Hydrogenic Heavy Metals Contamination of Fluvisols in the Middle Cis-Urals Region, Russia

In 1999, the Perm region ranked eighth among Russian regions in terms of technogenic load per unit of area (4.4 t/km²). The situation in the city of Perm is especially unfavorable in ecological terms due to aerial contamination and hydrogenic contamination, because of industrial wastes entering the small rivers that are tributaries of the Kama river. It was revealed that fluvisols of the city of Perm are contaminated by heavy metals of hydrogenic origin because of the unpurified sewage water entering them. The fluvisols of the city of Perm are contaminated by heavy metals of hydrogenic origin because of the unpurified sewage water entering them.Content of HMs in fine earth showed the deficit and excess compared with European Soil Clarke and Local Background. In relation to European Soil Clarkes elements can be divided into three groups: (1) scarce elements forming negative geochemical anomaly, (2) "normal" elements, which does not differ significantly from Clarke, (3) excess elements forming positive geochemical anomaly. Scarce elements include rubidium and arsenic. “Normal” elements are yttrium, gallium, zirconium and lead. Excess elements are nickel, copper, zinc, strontium and chromium. In the fluvisols, the Fe-rohrensteins are formed. Some elements are concentrated in the Fe-rohrensteins, and some others are not concentrated in them or are found in low concentrations. In Fe-rohrensteins the highly active group comprises As, Zn, Ni, Cu, Cr, and Pb; the moderately active one is represented by Sr, Nb, Ga, and Y; and the inert group contains Zr and Rb. The contents of some chemical elements in Fe-rohrensteins are much greater than those in the fine earth. The Pb and Zn contents in Fe-rohrensteins of the soil of small rivers basin are 440 and 890 mg/kg, respectively. In Fe-rohrensteins, the Pb and Zn contents are 42 % and 17 % of their concentrations in fine earth, respectively. Since some part of heavy metals is precipitated at the redox microbarriers around concretions (Fe-rohrensteins), it is removed from the biological cycle.