Assessment of Heavy Metal Contamination of Groundwater in Karaj Plain, Iran

The objective of the study is to reveal the seasonal variations in the groundwater quality with respect to heavy metal contamination. About 32 water well samples were analysed using Atomic Absorption Spectrophotometer for their mercury(Hg), cobalt (Co), cupper (Cu), zinc (Zn), nickel (Ni), chromium (Cr) and lead (Pb) content and their levels compared with international standards specified maximum contaminant level. Heavy metal contents of ground waters were below the permissible levels. Average total Hg, Co, Cu, Zn, Ni, Cr, Pb and As contents of ground waters were below the pollutant limits, but in some sampling sites for Hg and As concentrations were exceeded permissible limits. However, the average heavy metal evaluation index values for all metals in ground waters were below the critical value