Assessment of Heavy metal's health risk in underground water resources (case study some parts of northeastern villages of Mahneshan city, Dandi region, Zanjan provience)

Refer to the growing pollution of water resources and importance of their constant monitoring, in this section comprehensive review of rare elements and heavy metals in underground water in some parts of Mahneshan city and Dandi region was done to check the effects of mineral actions, related industries and agricultural activities in this region. During the research 12 samples from 6 deep rural drinking water provider wells were selected in 3 times and analyzed with ICP-OES for heavy metals such as (Lead,Arsenic,Cadmium, chrom).The highest level of contamination was compared with the guides of America's environmental protection agent and Iran's national standard. Results showed that measured elements were below the allowed level. Also human health risk was assessed, using EPA factor. Average of heavy metals's density in spring for Lead, Arsenic, Chrome and Cadmium was 0.00083, 0.0024 and 0.00079 and in summer 0.00090, 0.0029 and 0.00080 mg/l. Results showed that there is not any significant statistical difference between results of heavy metals's density that was measured with world and national standards. Assessment results for relation between risk of heavy metals and health of region residents was calculated 19*5-10 for cancer related diseases and 4*6-10 for nonrelated ones. Results of measured density of heavy metal and its comparison with standards (Iran’s national standard, world hygiene organization's standards, America's environmental protection agent) illustrated that the region of study is not threatened with any hygienic risk.