Slags from the Silesia–Cracow Upland (Poland), including ten historical slags (deposited in waste dumps) and four contemporary slags (from current production), were examined to compare their chemical and mineralogical properties as well as to assess their potential for the recovery of selected metals and critical raw materials. The historical slags associated with the smelting of polymetallic ores originating from Mississippi Valley-type (MVT) deposits consisted primarily of gypsum. The contemporary slags, obtained from industrial waste rich in zinc and lead, were predominantly spinels (magnesium-aluminate and ferric) that exhibited higher iron content (up to 46.6 wt% of Fe2O3) compared to the historical slags (up to 26.1 wt% of Fe2O3). The zinc content was similar for both the slag types (3.5 wt% Zn). The average titanium and arsenic contents in the old and contemporary slags were at the same level as well, with 0.21 wt% (Ti) and 0.13 wt% (As), respectively. The contemporary slags contained higher levels of critical raw materials, such as cobalt, nickel, copper, and manganese, compared to the historical slags. Rare earth elements (REEs) were also more abundant in the contemporary slags, with an average content of 212 ppm, while the historical slags averaged 124 ppm. These findings underscore the potential for recovering valuable metals and critical raw materials from such slags, presenting opportunities for resource optimisation and environmental management.
The article highlights sorptive properties of poultry litter. Preliminary studies on sorption of Cd2+, Cu2+, Ni2+, Pb2+, Zn2+ ions at the concentration range of 1–1000 mg L-1 were carried out. Langmuir and Freundlich models were used to determine the potential capacities of the poultry litter. Sorption parameter outcome from isotherms exhibited the following order: Pb > Cd > Cu > Zn > Ni. During the batch adsorption experiment, a decrease of the absorbance of solutions in the UV-Vis range was observed, proportional to the increase in the concentration of metals in the solutions. This phenomenon was associated with the precipitation of complexes of fulvic/humic-like compounds and uric acid with metals. The decrease in dissolved organic carbon (DOC) concentration confirmed previous assumptions. The FT-IR spectroscopy showed significant role of uric acid in Cd2+, Pb2+, Zn2+ sorption. FT-IR measurements allowed determining the type of active sites involved in sorption, especially carboxylic groups. The findings should be helpful in soil reclamation practices with poultry litter.
The secondary, substitute habitats are becoming more important for the survival of many valuable plant species, including medicinal plants—for example, bearberry Arctostaphylos uva-ursi. The aim of the conducted research is to compare the ability of A. uva-ursi to accumulate heavy metals in leaves from railways (anthropogenic substitute habitat) and the natural habitats (pine forests). We measured the concentration of five heavy metals (Cd, Hg, Ni, Pb, and Zn) in plant material and in the soil. The bioaccumulation factor was also calculated. Moreover, we measured biotic factors including A. uva-ursi height and abundance, along with the plant diversity indices, in the investigated plots. The presented results reveal that (1) none of the parameters concerning the content of the selected heavy metals described in the currently applicable legal acts were exceeded, (2) A. uva-ursi does not show the potential for heavy metal accumulation, except for zinc and partially mercury, (3) its individuals in the natural habitats are lower, (4) the abundance (percentage cover) of A. uva-ursi is the lowest in the natural habitat, and (5) the value of the Shannon–Wiener diversity index is the highest in the vegetation patches with A. uva-ursi developed in natural habitats.