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Heavy metals (Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, and Zn) in soils and plants of four different ecosystems (forest, grassland, agro and urban ecosystem) at different distances from the source of the pollution were analyzed in order to assess and compare soil contamination in the various ecosystems and determine the potential accumulation of plants depending on the place they inhabit. Correlation relationships among heavy metals in soils differ depending on the ecosystem, and between soil and plant, the heavy metals showed significant correlation for Cu, Mn, Ni, Pb and Zn. Contamination factor (C_f), degree of contamination (C_d) and pollution load index (PLI) were used in order to determine the level of environmental contamination of the study area. All studied ecosystems were rated as moderately contaminated (except agroecosystem, which was found as low contamination ecosystem) according to C_d and extremely polluted according to PLI. The highest pollution in both cases was found in urban ecosystem, and Cd, Cu and Fe were determined as the biggest pollutants.

Relationships between alien plant species and their aboveground effects have been relatively well studied, but little is known about the effects of invasive plants on belowground faunal communities. Nematodes are abundant, ubiquitous and diverse soil biota, and alterations of their community compositions can illustrate changes in belowground ecosystems. In 2016 and 2017, we determined the response of species diversity, community composition and trophic composition of the soil nematode communities to invasion by the alien plant Solidago gigantea in two ecosystems, forest and grassland, where invasion takes place. Nematode abundance was higher and number of identified nematode species was lower at invaded than uninvaded sites, indicated by lower species diversity, regardless of ecosystem. Herbivorous nematodes were the most affected trophic group. Herbivore abundance was higher at invaded than uninvaded sites and in grassland than forest. The herbivorous species Boleodorus thylactus, Geocenamus sp., Helicotylenchus spp., Paratylenchus bukowinensis, Pratylenchoides crenicauda and Rotylenchus robustus were more abundant at the invaded sites. Abundances of nematodes in the other tropic groups were limited or not affected. The invasion did not significantly affect the ecological and functional indices, except for the Channel Index in 2016. Differences were observed in values of Enrichment Index (indicator of resource availability), Channel Index (indicator of ascendant bacterial/fungal decomposition channel) and Basal Index (indicator of depleted-perturbed soil food webs) between grassland and forests. We can thus conclude that invasion by S. gigantea significantly alters nematode community indicators (abundance, species diversity and specific trophic groups); however, this effect seems to be significantly influenced by the type of ecosystem where invasion takes place.

The surrounding of the poorly maintained tailing ponds is endangered by the toxic substances and represents a serious risk for the health of the local population. The aim of the study was to determine the soil pollution by the hazardous elements (As, Cr, Cd, Cu, Fe, Mn, Ni, Pb, Zn) around the tailing pond using contamination factor (C_f), degree of contamination (C_d) and pollution load index (PLI). The health and the condition of soil were evaluated by soil enzyme activity (urease, acid and alkaline phosphatase, florescein diacetate, and ß-glucosidase). The spreading of the airborne hazardous elements from the body of the tailing pond was evaluated by moss and lichen bag technique and relative accumulation factor was used for the result expression. Cd, Fe, and Mn in soils reached above the limit values at all sampling sites. According to the degree of contamination (C_d), the soils at the sampling area were very high contaminated by As, Cd, Cu, Fe, Mn, Ni, and Pb. The most part of the assessed area was according to the PLI values extremely polluted. The air pollution was the most serious around the tailing pond, but serious levels of some hazardous elements were determined also in the remote distances.