ABSTRACT
The total content of As species in the investigated soils was determined after fusing with sodium hydroxide (NaOH) by Atomic Absorption Spectrometry (AAS) method. As species were extracted from soils using specific reagents. The original schema of 6 arsenic factions in soils was used. It was worked out on the basis of the previous experiments (Wenzel 2001) and our own investigations (Motuzova et al. 2006). The exchangeable ions, easily soluble salts were extracted with 1% ammonium sulfate [(NH4)2SO4] +0.25% ammonium molybdate [(NH4)2MoO4] (pH 5.5-6.0) (No. 1); specifically adsorbed ions-by 1 M ammonium dihydrogen phosphate [NH4H2PO4 (pH 5.5-6.0)] (No. 2); species, bound with hydro(oxides) Iron (Fe), Aluminium (Al) and Manganese (Mn) -by 0.5 M
1 INTRODUCTION
Arsenic (As) belongs to microelements, it is widespread in earth crust, and consequently it is present in all living organisms. Arsenic is a common element in multiphase heterogeneous soil systems (solid, liquid, gaseous, live organisms) which keep the element at the expense of different mechanisms with different force of bond. Primary minerals are sources of the element in natural landscapes. Arsenic species, strongly and weakly bound to soil components, are in constant interaction with soil solution. Their proportions and contents (as well as for other chemical elements) are important for the ecological state of landscape. Namely, soil As-species define the ability of the element to various kinds of migration (water, biogenic) and its influence on living organisms. Such circumstances provided the aim of the present investigation. Its purpose is to work out the informative indicators of the arsenic species in soils, to define them experimentally, to check their efficiency for the characteristic of ecological state of soils, that have been formed in different natural and technological conditions.
