The laboratory tests included: a) pH and electrical conductivity (EC)
determinations, as well as proximate, ultimate and maceral analyses, in order to characterize the samples, b)
major and trace element analyses of both the total and the easily exchangeable fractions (EEF), in order to
assess the phytotoxicity effect, c) cation exchange capacity (CEC) determination in mixtures of the samples
(5 wt.%) with a certain soil (95 wt.%), in order to evaluate the peat/coal impact, and d) the determination of
the contents of humic substances (HS), as well as of carboxylic and phenolic groups.