Remediation Practices Research Articles

Penicillium oxalicum induced phosphate precipitation enhanced cadmium (Cd) immobilization by simultaneously accelerating Cd biosorption and biomineralization

Soil cadmium (Cd) is immobilized by the progressing biomineralization process as microbial induced phosphate precipitation (MIPP), which is regulated by phosphate (P) solubilizing microorganisms and P sources. However, little attention has been paid to the implications of Cd biosorption during MIPP. In this study, the newly isolated Penicillium oxalicum could immobilize 5.4–12.6 % of Cd2+, while the presence of hydroxyapatite (HAP) considerably enhanced Cd2+ immobilization in P. oxalicum and reached over 99 % Cd2+ immobilization efficiency within 7 days. Compared to P. oxalicum mono inoculation, MIPP dramatically boosted Cd biosorption and biomineralization efficiency by 71 % and 16 % after 96 h cultivation, respectively. P. oxalicum preferred to absorbing Cd2+ and reaching maximum Cd2+ biosorption efficiency of 87.8 % in the presence of HAP. More surface groups in P. oxalicum and HAP mineral involved adsorption which resulted in the formation of Cd-apatite [Ca8Cd2(PO4)6(OH)2] via ion exchange. Intracellular S2-, secreted organic acids and soluble P via HAP solubilization complexed with Cd2+, progressively mineralized into Cd5(PO4)3OH, Cd(H2PO4)2, C4H6CdO4 and CdS. These results suggested that Cd2+ immobilization was enhanced simultaneously by the accelerated biosorption and biomineralization during P. oxalicum induced P precipitation. Our findings revealed new mechanisms of Cd immobilization in MIPP process and offered clues for remediation practices at metal contaminated sites.

Native freshwater lake microbial community response to an in situ experimental dilbit spill.

With the increase in crude oil transport throughout Canada, the potential for spills into freshwater ecosystems has increased and additional research is needed in these sensitive environments. Large enclosures erected in a lake were used as mesocosms for this controlled experimental dilbit (diluted bitumen) spill under ambient environmental conditions. The microbial response to dilbit, the efficacy of standard remediation protocols on different shoreline types commonly found in Canadian freshwater lakes, including a testing of a shoreline washing agent were all evaluated. We found that the native microbial community did not undergo any significant shifts in composition after exposure to dilbit or the ensuing remediation treatments. Regardless of the treatment, sample type (soil, sediment, or water), or type of associated shoreline, the community remained relatively consistent over a 3-month monitoring period. Following this, metagenomic analysis of polycyclic aromatic and alkane hydrocarbon degradation mechanisms also showed that while many key genes identified in PAH and alkane biodegradation were present, their abundance did not change significantly over the course of the experiment. These results showed that the native microbial community present in a pristine freshwater lake has the prerequisite mechanisms for hydrocarbon degradation in place, and combined with standard remediation practices in use in Canada, has the genetic potential and resilience to potentially undertake bioremediation.

Multi-tier life cycle assessment for evaluating low carbon strategies in soil remediation

Addressing soil pollution and achieving global carbon neutrality requires low carbon remediation practices. When selecting the optimal remediation techniques, a comprehensive model is required to assess the environmental and economic impacts accurately. In the present study, a spatial three-tier framework that combines process cycle assessment (PLCA), Input output analysis (IOA) and Multi-Regional Input Output analysis (MRIOA) has been used to evaluate the greenhouse gas (GHG) emissions of three commonly used remediation alternatives at a contaminated site in Hubei Province, China, as well as the indirect GHG emissions of the industry chain at provincial and national scale. The three remediation techniques were coprocessing in a cement kiln (CCK), ex-situ solidification and stabilization (ESS), and soil washing (SLW). Using a tiered hybrid life cycle assessment (THLCA) approach, the results demonstrated the importance of including off-site emissions in life cycle assessments. It was found that CCK had the lowest total GHG emissions among the three alternatives. Off-site greenhouse gas (GHG) emissions associated with three soil remediation alternatives vary significantly, with CCK exhibiting the lowest levels and ESS the highest. Soil remediation emissions mainly affected Hubei Province, with varying spillover effects on other regions, such as Inner Mongolia, Shanxi, Liaoning, and Gansu, which supplied material resources and power supply for the soil remediation project. The production and supply of electricity and heat (PSE) sector contributed the most to off-site emissions, accounting for 56.05%, 67.76%, and 67.30% of total emissions for CCK, ESS, and SLW, respectively. Overall, the present study provides fresh insights to support a more holistic low-carbon assessment of soil remediation options.

Phylogenetic Analysis of Bacterial Isolates Recovered from Salt-affected Soils of Haryana & Punjab, India

Excessive saline/alkaline conditions present a significant challenge to the environment and ecology, impacting yield, plant growth, and soil health. This study focuses on isolating and characterizing halophilic bacteria from salt-affected areas in Haryana and Punjab, India. Morphological, biochemical, and molecular analyses were conducted to assess their potential as plant growth-promoting rhizobacteria (PGPR) for mitigating salt stress in salt-affected soils. Four bacterial strains, identified as HR3-PM, PB01-KB, PB-424, and PB-466, were isolated and characterized. Morphological and biochemical assays revealed diverse traits among the isolates, including phosphate solubilization, indole-3-acetic acid (IAA) production, and ammonia excretion. Molecular identification via 16S rRNA sequencing confirmed their taxonomic classification and revealed close homology to known bacterial species such as Klebsiella aerogenes, Pseudomonas mosselii, Lysinibacillus acetophenoni, and Pseudomonas stutzeri. Phylogenetic analysis provided insights into their evolutionary relationships. These salt-tolerant bacteria exhibit promising PGPR activities, suggesting their potential for sustainable agriculture and soil remediation practices in salt-affected soils. Harnessing their abilities could offer cost-effective and environmentally friendly solutions to mitigate soil salinity, enhance plant productivity, and contribute to global environmental stresses. Further research is warranted to fully understand and harness the biotechnological potential of these halophilic bacteria in salt-affected ecosystems, paving the way for a more sustainable environmental future.

The dissolved organic matter from the co-decomposition of Chinese milk vetch and rice straw induces the strengthening of Cd remediation by Fe-modified biochar

Fe-modified biochar (FB) and co-using Chinese milk vetch and rice straw (MR) are two effective ways for mitigating the cadmium (Cd) contamination in paddy fields in southern China. Nevertheless, the effects of FB combined with MR on Cd passivation mechanism remain unclear. In the current study, the strengthening effects of FB induced by MR were found and the mechanisms of the extracted dissolved organic matter (DOM) from the co-decomposition of MR on Cd alleviation were investigated through pot experiment and adsorption experiment. Pot experiment demonstrated that co-incorporating FB and MR decreased available Cd by 23.1% and increased iron plaque concentration by 11.8%, resulting in a 34.7% reduction in Cd concentrations in brown rice compared with addition of FB. Furthermore, co-using FB and MR improved available nutrients in the soil. The molecular characteristics of DOM derived from the decomposition of MR (DOM-MR) were analyzed by fluorescence excitation emission matrix spectroscopy-parallel factor analysis (EEM-PARAFAC) and Fourier transform-ion cyclotron resonance mass spectrometry (FT-ICR MS). Results showed that lignin/carboxylic-rich alicyclic molecules and protein/amino sugar were the main compounds, potentially involved in the Cd binding. Adsorption experiments revealed that the addition of DOM-MR improved the functional groups, specific surface area, and negative charges of FB, inducing the strengthening of both physisorption and chemisorption of Cd(II). The maximum adsorption capacity of Fe-modified biochar after adding DOM-MR was 634 mg g−1, 1.30 times that without the addition of DOM-MR. This study suggested that co-incorporating MR, and FB could serve as an innovative practice for simultaneous Cd remediation and soil fertilization in Cd-polluted paddy fields. It also provided valuable insights and basis that DOM-MR could optimize the performances of Fe-modified biochar and enhance its potential for Cd immobilization.Graphical

Study on the remediation of uranium-contaminated soils by compound leaching: Screening of leaching agents and a pilot-scale application

To solve the problem of soil environmental pollution resulting from uranium mine development and production, a soil slurry reactor was used to evaluate the use of chemical leaching to remediate uranium-contaminated soils and to analyze possible uranium removal mechanisms through laboratory-scale trials and pilot-scale trials. A laboratory-scale trial comparing different reagents and operating methods revealed that the removal of total uranium from contaminated soil could reach 91.18% under optimal conditions when FeCl3, OA, NaClO2, and HEDP were used as eluents.Based on the optimal ratio and operating conditions determined from laboratory-scale trials, a pilot-scale trial was conducted around a uranium mining area: soil leaching remediation was conducted in two 3 m3 soil-slurry reactors to verify the practicality of the leaching technology and examine the functionality of the remediated soil. The experimental results showed that the rate of uranium removal from contaminated soil by the chemical leaching method was greater than 80%. FTIR, XRF and enzyme activity analysis proved that remediation restored the original soil function and reduced the ecological risk, indicating that the chemical leaching technology was environmentally friendly and economical. These findings provide insight to guide the future assessment and remediation practices of uranium-contaminated sites.

Robert Louis Stevenson and German Sāmoa

ABSTRACT This study revisits the writings of Robert Louis Stevenson on German Sāmoa as a valuable archive for understanding the impact of Western colonialism on the Pacific. It examines Stevenson’s anti-colonial perspectives in writings such as A Footnote to History: Eight Years of Trouble in Samoa (1892), his series of letters to The Times in London (1889–1894), and his private correspondence. Stevenson’s analysis of the impact of the Germans’ militarism and meddlesome officialdom, together with their extensive plantation system and use of unfree labour, also provides an important context for reading contemporary Oceanian writers and artists. The varied creative practices of recovery and remediation deployed by Albert Wendt, Sia Figiel, Yuki Kihara, Michel Tuffery and Tony Brunt, are often inspired by cultural memories of German Sāmoa.

Promoting denitrification via high electron conversion ratio in the iron valence Cycle: Prospects for Pseudomonas sp. JM-7 application in environmental engineering

The interdependence between iron and nitrogen in the environment is of utmost importance, and this study has explored the intricate relationship between denitrification and iron valence cycling using Pseudomonas sp. strain JM-7 (P. JM-7) as a model bacteria. Our research demonstrated that P. JM-7 had the ability to effectuate electron transfer from the periplasmic space to electron acceptors, such as nitrate, via Cytochrome c-proteins (c-Cyts). We found that iron valence state transformations with Fe(II)/Fe(III) promoted P. JM-7′s denitrification of nitrate coupled to yeast extract powder (YEP) oxidation. Denitrification rates depended on temperature (>21 °C) and pH (6–9). During logarithmic growth, 5 g/L YEP enabled 350 mg/L nitrate removal, increasing to 1650 mg/L in stable growth. Addition of 4 mM Fe(II)/Fe(III) increased denitrification to 500 mg/L during logarithmic growth. The dynamic test results displayed that compared to the SiO2 filler control group, iron-containing fillers could facilitate P. JM-7 to reduce 100 mg/L nitrate with 50 mg/L YEP electrons, corresponding to 6 times the maximum electron transfer efficiency in the static test. Overall, iron redox cycling significantly enhanced P. JM-7 denitrification, imparting insights into iron–nitrogen interactions. In summary, our research imparts valuable insights into the nexus between iron and nitrogen in the environment, highlighting the potential application of P. JM-7 in environmental engineering. Our findings indicate that P. JM-7 exhibits a significant denitrification capability, and further research is recommended to investigate its ability to remove phosphorus and promote sustainable environmental remediation practices.

Using L. minor and C. elegans to assess the ecotoxicity of real-life contaminated soil samples and their remediation by clay- and carbon-based sorbents

Toxic substances, such as polycyclic aromatic hydrocarbons (PAHs) and heavy metals, can accumulate in soil, posing a risk to human health and the environment. To reduce the risk of exposure, rapid identification and remediation of potentially hazardous soils is necessary. Adsorption of contaminants by activated carbons and clay materials is commonly utilized to decrease the bioavailability of chemicals in soil and environmental toxicity in vitro, and this study aims to determine their efficacy in real-life soil samples. Two ecotoxicological models (Lemna minor and Caenorhabditis elegans) were used to test residential soil samples, known to contain an average of 5.3, 262, and 9.6 ppm of PAHs, lead, and mercury, for potential toxicity. Toxicity testing of these soils indicated that 86% and 58% of soils caused ≤50% inhibition of growth and survival of L. minor and C. elegans, respectively. Importantly, 3 soil samples caused ≥90% inhibition of growth in both models, and the toxicity was positively correlated with levels of heavy metals. These toxic soil samples were prioritized for remediation using activated carbon and SM-Tyrosine sorbents, which have been shown to immobilize PAHs and heavy metals, respectively. The inclusion of low levels of SM-Tyrosine protected the growth and survival of L. minor and C. elegans by 83% and 78%, respectively from the polluted soil samples while activated carbon offered no significant protection. These results also indicated that heavy metals were the driver of toxicity in the samples. Results from this study demonstrate that adsorption technologies are effective strategies for remediating complex, real-life soil samples contaminated with hazardous pollutants and protecting natural soil and groundwater resources and habitats. The results highlight the applicability of these ecotoxicological models as rapid screening tools for monitoring soil quality and verifying the efficacy of remediation practices.

Formerly used defense sites on Unalaska Island, Alaska: Mapping a legacy of environmental pollution.

Unalaska Island, Alaska, served as a US military base during World War II. The military installed bases on Unalaska and nearby islands, many of which were built adjacent to Unangan communities. The military used toxic compounds in its operations and left a legacy of pollution that may pose health risks to residents and local wildlife. The goals of this study were to identify hotspots of contamination remaining at Unalaska formerly used defense (FUD) sites, evaluate the risk posed by arsenic, and examine "no US Department of Defense action indicated" (NDAI) status determinations for FUD sites near communities. We compiled soil chemistry data from remediation reports prepared by the US Army Corps of Engineers at 18 FUD sites on and near Unalaska. Nine had past and/or active remediation projects and on-site sampling data. Eight sites did not have sampling data and were characterized as NDAI. One site was listed as closed. For the nine sites with sampling data, we compiled data for 22 contaminants of concern (COC) and compared concentrations to soil cleanup levels for human health (18 AAC 75.341). We mapped contaminant concentrations exceeding these levels to identify hotspots of contamination. We found that concentrations of some of the 22 COC exceeded Alaska cleanup levels despite remediation efforts, including diesel range organics, arsenic, and lead. The highest COC concentrations were at the FUD site adjacent to the City of Unalaska. A quantitative risk assessment for arsenic found that the risk of exposure through drinking water is low. We highlight concerns with NDAI designations and current remedial practices at remote FUD sites located adjacent to communities. Our data suggest the need for further remediation and monitoring efforts on Unalaska for certain contaminants and research to examine potential threats to human and animal health associated with these sites. Integr Environ Assess Manag 2024;20:1420-1431. © 2024 SETAC.

Nutrient transport, shear strength and hydraulic characteristics of topsoils amended with mulch, compost and biosolids

Anthropogenic disturbance of soils can disrupt soil structure, diminish fertility, alter soil chemical properties, and cause erosion. Current remediation practices involve amending degraded urban topsoils lacking in organic matter and nutrition with organic amendments (OA) to enhance vegetative growth. However, the impact of OAs on water quality and structural properties at rates that meet common topsoil organic matter specifications need to be studied and understood. This study tested three commonly available OAs: shredded wood mulch, leaf-based compost, and class A Exceptional Quality stabilized sewage sludge (or biosolids) for nutrient (nitrogen and phosphorus) water quality, soil shear strength, and hydraulic properties, through two greenhouse tub studies. Findings showed that nitrogen losses to leachate were greater in the biosolids amended topsoils compared to leaf-compost, mulch amended topsoils, and control treatments. Steady-state mean total nitrogen (N) concentrations from biosolids treatment exceeded typical highway stormwater concentrations by at least 25 times. Soil total N content combined with the carbon:nitrogen ratio were identified to be the governing properties of N leaching in soils. Study soils, irrespective of the type of amendment, reduced the applied (tap) water phosphorus (P) concentration of ∼0.3 mg-P/L throughout the experiment. Contrary to the effects on N leaching, P was successfully retained by the biosolids amendment, due to the presence of greater active iron contents. A breakthrough mechanism for P was observed in leaf compost amended soil, where the effluent concentrations of P continued to increase with each rainfall application, possibly due to an saturation of soil adsorption sites. The addition of OAs also improved the strength and hydraulic properties of soils. The effective interlocking mechanisms between the soil and OA surfaces could provide soil its required strength and stability, particularly on slopes. OAs also improved soil fertility to promote turf growth. Presence of vegetative root zones can further reinforce the soil and control erosion.

Sequestration of chromium by Ananas comosus extract–coated nanotubes: synthesis, characterization, optimization, thermodynamics, kinetics, and antioxidant activities

AbstractHerein, a superior adsorbent was fabricated via immobilizing Ananas comosus juice extract on nanotubes (MWPJ) for the removal of chromium (VI) from simulated wastewater. The batch adsorption technique was used to establish the influence of solution pH, adsorbent dosage, solution temperature, initial Cr(VI) concentration, and contact time on the adsorption of chromium (VI). To comprehend the surface properties and to confirm chromium (VI) adsorption onto MWPJ and MWCNTs, TGA, SEM, and FTIR analyses were performed for MWPJ and MWCNTs before and after the adsorption process. These spectroscopic techniques revealed the temperature and surface characteristics responsible for the effectiveness of MWPJ. MWPJ and MWCNTs demonstrated optimum removal potential at solution pH 2, 0.05 g adsorbent dosage, and 180 min contact time. The MWPJ and MWCNTs had a maximum adsorption potential of 44.87 and 33.38 mg g−1 at 25 °C respectively. The reaction rate kinetics data for MWPJ and MWCNTs fitted well with Elovich and the pseudo-first-order kinetic model, respectively, while the saturated equilibrium data were best described by Freundlich isotherm. The thermodynamics analysis revealed that the uptake of Cr(VI) onto MWPJ and MWCNTs was a spontaneous and exothermic process. After five adsorption–desorption cycles of MWPJ, about 80% removal efficiency of Cr(VI) ions was sustained. Hence, MWPJ has demonstrated a superior capacity for practical applications in environmental remediation practice.

Comparative e-waste plastics biodegradation efficacy of monoculture Pseudomonas aeruginosa strain PE10 and bacterial consortium under in situ condition.

A significant amount of electronic obsoletes or electronic waste (e-waste) is being generated globally each year; of these, ~20% of obsolete electronic items have plastic components. Current remediation practices for e-waste have several setbacks due to its negative impact on the environment, agro-ecosystem, and human health. Therefore, comparative biodegradation studies of e-waste plastics by monoculture Pseudomonas aeruginosa strain PE10 and bacterial consortium consisting of Achromobacter insolitus strain PE2 (MF943156), Acinetobacter nosocomialis strain PE5 (MF943157), Pseudomonas lalkuanensis PE8 (CP043311), and Stenotrophomonas pavanii strain PE15 (MF943160) were carried out in situ. Biological treatment of e-waste with these candidates in soil ecosystems has been analyzed through diversified analytical techniques such as Fourier transform infrared spectroscopy (FTIR), thermogravimetric-derivative thermogravimetry-differential thermal analysis (TG-DTG-DTA), and scanning electron microscopy (SEM). Both P. aeruginosa strain PE10 and the bacterial consortium have a tremendous ability to accelerate the biodegradation process in the natural environment. However, FTIR analysis implied that the monoculture had better efficacy than the consortium, and it was consistent until the incubation period used for the study. Some polymeric bonds such as ν C=C and δ C-H were completely removed, and ν C=C ring stretching, νasym C-O-C, νsym C-H, etc. were introduced by strain PE10. Furthermore, thermal analysis results validated the structural deterioration of e-waste as the treated samples showed nearly two-fold weight loss (WL; 6.8%) than the untreated control (3.1%) at comparatively lower temperatures. SEM images provided the details of surface disintegrations. Conclusively, individual monoculture P. aeruginosa strain PE10 could be explored for e-waste bio-recycling in agricultural soil ecosystems thereby reducing the cost, time, and management of bioformulation in addition to hazardous pollutant reduction.

The long-term effect of Fe3O4 in activating persulfate to degrade refractory organic contaminants for groundwater remediation

Highly reactive metal-based materials for persulfate activation have been intensively studied for treatment of groundwater contaminants. However, the long-term efficacy of the readily available metal-oxide additives, which can be more important for groundwater remediation practice, has received minimal attention. In this study, the results of preliminary experiments demonstrated that Fe3O4 was superior to seven metal oxides (MnO, Fe2O3, MnO2, CuO, Cu2O, CoO, NiO) and zero-valent iron for activating persulfate to degrade 1,2-dichloropropane. Experiments were then conducted to examine the long-term effects of Fe3O4-activated persulfate degradation of four contaminants, i.e., 1,2-dichloropropane, 1,1,2-trichloroethane, 1,4-dioxane, and methyl tert-butyl ether (MTBE). The system achieved complete removal of the contaminants in approximately 72 h, which was contrasted to a removal efficiency less than 35 % in the absence of Fe3O4. Highly efficient use of persulfate for contaminant degradation was observed with insignificant production of soluble Fe before depletion of the contaminants. Production of sulfate radical (SO4•−) and hydroxyl radical (HO•) via surface reactions was likely the process responsible for the degradation. Ten and five cycles of 1,2-dichloropropane degradation experiments were conducted in deionized water and actual groundwater. These results suggested that the Fe3O4 could retain 80 % of its original activation capacity after 5 cycles, but partial oxidation of Fe3O4 eventually occurred. Production of some Cl-containing degradation-resistant intermediates from degradation of 1,2-DCP was observed and could be mitigated under specific conditions. The results show that Fe3O4 has a long-term effect in activating persulfate for contaminant degradation, which is promising for applications such as permeable reactive barriers and nanoparticle injection for groundwater remediation.

Intercropping of Pteris vittata and maize on multimetal contaminated soil can achieve remediation and safe agricultural production

Soil contamination by multimetals is widespread. Hyperaccumulator–crop intercropping has been confirmed to be an effective method for arsenic (As)- or cadmium (Cd)-contaminated soil that can achieve soil cleanup and agricultural production. However, the influencing factors and response of hyperaccumulator–crop intercropping to multimetal-contaminated soil are still unclear. In this study, intercropping of the As hyperaccumulator Pteris vittata and maize was conducted on two typical types of multimetal-contaminated soil, namely, Soil A contaminated by As, Cd, and lead (Pb) and Soil B contaminated by As, Cd, and chromium (Cr). Intercropping reduced As, Cd, and Pb in the maize grains by 60 %, 66.7 %, and 20.4 %, respectively. The concentrations of As, Cd, Pb, and Cr in P. vittata increased by 314 %, 300 %, 447.3 %, and 232.6 %, respectively, relative to their concentrations in the monoculture plants. Two soils with different levels of contamination showed that higher heavy metal content might diminish the ability of intercropping to reduce soil heavy metal risk. No notable difference in soil microbial diversity was found between the intercropped and monocultured plants. The composition of microbial communities of intercropping groups were more similar to those of monoculture P. vittata on two different soils (Soils A and B). An imbalance between the amount of As taken up by the plants and the reduction in As in the soil was observed, and this imbalance may be related to watering, As leaching, and heterogeneity of soil As distribution. Reducing the risk resulting from As leaching and enhancing the efficiency of phytoextraction should be emphasized in remediation practices.

Microbially mediated sulfur oxidation coupled with arsenate reduction within oligotrophic mining-impacted habitats.

Arsenate [As(V)] reduction is a major cause of arsenic (As) release from soils, which threatens more than 200 million people worldwide. While heterotrophic As(V) reduction has been investigated extensively, the mechanism of chemolithotrophic As(V) reduction is less studied. Since As is frequently found as a sulfidic mineral in the environment, microbial mediated sulfur oxidation coupled to As(V) reduction (SOAsR), a chemolithotrophic process, may be more favorable in sites impacted by oligotrophic mining (e.g. As-contaminated mine tailings). While SOAsR is thermodynamically favorable, knowledge regarding this biogeochemical process is still limited. The current study suggested that SOAsR was a more prevalent process than heterotrophic As(V) reduction in oligotrophic sites, such as mine tailings. The water-soluble reduced sulfur concentration was predicted to be one of the major geochemical parameters that had a substantial impact on SOAsR potentials. A combination of DNA stable isotope probing and metagenome binning revealed members of the genera Sulfuricella, Ramlibacter, and Sulfuritalea as sulfur oxidizing As(V)-reducing bacteria (SOAsRB) in mine tailings. Genome mining further expanded the list of potential SOAsRB to diverse phylogenetic lineages such as members associated with Burkholderiaceae and Rhodocyclaceae. Metagenome analysis using multiple tailing samples across southern China confirmed that the putative SOAsRB were the dominant As(V) reducers in these sites. Together, the current findings expand our knowledge regarding the chemolithotrophic As(V) reduction process, which may be harnessed to facilitate future remediation practices in mine tailings.

BioMagnetic-graphene-aminoclay nanocomposites for sustainable adsorption and precious metal recovery from industrial waste effluents

The recovery of precious metals from waste effluents using low-cost adsorbents is arousing widespread attention. This attention is driven by the depletion of natural resources, increasing industrial demand for these metals, and intensified awareness of environmental protection. In response to the growing trend of waste valorization, we have developed a novel, cost-effective, and environmentally friendly adsorbent that combines bio-magnetic nanoparticles derived from bacterial biofilm waste with graphene oxide (GO) and aminoclay. This biomag-GO-aminoclay nanocomposite adsorbent is synthetised using a simple, environmentally friendly and scalable sonication-assisted electrostatic stabilization approach. The adsorption performance for precious metal is demonstrated for silver ions recovery showing exceptional adsorption with nearly 100 % uptake of Ag+ ions across a wide pH range (pH 2–9), rapid adsorption kinetics, a high maximum sorption capacity (98.04 ± 5.6 mg/g) and 100 % silver recovery over five adsorption-desorption cycles. Furthermore, the biomag-GO-aminoclay facilitates the in-situ reduction of Ag+ ions to Ag0, thereby enhancing the economic viability of producing value-added silver products while promoting sustainable environmental remediation practices. Overall, this research underlines the potential of new biomag-GO-aminoclay adsorbent as a versatile and effective solution for recovering precious metals from industrial waste streams, offering a pathway towards both economic benefit and environmental stewardship.

Integrating Heavy Metal Adsorption on Organic Waste Materials into Defense and Security Studies: A Sustainable Approach

This study aims to examine the plausible fusion of heavy metal adsorption through lignin derived from organic waste materials into the realm of defense and safety studies. This study underscores the imperative nature of addressing heavy metal pollution within defense operations and environmental conservation. It proposes utilizing lignin, derived from organic waste materials, as a pivotal solution to combat heavy metal contamination. By synthesizing insights from existing literature, this research delves into lignin's potential as a highly effective adsorbent tailored for the defense sector. The study illuminates lignin's versatility in interacting with heavymetals through multifaceted adsorption mechanisms, offering a sustainable strategy to mitigate environmental harm while fortifying national resilience. Derived from diverse biomass sources, including peanut shells, cocoa pod shells, coconut shells, rice husks, and empty oil palm fruit bunches, lignin exhibits promising adsorption capacitiesattributed to its ample surface area and diverse functional groups. Emphasizing a holistic perspective, this research advocates for an integrated approach that harnesses lignin's robust adsorption capabilities to meet the specific demands of defense and security, envisioning a future that is both secure and sustainable. This is attributed to the inherent properties of lignin, such as its abundant surface area and diverse functional groups. The lignin derived from these biomasses offers a versatile and effective solution, showcasing high adsorption potential due to its ability to accommodate various heavy metal ions and contribute to sustainable environmental remediation practices. By synergizing lignin's robust adsorption attributes with therequisites of defense and security, this research advocates for a comprehensive approach, fostering a vision of a secure and sustainable future.

Harvest load transfer sites influence sugarcane billbug (Coleoptera: Curculionidae) spatiotemporal injury in sugarcane.

The sugarcane billbug, Sphenophorus levis Vaurie 1978, is a key soil-dwelling insect pest of sugarcane in Brazil and greatly affects plant development and yield. This insect presents an aggregated distribution pattern in production fields. The reasons for such behavior include intraspecific communication and attractivity due to the fermentation of sugar in stalk residues. During mechanized harvesting, part of the harvested material usually falls in the load transfer sites, becoming a potential source for increasing the infestation. We therefore evaluated whether producing areas near the harvest load transfer sites are more prone to S. levis injury. There are greater chances of finding billbug injury within a radius of 740 m from the harvest load transfer site. Additionally, injured areas are estimated to expand 11.96% each growing season. Our spatiotemporal models support higher injured areas surrounding the harvest load transfer site and show clear and significant signs of increased injury levels compared to the initial growing season surveyed. Our results reinforce the importance of harvest transfer sites in the dispersion and propagation of the sugarcane billbug. Based on this knowledge, sugarcane millers and growers can adopt preventive and remedial practices within the loading sites that can potentially contribute to the successful management of this insect pest. © 2023 Society of Chemical Industry.

Effects of tomato-Sedum alfredii Hance intercropping on crop production and Cd remediation as affected by soil types.

Intercropping crops with hyperaccumulators is a proven model for coupling crop safety production and soil heavy metal remediation. And both crop genotypes and soil properties might have great impacts on the effect of intercropping. Therefore, a greenhouse pot experiment was designed to investigate the effects of intercropping different tomato varieties with the cadmium (Cd) hyperaccumulator Sedum alfredii Hance (S. alfredii Hance) on different soils. The results showed that intercropping promoted Cd uptake by S. alfredii Hance and reduced soil total Cd concentration. There was no significant effect of intercropping on tomato yield and Cd concentration. Different tomato varieties had different effects on tomato yield and Cd concentration. The yield of cherry tomato was 1.04 times higher than that of common large fruit tomato, while the Cd concentration in all parts was lower than that of common large fruit tomato. Different typical zonal soils had different effects on tomato production and soil remediation. And among the four studied soils, tomatoes grown on ZJ soil had the highest yields and lowest fruit Cd concentration, making them more suitable for remediation coupled with safety production. This study provided a comprehensive analysis of tomato production benefits and soil remediation effects, which could be useful as a guide in vegetable safety production coupled with soil remediation practices in the Cd-contaminated greenhouse.