHO maximum permissible limits (MPL) showed a significant difference (P<0.05).
However, the mean concentrations of the metals were significantly lower than MPL, but the irregular and long-term usage of agricultural inputs especially heavy metal based pesticides and fertilizers, use of wastewater and sewage sludge in agriculture, over use of organic fertilizers and establishment of pollutant industries can threaten the ground water, and cause irreversible damages in this area.