The aim of the study was to use of geochemical, chemical, ecotoxicological and biological indicators for a comprehensive assessment of ecological risks related to the mobility, ecotoxicity and bioavailability of trace elements in the bottom sediment of the Rożnów reservoir. The study found three elements deserving attention in the sediments: cadmium, nickel and chromium. Cadmium proved to be the most mobile and bioavailable, although the total cadmium content and geochemical indicators did not reveal any risk to organisms. Geochemical indicators showed that the sediments are contaminated with nickel and chromium, but both elements had a low bioaccumulation factor. Fractional analysis also revealed relatively low mobility of Cr and Ni and a higher potential risk of bioavailability for nickel. Most of the tested sediment samples had low toxicity in relation to the tested organisms. For H. incongruens, 11% of the samples were non-toxic, 50% of the samples had low toxicity, and 39% of the samples were toxic. For A. fischeri, no toxicity was found in 7% of the samples, low toxicity in 76% of the samples and toxicity in 17% of the sediment samples. The As, Cd, Cu content in the F1 fraction correlated significantly positively with the content of these metals in mussel tissues. Both biotesting and chemical analysis can reveal a potential risk to aquatic organisms. For a real assessment of the ecological risks associated with trace elements, it is necessary to use bioindicators taken from the environment and exposed to trace elements in situ.

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Purpose Agricultural land use associated with intensification in plant growing affects the physicochemical parameters of soils and thus soil quality. The aim of this study was to identify the quality of soils in the Peshok catchment in the Eastern Himalayas under different types of land use (tea, horticulture, rice), under high monsoon rainfall conditions. Methods Physical and chemical analysis were used, e.g. bulk density, pH, TOC, major and trace element content (such as Ca, Fe, K, Mg, Mn, Na, P, Ag, As, Ba, Cd, Co, Cr, Cu, Ga, Li, Mo, Ni, Pb, Sr and Zn) based on AntonPaar Multiwave 3000 microwave system and nitrogen and sulphur content using CNS Elementar Vario MAX cube analyser. In addition, ecotoxicological analyses were performed using the Microtox test. Soil quality was assessed on the basis of chemical indicators related to the mobility of trace elements (risk assessment code, individual contamination factor and global contamination factor); geochemical indicators (geoaccumulation index, enrichment factor, contamination factor, contamination degree, modified contamination degree, pollution load index and improved Nemerow pollution index); and ecological indicators (potential ecological risk coefficient and potential ecological risk index). A statistical package of Statistica v13 was used for statistical analysis. Results Soils in the analysed catchment are characterised by low contents of macro- and microelements. It was shown that natural factors, such as high precipitation and steep slopes, favour strong leaching of elements from the soil, and farming systems based on natural and chemical fertilisation, terracing and irrigation are not able to balance them fully. The contents of TOC and N as well as pH were determined mainly by the land use. Results of statistical analyses and geochemical indicators revealed the predominantly natural origins of elements. The higher Ga content indicated a relationship with the local geology and the higher Cu content with the use of fertilisers. Indicators showed a low ecological risk related to the presence of trace elements, and soil ecotoxicity to A. fischeri was generally determined by the acidic pH of the tested soils. Low mobility was observed for most elements, and regardless of the land use, the residual fraction predominated. Conclusion The study showed that use of many indicators can more fully describe soil quality in relation to land use, especially in the case of a low content of trace elements. Moreover, this approach helps to better understand the changes taking place in soil quality under different land uses in mountains with high rainfall.

Purpose The aims of the study were to investigate the interaction between fractions of organic matter and polycyclic aromatic hydrocarbons (PAHs) in bottom sediments and to use mussels as passive biomonitors and consensus-based sediment quality guidelines for ecological risk assessment in sediments. Methods Bottom sediment samples were taken from 46 points located in the Rożnów reservoir (Poland). The sediment organic matter (SOM) characteristics included total carbon (TC), total organic carbon (TOC), humic acid carbon (Cha), fulvic acid carbon (Cfa), non-hydrolysing carbon (Cnh), and dissolved organic carbon (DOC). The extraction procedure was carried out in bottom sediments as well as in freeze-dried mussel tissue samples to directly determine the accumulation potential of PAHs to the living organisms in their natural environment. Results The content of organic matter fractions was in the following order: Cfa (fulvic acid) > Cnh (non-hydrolysing carbon) > Cha (humic acid) > DOC (dissolved organic carbon). The mean ∑16PAHs (μg kg−1) concentration was 1755.2 ± 724 (total) and 256 ± 254 (bioavailable) in sediments and 1740 ± 72.2 in the mussel tissues. A significant positive correlation was found between the concentration of PAHs in the mussel tissues and the total and bioavailable concentration of PAHs in bottom sediments. Conclusion The PAH concentration in bottom sediments depended on the stabile carbon forms Cnh. Principal component analysis (PCA) suggests that the fine fraction can significantly increase the bioavailability of PAHs and can be an important factor in the distribution of PAHs in the sediments.

Purpose The aim of the study was to propose a phytoremediation-based approach toward the proper utilization of post-industrial, metal-contaminated bottom sediments. The common ice plant, Mesembryanthemum crystallinum L. (Aizoaceae), an abiotic-stress tolerant, C3/CAM intermediate halophyte, was tested for growth in substrates containing bottom sediments and for biological removal of metal pollutants. In variant tests, the sediments were admixed with non-toxic components to reduce the ecotoxicity hazards and improve growth conditions. Materials and methods Bottom sediment samples were collected from Lake Chechło in the industrial area of Poland. They were amended with universal soil and other materials (sand, lime, plant ash) and then used as growth substrates. After 30-day growth the plant biomass and rhizospheric microbiota population were assessed. The elemental content was determined in the substrate as well as in plant organs with inductively coupled plasma–optical emission spectrometry (ICP-OES). Bioaccumulation factors (BAFs, indicating phytoextraction processes) and root-to-shoot translocation factors (TFs) were calculated for all the metals to trace their behavior upon phytoremediation. Ecotoxicity assessments were performed by using a set of biotests (Phytotoxkit, Ostracodtoxkit F, and Microtox). Results M. crystallinum proved its ability to grow under harsh conditions of toxic and poor-quality substrates, while allowing for proliferation of rhizosphere bacteria. The plant growth was accompanied by the accumulation of Na and several other metals which were partially removed from the bottom sediment-containing soils. Depending on the experimental variant, the maximum removal achieved upon the 30-day test was: for Cd, 18.1%, Cu, 47.6%, Cr, 32.7%, Pb, 36.6%, and Zn, 24.1%. M. crystallinum hyperaccumulated Zn and accumulated (either in roots or shoots) Cd, Cu, Cr, and Ni. The maximum BAF values (> 1.0,) were obtained for the following metals: Cd, Cr, Ni, Cu (roots) and Cd, Cr, Ni, Zn (shoots). The highest values of TF (> 1), confirming high phytoremediation potential, were calculated for Na (33.33), Cd (1.47), Cu (1.77), Cr (7.85), and Zn (4.02). Bottom sediments revealed class III toxicity (acute), which was decreased by admixing with other materials. Surprisingly, the treatment with M. crystallinum led to an increase of toxicity levels, possibly by mobilizing potentially toxic elements during plant growth and microbial population development. However, mixing the sediments with universal soil and lime enabled us to maintain class I (no acute toxicity). Conclusion The common ice plant reveals strong application potential for use in reclamation of soils or revitalization of industrially degraded areas containing bottom sediments.