ИСТИНА

In Moscow region It was found that in sod-podzolic soils As content did not exceed 2-6 mg/kg. However, in Fe-ortsteins isolated from these soils, the Arsenic content was 10-30 mg/kg. Wetland soils were characterized by high carbonate content and a combination of carbonate precipitation zones and iron-enriched layers in the profile. The total As content in these soils was higher in the zones of iron precipitation. Given that the studied area is former agricultural land, As-containing pesticides is one ofthe possible As sources. Study of the tumors formed in the floodplain have shown that most part of As (up to 100 mg/kg) was adsorbed by freshly deposited Fe-hydroxides, such as ferrihydrite 2Fe2O3 · FeOOH· 4H2O. The latter is the main Fe-hydroxide in rohrensteines.