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The aim of this study was to investigate the influence of residual glycerine (5 and 10% w/w) from the biodiesel industry, used as a co-substrate, on biogas production from maize silage. The experiments were conducted in a laboratory-scale, single-stage anaerobic digester at 39ºC and hydraulic retention time (HRT) of 60 d. Addition of 5% residual glycerine caused organic load rate (OLR) to increase to 1.82 compared with 1.31 g organic dry matter (ODM) L-1d-1 for maize silage alone. The specific biogas production rate and biogas yield were 1.34 L L-1d-1 and 0.71 L g ODM-1 respectively, i.e. 86% and 30% higher than for maize alone. Increasing the residual glycerine content to 10% increased OLR (2.01 g ODM L-1d-1), but clearly decreased the specific biogas production rate and biogas yield to 0.50 L L-1d-1 and 0.13 L g ODM-1 respectively. This suggested that 10% glycerine content inhibited methanogenic bacteria and organics conversion into biogas. As a result, there was accumulation of propionic and valeric acids throughout the experiment.

The paper evaluates the accumulation of selected risk elements in soils and biological tissues caused by railway transport. Samples of soil, pine (Pinus sylvestris L.) bark and needles, hoof fungus (Fomes fomentarius L.) and red-stemmed feathermoss (Pleurozium schreberi L.) were analyzed for the content of Cd, Cr, Cu, Ni, Pb and Zn. The samples were collected in five sites (A, B, C, D, E each separated by 500 m) covering a combined distance of around 2 km along railway tracks (Central Poland). The geo-accumulation index (Igeo), single pollution index (PI), contamination factor (Cf), degree of contamination (Cdeg), potential ecological risk (RI), and the probability of toxicity (MERMQ) index were calculated to determine soil pollution with risk elements. Soil toxicity was assessed with the Phytotoxkit biotest which measures the inhibition of seed germination and root growth in Sorghum saccharatum L. The calculated indices and the results of the phytotoxicity biotest revealed the highest levels of contamination in the proximity of a road overpass (site D). The accumulation of risk elements in soil was strongly correlated with pollutant levels in biological tissues. Zinc was the most abundant element in biological tissues, especially in pine bark and feathermoss. Soil pollution indices, biotest results, and plant and fungus bioindicators play an important role in environmental assessments of railway transport. [ABSTRACT FROM AUTHOR]

Pressures exerted on the soil ecosystem due to its exposure to lead have a significant and aggravating effect on the quality of life. This study was conducted to investigate the aided phytostabilization of Pb-contaminated soils by novel combined amendments. The pot experiment was run under greenhouse conditions, using the following mixtures of immobilizing amendments: halloysite and limestone as well as halloysite and compost. The Pb contents in plants, both total and CaCl2-extractable Pb concentration in soil, were determined using the spectrophotometric method. The use of halloysite and compost was shown to be the most effective and decreased the average Pb content in the above-ground parts of F. rubra and in the soil and was found to significantly increase soil pH and Pb content in roots of the test plant. New methods should be developed to minimize the environmental risk posed by the presence of heavy metal pollutants. The results show significant effects of immobilizing amendments on the chemical characteristics of soil contaminated with Pb and the uptake of Pb by plants. [ABSTRACT FROM AUTHOR]

Areas degraded by industrial activity demonstrate unfavorable chemical and physical conditions, including a high concentration of trace elements (TEs), which reduce the growth and development of appropriate plant cover. For the above reasons, in recent years, the demand for the development of natural and effective technologies for removing particularly hazardous compounds such as TEs from the environment has been growing. Because aided phytostabilization is a relatively new technology, examination of new additions immobilizing TEs in combination with an appropriately selected species plan poses a challenge in environmental protection and engineering. The novelty of this study is in the assessment of the usefulness of previously not applied soil amendments in processes of TEs immobilization in contaminated soils. This study presents the results of a vegetation experiment using a mix of grasses and rarely used mineral soil amendments (halloysite, diatomite, dolomite) for aided phytostabilization of soil originating from an area affected by industrial activity and characterized by high TEs concentrations. Additionally, the degree of phytotoxicity of the examined soils was determined. The greatest above‐ground biomass was observed when diatomite, dolomite, and halloysite were added to the soil. The concentrations of the analyzed TEs in test plants were higher in roots than in the above‐ground parts. This indicates that mineral amendments affected soil properties promoting TEs precipitation and decreasing TEs bioavailability. The highest increase in soil pH was observed after the application of dolomite to the soil. The average contents of Pb, Ni, Cu, and Cr in soil demonstrated the highest reduction after diatomite and halloysite application. The conducted research confirms the possibility of applying the examined soil additives to support phytostabilization of alkaline soil highly contaminated with TEs. [ABSTRACT FROM AUTHOR]