The Study of geochemistry contamination of heavy metals in travertine deposits and soil in Gorveh- Takab Region, NW Iran

Biogeochemical cycle begins with rock, so geology and geochemistry of rock and soil erosion play the most important role in the distribution and concentration of potentially toxic elements in each ecosystem. In this study, rock and soil samples from Gorveh, Bijar and Takab cities were analyzed using ICP-MS instrumental method. Geochemical analyses indicate high amounts of heavy metals such as As, Ni, Cd, Se and Co in soil and travertine samples, of which arsenic is prominent (>10000 ppm). XRD analysis revealed how heavy metals are present in the travertines of the area and by integrating mineralogical and geochemical results, the main reason for high concentration of As in these deposits was shown to be the presence of arsenic bearing minerals. The environmental indices including enrichment factor, contamination factor, pollution load index, potential ecological risk index were calculated and indicated that the majority of the samples are categorized as highly contaminated. Average arsenic concentration in rock and soil samples is 423 and 1089 (mg/kg) respectively. The main reason for such high heavy metals contents -especially arsenic- in the area is believed to be the existence of many hot springs representing waning stages of volcanic activity.