Abstract 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.
This paper presents experimental results from the use of biosurfactants in the remediation of a soil from a smelter in Poland. In the soil, concentrations of Cu (1659.1 mg/kg) and Pb (290.8 mg/kg) exceeded the limit values. Triple batch washing was tested as a soil treatment. Three main variants were used, each starting with a different plant-derived (saponin, S; tannic acid, T) or microbial (rhamnolipids, R) biosurfactant solution in the first washing, followed by 9 different sequences using combinations of the tested biosurfactants (27 in total). The efficiency of the washing was determined based on the concentration of metal removed after each washing (CR), the cumulative removal efficiency (Ecumulative) and metal stability (calculated as the reduced partition index, Ir, based on the metal fractions from BCR sequential extraction). The type of biosurfactant sequence influenced the CR values. The variants that began with S and R had the highest average Ecumulative for Cu and Pb, respectively. The Ecumulative value correlated very strongly (r > 0.8) with the stability of the residual metals in the soil. The average Ecumulative and stability of Cu were the highest, 87.4% and 0.40, respectively, with the S-S-S, S-S-T, S-S-R and S-R-T sequences. Lead removal and stability were the highest, 64–73% and 0.36–0.41, respectively, with the R-R-R, R-R-S, R-S-R and R-S-S sequences. Although the loss of biosurfactants was below 10% after each washing, sequential washing with biosurfactants enriched the soil with external organic carbon by an average of 27-fold (S-first variant), 24-fold (R first) or 19-fold (T first). With regard to environmental limit values, metal stability and organic carbon resources, sequential washing with different biosurfactants is a beneficial strategy for the remediation of smelter-contaminated soil with given properties.
Abstract The overuse of synthetic fertilizers has been associated with negative environmental consequences. The use of biochar in this regard has been recommended as a win–win strategy. However, our understanding on the comparative influences of biochar prepared from various feedstocks mixed with other bulking agents on soil health and crop performance remained limited. Therefore, in the present study, three types of biochar produced from sewage sludge, food, and agricultural waste were analyzed and compared for their effects on soil enzymes (dehydrogenase, DHA; β-glucosidase, GLU; phosphatase, PHOS; urease, URE; N-acetyl-β-D-glucosaminidase, NAG; and arylsulphatase, ARS), soil basal, as well as substrate-induced respirations and plant growth and physiology characters. The results revealed that food waste-derived biochar co-pyrolyzed with zeolite and/or sawdust was more effective in improving soil physicochemical properties and carbon and phosphorous cycling enzyme (DHA, GLU, and PHOS) activities in addition to soil basal respiration. While the influence of wastewater sewage sludge-derived biochar was more pronounced on urease, N-acetyl-β-D-glucosaminidase, and arylsulphatase enzymes as well as plant biomass accumulation and physiological attributes. Moreover, agricultural waste-derived biochar was found to be effective in enhancing substrate-induced respirations. This study thus concluded that biochar derived from various feedstocks has the tendency to improve soil health and plant growth attributes which further depend on the type of modification prior to pyrolysis.
Abstract. A potential effect of adjuvants/wetting agents added to the spray mixture on the water stability of soil aggregates (WSA) in agricultural soil was studied. Nine sites were chosen in the Czech Republic. Each site was mapped using representative soil pits (depth min. 1.3 m). A total of 54 mixed samples were collected from topsoil horizons on the selected sites. The samples were exposed to the action of four different types of wetting agents (organosilicone wetting agent; methyl ester of rapeseed oil; mixture of methyl ester palmitic and oleic acids; isodecyl alcohol ethoxylate), which are the most common wetting agents used in agriculture in the Czech Republic. WSA was determined before and after the addition of wetting agents (WA). Initial WSA values were at the same level in a majority of sampling points. Two sites were an exception, on which Haplic Luvisols and Relictistagnic Fluvisols occurred. These soil types featured the lowest WSA values. After the addition of WA across the sampling points, average WSA values exhibited a demonstrable trend: WSA of control sample (without the WA application) was at all times higher than in samples with the addition of WA. If the measured WSA values are compared in terms of overall means, it is evident that the control variant always exhibited the highest WSA value (on average 44.04 %) and the variants with the application of WA showed always WSA values lower by min. 16 %. The worst effect on WSA was that of wetting agents whose basic component was methyl ester of rapeseed. These wetting agents caused a decrease in WSA by more than 50 %. All soil samples were also analysed for basic soil parameters (glomalin, oxidizable carbon – Cox, pH, Na, P, Ca, K, Mg) in order to determine their potential influence on aggregate stability and to possibly eliminate the negative impact of WA. In this respect, only a significant influence of Cox content on WSA was recorded, which positively correlated with the stability of soil aggregates.
Fourier transform infrared spectroscopy (FTIR) spectroscopy detects functional groups such as vibrational bands like N-H, O-H, C-H, C = O (ester, amine, ketone, aldehyde), C = C, C = N (vibrational modes of a tetrapyrrole ring) and simply C = N. The FTIR of these bands is fundamental to the investigation of the effect of biochar (BC) treatment on structural changes in the chlorophyll molecules of both plants that were tested. For this, dried leaf of Spinacia oleracia (spinach) and Trigonella corniculata (fenugreek) were selected for FTIR spectral study of chlorophyll associated functional groups. The study’s primary goal was to investigate the silent features of infrared (IR) spectra of dried leave samples. The data obtained from the current study also shows that leaf chlorophyll can mask or suppress other molecules’ FITR bands, including proteins. In addition, the C = O bands with Mg and the C9 ketonic group of chlorophyll are observed as peaks at1600 (0%BC), 1650 (3%BC) and 1640, or near to1700 (5%BC) in spinach samples. In fenugreek, additional effects are observed in the FTIR spectra of chlorophyll at the major groups of C = C, C = O and C9 of the ketonic groups, and the vibrational bands are more evident at C-H and N-H of the tetrapyrrole ring. It is concluded that C-N bands are more visible in 5% BC treated spinach and fenugreek than in all other treatments. These types of spectra are useful in detecting changes or visibility of functional groups, which are very helpful in supporting biochemical data such as an increase in protein can be detected by more visibility of C-N bands in FTIR spectra.
The presented paper deals with the testing of a possibility to reduce emissions of undesirable greenhouse gases (CH4, CO2; NOx) and their mixture (biogas) during the storage of digestate using applications of secondary plant metabolites (tannins). The experiment was conducted in laboratory conditions in which the digestate was placed in fermentation chambers. Prior to the fermentation process, preparations were applied to the digestate, which contained tannins: Tanenol Antibotrytis (TA), Tanenol Clar (TC) and Tanenol Rouge (TR) in three concentrations (0.5, 1.0 and 2.0% w/w). The application of these preparations demonstrably affected the production of biogas and the contents of CH4, CO2 and N therein. The application of TR preparation in the concentration of 1.0% and 2.0% significantly reduced the production of biogas as compared with all variants. The preparation further inhibited the process of CH4 development. In contrast, the other preparations with the content of different kinds of TA and TC increased the production of biogas (on average by 15%), CH4 (on average by 7%) and CO2 (on average by 12%) as compared with the control variant and TR variant. These two variants reduced the concentration of N in biogas on average by 38%. Thus, the tested Tanenol tannin preparations can be used in different concentrations either to control emissions of greenhouse gases during the storage of digestate or, in case of increased production of CO2 for its reuse in order to increase methane yields in the process of anaerobic fermentation.
Abstract The rising prerequisite for developing novel green remediation methods for trace‐element‐contaminated lands is allied to the necessity to really mend the soil environs. The effectiveness of zeolite‐aided phytostabilization (AP) of soil contaminated with trace elements (TEs), from a scrap yard, using Lolium perenne as the plant for testing, was determined and discussed. The variability and activity of the rhizospheric bacterial community were also examined. The initial soil used in the AP experiment was characterized by especially high total contents of Zn, Pb, Cu and Cd. The TE total contents in roots and aboveground parts of L. perenne as well as in the phytostabilized soil materials were analyzed with flame atomic absorption spectrometry. The study revealed that the addition of natural zeolite into TE‐contaminated soil increased the relative plant biomass as well as the soil pH value as compared to the phytostabilized non‐amended series, whereas the total contents (with respect to an absolute value) of Zn, Pb, Cu and Cd were generally higher in roots than in the aboveground parts of L. perenne . In particular, the incorporation of zeolite to the soil contributed most significantly to the considerable relative decrease in the total contents of Cu, Pb, Cd and Zn in the soil, as well as the content of bioavailable and leachable speciations of Cd, Cu, Zn and Pb extracted from the soil using CaCl 2 solution as compared to the non‐amended series. In the phytostabilized zeolite‐amended soil, the overall bacterial diversity decreased but the presence of zeolite favoured the growth of microorganisms belonging to Gammaproteobacteria , Planctomycetia , and Thermomicrobia , in particular, the genera Mycobacterium , Williamsia , and Prochlorococcus .
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