Trace elements and stable sulfur isotopes in plants of acid mine drainage area:Implications for revegetation of degraded land

The abundances of trace elements,a low pH of water and soil in areas impacted by the acid mine drainage(AMD)may cause an excessive uptake of potentially toxic elements and nutritional imbalances in plants.Metal-tolerant,native plants are used for revegetation of degraded mining areas.We established levels of selected trace elements and stable sulfur isotopes in the above-ground plant biomass collected in a mining area in south-central Poland.In 2016,20 samples of the most common species were collected from sites with a different influence of acid mine drainage and analyzed for trace elements by the inductively coupled plasma mass spectrometry technique.On the basis of the results obtained in 2016,the most contaminated site was selected for a more detailed study,in which sulfur contents and stable sulfur isotope ratios were determined together with trace elements in 17 samples.The results confirmed that the plants native to the AMD area efficiently accumulated trace elements,especially As and rare earth elements.Mosses showed the highest content of trace elements,but exhibited the lowest concentrations of sulfur accompanied by the highestδ34S values.It has been shown for the first time that stable sulfur isotope composition of AMD plants in south-central Poland is significantly depleted in the 34S isotope showing an averageδ34 S value of–10.5‰in comparison with positiveδ34S values in local vegetation growing outside the AMD area and in local precipitation.

Hylocomium splendens (Hedw.) B.S.G.and Pleurozium schreberi (Brid.) Mitt.as trace element bioindicators:Statistical comparison of bioaccumulative properties

The principal objective of this study was to compare bioaccumulative properties of two terrestrial moss species Hylocomium splendens and Pleurozium schreberi from the Kielce area （south-central Poland）, using various statistical techniques. Forty-six moss samples from 23 sampling sites located within the city limits were analyzed for 33 trace elements. The results indicated that 17 elements （Ba, Ce, Co, Cu, Eu, Fe, Gd, Hg, La, Mo, Nd, Ni, Pb, Pr, Sm, V, Y） dominated in H. splendens, whereas only three elements （Mn, Sr, Zn） occurred in excessive amounts in P. schreberi. No differences in the distribution pattern of Dy, Er, Ho, Sn, Tb, Th and Yb were observed. The element concentration ratio （PI/Hy） varied from 0.50 to 1.19. For 14 elements （Ce, Co, Cu, Fe, Gd, Hg, La, Mo, Nd, Ni, Pb, Sm, Th, V）, PI/Hy 〈 1; for 4 elements （Cd, Mn, Sr, Zn）, PI/Hy 〉 1; for 7 elements （Ba, Dy, Er, Eu, Pr, Y, Yb）, PI/Hy = equalled 1. Czekanowski＇s method showed similarities in rare earth element concentrations for both moss species. The cluster analysis exhibited three significant clusters at D link /D max × 100 〈 50 for both moss species. Strong positive Spearman correlations between both moss species were recorded for the following pairs：Ba-Ba, Co-Co, Er-Er, Eu-Eu, Gd Gd, Mn-Mn, Ni-Ni, Pb-Pb, Pr-Pr, Sm-Sm, Th-Th, Y-Y, and Yb-Yb. Nonparametric tests （Sign test, Wilcoxon tests） showed statistically significant differences only for Cd, Ce, Co, Cu, Hg, Mo, Ni, Pb and Sr. The scanning electron microscope study of H. splendens and P. schreberi revealed a different morphology of these species with no injuries.