Soil Phytotoxicity Research Articles

FeAl-LDH-modified biochar (FeAl-LDH@BC): A high-efficiency passivator for hexavalent chromium (Cr(VI)) reduction and immobilization in contaminated soil

A composite FeAl-LDH@BC obtained by successfully loading FeAl-LDH onto biochar (BC) is used to the Cr(VI)-contaminated soil remediation. The efforts of loading, initial pH, concentration and dosage are investigated. The results indicate that the immobilization process of Cr(VI) in soil could be well described by the pseudo-second-order kinetic model and maximum adsorption capacity of FeAl-LDH@BC is 42.78 mg/g at a temperature of 298 K. Additionally, The physicochemical properties of FeAl-LDH@BC are characterized by SEM, EDS, XRD, FTIR and XPS. The characterization results suggest that the immobilization mechanism involved adsorption and reduction. Cr(VI) is immobilized by adsorption to the layers of FeAl-LDH, the reduction of Cr(VI) to Cr(III) is then accomplished using Fe(II) as a reducing agent. In order to demonstrated the stability of composites for environmental restoration, the TCLP tests, dry-wet, freeze-thaw aging cycles, soil phytotoxicity tests, and microbial community are analyzed. The study shows that we provided a material for soil immobilization with high performance for the remediation of Cr(VI)-contaminated soil.

Dynamics of Phytotoxicity Indicators of Ordinary Chernozem when it is Contaminated with Silver Nanoparticles

The dynamics of phytotoxicity indicators (germination and length of radish roots) of ordinary chernozem when contaminated with silver nanoparticles was studied. In laboratory conditions, ordinary chernozem was contaminated with silver nanoparticles (1, 10 and 100 mg/kg) for 3, 10, 30, 90 and 180 days. It was found that the more silver nanoparticles were introduced into the soil, the greater the decrease in germination and length of radish roots. There was no restoration of germination and length of radish roots with an increase in the period from the moment of contamination. In this study, the maximum toxic period from the moment of contamination for each indicator was identified by its sensitivity to silver nanoparticles and informativeness. The maximum toxicity of silver nanoparticles in relation to the root length and germination of radishes was noted on the 10th and 30th days, respectively. The results can be used to assess the phytotoxicity of soils contaminated with silver nanoparticles.

Wheat as a test object for determining the degree of soil contamination with petroleum products

Abstract Currently, the oil and gas industry remains the leader in meeting the global need for energy resources. The high intensity of hydrocarbon production naturally leads to an increase in the volume of petrochemical waste that ends up in the natural environment. In this regard, the implementation of toxicological assessment of oil-containing soils and water bodies is one of the most important environmental tasks. Biotesting allows for a quick integral assessment of the properties of a contaminated environment. This method of toxicity analysis is economical and does not require the use of special chemical reagents and equipment. The seeds of higher vegetation are the most accessible, easy to use and universal test objects. However, it is necessary to use only species that are highly sensitive to pollutants. This article is based on the results of a study of the phytotoxicity of gray forest soil contaminated with petroleum products using wheat. Experiments have shown that soil contaminated with oil waste has a strong inhibitory effect on wheat seedlings. It was found that small doses of petroleum products (0.31% oil) have a stimulating effect on seed germination in the analyzed soil.

Оценка фитотоксичности наночастиц серебра в черноземе обыкновенном

The effect of silver nanoparticles (AgNPs) in concentrations was evaluated 0.1; 0.5; 1; 5; 10; 50 and 100 mg/kg for the germination and root length of ordinary black earth radish 30 days after contamination. It was found that the degree of ecotoxic effect of AgNPs on the germination and length of radish roots is directly dependent on their dose in the soil. The content of AgNPs 1, 5, 10, 50, 100 mg/kg in ordinary chernozem caused a decrease in the germination of radish by 11, 13, 15, 18 and 38 % compared with the values in uncontaminated soil. Doses of AgNPs 0.5, 1, 5, 10, 50 and 100 mg/kg inhibited the length of radish roots by 19, 20, 25, 30, 37 and 43 % compared with the values obtained in uncontaminated soil. The radish root length index showed the greatest sensitivity to soil contamination by AgNPs compared to the germination index. The obtained results on the assessment of phytotoxicity of soils contaminated with AgNPs can be used for diagnostics and as an indicator of the ecological state of soils.

Reduction of phytotoxicity of oil-contaminated peat soils through the use of regenerative complexes based on surfactants

Reduction of phytotoxicity of oil-contaminated peat soils through the use of regenerative complexes based on surfactants

Influence of Carbons on Metal Stabilization and the Reduction in Soil Phytotoxicity with the Assessment of Health Risks

Despite notable achievements in the development and application of the remediation of metal-contaminated soils, the search for and study of promising immobilizing agents continues. This article presents a new approach to using brown coal and activated carbon and their application for metal stabilization. An experiment was conducted to test Medicago falcata L. on soils from industrial areas contaminated with varying levels of lead (Pb), cadmium (Cd), chromium (Cr), zinc (Zn), copper (Cu), and nickel (Ni) with the addition of carbons. This plant is a stress-tolerant leguminous species. In this study, the total content of metals in soil and the available forms to plants (single extractions with 0.02 M ethylenediaminetetraacetic acid, EDTA) were determined, along with metal contents in the plant. The use of carbons lowered the phytoavailable forms of metals for plants and thus, resulted in a reduction in the phytotoxicity of the soils. The contents of the tested metals in the roots and shoots were lower than in the combinations of soils with no carbon added. The activated carbon had a stronger effect on limiting the availability of metals than brown coal in relation to plants growing on soils without added carbon; the percentage of reduction for the shoots was Cr (18.2%) > Zn (11.5%) > Ni (10.7%) > Cu (10.3%) > Cd (8.9%) > Pb (2.4%) and Cu (13.3%) > Cr (12.5%) > Zn (10.5%) > Pb (9.0%) > Ni (5.7%) > Cd (4.6%) for roots. Metals reduced the growth of Medicago falcata L. roots from 44 to 21%, while the growth of shoots was reduced from 25 to 2%. Adding carbons to soils in all combinations resulted in a decrease in the following pollution indices: pollution index (PI), pollution load index (PLI), and non-carcinogenic (HQ) and carcinogenic risk factors (ILCR).

Исследование фитотоксичности почв Астраханской области, подверженных пастбищной дигрессии

Pasture digression is one of the main factors of degradation and desertification of territories in the South of Russia. The impact of unsustainable grazing of agricultural animals on plant and soil cover has significant negative consequences, as a result of which the modern vegetation of the semi-desert of the Northern Caspian region has changed greatly over the decades and has taken on unfavorable dynamics. The object of the study was the soils of the Astrakhan region, subject to various stages of pasture digression. Phytoindication was carried out according to the indicators of germination and intensity of initial growth using a traditional test culture (Raphanus sativus L.). As a result of the study, no dependence was established between the indicators of germination and intensity of initial growth of radish on the stages of pasture digression. Soil phytotoxicity depended on soil properties, such as humus content, mobile phosphorus, soil solution reaction, and soil density.

The impact of the military actions on the soil ecosystem of Mykolaiv region

A study has been conducted on the changes occurring in the soil cover of the Mykolaiv region due to military activities, aiming to develop strategies for protecting ecosystems and their revitalization. Military actions lead to significant soil pollution with inorganic chemicals and petroleum products and have a toxic impact on biota. Explosions and bombardments result in soil cover degradation and erosion. Additionally, the destruction of vegetation and disruption of the biological cycle threaten soil fertility. Ignoring such processes could have devastating consequences. In certain areas affected by military influence, doubts or concerns arise regarding land resource eco-safety and its appropriate consumer use. Radioecological monitoring, due to military actions, is particularly relevant. Environmental security issues are becoming increasingly significant, and preserving the ecological integrity of soil is becoming a crucial priority. One of the critical areas of interaction between humans and the environment is agriculture, which plays a vital role in forming the food base and utilizing natural resources. Developing agroecological systems is becoming increasingly important as they influence the biosphere and require systemic analysis to ensure ecological sustainability. Agroecosystems reflect all aspects of human-environment interaction, assessing its ecological consequences as a crucial element of sustainable development. The research aimed to identify signs of soil phytotoxicity in the context of ecocide caused by military actions. Preserving soils is a prerequisite for the region's sustainable development and food security. Thus, a study aimed at identifying various impacts on the soils of the Mykolaiv region is of great importance for developing strategies for conserving and restoring soils that meet modern needs.

Assessment of the influence of the toxic effect of municipal solid waste on the ecological state of the soil

Introduction. Тhe municipal solid waste of pollution negatively affects on the state of the environment, since during their storage on the territory of landfills and the adjacent territory, accumulation of heavy metals (HM) can change the biological indicators of soil conditions: microbiological, biochemical, and phytotoxic.
 The aim of the study was to assess the influence of the toxic effect of the municipal waste landfill “Azov” in the Rostov region on the ecological state of the soil. 
 Materials and methods. It was explored the influence of municipal solid waste landfill “Azov” of the Rostov region on the ecological condition of the ordinary chernozem in the landfill and adjacent territory (140, 260, 380, and 540 m). The content of heavy metals in the soil, such as chromium (Cr), strontium (Sr), zinc (Zn), vanadium (V), copper (Cu), nickel (Ni), cobalt (Co), lead (Pb), and arsenic (As) were defined. The ecological state is assessed by sensitive and informative-biological indicators of soil pollution: the abundance of bacteria of the genus Azotobacter, the total prevalence of soil bacteria, the activity of catalase, dehydrogenases. 
 Results. Soils were found to contaminate with arsenic by MAC / TAC (exceeding the MAC by 7 times at the landfill and exceeding the MAC by 4 to 6 times in the territory). Pollution with heavy metals according to German MACs with chromium exceeded by 1.4 times). The highest concentration of heavy metals prevailed in the body of the landfill. Depending on distance from the landfill the concentration of heavy metals in the soil decreased. HM contamination leads to negative consequences for the ecological state of ordinary chernozem: the total number of bacteria decreases (until to 95% of the control), the number of the genus Azotobacter decreases (up to 95% of the control), the activity of catalase (up to 25% of the control) and dehydrogenase decreases (up to 30% of control) and increased soil phytotoxicity (up to 60% of control). It can be concluded that the exploitation of the landfill leads to a deterioration of the environmental situation on the territory of the landfill and beyond.
 Limitations. The ecotoxic effect of HMs on soils less buffered to pollution will be higher than on the chernozems studied in the article.
 Conclusion. The Landfill “Azov” was found to impact on the microbiological, biochemical, and phytotoxic parameters of the soil negatively. This problem connects with influence of heavy metals which get into the soil of during the operation of the landfill. The most sensitive and informative biological indicators are total number of bacteria and length of radish roots.

Biotesting for adsorptive bioremediation of oil-contaminated podzolic soil in Western Siberia

The majority of Russia’s oil and gas-producing regions are situated in the northern part of Western Siberia, where sandy podzolic soils are prevalent. Due to the low buffering capacity of these soils and the severe Arctic climate, the conventional method of bioremediation for removing oil contamination is not effective. This study, for the first time, explores the potential of adsorptive bioremediation for purifying oil-polluted gley-podzolic soil. This approach involves introducing natural sorbents of various classes before soil treatment through bioremediation. The optimal conditions for soil treatment can be determined using the express phytotests based on white clover ( Trifolium repens ) seed germination. The results indicate that under the best conditions, which involve adding 2 % mixed sorbent based on granulated activated carbon (GAC) and diatomite (4:1) or Spilsorb, it is possible to minimize soil phytotoxicity after 2-3 warm seasons and reduce the content of total petroleum hydrocarbons to the permissible residual oil content (≤5 g/kg) established in the territory of the Khanty-Mansiysk Autonomous Okrug for recultivated agricultural soils. Moreover, other sorbents, such as peat, GAC, vermiculite, zeolite, and diatomite, can be used to reduce phytotoxicity to <33 %, allowing for additional soil decontamination through phytoremediation.

Оценка фитотоксического воздействия нефтепродуктов на всхожесть овса посевного (Avena sativa L.)

The purpose of the study was to assess the phytotoxic effect of petroleum products on the germination of oats (Avena sativa L.) for further selection of ameliorants to increase the germination of agricultural crops and reduce the concentrations of pollutants. The research was carried out in the Perm Territory, on the territory confined to the catchment area of the Kama River. Phytotoxicity of oil-contaminated soil was assessed by seed germination, germination energy, growth and development of roots and shoots. Seed germination was estimated on day 7 as the percentage of germinated seeds out of the total number sown. Analyses on the agrochemical composition of soils and the content of trace elements in soil moisture were carried out every week for a month in 5 agility. The results showed that the soil contains a significant amount of mobile phosphorus and a negligible amount of nitrate nitrogen. Studies to identify the number of dead oat cells lasted up to 15 days. A significant deviation from the control was observed at the concentration of petroleum products more than 500 mg/kg, while the number of dead oat cells was more than 30%.

Assessment of the phytotoxicity of petroleum-polluted black soil in relation to agricultural and wild species of phytoremediator plants

The effect of petroleum pollution on soil was assessed for its impact on the adaptation properties of 12 agricultural and 5 wild plant species. The influence of petroleum on seed germination was determined at concentrations of 1%, 3%, 4%, 6%, and 8% in the soil. Wild plants exhibited lower germination rates compared to cultivated species. For most cultivated plants, a 1% concentration of petroleum did not inhibit seed germination, but germination decreased to 60-80% of the control under concentrations of 2% and 4%. In soil containing 6% petroleum, peas, clover, alfalfa, and sunflower exhibited germination rates of more than 50%, while alfalfa and sunflower germinated only at an 8% concentration. The assessment of soil phytotoxicity revealed that sunflower plants are the most resistant to petroleum pollution. A comparison of resistance to soil petroleum pollution among four sunflower varieties showed that the ’Bombardir’ cultivar exhibited the best growth parameters.

Оценка фитотоксичности рекультивированных нефтезагрязненных почв методом проростков

The article presents the results of assessing the phytotoxicity of oil-contaminated soils after reclamation measures. Phytotoxicity was assessed by the method of seedlings, the results of seed germination, the total phytomass of the test culture and the phytotoxic effect were taken into account. The use of a test culture on recultivated oil-contaminated soil made it possible to evaluate the effectiveness of recultivation measures. The conducted studies have shown that recultivation of oil-contaminated soil by mechanical method is not effective enough and needs additional cleaning. Keywords: OIL-CONTAMINATED SOIL, SOIL RECLAMATION, PHYTOTOXICITY, GERMINATION, PHYTOMASS, TEST CULTURE

Key factors influencing arsenic phytotoxicity thresholds in south China acidic soils

Arsenic (As) toxicity threshold values (TTVs) for plants are fundamental to both establishing regional As reference values in soil and performing risk assessment. However, TTVs vary with plant species and soil types. In this study, a hydroponic experiment with 16 plant species was conducted to screen the most As-sensitive plant species. The results showed that the EC20 (available As concentration at which shoot biomass or height is inhibited by 20%) values were 1.38–104.4 mg L−1 for shoot height and 0.24–42.87 mg L−1 for shoot fresh biomass. Rice was more sensitive to As toxicity than the other species. Therefore, it was chosen as the ecological receptor in the pot experiment on As phytotoxicity in nine types of soils collected from Fujian Province in South China. The EC10 and EC20 with respect to rice shoot height were 3.72–29.11 mg kg−1 and 7.12–45.60 mg kg−1, respectively. Stepwise regression analysis indicated that free iron oxide concentration is the major factor that affects As bioavailability in soil, and ECx (x = 10, 20, and 50) of soil available As for shoot height was positively related to free iron oxide concentration in soil. In addition, soil cation exchange capacity, clay (<0.002 mm) content, and exchangeable magnesium content are also important factors influencing As phytotoxicity in acidic soils. The regression models can be used to predict As phytotoxicity in acidic soils.

Assessment of the influence of using green tea waste and fish waste as soil amendments for biosolarization on the growth of lettuce (Lactuca sativa L. var. ramosa Hort.)

IntroductionSafe and efficient treatment of organic waste is crucial to developing a sustainable food system around the world. Soil biosolarization (SBS) is a soil treatment technique that can use organic solid wastes to treat the soil in a way that is alternative to the use of chemical fumigants to improve soil fertility in agriculture.MethodsIn this study, two types of organic food wastes, green tea waste (GTW) and fish waste (FW), were evaluated for the feasibility of being applied as soil amendments within simulations of high-temperature cycle SBS. The evaluation was conducted by execution of three groups of measurements: gas and organic volatile emission profile, residual soil phytotoxicity and weed suppression, and cultivar growth (Lactuca sativa L. var. ramosa Hort.).Results and DiscussionGreen tea waste contributed to elevated levels of soil respiration and the evolution of signature volatile organic compounds during the simulated SBS. In the soil amended with green tea waste and then undergoing SBS the phyto compatibility was restored after residual phytotoxicity dissipation and a complete weed suppression was achieved. By using an application rate of 2.5% (w/w, mass fraction of green tea waste in total soil-waste mixture) green tea waste cultivar growth comparable to that of the non-treated soil (NTS) group was attained, with a more efficient nitrogen utilization and higher residual soil nitrogen content enabling the improvement of the continuous cropping system. FW at 1% (w/w, mass fraction of FW in total soil-waste mixture) promoted cultivar growth despite the significant reduction of the nitrogen (p value=0.02) and phosphorus (p value=0.03) contents in the cultivar leaves. A significant increase of the sodium content together with an increase of iron and chromium, which exceeded the permissible limit, were observed. These results provide new information about amendment selection for the SBS process.

Natural ageing of biochar improves its benefits to soil Pb immobilization and reduction in soil phytotoxicity.

Amendments are good tools for immobilizing metal(loid) and improving phytoremediation success. However, the amendment effect is variable and depends on multiple parameters, including amendment type and ageing. Such an ageing effect is rarely studied. Our study is one of the first focusing on how biochar storage affects its effect on soil properties and metal(loid) immobilization, when biochar was applied alone or in combination with green manure. To answer this, a 33-day pot incubation experiment was set up using contaminated soil, amended with two biochars (differing in ages: old (Bo) and new (Bn)) and/or two green manures (leaves of clover or poplar) and sown with Phaseolus vulgaris (bioindicator plant). Soil pore waters, plant growth and metal(loid) accumulation were evaluated. Biochar reduced soil acidity (Bn: + 0.75 pH unit, Bo: + 0.72 unit) and Pb mobility (Bn: - 42%, Bo: - 50%), while green manures acidified the soil (- 0.30 pH unit) and immobilized Pb only after 10days (- 44%). All amendments reduced soil phytotoxicity. Moreover, the biochar stored at room temperature for a few years demonstrated better abilities to improve soil properties, particularly for Pb immobilization, than the biochar freshly prepared. Finally, as mixtures maturated, soil parameters changed until about ten days, then tended to stabilize. Therefore, it can be concluded that (1) biochar storage will affect its chemical properties and ameliorate its effects, (2) biochar can ameliorate soil properties and immobilize metal(loid)s, while green manures tended to have adverse effects at first, and (3) soil/amendment mixtures should be left to mature about two weeks before potential plant implementation.

Glyphosate Effects on Some Characteristics of Biological Activity and Phytotoxicity of Soddy-Podzolic Soil in a Short-Term Model Experiment

Glyphosate Effects on Some Characteristics of Biological Activity and Phytotoxicity of Soddy-Podzolic Soil in a Short-Term Model Experiment

Glyphosate Effects on Some Characteristics of Biological Activity and Phytotoxicity of Sod-Podzolic Soil in a Short-Term Model Experiment

In a model laboratory experiment on infertile arable soil with low biological activity, it was found that the introduction of glyphosate leads to a short-term change in the intensity of the main processes of microbial transformation of nitrogen in the soil. When incubating soil with glyphosate at the maximum recommended dose of 8 l/ha for 22 days, there is an increase in nitrogen-fixing and denitrifying activity by 30–80% and 300% and a decrease in the nitrification process by 20–40%. The effects are of a short-term nature and do not reflect the entire complex of ongoing microbiological processes: no effect of glyphosate was detected on the emission of CO2, which is an integral indicator of biological activity. At the end of incubation in the soil with the introduced glyphosate, there was an increase in the number of bacteria by 40% and a decrease in the number of micromycetes by 70%. In general, under the selected conditions, the introduction of glyphosate led to a marked deterioration in the biological activity of the soil. By the method of multisubstrate testing, it was shown that under the action of the herbicide there is an increase in the value of the coefficient of rank diversity of the consumption spectra of substrates d, accompanied by a decrease in the specific metabolic work W and the integral vitality index G. It was shown for the first time that when glyphosate is introduced into soil with low biological activity and availability of phosphorus and the herbicide is degraded along the sarcosine pathway with a break in the C–P bond, excluding the formation of toxic metabolites, there is a pronounced negative effect of glyphosate on soil microorganisms, which leads to inhibition of wheat plant growth.

КОМПЛЕКСНАЯ ОЦЕНКА СОСТОЯНИЯ ПОЧВЫ ПОСЛЕ РАЗЛИЧНЫХ СЕЛЬСКОХОЗЯЙСТВЕННЫХ КУЛЬТУР

The paper presents an assessment of the state of the soil after harvesting crops (cereals, legumes, technical, perennial grasses) on the experimental fields of the Agrobiotechnopark of Kazan State Agrarian University in industrial crops. The studies were carried out in 2022, which was characterized by significant differences in moisture conditions during the growing season of plants (the first half of the growing season is wet, the second half is dry). All plots were located on highly cultivated, gray forest, medium loamy soil. A comprehensive assessment of soils was carried out using the methods of agrophysical studies of soils and methods of soil biology. To assess the state of soil biology, the number of microorganisms, Protozoa and nematodes was taken into account. Simultaneously, the phytotoxicity of soils for model plants was determined. Analysis of the accumulation of available water in the soil and the share of agronomically valuable aggregates showed that the maximum values were after mustard. After this crop, there was a decrease in the density of soil composition. The deterioration of the agrophysical properties of the soil was noted after spring crops. A pronounced phytotoxic effect of soil extracts after spring barley, peas and potatoes was established in relation to lettuce test plants. A similar effect on the wheat test plant was noted after potatoes. Improvement in agrophysical properties, low phytotoxicity and suppression of the development of Fusarium fungi among the studied crops, the advantage was noted for Sarepta mustard. After peas, an increase in the number of Azotobacter bacteria in the soil was noted, and after winter wheat, an increase in the number of ciliates in the soil was noted. The results obtained confirmed the differences in the state of soils after various crops, which must be taken into account when selecting predecessors in crop rotation.

Involvement of Soil Microorganisms in C, N and P Transformations and Phytotoxicity in Soil from Post-Industrial Areas Treated with Chemical Industry Waste

Soil degradation is an unavoidable phenomenon that poses a real threat, as it limits soil utility and reduces its resources. Early assessment of soil degradation can prevent its further deterioration. Various parameters of soil microbial activity may be helpful in this evaluation. Therefore, the purpose of the study was to assess the usefulness of microbiological (total abundance of oligotrophic bacteria and filamentous fungi), biochemical (soil respiration) and enzymatic (dehydrogenase, protease, acid and alkaline phosphatase activity and fluorescein hydrolytic activity) indicators, as well as phytotoxicity, in monitoring the condition of chemically degraded soils due to severe alkalization. The experimental material was soil collected in three sites located at different distances from the reservoir with liquid post-production waste. The analyzed indicators were correlated with the physical and chemical properties of the soil in three variants at the level of sampling sites, soil profile and seasonal variability. All analyzed parameters showed significant changes in the level of their activity at individual sampling sites. The location closest to the waste reservoir was characterized by the lowest values of the discussed activities and the highest phytotoxicity. Individual activities also showed changes depending on the season and soil layer. Considering the usefulness in monitoring changes in soils exposed to chemical degradation, total bacterial and fungal counts, as well as acid and alkaline phosphatase activities and fluorescein hydrolytic activity proved to be the most sensitive indicators.