Anna Hołtra

The purpose of this investigation was to assess anthropogenic soil contamination by heavy metals (HMs) from rail transport-related activities in Wrocław. The concentrations of copper, zinc, lead, chromium, nickel, and cadmium were analysed in the surface soil layer along the railway tracks and perpendicularly, at increasing distance from the rail line. Pollution indices were used to assess the level of enrichment by single elements, the degree of total HM contamination, and the ecological risk associated with their presence in soils. The results indicated moderate enrichment with Cu, Zn, and Pb, while Cr and Ni occurred at geochemical background levels. The highest degree of accumulation and ecological risk was found for Cd, indicating its strong anthropogenic origin. Multi-elemental indices classified the overall level of soil contamination as low, although locally elevated metal concentrations were observed. A considerable proportion of samples exhibited high ecological risk. The phytotoxicity tests using Lepidium sativum L. and Avena sativa L. confirmed a slight inhibition of plant growth.

The challenge still is to quantify the impact of traffic volume, road type, age of the road, and the presence of road infrastructure on the content of trace elements in road dust. Samples of road dust were collected at the intersections and roundabouts of the main roads of Wrocław and the county, where traffic was accelerated. This research aimed to identify the level of Cu, Zn, Pb, Cr, Ni, and Cd in road dust, and determine the quality of road dust using individual and integrated pollution indices. A strong anthropogenic influence was noted, which causes a heterogeneous distribution of metal concentrations in the tested road dust. The principal component analysis (PCA) analysis showed that traffic intensity affects mainly the metal content in road dust. The strong Spearman’s correlations indicate the connection of trace elements to road traffic. Individual and integrated pollution indices confirm the enrichment of road dust with tested elements, although the permissible metal concentrations according to the Polish standard were not exceeded. A medium or high probability of road dust toxicity was recorded.

Mercury contamination from human activities is a severe environmental problem. The low cost of rhizofiltration of heavy metal-contaminated environments is causing an increasing interest in these technologies. The present study demonstrates the effectiveness of mercury removal from water by phytoremediation using S. natans. Plants cultured and collected from the environment were used. The study used Hoagland’s liquid medium contaminated with mercury: 0.15, 0.20, and 0.30. The bioconcentration factor obtained was 275–780. The relative growth rate was up to 0.12 g/gd and was much better for cultured plants than those collected from the environment. The removal rate of toxic metal was up to 94%. Total protein increased for cultures plants by up to 84%, while it decreased by up to 30% for those taken from the environment. Total chlorophyll for cultured plants decreased by up to 54%, which could be due to the toxic effect of the metal.

Trace elements emitted by road transport cause long-term contamination of road soils. This study showed the effect of the noise barrier on the spatial distribution of metals in soils at the City Centre Ring Road in Wrocław (Poland). Samples were taken along the barrier every 150 m and across the screen at distances of 0.5, 2.5, 5 (only on the left side), 10, 20, and 50 m from the noise screen on both sides of road no. 5. The contamination of soils was assessed with the use of commonly used individual pollution indices, integrated pollution indices based on the PI index or metal concentrations, and a potential ecological risk index (RI). The geoaccumulation index (Igeo) and the single pollution index (PI) indicate moderate contamination of soils by Cu, Pb, and Zn at most measuring points. The significant risk was reported from Cd in all samples. Integrated pollution indices, especially the PI_Nemerow, PI_avg, and RI confirm the poor quality of studied soils. The presence of elements in soil is related to anthropogenic factors. The spatial distribution of pollution indices and results of statistical analysis (HCA) indicate that Cr and Ni are of natural origin. Remaining elements (Cd, Pb, Cu, Zn) are of mixed origin with a large share from car transport (the significant Spearman’s correlation coefficients). In the case of cadmium, dendograms suggest the existence of an additional anthropogenic source, which is also confirmed by moderately strong correlations of this element with other metals.

The quality of soils polluted by trace elements around the facilities with the Cu and Zn smelting activities and the post-flotation tailings pond from copper industry were assessed. The level of the contamination of soils was determined on the basis of the contamination factor and the geoaccumulation index. The geoaccumulation index allows to distinguish more degrees of soil contamination and simplifies the assessment of the useable value of soil. The degrees of soil contamination and the pollution load index were shown. It has been shown that the pollution indices are a useful tool in describing the soil quality and planning corrective actions in the areas contaminated as a result of industrial activity. Histograms of pollution indices were used in order to detect the distribution of trace elements in soils. The content of metals in biomass was assessed using bioaccumulation indices. Triticum L. and Brassica napus L. show low bioaccumulation of studied metals in cereal plants. The correlations were used in order to detect the relationship among trace elements in soil as well as the relationship of metal (soil)-metal (plant) and metal bioaccumulation (plant)-metal (soil). The highest values of indices were recorded for the Oława smelter, presumably due to the long operation period before technological changes limiting the emission of pollutants were introduced. This research area was classified as very highly contaminated with all trace elements. Soils around other facilities are at least moderately contaminated.

The concentrations of metallic pollution in soils and plants along the ring road of Wrocław, Poland, have been determined. Environmental samples were collected from the surface layer of the profile within 2–3 m from the edge of the road. The analysis of metals (Pb, Cd, Cr, Zn, Cu and Ni) has been carried out through FAAS and GFAAS methods. The mineralizates of soils and plants were prepared in HNO3, 65% supra pure, using the Microwave Digestion System. The pH and conductivity of the soil solutions were measured to evaluate their active and exchangeable acidity and the salinity of the soils. The index of the enrichment of soils in metals (Wn) and the bioaccumulation coefficient (WB) have been determined. Also, histograms of the frequency of the occurrence of metals in the environmental samples and the Pearson's correlation coefficients were presented. The results of metal concentrations in soils were compared to the geochemical background in uncontaminated soils of Poland. The assessment of the results in the soils was also made relative to the standard, according to the Polish Ministry of Environment Regulation from September 1st, 2016. During the assessment of the bioaccumulation coefficients of metals in plants a reference was made to the content of undesirable substances in feed in agreement with the Polish Ministry of Agriculture and Rural Development Regulation from January 23rd, 2007.

E3S Web of Conferences, open access proceedings in environment, energy and earth sciences

E3S Web of Conferences, open access proceedings in environment, energy and earth sciences