This paper presents the results of a geochemical and isotopic study of technogenic soils and acid pool waters in the abandoned mine tailings pile and its potential impact on the adjacent farmers' wells at the village of Serwis (south-central Poland). The acid tailings pools showed strong trace element and REE signals. These acid pools were featured by the predominance of medium rare earth elements (MREE) with a strong positive Gd anomaly. The technogenic soils also revealed a MREE roof-shaped pattern, but with distinct positive excursions in Gd, Sm, Eu and Ce. The d 34 S-SO 4 2signatures of acid pool waters (mean of 1.3 %) were close to those of soils and pyrite (means of 2.3 and 3.2 %, respectively). The waters of four farmers' wells exhibited nearly the same d 34 S-SO 4 2values (0.7-4.0 %) as the nearby acid pool waters (0.3-3.1 %). The similar d 34 S isotope signatures combined with the highest contents of dissolved SO 4 2-(181-577 mg/L) in these wells suggest that the tailings pile is a potential source of SO 4 2derived from pyrite weathering. This relationship may also be evidenced by a spatial (site) variable dendrogram that groups these four wells into one cluster at the linkage distance (D link /D max 9 100) \ 53. Keywords Mine tailings Á Acid mine drainage Á Farmer's wells Á Trace elements Á REE Á Stable isotopes Á Geochemical interactions Á Environmental impact

Specific plant species that can take up and accumulate abnormally high concentrations of elements in their aboveground tissues are referred to as "hyperaccumulators". The use of this term is justified in the case of enormous element-binding capacity of plants growing in their natural habitats and showing no toxicity symptoms. An increasing interest in the study of hyperaccumulators results from their potential applications in environmental biotechnology (phytoremediation, phytomining) and their emerging role in nanotechnology. The highest number of plant species with confirmed hyperaccumulative properties has been reported for hyperaccumulators of nickel, cadmium, zinc, manganese, arsenic and selenium. More limited data exist for plants accumulating other elements, including common pollutants (chromium, lead and boron) or elements of commercial value, such as copper, gold and rare earth elements. Different approaches have been used for the study of hyperaccumulators - geobotanical, chemical, biochemical and genetic. The chemical approach is the most important in screening for new hyperaccumulators. This article presents and critically reviews current trends in new hyperaccumulator research, emphasizing analytical methodology that is applied in identification of new hyperaccumulators of trace elements and its future perspectives.

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Background and aim The presence of chlorides in soils, e.g., from de-icing salts may change metal availability to plants. Methods To assess the role of de-icing chlorides on bioavailability of metals, the samples of the rhizosphere soils, roots and shoots of Juncus effusus L. were collected monthly from April to June of 2019 in the vicinity of roads and analyzed for trace (Ag, Cd, Co, Cu, Pb, Zn) and rare earth elements (from La to Lu). Results Concentrations of Cl− were distinctly higher in the shoots than in the roots. Apart from Cd, the concentration sequence of the other metals was as follows: rhizosphere soils>roots>shoots. The bioaccumulation and translocation factors indicated that Cd was the most preferably transported to the shoots as opposed to Ag, Co, Pb and REEs that showed a very low translocation potential. Negative correlations, which were noted between Cu and Co in the shoots and Cl− in soils, revealed their role in salinity stress alleviation. All soil samples showed a positive anomaly of Ce and a negative anomaly of Eu, whereas the shoots showed in turn a negative anomaly of Ce and a distinct positive anomaly of Eu. The lowest salinity factors (K/Na, Ca/Na) of the shoots resulted from an increase of salinity in J. effusus by higher sodium concentrations derived from de-icing NaCl. Conclusions De-icing agents may change the uptake of other elements. In natural habitats, the factors affecting this process include: type of element, soil metal concentrations and interactions, and individual plant features.

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A vulnerable point of the currently used approach to the search for the new species capable of abnormal accumulation (hyperaccumulation) of trace elements is that most studies have been conducted in laboratory conditions and focused on the determination of a limited number of elements. We propose a methodology that enables screening for multi-element accumulating plants. This methodology is based on two analytical steps: a semiquantitative analysis mode by ICP-MS that allows selection of plant samples which are enriched in one or more trace elements, and a quantitative analysis necessary for confirmation of the results derived from the first step. The proposed methodology was tested in the study of 30 plant samples. Ten elements with the highest concentrations obtained in the semiquantitative analyses were determined quantitatively with the following detection limits (in mg/kg): 0.001 for Ag, 0.08 for Ba, 0.002 for Cd, 0.005 for Co, 0.01 for Cr, 0.003 for Cu, 1.4 for Fe, 0.012 for Mn, 0.03 for Ni, 0.006 for Pb, 0.001 for Sc, 0.001 for Tl and 0.06 for Zn. The CRM recovery values obtained were in the range of 80-103 %, and the precision of the measurements (as RSD) was in the range of 0.34-4.05 %. We also propose a simple method for evaluation of typical element concentrations in plants collected for analyses. Our approach provides a novel screening method for both identification of new hyperaccumulators and for studying a larger number of elements accumulated by plants. This method may find its application in environmental biotechnology.

Soils, next to vegetation, are one of the most popular indicators in environmental quality studies. The response of soils to air pollution is less complex than the response of vegetation. In soils, mainly in their upper layers, the deposition of compounds may occur almost undisturbed, therefore results of chemical analyses are readily used in the assessment of changes caused by natural processes and anthropogenic activities. In a temperate climate zone, the outermost layer of forest soils is formed by an organic horizon (-O), which comprises two basic subhorizons, of which the organic fermentative-humic subhorizon (-Ofh) is recognized as the most noteworthy. The subhorizon-Ofh encompasses partially and fully decomposed organic matter (humic and fulvic acids, humins), as well as Fe, Mn and Al oxides and hydroxides, forming a characteristic tangled mat. The structure pattern of this subhorizon is responsible for the higher concentrations of elements and organic compounds, which are immobilized through sorption, complexation or precipitation. Some previous studies have shown that the subhorizon-Ofh has enhanced accumulative properties in comparison to the remaining subjacent soil horizons. Results derived from soil studies in the Holy Cross Mountains/HCMs (south-central Poland) have also revealed that this subhorizon is mainly enriched in polycyclic aromatic compounds (PAHs) and some trace elements (Hg, Cd, Cu, Pb, Zn). This could make the subhorizon-Ofh a potential geoindicator of soil quality in relation to these compounds over the temperate climate zone. However, further study on this issue is needed to confirm its application in environmental monitoring.

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