Soil Pollution Research Articles

Predicting soil ecological criteria of 17 metal(loid)s in China based on quantitative ion character-activity relationship - Species sensitivity distribution (QICAR-SSD) coupled model

Soil pollution caused by metal(loid)s is increasingly serious and poses unexpected risks to terrestrial organisms. Establishing soil quality standards is essential for assessing ecological risks of metal(loid)s and protecting soil ecosystems. However, the limited availability of metal(loid) ecotoxicological data has hampered the development of soil quality standards due to financial and practical constraints on toxicity testing. This study collected 77 normalization equations and 58 cross-species extrapolation equations to calculate the normalized EC10 (the added concentration causing a 10 % inhibition effect) of metal(loid)s under a representative scenario. A set of quantitative ion character-activity relationship (QICAR) models were then constructed using normalized EC10 and nine critical ionic characters (AR, AR/AW, BP, MP, Z/r2, Z/r, Xm, σp, and |Log(KOH)|). Subsequently, these QICAR models were employed to predict ecotoxicological EC10 of 17 metal(loid)s to 12 soil species and coupled with species sensitivity distribution (SSD) to determine Predicted No Effect Concentration (PNEC). The results demonstrated the coupled QICAR-SSD model could effectively derive terrestrial PNEC for data-poor metal(loid)s, with errors between the predicted PNEC and reported soil standards (excluding soil background levels) from different countries mostly <0.3 orders of magnitude. Finally, soil ecological criteria (SEC) for 17 metal(loid)s were calculated using an added risk approach based on PNEC and national soil background concentration. Overall, the coupled model proposed here can provide a valuable supplement to the development of soil quality standards for numerous metal(loid)s in soil components.

Facing Heavy Metal Stress, What Are the Positive Responses of Melatonin in Plants: A Review

With the growth of the population and the development of modern industry and the economy, the problem of heavy metal pollution in cultivated soil has become increasingly prominent. Moreover, heavy metal poses a serious threat to plant growth due to its characteristics of difficult degradation, high mobility, easy enrichment, and potential toxicity and has become a social topic. Melatonin is a new type of plant hormone widely present in animals, plants, fungi, and bacteria, and its biological role has begun investigated in the last dozen years. Facing heavy metal stress, melatonin can play a pleiotropic role in the physiological processes of plants, such as stress resistance and growth regulation, mitigate the damage caused by stress on plants, and provide a new research idea for alleviating heavy metal stress in plants. From the aspects of the plant phenotype, physiology, element absorption, and molecular structure, this paper, therefore, mainly reviews the effects of melatonin on plants subjected to heavy metal stress and the mechanism of melatonin alleviating heavy metal stress and then puts forward future research directions. This information may be of great significance to the normal growth of crops under heavy metal stress and will provide an important theoretical basis for the genetic improvement of crop resistance in the future.

Bimetallic PdCu anchored to 3D flower-like carbon material for portable and efficient detection of glyphosate

Glyphosate (Gly), as a widely used broad-spectrum herbicide, may lead to soil and water pollution due to its persistence in the environment. Herein, the co-reduction method was employed to anchor bimetallic PdCu onto the Ni and nitrogen-doped 3D Flower-like Carbon Materials (Ni@NC), creating a composite material (PdCu/Ni@NC) with high specific surface area and good catalytic performance. This composite was used to modify screen-printed electrodes (SPE) to develop a portable and efficient Gly detection platform. In the presence of Cl⁻, the copper active sites convert to CuCl, achieving signal amplification. Upon the addition of Gly, a competitive reaction between Cu and Gly converts CuCl into a Cu-Gly complex, resulting in a sharp decrease in the electrochemical signal. This signal drop is used to detect Gly. The bimetallic PdCu nanoparticles (NPs) endowed the sensing platform with better stability and electrochemical performance due to their synergistic effect, and their stability was simply verified by Density functional theory (DFT). The sensor demonstrates a linear detection range spanning from 1 × 10⁻¹ ³ to 1 × 10⁻⁵ M, with a limit of detection (LOD) of 3.72 × 10⁻¹ ⁴ M. The sensor demonstrated a recovery rate of 95.9 % to 104.5 % in actual samples such as water and soil, indicating its potential for practical application.

Frontiers in environmental cleanup: Recent advances in remediation of emerging pollutants from soil and water

Recent advancements in environmental remediation have significantly improved the treatment of soil and water pollution, yet the complexity and dispersion of emerging pollutants remain major challenges. This review highlights the most promising technologies and strategies in remediation emphasizing their potential to protect ecosystems and human health. In soil remediation, phytoremediation utilizes plants to absorb and immobilize pollutants while bioremediation employs microorganisms to degrade organic contaminants in a sustainable manner. Nanotechnology offers innovative solutions through the use of nanoparticles as efficient sorbents or catalysts. For water remediation, advanced oxidation processes (AOPs) such as photocatalysis and ozonation effectively degrade recalcitrant pollutants enhancing water quality. Biochar and other sorbents present viable options for pollutant removal and membrane technologies like reverse osmosis provide selective purification for diverse applications. The review underscores the importance of multidisciplinary collaboration in advancing remediation technologies. Integrating artificial intelligence and machine learning can further optimize these processes by analyzing complex data and predicting pollutant behavior. As environmental challenges evolve, continuous innovation and research are essential to combat emerging pollutants. This review serves as a call to action for the scientific community to embrace interdisciplinary approaches and cutting-edge technologies to safeguard the environment for future generations.

Biostimulation of Used Engine Lubricant Polluted Soil Amended with Pig Dung

Biostimulation of Used Engine Lubricant Polluted Soil Amended with Pig Dung

Post-synthetic modification fluorescence UiO-66-Eu immunochromatography for high-performance detection of sodium pentachlorophenoate

Sodium pentachlorophenate (PCP) is widely used as a herbicide, fungicide, or molluscicide. It is highly toxic, easily soluble in water, making it highly prone to diffusion and causing water and soil pollution. Through the food chain, it enters animal bodies and remains in food, causing toxicity to humans and animals. Therefore, establishing a rapid and simple detection method for PCP is crucial for human health and environmental protection. Herein, lanthanide metal Eu3+ was introduced into UiO-66-(COOH)2 by post-synthesis modification, and the nanomaterials prepared based on this method have the advantages of both UiO-66-(COOH)2 and Eu3+. The rigid skeleton structure of UiO-66-(COOH)2 can protect the activity of antibody, the detection environment pH tolerance range of UiO-66-Eu is 3–11. While Eu3+ has long fluorescence lifetime, high fluorescence intensity, high signal-to-noise ratio, and low photobleaching rate. UiO-66-Eu-based immunochromatography assay was successfully applied in PCP detection with the detection limits of 0.84, 0.98, and 0.37 μg/kg for pork, chicken, and shrimp, respectively, which was up to 10-fold more sensitive than the reported ICAs. The recoveries ranged from 79.7 %−113.1 %, with the coefficient of variation from 6.6 %−17.1 %. Parallel detection of 30 samples by LC-MS/MS showed a good correlation with that of our proposed method (R2 >0.98). This work not only provides a creative attempt for UiO-66-Eu based highly sensitive and strongly tolerant ICAs, but also guarantees human health and environmental protection.

Predicting the ecological risk thresholds of soil metals in Europe using the quantitative ion character-activity relationships (QICAR) model

Metal pollutants have become increasingly diverse. Therefore, managing the ecological risks associated with these elements in soil is urgently required. However, determining the soil ecological risk thresholds of elements through routine toxicological tests is time-consuming and laborious, establishing prediction models is vital to risk management. Accordingly, this study aimed to predict the element toxicity to soil organisms by collecting the toxicological data of eight elements to soil organisms at 18 European and 17 Chinese sites through literature and toxicology databases, using the quantitative ion character-activity relationship (s-QICAR) model. Firstly, the toxicity values (logEC10) of eight elements to five biological species and three microbial processes were obtained through clustering and soil normalization methods in three typical soil scenarios. Correlation analysis revealed that for different species and microbial processes, there are three to six physicochemical properties of elements related to their toxicity, among which, the covalent radius of the element was the best significantly correlated with logEC10 of all organisms (R2 = 0.77–0.95). Based on this, the s-QICAR model was established and used to predict the logEC10 of Sc, Ti, V, Cr, Co, Ni, Cu, and Zn to eight organisms. Furthermore, along with the species sensitivity distribution curve, the HC5 values (i.e., 95% species protection level) for the above eight elements were calculated. Following correction, the predicted no-effect concentrations of these elements ranging from 9 to 189 mg/kg, and the ecological risk threshold map has been produced. In summary, we present a new method to quantify the ecological risk of metal-induced pollution in European soils without routine toxic measurements, and provide important insights into soil pollution risk assessment and management.

Impact of Plant Growth-Promoting Rhizobacteria on Spinach Growth Concerned with Industrial Effluents Contaminated with Chromium

Heavy metal pollution in soil poses a significant threat to the environment and human health as it accumulates throughout the food chain. Remediation of soil contamination involves biological, chemical, and physical methods. Plant growth-promoting rhizobacteria inoculation helps some plants stabilize heavy metals in polluted soil by forming chelates with the metals. An experiment was conducted to examine the impact of Plant growth-promoting rhizobacteria on spinach growth and heavy metal stability in polluted soil with industrial effluents. The study found that Plant growth-promoting rhizobacteria (S1 and S2) enhanced growth and yield parameters, with fresh weights reaching 18% and 14%, highest dry weights at 10% and 40%, and longest roots at 11%. The treatment with Plant growth-promoting rhizobacteria S1 recorded the highest SPAD values (27%). Chemical parameters revealed that Cr levels in roots peaked in treatments without PGPR. The results concluded that PGPR can effectively remediate heavy metal-contaminated soils and industrial effluent-irrigated soils used for food crop growth.

Sorbents based on foamed phosphate glass for collecting petroleum oil products from contaminated soils and water surfaces

Relevance. The need to clean from pollution soils and water areas contaminated with oil and chemical industry wastes. Physico-chemical methods are one of the effective ways of cleaning, provided that sorbents are applied in time to collect contaminants from the surface of water areas and landscapes. Sorption is the most efficient and cost-effective method for relatively small scale pollution. Despite the variety of existing sorbents, in most cases when cleaning up accidental spills, first of all, economic benefits and oil capacity value of the sorbent are guided. However, such essential criteria as: 1) main purpose (type of polluted surface and nature of pollution); 2) physical and chemical properties, including structural characteristics and acid-base adsorption centers; 3) peculiarities of oil or other pollutants adsorption. Taking into account these factors, it is possible to develop and improve the formulation of sorbents based on phosphate foams. Introduction of various modifying additives into material composition is likely to expand their field of application. Aim. Development of formulation and technological features of obtaining new phosphate sorbents in relation to their intended purpose: for collecting oil and petroleum product spills from soil or water surfaces. Methods. Gravimetric, microscopic spectroscopic, statistical and comparative methods. Results and conclusions. The authors have compared sorbents no. 1 and 2 in terms of physical and chemical properties, morphology and cleaning efficiency. Based on our laboratory studies, we concluded that sorbent no. 1 is better suited for sorption from aqueous surfaces and sorbent no. 2 is better suited for soil cleaning. Both sorbents have the potential to improve their technological properties. This allows refining the formulation of these materials with further testing in laboratory and field conditions, for example, at oil spill sites. For this purpose, it is possible to change the material composition using a different foaming agent, applying modifying additives and varying the temperature mode of firing. Development of new compositions and methods of sorbent foaming will make it possible to select optimal characteristics for each type of contamination. The author proposed as well to create phosphate biosorbent obtained by immobilization of fungi and bacteria on the surface of highly porous carrier. In this case, after sorption of pollution, adsorbed substances will undergo biodegradation with the formation of safe products, and the sorbent will perform the role of fertilizer.

Preparation of Polymeric Aluminum Chloride-Loaded Porous Carbon and Evaluation of Its Pb2+ Immobilization Mechanisms in Soil

In recent years, the remediation of heavy metal-contaminated soils has attracted great attention worldwide. Previous research on the removal of toxic heavy metals from wastewater effluents through adsorption by typical solid wastes (e.g., fly ash and coal gangue) has mainly focused on the control of wastewater pollutants. In this study, a coal gangue (CG) by-product from Hancheng City was used as a raw material to prepare polymeric aluminum chloride-loaded coal gangue-based porous carbon (PAC-CGPC) by hydrothermal synthesis. This material was subsequently employed to assess its performance in mitigating Pb2+ in soils. In addition, the effects of the pore structure of the prepared material on the adsorption rates, adsorption mechanisms, and plant root uptakes of soil Pb2+ were investigated in this study. The raw CG and prepared PAC-CGPC materials exhibited specific surface areas of 1.8997 and 152.7892 m2/g, respectively. The results of adsorption kinetics and isotherms indicate that the adsorption of Pb2+ based on PAC-CGPC mainly follows a pseudo-second-order kinetic model, suggesting that chemisorption may be the dominant process. In addition, the adsorption isotherm results showed that the Freundlich model explained better the adsorption process of Pb2+, suggests that the adsorption sites of lead ions on APC-CGPC are not uniformly distributed and tend to be enriched in APC, and also shows the ion exchange between aluminum and lead ions. The thermodynamic model fitting results demonstrated the occurrence of spontaneous and exothermic PAC-CGPC-based adsorption of Pb2+, involving ion exchange and surface complexation. The effects of the PAC-CGPC addition on soybean plants were further explored through pot experiments. The results revealed substantial decreases in the Pb2+ contents in the soybean organs (roots, stems, and leaves) following the addition of the PAC-CGPC material at a dose of 3% compared with the control and raw CG groups. Furthermore, the addition of the PAC-CGPC material at a dose of 3% effectively reduced the bioavailable Pb2+ content in the soil by 82.11 and enhanced soybean growth by 15.3%. These findings demonstrated the inhibition effect of the PAC-CGPC material on the translocation of Pb2+ in the soybean seedlings. The modified CG adsorbent has highly pore structure and good hydrophilicity, making it prone to migration in unsaturated soils and, consequently, enhancing Pb2+ immobilization. This research provides theoretical support for the development of CG-based materials capable of immobilizing soil pollutants.

The impact of kaolin mining activities on bacterial diversity and community structure in the rhizosphere soil of three local plants.

Thus far, the impact of kaolin mining activities on the surrounding native plants and rhizosphere microecology has not been fully understood. In this study, we used 16S rRNA high-throughput sequencing to examine the impact of kaolin mining on the rhizosphere bacterial communities and functions of three local plant species: Conyza bonariensis, Artemisia annua, and Dodonaea viscosa. The results showed that kaolin mining significantly reduced the diversity of rhizosphere bacteria in these plants, as indicated by the Shannon, Simpson, Chao1, and observed species indices (p < 0.05). Kaolin mining had an impact on the recruitment of three rhizosphere bacteria native to the area: Actinoplanes, RB41, and Mycobacterium. These bacteria were found to be more abundant in the rhizosphere soil of three local plants than in bulk soil, yet the mining of kaolin caused a decrease in their abundance (p < 0.05). Interestingly, Ralstonia was enriched in the rhizosphere of these plants found in kaolin mining areas, suggesting its resilience to environmental stress. Furthermore, the three plants had different dominant rhizosphere bacterial populations in kaolin mining areas, such as Nocardioides, Pseudarthrobacter, and Sphingomonas, likely due to the unique microecology of the plant rhizosphere. Kaolin mining activities also caused a shift in the functional diversity of rhizosphere bacteria in the three local plants, with each plant displaying different functions to cope with kaolin mining-induced stress, such as increased abundance of the GlpM family and glucan-binding domain. This study is the first to investigate the effects of kaolin mining on the rhizosphere microecology of local plants, thus contributing to the establishment of soil microecological health monitoring indicators to better control soil pollution in kaolin mining areas.

AI-Driven Waste Management Solutions in the Mining Industry: Reducing Environmental Impact

Soil, water, and air pollution are mainly resulted from the waste of mining industry. This ecological pollution resulted from mining activities must be managed and reduced effectively. With the emergence of AI, AI has the ability to help in driving an innovative and technological waste management model. The capacity of AI in predicting, modelling and automating waste management process will be studied through the use of the theory and approach based on Machine learning’s methodologies and algorithms. A comparative analysis between traditional methods and AI integrated methods of waste management will be conducted to evaluate the effectiveness of AI in driving waste management. Thus, this will require a specific case of mining activity to be studied. The data collection and data analysis consist of conducting a literature review and documents analysis, which includes a qualitative and quantitative analysis. All in all, the study will assess the effectiveness, operationality, efficiency and economic viability of AI-driven methods, in reducing pollution from mining activities. The results will emphasize the significant enhancement brought by AI-driven waste management. The prediction made by AI in the waste production will be demonstrated as accurate and optimizing waste discharge methods. This improvement is crucial in the reduction of environmental impact of mining activities. Seen as efficient, sustainable and cos-effective operations, the AI-driven waste management will transform and improve the environmental protection in the mining industry. The research offers innovative recommendations to stakeholders such as mining companies, policymakers and researchers.

Content, Sources, and Ecological Risk Assessment of Heavy Metals in Soil of Typical Karst County

Soil heavy metals in karst areas have obvious high background value characteristics. Conducting county-level soil heavy metal ecological risk assessment and identifying heavy metal sources in karst areas are of great significance for soil pollution control and land resource management. Taking Pingguo City, a typical karst county in Guangxi Province, as the study object, 3 151 surface and deep soil samples were collected using the grid method and combined to form 785 analytical samples. The contents of eight heavy metal elements, including As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn, were determined. The content characteristics and sources of heavy metals were analyzed using statistical analysis, interpolation analysis, factor analysis, and the absolute principal component-multiple linear regression model （APCS-MLR）. Using the content of heavy metal elements in deep soil （150-200 cm） as background values, the ecological risk assessment of heavy metals in surface soil （0-20 cm） in the study area was conducted using the geo-accumulation index （Igeo） and potential ecological risk index （RI） methods. The results showed that the average content of heavy metal elements in the deep soil of the study area was significantly higher than the background value of the C layer soil in Guangxi Province, and the average content of heavy metal elements in the surface soil was significantly higher than the background value of the A layer soil in Guangxi Province. The spatial distribution of soil heavy metal element content generally showed the characteristics of high in karst areas and low in non-karst areas. The main sources of As, Cr, Ni, Pb, and Zn were soil parent materials, with contribution rates of 74.36%, 84.59%, 93.69%, 79.67%, and 78.17%, respectively. The main sources of Cd were soil parent material sources and unknown sources, with contribution rates of 37.33% and 31.05%, respectively. The main sources of Cu were soil parent materials and unknown sources, with contribution rates of 59.07% and 40.23%, respectively. The main sources of Hg were tectonic activity and mineralization, as well as unknown sources, with contribution rates of 52.49% and 30.65%, respectively. The geo-accumulation index （Igeo） showed that the surface soil was mainly polluted by Cd, with mild or above pollution accounting for 47.78%. The potential ecological risk index （RI） showed that the proportion of surface soil heavy metal comprehensive potential ecological hazards with mild, moderate, strong, and very strong levels was 80.78%, 14.97%, 2.51%, and 1.64%, respectively.

Pollution Characteristics and Source Apportionment of Heavy Metals in Topsoil of Counties Along the Shandong Section of the Yellow River

The 25 counties along the Shandong section of the Yellow River are the core areas for promoting the ecological protection and high-quality development of the Yellow River in Shandong Province. Moreover, it is of great significance to study the current situation, sources, and potential risks of heavy metal pollution in the topsoil in this region. In this study, 103 soil samples were collected from the 25 counties along the Shandong section of the Yellow River, and the contents of eight heavy metals （As, Cu, Pb, Cr, Zn, Ni, Cd, and Hg） were determined. The pollution characteristics of heavy metals were analyzed and evaluated using the geological accumulation index and potential ecological risk index. Correlation analysis and the positive matrix factorization （PMF） model were used to analyze the sources of heavy metals. The results showed that the average contents of Cu and Cr were lower than that of the background values of soils, whereas the average contents of As, Pb, Zn, Ni, Cd, and Hg were 1.16, 1.42, 1.05, 1.14, 2.29, and 1.85 times higher than that of the background values, respectively, and the average contents of all eight elements were lower than the screening value of soil pollution risk in agricultural land. In terms of different heavy metal variations, the coefficient of variation （CV） of Cu and Cd was higher than 0.500, indicating high variations, whereas As, Pb, Cr, Zn, Ni, and Hg showed moderate variation. Cd and Hg were slightly polluted, whereas the other six elements were not polluted. Cd and Hg had a moderate potential ecological risk level, whereas the other six elements were at a low level. Correlation analysis and PMF model showed that the sources of heavy metals in the study area were influenced by four factors, i.e., agricultural activities, natural sources, industrial emissions, and atmospheric dust from coal combustion and vehicle exhaust emissions, and the relative contribution rates were 32.4%, 34.9%, 16.5%, and 16.2%, respectively.

The Comparative Effects of Phosphorus-Enriched Organomineral Fertilization on Some Chemical Properties of Calcareous Soils

ABSTRACT Phosphorus is a very important plant nutrient for the development of plants and its production is not unlimited in the world. In addition, excessive use can lead to soil and water pollution. In this respect, phosphorus should be used effectively in plant production, especially in calcareous soils. The aim of this study was to comparatively determine the effects of phosphorus-enriched organomineral fertilization (p-OMF), chemical phosphorus fertilization (CF), and organic fertilization (OF) on some chemical properties of a calcareous soil. The experiment was established in Söke county of Aydın province in the Southwest of Türkiye. In this study, four doses of dairy manure (DM1: 10, DM2: 20, DM3:30, and DM4: 40 t ha−1) in OF, four phosphorus doses (P1: 10, P2: 20, P3:30, and P4: 40 kg P ha−1) in the CF system, and sixteen different doses of OMF formed by the combinations of these two fertilizers were applied excluding control. According to the main research findings, p-OMFs increased the soil organic matter (SOM), salinity, total nitrogen (N), available phosphorus (P), and potassium (K) by 60.1%, 20.9%, 22.1%, 140%, and 17.2%, respectively. They also decreased soil pH by 4%. As a result, it was determined that the most effective organomineral fertilizer combination that maintains soil properties at appropriate levels in calcareous soils is DM3+P2 (30 t ha−1 dairy manure +20 kg P ha−1).

The role of soil amendments in limiting the leaching of agrochemicals: Laboratory assessment for copper sulphate and dicamba

Agriculture is among the major contributors to soil and groundwater pollution, primarily through the widespread leaching of pesticides and fertilizers from crops, as well as accidental releases from point sources. Therefore, alongside restrictions on the use of highly soluble agrochemicals and enhanced application guidelines, there is a significant demand for low-impact and cost-effective solutions aimed at reducing the mobility of agrochemicals in the soils. This study evaluates the potential of soil amendments—commonly used to enhance soil structural properties, water holding capacity, and fertility—to also absorb highly soluble pesticides, thereby controlling their leaching into the subsoil. Specifically, zeolite, biochar, and milled corncob were examined in laboratory tests under static (batch tests) and dynamic (column leaching tests) conditions to assess their effectiveness in adsorbing two widely used pesticides, copper sulphate and dicamba. Batch adsorption tests were performed using the amendments as pure materials and in mixtures with sand at various application rates (1–20% by weight). The highest affinity to copper sulphate was recorded for biochar, while dicamba exhibited a higher affinity to corncob, thanks to its higher content of organic carbon. Column leaching tests, performed at an amendment application rate of 5%, confirmed the different affinity observed in batch tests among pesticides and amended soil. Less than 2% of copper sulphate leached out from biochar- and zeolite-sand columns, while a recovery of 10% and 56% was observed for the corncob-sand mixture and for pure sand, respectively. Dicamba leaching from biochar- and corncob-sand columns was halved compared to pure sand. In conclusion, the tested soil amendments resulted highly effective in reducing pesticide leaching, opening the way for their possible applications in agriculture to reduce or prevent both diffuse and punctual contamination.

Pollution of Soil by Pharmaceuticals: Implications for Metazoan and Environmental Health.

The use of pharmaceuticals has grown substantially and their consequential release via wastewaters poses a potential threat to aquatic and terrestrial environments. While transportation prediction models for aquatic environments are well established, they cannot be universally extrapolated to terrestrial systems. Pharmaceuticals and their metabolites are, for example, readily detected in the excreta of terrestrial organisms (including humans). Furthermore, the trophic transfer of pharmaceuticals to and from food webs is often overlooked, which in turn highlights a public health concern and emphasizes the pressing need to elucidate how today's potpourri of pharmaceuticals affect the terrestrial system, their biophysical behaviors, and their interactions with soil metazoans. This review explores the existing knowledge base of pharmaceutical exposure sources, mobility, persistence, (bio)availability, (bio)accumulation, (bio)magnification, and trophic transfer of pharmaceuticals through the soil and terrestrial food chains.

Modulation of Cd carriers by innovative nanocomposite (Ca+Mg) and Cd-resistance microbes (Bacillus pumilus): a mechanistic approach to enhance growth and yield of rice (Oryza sativa L.).

Cadmium (Cd) is a well-known pollutant in agricultural soil, affecting human health through the food chain. To combat this issue, Ca + Mg (25 mg L-1) nanocomposite and Bacillus pumilus, either alone or combined, were applied to rice plants under Cd (5 mg kg-1, 10 mg kg-1) contamination. In our study, growth and yield traits demonstrated the beneficial influence of Ca + Mg and B. pumilus application in improving rice defense mechanism by reducing Cd stress. Combined Ca + Mg and B. pumilus application increased SPAD (15), total chlorophyll (18), chlorophyll a (11), chlorophyll b (22), and carotenoids (21%) with Cd (10 mg kg-1), compared to the application alone. Combined Ca + Mg and B. pumilus application significantly regulated MDA (15), H2O2 (13), EL (10), and O2 •- (24%) in shoots under Cd (10 mg kg-1), compared to the application alone. Cd (10 mg kg-1) increased the POD (22), SOD (21), APX (12), and CAT (13%) in shoots with combined Ca + Mg and B. pumilus application, compared to the application alone. Combined Ca + Mg and B. pumilus application significantly reduced Cd accumulation in roots (22), shoots (13), and grains (20%) under Cd (10 mg kg-1), compared to the application alone. Consequently, the combined application of Ca + Mg and B. pumilus is a sustainable solution to enhance crop production under Cd stress.

DESIGN OF LANDFILLS AND THE UTILIZATION OF WASTES AS SUSTAINABLE LINER MATERIALS: A MINI-REVIEW

Modern landfills, designed to minimize environmental and health risks, play a crucial role in solid waste disposal. Poorly managed municipal solid waste facilities have severe environmental consequences, prompting intervention and remediation. Landfill construction is not enough; regular maintenance is essential to prevent harm. Landfills' historical evolution reflects societal needs, technological advancements, and environmental awareness. The 20th century saw engineered landfills with practices like compaction, daily covering, and leachate collection. Despite progress in recycling and incineration, landfills remain dominant, posing challenges like methane emissions, leachate contamination, and land use. Research emphasizes integrating landfills with recycling, composting, and waste-to-energy technologies for a sustainable future. Engineered landfills are advantageous over dumpsites, in terms of groundwater and air protection, odor control, energy generation, and job creation. Seismic analysis of landfills addresses deformation and seismic reactivity, emphasizing proper liner construction to reduce seismic impact. Leachate, a potential environmental hazard, requires careful management with effective liners to prevent groundwater and soil pollution. Various materials, including fly ash, paper mill sludge, waste foundry sand, recycled concrete aggregate, rice husk ash, and plastic waste, are reviewed for landfill liners. Research shows these materials can offer effective barriers, reducing environmental impact and promoting sustainability. Future studies should continue exploring alternative materials, considering factors like strength, hydraulic conductivity, and environmental protection.

Removal mechanism of phosphorus in water by calcium hydroxide modified copper tailings

With the development of industry and agriculture, eutrophication caused by increasing amounts of phosphorus in the environment has attracted people's attention. On the other hand, copper tailings (CT) is a kind of solid waste with large quantity, large area, and easy to cause groundwater and soil pollution. CT is also a potential resource because of its large specific surface area. CT is intended to be used as an adsorbent for removal phosphate in water, but trace heavy metals and a small amount of phosphate in CT may bring negative effects. Calcium hydroxide (Ca(OH)2) was used to modify CT (CCT), hoping to fix the heavy metals and phosphate in CT at the same time. It was found that the removal capacity of CCT was significantly higher than that of CT. The process of phosphate removal by CCT involves electrostatic sorption and surface precipitation, and there is a synergistic effect between CT and Ca(OH)2. The phosphate removal rate of CCT-0.4 increased with the increase of pH value under alkaline conditions. The XRD patterns of phosphate sorption by CCT mean that Ca3(PO4)2, Ca5(PO4)3(OH) and AlPO4 exist in CCT after phosphate removal, indicating that surface precipitation occurs during the removal process. In summary, the removal mechanism of phosphate by CCT is mainly electrostatic attraction and surface precipitation.