survey of heavy metals in the wastewater of a canal after irrigation of vegetable farms in south of tehran

the overall objectives of this study have been, 1). to review the existing literature in order to evaluate observations of significant quantifiable health erects on population exposed through occupation or nearby residence, or as consumers, to the irrigation of crops with raw wastewater of firouz abad canal in irrigation crops for more than 30 years. 2) to determine the effects of heavy metals (cd, pd.cr , ni, hg, zn) in soil and plants irrigated by the wastewater of firouz abad canal. the following conclusing were obtained from these research. the maximum and minimum levels of cadmium, zinc in the earth’s depth from zero to 20 centimeter by accuracy of 99% were 1.5-0.8, 8.68-5.51, 2-6- 1.4, 218.5-93.46 respectively. the concentration of cadmium in the 100 g mixed dry vegetables (1000 g mixed wet vegetables) was less than 45% of tolerable intake of cadmium for on adult, i.e., 57-71 ug/day. this concentration of cd and other heavy metals mentioned above are not harmful to human beings according to fao and who criteria.