Arsenic Mapping in the East Azarbaijan Province and the Feasibility Study of Decreasing Arsenic Release (A Case Study of Hashtrood)

The increased levels of Arsenic, a poison element, in the soils and waters of Hashtrood city have caused different health issues for the people. Due to the lack of information about the arsenic content of the soils, the present study was conducted to survey the soil arsenic distribution and the possibility of reducing arsenic release from the soils. For this purpose, 53 soil samples from the top layer were collected and the arsenic concentration and distribution map was determined. Additionally, in order to evaluate the effect of iron hydroxide and gypsum as soil amendments, five polluted soil samples were selected and treated with the proposed amendments; each at three levels. The results revealed that the agricultural soils of the studied area are polluted by arsenic, as its average concentration was 49.36 mg/kg, but more than 80 percent of the studied soils had a lower concentration than the standard level. The agricultural soils of Ghopoz and Ghezellou showed the highest arsenic contamination. Application of iron hydroxide reduced the arsenic releasement in different soils significantly, as 10 ton/hectare iron hydroxide application reduced arsenic solution 64.5, 82.4, 83.7, 98.9, and 100 percent in the soils of 1, 2, 3, 4, and 5, respectively. Increasing the level of iron hydroxide application decreased arsenic release more intensively. Similarly, the gypsum decreased the arsenic release significantly and its reduction was more by increasing gypsum application In comparison to gypsum, the iron hydroxide was much more effective in controlling the arsenic releasement.