ELECTRON-MICROPROBE STUDIES ON SOIL SAMPLES WITH VARYING HEAVY-METAL CONTAMINATION .1. METHODS AND ANALYSIS OF ELEMENTS IN PEDOGENIC OXIDES

EMA point analysis, line scan profiles and microprobe photos were performed on thin sections from 19 soil samples with variing heavy metal content to show the distribution of elements in soil particles on a microscopic level. The investigations showed that the detection limits generally have a range of 110-830 mg/kg in anorganic soil matrix respectively 80-320 mg/kg in organic soil matrix. The element specific heavy metal accumulation capacities on the pedogen oxides compared to the average content of the soil samples can be described for Co, Ni, Cu, Zn, Cd and Pb. The maximum trace element accumulations in concretions related to their element total content in the soil samples were by Co 3.170 times, Ni 6.635 times, Cu 323 times; Zn 112 times, Cd 2.000 times and by Pb 745 times. The accumulation and immobilization of heavy metals by iron oxides suggests that additions of Fe oxides could be used to reduce heavy metal availability and leaching to the subsoil on highly contaminated soils.