Mercury and Lead Contamination Study of Drinking Water in Ahvaz ,Iran

Heavy metal contamination of water could occur anywhere at resources, course of distribution or consumption place. Precise knowledge on amount and type of water pollutants especially heavy metal are essential to protect the environment, and public health. Heavy metal owning long biological half-life and their excessive amount in the body are a life treating hazard. Some trace elements of heavy metals constitute in nature. Entry of heavy metals into water supplies from various ways, cause side effect such as poisoning hazards, cancer. This survey aimed to evaluate concentration of heavy metal (Lead, Cadmium, and Hg) in drinking tap water of Ahvaz city by atomic absorption spectroscopy methods. A descriptive – analytical and cross-sectional study was conducted for determination of Lead, Cadmium and Mercury as heavy metals in 100 samples of six geographical regions from 48 sites in three consequent months in spring 2013. Samples prepared with concentrated nitric acids then Concentration of Pb and Cd determined by electro thermal methods and Hg concentration evaluated using cold vapor technique. Result shows that concentrations of Cd in drinking water (about 0.0012 mg/L) are below standard limits of World Health Organization (WHO). Unlike Cd, concentration of Pb crossed WHO standard limits among all samples. Mean concentration of Pb was 0.02 mg/L where highest amount recorded in western regions. Approximately 33% of samples show high concentration of Hg in camper to national standards of 0.006 mg/L. Mean concentration of Hg was 0.0047 mg/L. Lowest and highest value reported in eastern and north east of Ahvaz, respectively. We found similar concentration of Pb through all regains. However, mean concentration of Hg and Cd varied from site to site. Our study showed concentration of selected heavy metal (Pb and Hg) in drinking water of Ahvaz is higher than standards levels. We recommend further studies to determine the sources and cause of the pollution.