TOTAL CONTENTS AND AVAILABLE FORMS OF NICKEL IN AGRICULTURAL ALLUVIAL SOILS

Alluvial soils located in river valleys constitute a diverse cover, which consists of mineral as well as mineral-organic and organic soils, with very different physicochemical properties. The subject of this study was to determine the nickel content in alluvial soils formed from gyttia of the biogenic plain of the Unislawski Basin. Soil samples were collected from seven soil profiles. Selectd physicochemical properties were determined aplying the methods commonly used in soil science laboratories. In the samples analysed the total nickel content was defined after mineralization in a mixture of acids HF + HClO4 and its easily available DTPA-extracted forms. The content of total and mobile forms was reported using the atomic absorption spectrophotometry method using the PU 9100X spectrometer (Philips). The total content of nickel ranged from 0.6 mg.kg(-1) to 18.04 mg.kg(-1). The highest content of this element was noted in surface and subsurface horizons and the enrichment horizons of organic matter. In the soil samples the total nickel content was similar to the geochemical background level, while the content of mobile forms of this element was lower than the values considered toxic. In the soils analysed the content of DTPA-extractable forms ranged from 0.14 mg.kg(-1) to 2.09 mg.kg(-1).