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Abstract\nNOVELTY STATEMENTThe use of organic and inorganic amendments like stilbite-zeolite (SZ) and nano-biochar (NBC) in phytoremediation holds immense promise, long-term stability, and its effectiveness necessitate comprehensive research. This study aimed to evaluate their potential in mitigating heavy metal contamination in soil and plants. Our results shows that SZ and NBC treatments significantly impacted heavy metal levels, notably reducing arsenic (As), nickel (Ni), lead (Pb), cadmium (Cd), and mercury (Hg) accumulation in plant tissues. The treatments exhibited varying degrees of effectiveness in reducing heavy metal levels. Notably, SZ2 treatment decreased As and Pb levels by 33.33% and 20%, respectively, while NBC3 achieved even greater reductions, lowering As by 53.33% and Pb by 30%. Moreover, SZ2, SZ5, and NBC3 treatments halved Cd levels, showcasing their potential in mitigating heavy metal contamination in rice. However Hg levels remained largely unaffected, except for NBC1, which unexpectedly doubled its concentration. In soil, SZ2 treatment significantly reduced metal concentrations, particularly Cd (66.8% reduction) and Hg (70.7% reduction). Conversely, SZ3 and SZ7 treatments increased metal concentrations, suggesting that certain zeolite applications might enhance metal bioavailability. NBC treatments showed varying effectiveness, with NBC3 being the most effective, substantially reducing As, Pb, and Cd levels.The study uniquely evaluates the synergistic effects of SZ and NBC treatments on heavy metal reduction in rice grain. It identifies specific SZ and NBC treatments that significantly decrease arsenic, lead, and cadmium levels, with detailed analysis of both reductions and potential increases in metal bioavailability. This research provides critical insights into optimizing remediation strategies for enhanced soil health and food safety. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Engineering (17264073) is the property of Republic of Iraq Ministry of Higher Education & Scientific Research (MOHESR) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Due to environmental pollution, the risk of cadmium stress for crops is soaring, so researchers are exploring inexpensive solutions to enhance cultivated crops in contaminated soil. Using microorganisms to reduce cadmium risk has been one of the most effective strategies in recent decades. Serendipita indica (Piriformospora indica) is one of the best endophyte fungi that, in addition to reducing heavy metal stress for crops, can significantly reduce the threat of other abiotic stresses. As part of this research, cadmium in soil has been investigated, as well as its effects on plants' morphophysiological and biochemical characteristics. The present review has also attempted to identify the role of Serendipita indica in improving the growth and performance of crops, as well as its possible effect on reducing the risk of cadmium. The results showed that Serendipita indica enhance the growth and productivity of plants in contaminated environments by improving soil quality, reducing cadmium absorption, improving the activity of antioxidant enzymes and secondary metabolites, raising water and mineral absorption, and altering morphophysiological structures. [ABSTRACT FROM AUTHOR]

The risk of arsenic contamination is rising globally, and it has negative impacts on the physiological processes and growth of plants. Metal removal from contaminated soils can be accomplished affordably and effectively with plant growth promoting rhizobacteria (PGPR)-based microbial management. From this angle, this research evaluated the mitigation of arsenic toxicity using the bacteria isolated from contaminated site, Mettur, Salem district, South India. The newly isolated bacterial strain was screened for plant growth promotion potential and arsenic tolerance such as (100 ppm, 250 ppm, 500 ppm, 800 ppm and 1200 ppm). The metal tolerant rhizobacteria was identified using 16S rRNA gene sequence analysis as Pseudomonas alcaliphila strain PAS1 (GenBank accession number: OQ804624). Pigeon pea (Cajanus cajan) plants were used in pot culture experiments with varying concentrations of arsenic, (5 ppm, 10 ppm and 25 ppm) both with and without bacterial culture, for a period of 45 days. At the concentration of 25 ppm after the application of PAS1 enhanced the plant growth, protein and carbohydrate by 35.69%, 18.31% respectively. Interestingly, P. alcaliphila strain PAS1 significantly reduced the stress-induced elevated levels of proline, flavonoid, phenol and antioxidant enzyme in pigeon pea plants was 40%, 31.11%, 27.80% and 20.12%, respectively. Consequently, PAS1 may significantly reduce the adverse effects that arsenic causes to plant development in acidic soils, improve plant uptake of nutrients, and increase plant production. The findings of this study reveal that P. alcaliphila PAS1 is intrinsic for phytoremediation by reducing arsenic accumulation in the root and shoot. [ABSTRACT FROM AUTHOR]

A novel technique that couples microbially induced calcite precipitation (MICP) and calcium carbide residue (CCR) is proposed for immobilizing Cd2+ in contaminated soil. The properties and mechanism of CCR-enhanced MICP were investigated through a series of experimental analyses considering factors such as heavy metal concentration, curing time, and the effect of Ca2+. The unconfined compressive strength (UCS) increased with increasing curing time and reached a maximum value at 28 d, and the leaching concentration of Cd2+ decreased and tended to level off with increasing curing time. The addition of CCR enhanced the immobilization performance of Cd2+ through the MICP method, resulting in UCSs that were 3.8–4.2 times those of samples without CCR and leaching concentrations of Cd2+ that were 38.9–69.2% lower at a curing time of 28 d. The addition of Ca2+ to cementation solutions further improved the immobilization effectiveness, resulting in the UCSs of the samples increasing by 18.7–49.8% and the leaching concentrations of Cd2+ decreasing by 11–40% CaCO3 and its hydration products can immobilize Cd2+ through coprecipitation, reducing its toxicity by converting weak acid-extractable cadmium into residual cadmium. Consequently, Sporosarcina pasteurii combined with CCR improved the UCS of the treated contaminated soil and greatly decreased cadmium migration. [ABSTRACT FROM AUTHOR]

Arbuscular mycorrhizal fungi (AMF) play an essential role in plant growth and have great potential to enhance plant tolerance under polluted and toxic conditions. This study deals with a survey of five contaminated sites of the Baddi Barotiwala Nalagarh (BBN) industrial corridor/hub to investigate the morpho-diversity of endotrophic AM fungi associated with native plants. The high contamination factor of Cd and Fe in different study sites revealed a high intensity of contamination, indicating that the sites were significantly polluted with Cd and Fe. Results showed that AM symbioses were successfully established in the roots of native plants, highlighting their role in mitigating the harmful effects of potentially toxic elements (PTEs) through bioremediation. A total of 50 AMF morphotypes across 9 genera (Acaulospora, Entrophospora, Ambispora, Diversispora, Gigaspora, Scutellospora, Glomus, Rhizophagus, and Sclerocystis) were identified, with Glomeraceae being the most abundant (46%), followed by Acaulosporaceae (39%) and others contributing less (15%). The study also indicated that the hyphal and vesicular infections were prominent than arbuscular infections in roots. This is the first report on the diversity of native and putative AMF species associated with plants in the BBN industrial corridor, suggesting that these fungi could be cultured for further use as a sustainable organic approach in agriculture and rehabilitation practices in polluted areas. [ABSTRACT FROM AUTHOR]

In order to study the solidification / stabilization effect of environmental protection material geopolymer on lead contaminated soil, based on the research background of heavy metal lead pollution and solid waste resource utilization in arid and semi-arid areas, a new solidified material geopolymer was prepared by using blast furnace slag and cement, and the macroscopic mechanical performance and microscopic mechanism of solidified heavy metal lead were discussed. Based on the cement-based solidification of heavy metal lead-contaminated soil, the strength performance and toxicity leaching performance of geopolymer-cement under different proportions were explored, and the microscopic test characterization of the outstanding performance group was carried out. The test results show that compared with cement-based and other groups, 80% slag geopolymer combined with cement has better performance of solidification / stabilization of heavy metal lead, and the compressive strength and toxicity leaching results under pollution degree ③ are significantly better than other groups. phase analysis of X-ray diffraction (XRD), scanning electron microscope (SEM), nuclear magnetic resonance (NMR) and other tests show that the internal structure of 80% slag geopolymer is complete and dense, the internal changes of cement solidified body are severe, the hydration reaction is inhibited by heavy metals, the overall structure is loose, and the density is low and discontinuous. [ABSTRACT FROM AUTHOR]

Aims: This study was aimed to investigate the effect of earthworm Amynthas morrisi on the metal bioaccumulation by two plant species, Sedum alfredii Hance (Sedum) and maize (Zea mays L.), in a co-cropping system and possible influencing pathways, and assess the remediation potential of all combination of these organisms to identify the best option. Methods: In this study, an eight-week microcosm experiment was conducted to investigate the main and interactive effects of the earthworm Amynthas morrisi, the hyperaccumulator plant Sedum alfredii Hance (Sedum), and maize (Zea mays L.) on C and N forms, and microbial characteristics and diethylene triamine penta acetic acid (DTPA) extractable metals of a soil heavily contaminated by multiple metals (i.e., Cd, Zn, Pb, and Cu). In addition, plant growth and metal accumulation were evaluated and the possible influencing pathways of metal accumulation by the two plant species were assessed. Finally, a remediation strategy was proposed based on the amounts of metals removed by sedum and maize. Results: The soil quality index achieved after eight weeks of experiments, was best with Sedum, and worst in the control with no plants and no earthworms. A path analysis suggests that earthworms exerted strong effects on plant metal accumulation by changing plant growth, with soil microbes playing a mediating role. The association of Sedum and Maize significantly increased the Zn concentration and decreased the Pb and Cu concentrations in the aboveground parts of Sedum compared with Sedum alone, whereas Sedum decreased the Zn, Cd, Pb, and Cu concentrations in the aboveground parts of maize compared with maize alone treatment. PCA showed that when maize was co-cropped with Sedum, metal transfer from its roots to the aboveground parts decreased. Conclusions: The Earthworm + Sedum + Maize treatment displayed the most effective Cd and Zn removal, indicating that the combined introduction of A. morrisi and S. alfredii can effectively remediate soils co-contaminated by Cd and Zn in maize cropping systems. [ABSTRACT FROM AUTHOR]

The dwindling availability of agricultural land, caused by factors such as rapid population growth, urban expansion, and soil contamination, has significantly increased the pressure on food production. To address this challenge, cultivating non-food crops on contaminated land has emerged as a promising solution. This approach not only frees up fertile soil for food production but also mitigates human exposure to contaminants. This work aimed to examine the impact of soil contamination with Cd, Pb, Ni, and Zn on the growth, productivity, metal accumulation, and the tolerance of five lignocellulosic non-food crops: switchgrass (Panicum virgatum L.), biomass sorghum (Sorghum bicolor L. Moench), giant reed (Arundo donax L.), African fodder cane (Saccharum spontaneum L. spp. aegyptiacum Willd. Hackel), and miscanthus (Miscanthus × giganteus Greef et Deu.). A two-year pot experiment was conducted in Greece, Italy, and Portugal, following the same protocols and applying various levels of metals: Cd (0, 4, 8 mg kg−1), Pb and Zn (0, 450, 900 mg kg−1), and Ni (0, 110, 220 mg kg−1). The experimental design was completely randomized, with three replicates for each treatment. The results showed that switchgrass and sorghum generally maintained their height and productivity under Cd and Pb stress but were adversely affected by high Zn and Ni concentrations. Giant reed and African fodder cane showed reduced height and productivity at higher Ni and Zn levels. Miscanthus exhibited resilience in height but experienced productivity reductions only at the highest Zn concentration. Heavy metal uptake varied among crops, with switchgrass and sorghum showing high Cd and Pb uptake, while giant reed accumulated the most Cd and Zn. Miscanthus had the highest Ni accumulation. The tolerance indices indicated that switchgrass and sorghum were more tolerant to Cd and Zn at lower concentrations, whereas miscanthus had lower tolerance to Cd but a higher tolerance to Zn at higher concentrations. Giant reed and African fodder cane demonstrated stable tolerance across most heavy metals. Accumulation indices highlighted the effectiveness of switchgrass and sorghum in Cd and Pb uptake, while miscanthus excelled in Ni and Zn accumulation. The cluster analysis revealed similar responses to heavy metal stress between African fodder cane and giant reed, as well as between sorghum and miscanthus, with switchgrass displaying distinct behavior. Overall, the study highlights the differential tolerance and accumulation capacities of these crops, indicating the potential for phytoremediation applications and biomass production in heavy metal-contaminated soils. [ABSTRACT FROM AUTHOR]

Geopolymers derived from solid waste can effectively remediate heavy metal polluted sites, achieving the ideal fusion of solid waste utilization and environmental remediation. Red mud and blast furnace slag were used to develop a geopolymer for the remediation of composite heavy metal-contaminated soils, focusing on Cd(II)-, Pb(II)-, Cu(II)-, and Zn(II)-contaminated soils. Uniaxial compressive strength tests, toxicity characteristic leaching procedures, pH change characteristics, and pH gradient tests were performed on the solidified/stabilized soil. The results showed that increasing the red mud-blast furnace slag content and curing age significantly enhanced the unconfined compressive strength. Furthermore, it suppressed the leaching of heavy metals in the solidified/stabilized soil. Notably, the treatment effectiveness of Cu(II) and Zn(II) was superior to that of Cd(II) and Pb(II). The leaching concentrations of Cd(II), Pb(II), and Zn(II) decreased in acidic to weakly alkaline environments but increased in strongly alkaline environments. However, the impact of curing age and initial heavy metal content on the pH of the solidified/stabilized soil was the opposite. In conclusion, red mud and blast furnace slag exhibited superior solidification/stabilization effects compared to cement. As environmental protection awareness grows and technology continues to evolve, geopolymers derived from red mud and blast furnace slag will play a greater role in pollution control and remediation, showcasing broad application prospects. [ABSTRACT FROM AUTHOR]

【Objective】To explore the effects of phosphate-solubilizing bacteria (PSB) and their fermentation products on the properties of maize (Zea mays L.) rhizosphere soil and the composition and diversity of microbial community in lead-contaminated soil. 【Method】Based on the screening of Klebsiella pasteurii with lead-resistant and phosphate-solubilizing function, corn was cultivated in lead-contaminated soil by pot experiment. LB medium, supernatant (bacterial secretion), bacterial solution (only bacterial cells) and fermentation broth (supernatant + bacterial cells) were applied to the rhizosphere, and sterile water control was set to explore the effects of phosphate-solubilizing bacteria on the physical and chemical properties of rhizosphere soil and microbial community structure.【Result】The supernatant, bacterial liquid and fermentation liquid of K.baumannii had no significant effect on the diversity of bacterial community in maize rhizosphere, while the bacterial liquid significantly increased the Shannon index and Chao index of soil fungal community. The supernatant, bacterial liquid and fermentation liquid of the strain increased the relative abundances of heavy metal-resistant microbial groups such as Bacteroidetes and Actinobacteria, while the supernatant and fermentation liquid increased the abundances of Proteobacteria and Mortierellomycota. The supernatant increased the relative abundances of Sphingomonas, Blastococcus, Bradyrhizobium and Archaeorhizomyces. In addition, Pearson correlation analysis of differential genera in the maize rhizosphere soil showed that there were positive correlations among 7 groups of differential genera, which revealed that different microbial genera tended to form mutually beneficial symbiotic relationships. The supernatant, bacterial liquid and fermentation liquid of the strain significantly increased the activities of soil acid phosphatase (Acp) . Among them, the Acp activity of maize rhizosphere soil in the fermentation liquid treatment group was the highest (574.44 mg/g, 24-1) . The application of supernatant and bacterial liquid significantly increased the content of alkali-hydrolyzed nitrogen (AN) in the rhizosphere soil, which was 47.4% and 39.5% higher than that of the control, respectively. The three treatment groups significantly reduced the soil pH value. Through redundancy analysis (RDA), it was found that soil AN, Acp, pH value and available phosphorus (AP) were the main factors affecting the microbial community structure.【Conclusion】This study reveales that exogenous application of PSB and their fermentation products was beneficial to improving the fertility of lead-contaminated soil, and affectes the composition and structure of soil microbial community, which provides a theoretical basis for inoculating PSB and improving soil nutrients and soil microbial community structure in lead-contaminated farmland. [ABSTRACT FROM AUTHOR]

Pollution caused by heavy metals, due to their toxicity and harmful effects on plant species, is considered one of the fundamental problems. The unique properties of graphene oxide (GO) in adsorbing heavy metals from contaminated soil systems have garnered attention in the past decade. This study evaluates the effects of different doses of graphene oxide (0.5 and 1.5 g kg-1) on the adsorption and distribution of heavy metals, including Cadmium (Cd) and Copper (Cu) fractions, in soil contaminated with two rates (2% and 10%) of sewage sludge (SS) over a 92-day period. Subsamples were collected from the soils at intervals of 5, 15, 29, 57, and 92 days, air-dried, and subjected to metal fractionation. The aim was to evaluate the separation of Cd and Cu by employing a five-stage sequential extraction technique, where each stage involved 2 grams of air-dried soil as a sample. The overall metal quantity in the treatments was determined by utilizing aqua regia digestion. The recovery rate was determined by calculating the percentage of the total metal concentration obtained from acid digestion, involving the summation of the concentrations of the five metal fractions. The results showed that the F1 fraction of heavy metals in the soil with a 2% SS rate decreased with an increase in GO dosage. The calculated mobility factor of the metals at five incubation times (5, 15, 29, 57, and 92 days) was found to be in the range of 28.1-60.9 for Cd and 14.4-25.3 for Cu, indicating a higher mobility of Cd. The findings suggest that the presence of GO as an adsorbent and the incubation time were critical parameters in stabilizing heavy metals in the soil with different rates of SS. Additionally, the nature of the applied SS was found to influence the fractionation of heavy metals in the soil, besides providing elements. [ABSTRACT FROM AUTHOR]

The agro-waste derived valuable products are prime interest for effective management of toxic heavy metals (THMs). The present study investigated the efficacy of biochars (BCs) on immobilization of THMs (Cr, Zn, Pb, Cu, Ni and Cd), bioaccumulation and health risk. Agro-wastes derived BCs including wheat straw biochar (WSB), orange peel biochar (OPB), rice husk biochar (RHB) and their composite biochar (CB) were applied in industrial contaminated soil (ICS) at 1% and 3% amendments rates. All the BCs significantly decreased the bioavailable THMs and significantly (p < 0.001) reduced bioaccumulation at 3% application with highest efficiency for CB followed by OPB, WSB and RHB as compared to control treatment. The bioaccumulation factor (BAF), concentration index (CI) and ecological risk were decreased with all BCs. The hazard quotient (HQ) and hazard index (HI) of all THMs were <1, except Cd, while carcer risk (CR) and total cancer risk index (TCRI) were decreased through all BCs. The overall results depicted that CB at 3% application rate showed higher efficacy to reduce significantly (p < 0.001) the THMs uptake and reduced health risk. Hence, the present study suggests that the composite of BCs prepared from agro-wastes is eco-friendly amendment to reduce THMs in ICS and minimize its subsequent uptake in vegetables. Novelty statement: The present study has a scientific research scope, based on reduction of bioavailability and bioaccumulation of toxic heavy metals (THMs) by the addition of biochars derived from agro-wastes and their composite biochar (CB), thereby decreasing the potential health risk. Limited study has been conducted, especially on the impact of CB in THMs-contaminated soil. This study could fill the scientific research gap and provides useful information for mitigation of THMs present in contaminated soil, which could be followed by the Environmental Protection Agency, Ministry of Agriculture and farmers in degraded lands. [ABSTRACT FROM AUTHOR]

Abstract A novel technique that couples microbially induced calcite precipitation (MICP) and calcium carbide residue (CCR) is proposed for immobilizing Cd2+ in contaminated soil. The properties and mechanism of CCR-enhanced MICP were investigated through a series of experimental analyses considering factors such as heavy metal concentration, curing time, and the effect of Ca2+. The unconfined compressive strength (UCS) increased with increasing curing time and reached a maximum value at 28 d, and the leaching concentration of Cd2+ decreased and tended to level off with increasing curing time. The addition of CCR enhanced the immobilization performance of Cd2+ through the MICP method, resulting in UCSs that were 3.8–4.2 times those of samples without CCR and leaching concentrations of Cd2+ that were 38.9–69.2% lower at a curing time of 28 d. The addition of Ca2+ to cementation solutions further improved the immobilization effectiveness, resulting in the UCSs of the samples increasing by 18.7–49.8% and the leaching concentrations of Cd2+ decreasing by 11–40% CaCO3 and its hydration products can immobilize Cd2+ through coprecipitation, reducing its toxicity by converting weak acid-extractable cadmium into residual cadmium. Consequently, Sporosarcina pasteurii combined with CCR improved the UCS of the treated contaminated soil and greatly decreased cadmium migration.

Objectives Heavy metals eluted from mine waste pollute surrounding soil and water systems, which can spread to crops and have a harmful effect on the human body. The purpose of this study was to evaluate the feasibility of recycling discarded mussel shells(MS) and manila clam shells (MC) as stabilizers for the immobilization of arsenic(As) and heavy metals(Pb, Zn) in soil. Methods MS and MC were processed with -#10 mesh natural material, -#20 mesh natural material, and -#10 mesh calcined material and treated at 0-10 wt%. After 1 week or 4 weeks of wet curing, it was eluted with 0.1 N HCl and the concentrations of As, Pb, and Zn in the soil were analyzed through inductively coupled plasma optical emission spectroscopy(ICP-OES) analysis. In addition, red lettuce was cultivated in the stabilized soil and the concentration of heavy metals that were transferred to crops was evaluated. The stabilization mechanism was investigated by scanning electron microscopy-energy dispersive X-ray spectroscopy(SEM-EDX) analysis. Results and Discussion The stabilization efficiency for arsenic and heavy metals was in the order of natural -#10 mesh < natural -#20 mesh < calcined -#10 mesh. The calcined stabilizer showed a high stabilization efficiency of 98% at a 2 wt% treatment level. Pb was not detected in the red lettuce grown in the stabiliz ed soil, and the standard for leafy vegetables (Pb-0.3 mg/kg or less) was satisfied according to the Ministry of Food and Drug Safety. The SEM-EDX analysis revealed that As was stabilized through Ca-As precipitation and heavy metals(Pb, Zn) were stabilized through pozzolanic reactions. Conclusion Stabilizers developed from MS and MC can be effectively applied to the stabilization of As and heavy metal-contaminated soil, and are expected to be used as economical and environmentally friendly stabilizers.

There have been reports of potential health risks for people from hydrophobic organic pollutants, such as polycyclic aromatic hydrocarbons (PAHs), polychlorinated hydrocarbons (PCHs), and organophosphate flame retardants (OPFRs). When a contaminated site is used for residential housing or public utility and recreation areas, the soil-bound organic pollutants might pose a threat to human health. In this study, we investigated the contamination profiles and potential risks to human health of 15 PAHs, 6 PCHs, and 12 OPFRs in soils from four contaminated sites in China. We used an in vitro method to determine the oral bioaccessibility of soil pollutants. Total PAHs were found at concentrations ranging from 26.4 ng/g to 987 ng/g. PCHs (0.27‒14.3 ng/g) and OPFRs (6.30‒310 ng/g) were detected, but at low levels compared to earlier reports. The levels of PAHs, PCHs, and OPFRs released from contaminated soils into simulated gastrointestinal fluids ranged from 1.74% to 91.0%, 2.51% to 39.6%, and 1.37% to 96.9%, respectively. Based on both spiked and unspiked samples, we found that the oral bioaccessibility of pollutants was correlated with their log K ow and molecular weight, and the total organic carbon content and pH of soils. PAHs in 13 out of 38 contaminated soil samples posed potential high risks to children. When considering oral bioaccessibility, nine soils still posed potential risks, while the risks in the remaining soils became negligible. The contribution of this paper is that it corrects the health risk of soil-bound organic pollutants by detecting bioaccessibility in actual soils from different contaminated sites. [Display omitted] [ABSTRACT FROM AUTHOR]

In this work, a new electrokinetic remediation technology was used to remove heavy metal and hydrocarbon from contaminated soil. The surfactant combined with PASP (Polyaspartic acid) was used to enhance heavy metal and hydrocarbon removing from contaminated soil. Electric current, soil pH, electroosmotic flow, water content variation, heavy metal removal efficiency and residual content distribution, heavy metal speciation, removal of TPH (total petroleum hydrocarbons), group composition of oil, mechanism of enhance electrokinetic remediation were investigated during the electrokinetic remediation process. Results indicated that Rhamnolipid, PASP, Tween 80 and SDS (sodium dodecyl sulphate) can reduce the heavy metal precipitation during the electrokinetic remediation process. Also, it can promote EOF (electroosmotic flow) and electrolyte evaporation during the EK remediation. The rhamnolipid (3.0 g.L−1) combined with PASP (3.0 g.L−1) can significantly improve Cu, Cr, Ni, Pb and hydrocarbon mobility and solubility during the EK remediations. Cu, Cr, Ni and Pb obtained the dominant removal efficiencies, which were 66.0 ± 3.45%, 61.2 ± 4.35%, 67.1 ± 3.21%, 61.8 ± 4.22%, respectively. Also, the TPH has attained a dominant removal efficiency of 80.2 ± 4.36% after the enhanced electrokinetic remediation. This research provides a novel in-situ remediation approach for reducing heavy metals and hydrocarbon from contaminated soil in an environmentally friendly way. [ABSTRACT FROM AUTHOR]

Copyright of Baghdad Science Journal is the property of Republic of Iraq Ministry of Higher Education & Scientific Research (MOHESR) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Study’s Novelty/Excerpt • This study presents comprehensive overview of the roles of various bacterial genera, including Alcaligens, Achromobacter, and Bacillus, in the biosorption of chromium from contaminated soils, highlighting specific factors influencing biosorption efficiency. • It uniquely addresses the optimization of environmental conditions such as pH, temperature, and nutrient availability to enhance large-scale biosorption processes, bridging gaps noted in previous literature regarding the scalability of bacterial biosorption. • Additionally, the manuscript underscores the necessity for further research in biotechnology and molecular engineering to fully harness the potential of bacterial biosorption for chromium remediation, presenting a forward-looking perspective on advancing this bioremediation strategy. Full Abstract Chromium possesses detrimental effects on the health of both plants and animals. Biosorption is a process where biological materials (bacteria, fungi, algae, or agricultural waste) are used to remove pollutants from contaminated sites. Conventional methods of remediating heavy metal-contaminated soils, such as excavation and chemical treatment, are expensive and disruptive, making them less desirable. Factors influencing bacterial biosorption efficiency are promising approaches involving bacteria to remove heavy metals such as Chromium, lead, nickel, cadmium, arsenic, etc., from contaminated soil. Some bacterial genera involved in biosorption include Alcaligens, Achromobacter, Acinetobacter, Alteromonas, Arthrobacter, Burkholderia, Bacillus, Enterobacter, Flavobacterium, and Pseudomonas. These bacteria can adsorb heavy metals such as Chromium and biotransform them into less toxic forms. Some factors influencing bacteria biosorption efficiency include pH, temperature, concentration, bacterial surface compositions, metal ion characteristics, and soil composition. Challenges associated with using bacteria for biosorption, as outlined in previous literature, include the slowness of the process and the fact that it may not be suitable for large-scale application, even though many other authors have proven its applicability on a large scale. Also, the key quality needed from the bacterial biosorbent must be tolerating the heavy metals. Another area of focus in current research is optimizing environmental conditions, such as temperature, pH, and nutrient availability, to achieve a more efficient biosorption at a larger scale. This overview highlighted the roles of bacteria in the biosorption of chromium heavy metal as a strategy for the bioremediation of Chromium contaminated soil. Conclusively, bacterial biosorption has a great potential for use in Chromium- contaminated soil remediation, and more research is needed to fully realize this potential, especially in biotechnology and molecular engineering.

The prolonged duration of phytoremediation poses a risk of heavy metal dispersal to the surrounding environment. This study investigated a combined remediation approach for cadmium (Cd)- and arsenic (As)-contaminated soil by integrating phytoremediation with stabilization techniques. Bidens pilosa was utilized as the phytoremediator, and steel slag, pyrolusite, and FeSO4 were employed as stabilizing agents in the pot experiments. Key metrics such as soil moisture content, root length, plant height, and heavy metal concentrations in Bidens pilosa were measured to evaluate the remediation efficacy. Additionally, the bioavailability, leaching toxicity, and chemical forms of Cd and As, along with other soil properties, were analyzed. The results indicated that the optimal restoration effect was achieved by combining steel slag, pyrolusite, and FeSO4 with stabilizers in a ratio of 2:1:10. Additionally, the optimal dosage of these materials was found to be 9% by weight. Mechanistic studies, including heavy metal speciation analysis, X-ray photoelectron spectroscopy (XPS), and microbial community diversity analysis, revealed that the stabilization effects were primarily due to the interactions of anionic and cationic ions, chelation by organic acids secreted by plant roots, and enhanced microbial activity. A cost–benefit analysis demonstrated the technical, economic, and commercial viability of the combined remediation approach. [ABSTRACT FROM AUTHOR]

The stabilization/solidification method can improve the engineering properties and reduce the environmental risks of heavy metal-contaminated expansive soil. However, the solidification effects deteriorate for soils experiencing wetting–drying (W–D) cycles. For this objective, the expansion/shrinkage, cracking, and leaching behaviors, as well as the corresponding internal relations, of lime-solidified lead-contaminated expansive soil were investigated. The results showed that during the W–D process, the volumetric strain increased, particularly along the radial direction. The cracks gradually developed and increased in length, width, and surface-crack ratio. Contaminant leaching and mobility increased, increasing environmental risk. In addition, a higher Pb(II) concentration in the solidified soil exhibited a more notable expansion potential release, crack development, and leaching capacity. X-ray diffraction and scanning electron microscopy results revealed the redistribution of soil particles and pores rather than chemical changes in mineral components during the deterioration process, and increasing the lead concentration accelerated the deterioration of W–D cycles. Finally, based on the grey correlation analysis, deterioration effects in leaching behaviors were controlled by expansion/shrinkage exponential release for solidified soil experiencing lower W–D cycles and higher Pb(II) concentrations, whereas leaching behaviors were controlled by crack behavior for solidified soil experiencing higher W–D cycles and lower Pb(II) concentrations. [ABSTRACT FROM AUTHOR]

In this study, we developed a high efficiency sample pretreatment technique using microwave-assisted acid digestion (MAD) under a mixture of HNO3-HCl-HF-H2O2 conditions, capable of leaching various radioactive nuclides from contaminated soil within 2 h. Our validation results using SRM 2709a soil standard material confirmed that when the MAD process was performed and then repeated, the chemical recovery rates of all 9 elements were consistently above 90%, demonstrating an outstanding leaching efficiency compared to conventional acid leaching (AL) methods. The activity of radionuclides obtained through AL were found to be underestimated compared to those obtained through MAD. We anticipate that the application of this technique for precise activity of radionuclides will contribute to cost savings in decommissioning waste management. [ABSTRACT FROM AUTHOR]

The increase in environmental pollution caused by inadequate anthropogenic practices is emerging as a global threat to human health and ecosystems. Addressing this issue is crucial, and bioremediation stands out as a sustainable solution for remediating contaminated soils. This study evaluates the feasibility of bioremediation to mitigate soil contamination by petroleum hydrocarbons using laying hen manure as a biostimulating agent, in the forms of manure stabilized by simple drying and compost from fresh manure. The specific objectives included analyzing the interaction between manure and contaminants, evaluating the influence of physicochemical and microbiological variables, comparing the efficiency of different manure proportions, and assessing contaminant reduction rates. Physicochemical and biological monitoring and statistical analysis were conducted. The results indicate that the treatment with stabilized manure significantly differed from the control sample, achieving up to 98% reduction in total petroleum hydrocarbons concentrations within 60 days and microorganism populations of around 107 CFU/mL. In contrast, the treatment with compost did not show significant differences from the control. Furthermore, while both treatments increased microbial populations, only the compost treatments maintained non-toxic conditions for soybean seed germination and root elongation, highlighting its potential for agricultural applications post-remediation. Stabilized poultry manure, though effective in total petroleum hydrocarbons degradation, resulted in soil toxicity due to high salinity and potassium levels, necessitating careful management. Its combined application with sawdust is recommended to improve soil structure and counteract compaction. These findings underscore the effectiveness of stabilized manure in accelerating bioremediation and the potential of compost to enhance soil health, suggesting tailored applications depending on specific remediation goals. [ABSTRACT FROM AUTHOR]

To enhance risk assessment for contaminated sites, incorporating bioavailability through bioaccessibility as a corrective factor to total concentration is essential to provide a more realistic estimate of exposure. While the main in vitro tests have been validated for As, Cd, and/or Pb, their potential for assessing the bioaccessibility of additional elements remains underexplored. In this study, the physicochemical parameters, pseudototal Cr and Ni concentrations, soil phase distribution, and oral bioaccessibility of twenty-seven soil samples were analysed using both the ISO 17924 standard and a simplified test based on hydrochloric acid. The results showed wide variability in terms of the concentrations (from 31 to 21,079 mg kg−1 for Cr, and from 26 to 11,663 mg kg−1 for Ni) and generally low bioaccessibility for Cr and Ni, with levels below 20% and 30%, respectively. Bioaccessibility variability was greater for anthropogenic soils, while geogenic enriched soils exhibited low bioaccessibility. The soil parameters had an influence on bioaccessibility, but the effects depended on the soils of interest. Sequential extractions provided the most comprehensive explanation for bioaccessibility. Cr and Ni were mostly associated with the residual fraction, indicating limited bioaccessibility. Ni was distributed in all phases, whereas Cr was absent from the most mobile phase, which may explain the lower bioaccessibility of Cr compared to that of Ni. The study showed promising results for the use of the simplified test to predict Cr and Ni bioaccessibility, and its importance for more accurate human exposure evaluation and effective soil management practices. [ABSTRACT FROM AUTHOR]

Bioremediation is a crucial strategy in combating environmental pollution, particularly in soil. The escalation of industrial and agricultural activities, coupled with the introduction of non-degradable and toxic pollutants, has exacerbated soil contamination. Heavy metals, such as lead and zinc, resistant to degradation over time, potentially accumulating in the food chain and posing persistent threats to both the environment and human health. Similarly, chemical compounds like herbicides and insecticides present challenges due to their prolonged stability and persistence. Although various chemical and physical methods exist for soil remediation, the biological approach gains more attention due to its sustainability and minimal impact on native ecosystems. Bioremediation leverages natural organisms to transform hazardous substances into less harmful forms. Microorganisms play a pivotal role in this process. Furthermore, plants can enhance bioremediation efficiency through symbiotic relationships with bacteria, accelerating the degradation of pollutants and accelerating soil productivity restoration. The use of native plants and microorganisms, especially in countries with high biodiversity such as Iran, is an important step towards the sustainable use of this technology. Native plants and microorganisms have the ability to make better use of environmental conditions and are most efficient with minimal environmental changes. Recent advancements in 'omics' technologies, such as genomics, proteomics, and metabolomics, have opened new avenues for the exploration and application of bioremediation techniques. These advance technologies enable molecular-level studies of organisms by generating big data to identify the most effective microorganisms for specific pollutants. Bioremediation can be applied in two primary ways: in situ or ex situ. In-situ bioremediation addresses contaminated soil directly on-site, whereas ex-situ bioremediation involves the removal of contaminated soil to another location for remediation. Each approach has its advantages and limitations, necessitating careful consideration prior to implementation. The integration of phytoremediation and microbial bioremediation methods can enhance efficiency and reduce costs, making the process economically viable. This study aims to serve as a comprehensive guide to understanding the diverse methodologies in bioremediation. Furthermore, it proposes sustainable and effective strategies to transform non-arable polluted lands into arable areas, offering environmental and economic benefits for future land reuse. Finally, what is ahead of bioremediation is turning bioremediation into a central tool in sustainable development. In addition, from the decomposition of industrial pollutants to the restoration of damaged natural environments, bioremediation can play an important role in providing a better and healthier life for future generations. This multifaceted and expandable approach can be one of the keys to success in sustainable environmental management in the 21st century. [ABSTRACT FROM AUTHOR]

Background and Objectives: Plant remediation with native plants is considered an emerging technology for the remediation of soils contaminated with organic substances and heavy metals due to its many advantages and cost-effectiveness. The present study aimed to determine the effectiveness of the plant remediation process in removing pyrene and cadmium from contaminated soils using Prosopis Cineraria from October 2021 to 2022 at Bushehr University of Medical Sciences. Materials and Methods: In this laboratory study, the role of each matrix of clay, animal manure, and anionic surfactant sodium dodecyl sulfate and non-ionic Tween 80 with the cultivation of Prosopis Cineraria tree were examined and analyzed separately and combined in the removal of pyrene and cadmium in concentrations of 50 to 200 mg/ Kg, in the period of one to three months. The samples were analyzed by gas chromatography and atomic absorption. The final data was analyzed using Excel software. Results: In the current study, the concentration of pyrene and cadmium in clay containing surfactant and animal manure decreased with time in the phytoremediation process with the help of the Prosopis Cineraria tree. By increasing the concentration of pyrene from 50 to 200 mg/kg, the maximum efficiency of pyrene removal was obtained between 85.43 and 57.55% and with the increase of cadmium concentration from 50 to 100 mg/kg, the maximum efficiency of cadmium removal was obtained between 83.68 and 67.80% at the end of the third month. Conclusion: The results of the present study showed that among the various enhancers, clay soils containing animal manure and surfactants significantly increase the remediation of soils contaminated with cadmium and pyrene by plant remediation. [ABSTRACT FROM AUTHOR]

Polycyclic aromatic hydrocarbon (PAH) contamination in soil poses a serious threat to ecological safety, human life, and health. Thermal desorption is commonly used to remediate PAH-contaminated soil. Current thermal desorption research primarily focuses on parameters for engineering designs through in-house simulations. In this study, based on a PAH-contaminated site thermal desorption remediation project, the removal efficiency of PAHs in soil (S1, S2) after disposal at different heating temperatures (400, 450, 500, 550 °C) and different residence times (20, 25 min) was investigated, and changes in soil properties before and after disposal were analyzed. The removal rate of 16 PAHs from soil at two concentrations reached 100% after 20 min at 500 °C and 550 °C, respectively. The three-phase structural distances of S1 and S2 soils, respectively, increased by 1.65 and 2.99 times after disposal, sand content increased by 3.20% and 8.27%, water-stable macroaggregates decreased by 8.14% and 2.06%, organic carbon content decreased by 7.27% and 27.05%, heavy fraction organic carbon increased by 33.68% and 5.12%, pH decreased from 10.00 and 10.35 to 8.81 and 8.69, and cation exchange decreased by 13.79% and 26.65%. Soil nutrient content such as TP, AP, TK, and AK increased after thermal desorption, and TN content decreased; approximately 1.0 mg/kg of NO3−-N remained. Our results are expected to support the design of programs for soil reuse after disposal. [ABSTRACT FROM AUTHOR]

Soil pollution by oil hydrocarbons is one of the most important kinds of pollution. In this study, clay soil from the CL class were contaminated with gasoil synthetically in 3, 6 and 9 percent by weight, and then the soil containing 6 percent of pollution reinforced with polypropylene fibers at amounts of 0.25, 0.5, 0.75 and 1 percent by weight. According to the results in all samples, Atterberg limits were reduced compared to the base soil. By increasing the percentage of contamination from 0 to 6 percent, the liquid limit and plastic index of the contaminated samples decreased. Moreover by increasing the amount of contamination to 9 percent, these values increased. Investigation of changes trend and amount of compaction characteristics (maximum dry density and optimum moisture) of samples also showed that with soil contamination, maximum dry density and optimum moisture content, had an upward and descending trend compared to the corresponding values in base soil, respectively. According to the results, the presence of contaminant in the soil was led to a decrease of consolidation coefficient, decrease of void ratio, increase of coefficient of volume compressibility and increase of permeability coefficient. The highest rate of decrease in consolidation coefficient (equivalent to 1.7 percent) and the highest increase in permeability coefficient (equivalent to 23.01 percent) was related to the contaminated sample reinforced with 0.75 percent by weight of fibers. [ABSTRACT FROM AUTHOR]

This study investigated the effect of pulverized rice straws (PRS, Oryza sativa) on the water retention capacity (WRC) of diesel-contaminated soils and the leaching of diesel-range organics (DROs). Diesel contamination at levels of 5, 10, and 15% reduced the WRC by ~ 6, 11, and 26%, respectively. However, adding PRS to 15% diesel-contaminated soils improved the WRC by ~ 18, 31, 53, and 75% for PRS concentrations of 1, 2.5, 5, and 10%, respectively. Furthermore, PRS concentrations of 2.5, 5, and 10% decreased the DROs leaching from 20% diesel-contaminated soil by 34, 75, and 100%, respectively. The findings of this study indicate that composting with PRS enhances WRC and significantly reduces contamination leaching in oil-contaminated soils. This suggests that PRS and similar green composts could optimize landfarming of organically contaminated soils, offering an innovative approach to repurposing waste plant biomass. [ABSTRACT FROM AUTHOR]

Purpose: In this study, a methodology is developed that involves geochemical and geophysical prospecting methods to identify the type and concentration of hydrocarbons, soil and water resistivity-salinity, and the delineation of hydrocarbon migration in the subsurface within an agricultural region in the northern part of the state of Veracruz, Mexico, where a landfill resulting from hydrocarbon exploitation is the contamination source. Materials and methods: The methodology involves hydrocarbon fractionation by packed open column liquid chromatography (SARA: Saturates, Aromatics, Resins, and Asphaltenes), textural analysis by sieving, Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy with Energy Dispersive X-ray Spectroscopy (SEM–EDX), salinity concentration, total petroleum hydrocarbon concentration in water (TPH), water resistivity, and salinity determination using a laboratory geo-electrical method and Electrical Resistivity Tomography (ERT). Results and discussions: The hydrocarbon exhibited a stable colloidal stability, and the soil composition is of the general type, classified as clay-sandy with high concentrations of iron and strong salinity. The water showed TPH concentrations, and the resistivity and salinity exceeded the permissible limits set by Mexican standards. Electrical Resistivity Tomography delineated both recent and mature contamination. Conclusions: With this methodology, it was determined that the region exhibits active contamination directly related to the exploration, exploitation, and pipeline leakage of hydrocarbons. The most affected area was the agricultural zone (low-lying area) due to the overflow of contaminated water from the landfill. [ABSTRACT FROM AUTHOR]

Human activities such as mining, industrial operations and waste management can lead to soil pollution by heavy metals including chromium, cadmium, mercury, lead and arsenic. These contaminants cause harm both to humans and the ecosystems where they are found. Of all the previously used techniques, phytoremediation is the most promising one for cleaning up heavy metal-contaminated soils. Phytoremediation refers to a technique where plants use roots for absorbing, storing and immobilizing soil contaminants while also removing them. Bioleaching is a method which uses microorganisms to dissolve metals that have been shown to facilitate phytoextraction in increasing the availability of metals. It is anticipated that research advancements and technological innovations will make it more efficient and appropriate. Root absorption is increased by bioleaching through modification of rhizosphere thus making it more bioavailable for plant uptake. Plant-bacterial interactions are proven to speed up the remediation rates. Both processes can help clear off pollutants from the soil environment. However, further research is needed to find and improve the best strains of microorganisms, assess long-term soil impacts and control massive influxes of bacteria. The combination of bioleaching and phytoextraction offers a reliable and efficient system for removing metals from polluted soils.

Cadmium (Cd)-contaminated soils may pose a significant threat on human health. They are often treated with quick lime (CaO) and reactive magnesia (MgO), but these treatments often result in low strength. Hence, in this study, partial and full carbonation are used to enhance the stabilization/solidification of CaO- and MgO-treated Cd-contaminated soils, aiming to achieve CO2 sequestration, strength improvement, and Cd immobilization. Performance of treated contaminated soils is evaluated through unconfined compressive strength (UCS), leaching, X-ray diffraction (XRD), and thermogravimetric analysis (TGA) tests. The results indicate that carbonation significantly enhances the UCS of both CaO- and MgO-treated Cd-contaminated soils. After carbonation, MgO-treated soils exhibit higher UCS than CaO-treated soils. Partial and full carbonation yield similar UCS in CaO-treated soils, while full carbonation results in higher UCS in MgO-treated soils. For CaO-treated soils, partial carbonation keeps Cd leachability below the 1 mg/kg limit, but full carbonation increases it beyond this limit. In contrast, fully carbonated MgO-treated soils maintain Cd leachability below the limit, though partial carbonation leads to higher leachability. Formation of Ca and Mg carbonates contributes to the strength improvement of soils. Cd(OH)2 and its complex, as well as CdCO3 exist in partially and fully carbonated soils, lowering leached Cd concentration. Overall, partial carbonation is better for CaO-treated soils, while full carbonation is preferable for MgO-treated soils.

The severity of soil molybdenum (Mo) pollution is increasing, and effective management of contaminated soil is essential for the sustainable development of soil. To investigate this, a pot experiment was carried out to assess the impact of different rates of humic acid (HA) and fulvic acid (FA) on the mobility of Mo in soil solution and its uptake by alfalfa, wheat and green bristlegrass. The concentration of Mo in Plants and soil was determined using an Atomic Absorption Spectrophotometer. The findings revealed that the application of HA led to an increase in Mo accumulation in the shoot and root of green bristlegrass and wheat, ranging from 10.56 % to 28.73 % and 62.15–115.79 % (shoot), and 17.52–46.53 % and 6.29-81.25 % (root), respectively. Nonetheless, the use of HA resulted in a slight inhibition of plant Mo uptake, leading to reduced Mo accumulation in alfalfa roots compared to the control treatment (from 3284.49 mg/kg to 2140.78–2813.54 mg/kg). On the other hand, the application of FA decreased Mo accumulation in the wheat shoot (from 909.92 mg/kg to 338.54–837.45 mg/kg). Furthermore, the bioavailability of green bristlegrass (with HA) and wheat (with FA) decreased, and the percentage of residual fraction of Mo increased (from 0.39 % to 0.78–0.96 %, from 3.95 % to 3.97∼ 4.34 %). This study aims to elucidate the ternary interaction among Mo, humic substances, and plants (alfalfa, wheat, and green bristlegrass), to enhance both the activation and hyperaccumulation of Mo simultaneously.

The current understanding of the legacy and emerging organic pollutants in the soil of Bangladesh remains limited. Inadequate disposal practices, particularly in e-waste, landfills, and industrial operations, may lead to the pervasive presence of persistent organic pollutants (POPs) and polycyclic aromatic hydrocarbons (PAHs) in the country. This study aimed to systematically investigate the concentrations, sources, and risk assessment of halogenated flame retardants (HFRs), polychlorinated biphenyls (PCBs), polychlorinated naphthalenes (PCNs), organochlorine pesticides (OCPs), chlorinated paraffins (CPs), and PAHs in the contaminated soil of Dhaka's dumpsites, e-waste, and industrial areas collected in 2017. The total concentration of investigated pollutants averaged at 4790 ± 4040 ng g−1 dw, with the following order: ∑44CPs (4110 ± 4140 ng g−1 dw) > ∑16PAHs (422 ± 491 ng g−1 dw) > ∑16HFRs (190 ± 538 ng g−1 dw) > ∑209PCBs (43.5 ± 73.5 ng g−1 dw) > ∑50PCNs (17.7 ± 21.0 ng g−1 dw) > ∑27OCPs (9.41 ± 9.61 ng g−1 dw). The e-waste site exhibited the highest total concentration of the target pollutants, reaching 12,700 ng g−1 dw. CPs were the predominant contributors, accounting for averages of 81.8%, 70.5%, and 68.5% to waste landfills, e-waste, and industrial sites, respectively. A comprehensive analysis of 209 PCB congeners revealed their primary origin from Aroclor PCBs, with minor contributions from unintentionally produced PCBs. The highest incremental lifetime carcinogenic risk (ILCR) occurred in e-waste sites, contributed by dioxin-like PCBs, with a maximum value of 5.9 × 10−5 for adults, exceeding the limit 1.0 × 10−6 set by the U.S. EPA. The non-carcinogenic hazard quotients (HQs) were much lower, suggesting no significant risk from the investigated pollutants. Our findings highlight the importance of proper waste management and regulated e-waste recycling to mitigate potential hazardous risks to the Bangladeshi population.

This study investigates the presence of Trichuris trichiura eggs in soil samples collected from urban areas in Lahore, Pakistan. A total of 3600 soil samples were collected over two years from Lahore’s urban regions. The detection of helminth eggs in these samples was performed using sodium hypochlorite (NaOCl) as a diagnostic technique. The study reveals an overall prevalence rate of T. trichiura at 0.97 % (35 out of 3600) in the contaminated soil samples from Lahore’s slum areas. When analyzing the data by geographical areas, the study found the highest prevalence of T. trichiura in Allama Iqbal Town (1.83 %, 11 out of 600), followed by Samanabad (1.16 %, 7 out of 600), Wapda Town (1.00 %, 6 out of 600), Gulberg (1.00 %, 6 out of 600), and Cantt (0.50 %, 3 out of 600). Conversely, Valencia Town had the lowest prevalence rate at 0.33 % (2 out of 600). However, these variations in prevalence rates were not statistically significant (p = 0.117). Prevalence rates of T. trichiura’s eggs varied significantly across different sampling seasons (p>0.001). In autumn, a total of 900 soil samples were collected, with 19 samples (2.11 %) testing positive for T. trichiura. This rate was notably higher compared to the prevalence rates observed in winter, spring, and summer, which were 0.66 %, 0.22 %, and 0.88 %, respectively. Regarding the sampling months, the study observed a significantly higher prevalence during September (3.33 %, 10 out of 300), followed by October (2.33 %, 7 out of 300), and August (1.33 %, 4 out of 300). Prevalence rates gradually decreased in other months, ranging from 1 % to 0.33 % (3 to 1 out of 300), with no parasite detection in March (0 %, 0 out of 300) (p < 0.001). This research underscores soil contamination due to fecal waste and highlights public unawareness of parasite biology, driven by open defecation practices.

The objective of this study is to develop a remediation technology for composited heavy metal-contaminated soil. Biochars (BC300, BC400, and BC500) derived from corn were combined with potassium dihydrogen phosphate (KH2PO4) to immobilize and remove heavy metal ions, including mercury (Hg2+), cadmium (Cd2+), and lead (Pb2+). The adsorption kinetics of metal ions in aqueous solutions with different concentrations was tested, and the fitting effects of the two models were compared. The findings demonstrate that the joint application of biochar and KH2PO4 could markedly enhance the immobilization efficacy of Pb2+, whereas the utilization of KH2PO4 on its own exhibited a more pronounced immobilization impact on Cd2+. Furthermore, the present study underscores the shortcomings of various remediation techniques that must be taken into account when addressing heavy metal-contaminated soils. It also emphasizes the value of comprehensive remediation techniques that integrate multiple remediation agents. This study offers a novel approach and methodology for addressing the intricate and evolving challenges posed by heavy metal contamination in soil. Its practical value and potential for application are significant. [ABSTRACT FROM AUTHOR]

Soil contamination with petroleum hydrocarbons has imposed drastic damages to plant, animal, and human life, leading to the development of various remediation technologies. However, the implementation of these methods is often difficult or requires a long time. In this study, the performance of synthetic (salts) and natural (sawdust, cow manure, and hen manure) sources of nitrogen:phosphorus:potassium (NPK) fertilizer was compared in the biostimulation of petroleum-contaminated soil, by measuring the total petroleum hydrocarbon (TPH) reduction after 28 days, via gas chromatography (GC). Four types of isolates with the potential for hydrocarbon degradation were identified and characterized based on morphological and biochemical tests. The results showed more efficiency of natural sources compared to synthetic sources, as a TPH reduction of 84.4, 81.9, and 79.7% was obtained by adding 4 wt.% of hen manure, cow manure, and sawdust, respectively. The analysis of variance (ANOVA) of the designed experiment for the synthetic sources showed the NPK of 1275:497:112 as the optimum ratio and the N and K as the most effective elements. The finding of this study can pave a way for proving the high efficiency of natural waste materials as a cost-effective and simple method, for bioremediation of petroleum hydrocarbon soils. [ABSTRACT FROM AUTHOR]

This study encompassed lab-scale thermal desorption experiments and pilot-scale demonstration of soil contaminated with polycyclic aromatic hydrocarbons (PAHs) during cement manufacturing. The lab-scale experiments aimed to investigate the impacts of thermal temperature and residence time on the PAHs removal efficiency, residual PAHs concentration and variation in composition profiles of PAHs. Results showed that at the temperature of 400 ℃ and the residence time of 30 min, the total removal efficiency of PAHs exceeded 99%, with each individual PAH compound exhibited a removal efficiency over 97%. The temperature of 600 ℃ and the residence time of 10 min was found to effectively detoxify PAHs-contaminated soil, satisfying the requirements outlined in the DB11/T 811-2011 standard. Increasing the thermal desorption temperature and residence time resulted in higher total removal efficiency of PAHs and lower residual concentrations. During the pilot-scale demonstration, disposal of PAHs-contaminated soil led to an increase in the concentration of alkali materials and a decrease in the concentrations of sulfur and chlorine. Although there was minor coating probability of coating, this had only a slight impact on operating conditions of cement kiln. The impact of PAHs-contaminated soil disposal on air pollutant emissions, compressive and flexural strengths, water demand for normal consistency and soundness may be deemed insignificant. Our research found that thermal desorption was a viable method for detoxification of PAHs-contaminated soil and the technical route employed in this study was effective. [ABSTRACT FROM AUTHOR]

The use of pesticides and the subsequent accumulation of residues in the soil has become a worldwide problem. Organochlorine (OC) pesticides have spread widely in the environment and caused contamination from past agricultural activities. This article reviews the bioremediation of pesticide compounds in soil using microbial enzymes, including the enzymatic degradation pathway and the recent development of enzyme-mediated bioremediation. Enzyme-mediated bioremediation is divided into phase I and phase II, where the former increases the solubility of pesticide compounds through oxidation–reduction and hydrolysis reactions, while the latter transforms toxic pollutants into less toxic or nontoxic products through conjugation reactions. The identified enzymes that can degrade OC insecticides include dehalogenases, phenol hydroxylase, and laccases. Recent developments to improve enzyme-mediated bioremediation include immobilization, encapsulation, and protein engineering, which ensure its stability, recyclability, handling and storage, and better control of the reaction. [ABSTRACT FROM AUTHOR]

In order to effectively repair and beautify the polluted soil and reduce the pollution of heavy metals, the cultivation of biological agents and two enrichment plants were combined to repair the lead soil. After 30 and 60 days of combined remediation with 400 mg / kg, the concentration of heavy metals in soil was decreased 19. 61% and 19. 48%, respectively. So the adsorption rate were increased by 16. 82% and 17. 83%, respectively. The activity of catalase was increased from 5. 6 mg / kg to 11. 4 mg / kg and 15. 9 mg / kg. The activity of alkaline phosphatase was increased from 45. 6 mg / kg to 88. 4 mg / kg and 93. 4 mg / kg, respectively. The activity of sucrase was increased from 4. 2 mg / kg to 9. 6 mg / kg and 9. 9 mg / kg, respectively. So the activity of urease was increased from 32. 6 mg / kg to 66. 3 mg / kg and 71. 2 mg / kg, respectively. The content of chlorophyll was increased 9. 16% and 9. 18%, respectively. The number of heavy metal resistant bacteria was decreased 21. 31% and 20. 27%, respectively. The number of bacteria, fungi and actinomycetes were increased by 97. 68%, 67. 63% and 210. 09%, respectively. The diversity and abundance of microbial community were increased 2. 7% and 2. 9%, respectively. The results showed that the photosynthesis of plants were enhanced. The adsorption and transport of heavy metals were accelerated. So were the enzyme activity, and the tolerance of plants to heavy metals were enhanced gradually. Meantime, the number of heavy metal-resistant bacteria were decreased apparently. And so on, the number of bacteria, fungi and actinomycetes were increased significantly. It was concluded that the plants and microbial agents could effectively promote the adsorption of plants to heavy metals and strengthen the repair effect, and which could provided scientific basis for the study of heavy metal pollution remediation. [ABSTRACT FROM AUTHOR]

Microorganisms are cost-effective and eco-friendly alternative methods for removing heavy metals (HM) from contaminated agricultural soils. Therefore, this study aims to identify and characterize HM-tolerant (HMT) plant growth-promoting rhizobacteria (PGPR) isolated from industry-contaminated soils to determine their impact as bioremediators on HM-stressed pepper plants. Four isolates [Pseudomonas azotoformans (Pa), Serratia rubidaea (Sr), Paenibacillus pabuli (Pp) and Bacillus velezensis (Bv)] were identified based on their remarkable levels of HM tolerance in vitro. Field studies were conducted to evaluate the growth promotion and tolerance to HM toxicity of pepper plants grown in HM-polluted soils. Plants exposed to HM stress showed improved growth, physio-biochemistry, and antioxidant defense system components when treated with any of the individual isolates, in contrast to the control group that did not receive PGPR. The combined treatment of the tested HMT PGPR was, however, relatively superior to other treatments. Compared to no or single PGPR treatment, the consortia (Pa+Sr+Pp+Bv) increased the photosynthetic pigment contents, relative water content, and membrane stability index but lowered the electrolyte leakage and contents of malondialdehyde and hydrogen peroxide by suppressing the (non) enzymatic antioxidants in plant tissues. In pepper, Cd, Cu, Pb, and Ni contents decreased by 88.0-88.5, 63.8-66.5, 66.2-67.0, and 90.2-90.9% in leaves, and 87.2-88.1, 69.4-70.0%, 80.0-81.3, and 92.3%% in fruits, respectively. Thus, these PGPR are highly effective at immobilizing HM and reducing translocation in planta. These findings indicate that the application of HMT PGPR could be a promising "bioremediation" strategy to enhance growth and productivity of crops cultivated in soils contaminated with HM for sustainable agricultural practices. [ABSTRACT FROM AUTHOR]

Herbicide-/dioxin-contaminated contamination in Vietnam is an environmental issue nowadays, despite Agent Orange being sprayed a long time ago. High levels of dioxin in military airbases cause hot spots of dioxin contamination sites in which potential biological source of microorganisms has developed. Understanding microorganism structure in contaminated soil is crucial for the bioremediation of the sites. Illumina Miseq platform was applied to sequence V3-V4 amplicons of long-term contaminated communities to evaluate the bacterial distribution. Contaminated soil from different regions Bien Hoa and Phu Cat showed a low level of connectedness; the species richness of Bien Hoa was much higher than that of Phu Cat. However, they shared similarities in the most abundant bacterial phyla: Actinobacteriota, Chloroflexi, Proteobacteria, Acidobacteriota, and Planctomycetota. Several xenobiotic-degrading genera were found, such as Terrabacter, Nocardioides, and Streptomyces of Actinobacteriota; Bacillus, Paenibacillus, and Clostridium of Firmicutes; Burkholderia, Sphingomonas, Pseudomonas and Klebsiella of Proteobacteria. Seven bacterial isolates grew on dioxin-containing medium belonging to Firmicutes, they were classified in order Bacillales, in which two strains belong to Paenibacillaceae, and the rests are in Bacillaceae. Two isolates removed more than 80% of total toxicity (mainly 2,3,7,8-Tetrachlorodibenzo-p-dioxin); strain PC5 is the first dioxin-degrading bacterium recognized in the genus Neobacillus. [ABSTRACT FROM AUTHOR]

To investigate the irradiation resistance of the microwave sintered contaminated soil samples, the samples were irradiated with 0.5 MeV He2+ ions. The property changes of the irradiated samples were investigated. After irradiation, the Vickers hardness values of the samples showed a relatively low degree of decrease, with a maximum reduction of 1.36%. The magnitude of NLCe of samples before and after irradiation was in the order of 1 × 10–5 g·m−2·d−1. This result will provide a useful reference for the treatment of the contaminated soil. [ABSTRACT FROM AUTHOR]

The in-lab incubation experiments were conducted to identify the passivation effect of corn vinasse biochar, which was prepared at different temperatures, on heavy metal Pb in paddy soil of the Pb-Zn mining area. The results showed that after 30 days of biochar amended to the soil, the soil pH and organic carbon content increased by 2.72%-8.47% and 27.79%- 65.26%, respectively. The CO32- and OH- contained in corn vinasse biochar could react with Pb and generate carbonate and hydroxide of Pb. In comparison with the treatment control, the bioavailable fractions of Pb were reduced by 26.6%, 23.30%, 26.95%, and 35.33%, respectively, in biochar-amended treatments. Exchangeable fractions of Pb decreased by 21.50%, 21.33%, 22.58%, and 22.58% for the treatment 3% (300°C), 6% (300°C), 3% (600°C), and 6% (300°C) corn vinasse biochar, respectively, compared with the treatment control. As a whole, corn vinasse biochar could effectively promote the transformation of Pb in soil from the exchangeable fractions into the Fe-Mn oxide-bound fractions and residue fractions, with a significant passivation effect for Pb in soil and more effective passivation by high-temperature preparation and increased dosage of biochar. [ABSTRACT FROM AUTHOR]