Chemical Composition of Soil Solutions of Technosols from a Coal Mine Region in South- Eastern Europe

The cationic and anionic composition, i.e. K+, Na+, Ca2+, Mg2+, Cl-, NO3 -, phosphates, SO4 2- and dissolved organic carbon (DOC) in soil solutions of Technogenic soils (Technosols)from the area of Maritsa-Iztok coal mine basin in Bulgaria was analyzed and links with overburden strata were discussed. Two sites are located at the Mednikarovo village with humus and non- humus reclamation under grass vegetation. The other two are situated near the village of Obruchishte (non-vegetated and pine-vegetated). The sites differ in their textural composition, physico-chemical and hydro-physical properties. It was found that major cations and anions in the soil solutions at Mednikarovo site did not exceed the maximum permissible concentration limits (MPCL) for drinking water, while in solutions from the Obruchishte Technosols, composed of black clays intermixed with coal ash maximum permissible concentrations of sulphate (250 mg.l-1), phosphate (0.5 mg.l-1), calcium (150 mg.l-1) and magnesium (80 mg.l-1) were exceeded and may pose a threat to contamination of surface and sub-surface water of reclaimed soils.