Oxidation of chromium(â ¢): A potential risk of using chemical oxidation processes for the remediation of 2-chlorophenol contaminated soils.

Chemical oxidation processes are widely used for the remediation of organically contaminated soils, but their potential impact on variable-valence and toxic metals such as chromium (Cr) is often overlooked. In this study, we investigated the risk of Cr(Ⅲ) oxidation in soils during the remediation of 2-chlorophenol (2-CP) contaminated soils using four different processes: Potassium permanganate (KMnO4), Modified Fenton (Fe2+/H2O2), Alkali-activated persulfate (S2O82-/OH-), and Fe2+-activated persulfate (S2O82-/Fe2+). Our results indicated that the KMnO4, Fe2+/H2O2, and S2O82-/Fe2+ processes progressively oxidized Cr(III) to Cr(Ⅵ) during the 2-CP degradation. The KMnO4 process likely involved direct electron transfer, while the Fe2+/H2O2 and S2O82-/Fe2+ processes primarily relied on HO• and/or SO4•- for the Cr(III) oxidation. Notably, after 4 h of 2-CP degradation, the Cr(VI) content in the KMnO4 process surpassed China's 3.0 mg kg-1 risk screening threshold for Class I construction sites, and further exceeded the 5.7 mg kg-1 limit for Class II construction sites after 8 h. Conversely, the S2O82-/OH- process exhibited negligible oxidation of Cr(III), maintaining a low oxidation ratio of 0.13%, as highly alkaline conditions induced Cr(III) precipitation, reducing its exposure to free radicals. Cr(III) oxidation ratio was directly proportional to oxidant dosage, whereas the Fe2+/H2O2 process showed a different trend, influenced by the concentration of reductants. This study provides insights into the selection and optimization of chemical oxidation processes for soil remediation, emphasizing the imperative for thorough risk evaluation of Cr(III) oxidation before their application.

Biochar with enhanced performance prepared based on "graphite-structure regulation" conjecture designed to effectively control water pollution.

In this work, corn straw was used as raw material, Hummers method and activation were used to adjust the graphite structure in biochar, and preparing straw based biochar (H-BCS) with ultra-high specific surface area (3441.80 m2/g), highly total pore volume (1.9859 cm3/g), and further enhanced physicochemical properties. Compared with untreated straw biochar (BCS), the specific surface area and total pore volume of H-BCS were increased by 47.24 % and 55.85 %, respectively. H-BCS showed good removal ability in subsequent experiments by using chloramphenicol (CP), hexavalent chromium (Cr6+), and crystal violet (CV) as adsorption models. In addition, the adsorption capacities of H-BCS (CP: 1396.30 mg/g, Cr6+: 218.40 mg/g, and CV: 1246.24 mg/g) are not only higher than most adsorbents, even after undergoing 5 cycles of regeneration, its adsorption capacity remains above 80 %, indicating significant potential for practical applications. In addition, we also speculated and analyzed the conjecture about the "graphite-structure regulation" during the preparation process, and finally discussed the possible mechanism during the adsorption processes. We hope this work could provide a new strategy to solve the restriction of biochar performance by further exploring the regulation of graphite structure in carbon materials.

Synchronizing positive effect of vitamin C and chromium on hyper lipidemia, hyperglycemia, liver enzymes and BMI of diabetes mellitus type 2 patients.

This study investigates the combined effect of vitamin C and chromium on BMI, lipid profile, LFTs and HbA1c of Diabetes Mellitus type 2 patients. This is randomized controlled trial study. For this study a total of 60 patients (n=28 female, n=32 male) Diabetes Mellitus type 2 patients were selected. They were divided into treatment group (vitamin C (500mg) Chromium (200µg) and control group (placebo) comprising thirty patients per group. Mean age in control group and treatment group is 33± 5.729 and 33±7.017 respectively. Statistical analysis showed significant results of lipid profile; total cholesterol (mg/dl) 198±66.1 P=0.008, High-Density Lipoprotein 38±7.5, P<0.001, Low Density Lipoprotein (LDL) (mg/dl) 105.1±22.4, P=0.002 and Triglycerides 191±64.3, P=0.02 are respectively. Levels of serum ALT (u/l) (34.7±9.1, P<0.001) and AST (u/l) (31.6 ±8.6, P<0.001) were significantly lower as compared to control group. HbA1c percentages were also normalized (5.45±0.2, P<.001) as compared to group 2. BMI values were also improved (P=0.01) after treatment. Combined supplementation of vitamin C and chromium reduce the plasma lipid percentage, blood glucose levels and also improve the ALT and AST functions.

Treatment of chromium-containing sludge using sintering and ironmaking combined technology: A risk-reducing strategy for environmental impact.

The efficient, safe and eco-friendly disposal of the chromium-containing sludge (CCS) has attracted an increasing concern. In this study, Co-processing of CCS was developed via employing sintering and ironmaking combined technology for its harmless disposal and resource utilization. Crystalline phase and valence state transformation of chromium (Cr), technical feasibility assessment, leaching risk, characteristics of sintered products, and pollutant release during CCS co-processing were investigated through a series of laboratory-scale sintering pot experiments and large scale industrial trials. The results showed that the content of Cr(VI) in sintered products first increased then decreased with increasing temperature ranges of 300 °C-800 °C, and reached a maximum of 2189.64 mg/kg at 500 °C. 99.99% of Cr(VI) can be reduced to Cr(III) at above 1000 °C, which was attributed to the transformation of the Cr(VI)-containing crystalline phases (such as, MgCrO4 and CaCrO4) to the (Mg, Fe2+)(Cr, Al, Fe3+)2O4. The industrial trial results showed that adding 0.5 wt‰ CCS to sintering feed did not have adverse effects on the properties of the sintered ore and the plant's operating stability. The tumbler index of sinter was above 78% and the leaching concentrations of TCr (0.069 mg/L) was significantly lower than the Chinese National Standard of 1.0 mg/L (GB5085.3-2007). The TCr contents of sintering dust and blast furnace gas (BFG) scrubbing water were less than 0.19 wt‰ and 0.11 mg/L, respectively, which was far below the regulatory limit (1.5 mg/L, GB13456-2012). The mass balance evaluation results indicated that at least 89.9% of the Cr in the CCS migrated into the molten iron in the blast furnace (BF), which became a useful supplement to the molten iron. This study provided a new perspective strategy for the safe disposal and resource utilization of CCS in iron and steel industry.

Mechanistic approach of tannery wastewater and sulfadiazine mutual toxicity in wheat (Triticum aestivum L.) and mitigation through exogenous application of gallic acid.

Excessive release of chromium (Cr) from the tanning industry and antibiotics from livestock caused severe hazards to humans. Gallic acid (GA 10 mM) alleviated alone/combined SDZ 30 mg kg-1 and TWW 40, 60, and 100% stress in wheat. GA (10 mM) decreased the TSP 12 and 13%, TFAA 8 and 10%, TSS 14 and 16%, RS 18 and 16%, and NRS 11 and 9% in shoots and grains under SDZ + TWW (30 mg kg-1+100%), compared without foliar. GA (10 mM) declined the MDA 20 and 31, EL 13 and 36%, H2O2 17 and 15%, O2•- 10 and 11% in leaves and roots, under combined SDZ + TWW (30 mg kg-1+100%), compared without foliar. GA (10 mM) improved the POD 106 and 30%, SOD 145 and 31%, CAT 78, and 35%, APX 100 and 25% in leaves and roots under combined SDZ + TWW (30 mg kg-1+100%), compared without foliar application. Considerably GA (10 mM) reduced total Cr 18, CrIII 20, and CrVI 50% in roots and shoots 19, 41, and 48%, and grains 15, 27, and 29% respectively, under combined SDZ + TWW (30 mg kg-1+100%) stress, compared without foliar. Overall, GA boosted the wheat growth, physiology, and defence system by inhibiting the combined SDZ + Cr toxicity.

Effect of erbium, chromium-doped: yttrium, scandium, gallium, and garnet laser-assisted periodontal therapy using radial firing tip during early healing period: a randomized controlled split-mouth clinical trial.

BACKGROUND: This study aimed to demonstrate the efficacy of erbium, chromium-doped:yttrium, scandium, gallium, and garnet (Er,Cr:YSGG) laser-assisted nonsurgical periodontal therapy in periodontitis patients during 8 weeks of healing. METHODS: A split-mouth, single-blinded, randomized controlled clinical trial was conducted on 12 patients diagnosed with stage III/IV periodontitis and had a minimum of two teeth with probing pocket depth (PPD) > 5 mm in at least two quadrants. Upon randomization, each quadrant was assigned for conventional scaling and root planing (SRP) procedure or laser-assisted therapy (SRP + laser) using radial firing tip (RFPT 5, Biolase). Clinical measurements and gingival crevicular fluid collection were performed for statistical analysis. RESULTS: In the initial statistical analysis on the whole subject teeth, modified gingival index (MGI) reduction was greater in test group at 1(P = 0.0153), 4 (P = 0.0318), and 8 weeks (P = 0.0047) compared to the control in the same period. PPD reduction at 4 weeks in test group was -1.67 ± 0.59 showing significant difference compared to the control (-1.37 ± 0.63, P = 0.0253). When teeth with mean PPD ≥5 mm were sorted, MGI decrease was significantly greater in test group at 1 (P=0.003) and 8 week (P=0.0102) follow-ups. PPD reduction was also significantly greater in test group at 4 week period (-1.98 ± 0.55 vs -1.58 ± 0.56, test vs control, P=0.0224). CONCLUSIONS: Er,Cr:YSGG-assisted periodontal therapy is beneficial in MGI and PPD reductions during early healing period.

Chromium nanoparticles improve bone turnover regulation in rats fed a high-fat, low-fibre diet.

The aim of the study was to investigate the effect of returning to a balanced diet combined with chromium picolinate (CrPic) or chromium nanoparticles (CrNPs) supplementation at a pharmacologically relevant dose of 0.3 mg/kg body weight on the expression level of selected genes and bone turnover markers in the blood and bones of rats fed an obese diet. The results of the study showed that chronic intake of a high-fat obesogenic diet negatively affects bone turnover by impairing processes of both synthesis and degradation of bones. The switch to a healthy diet proved insufficient to regulate bone metabolism disorders induced by an obesogenic diet, even when it was supplemented with chromium, irrespective of its form. Supplementation with CrPic with no change in diet stimulated bone metabolism only at the molecular level, towards increased osteoclastogenesis (bone resorption). In contrast, CrNPs added to the high-fat diet effectively regulated bone turnover by increasing both osteoblastogenesis and osteoclastogenesis, with these changes directed more towards bone formation. The results of the study suggest that unfavourable changes in bone metabolism induced by chronic intake of a high-fat diet can be mitigated by supplementation with CrNPs, whereas a change in eating habits fails to achieve a similar effect.

Preparation of a Novel Oat ß-Glucan-Chromium(III) Complex and Its Hypoglycemic Effect and Mechanism.

This study synthesized a novel oat ß-glucan (OBG)-Cr(III) complex (OBG-Cr(III)) and explored its structure, inhibitory effects on α-amylase and α-glucosidase, and hypoglycemic activities and mechanism in vitro using an insulin-resistant HepG2 (IR-HepG2) cell model. The Cr(III) content in the complex was found to be 10.87%. The molecular weight of OBG-Cr(III) was determined to be 7.736 × 104 Da with chromium ions binding to the hydroxyl groups of OBG. This binding resulted in the increased asymmetry and altered spatial conformation of the complex along with significant changes in morphology and crystallinity. Our findings demonstrated that OBG-Cr(III) exhibited inhibitory effects on α-amylase and α-glucosidase. Furthermore, OBG-Cr(III) enhanced the insulin sensitivity of IR-HepG2 cells, promoting glucose uptake and metabolism more efficiently than OBG alone. The underlying mechanism of its hypoglycemic effect involved the modulation of the c-Cbl/PI3K/AKT/GLUT4 signaling pathway, as revealed by Western blot analysis. This research not only broadened the applications of OBG but also positioned OBG-Cr(III) as a promising Cr(III) supplement with enhanced hypoglycemic benefits.

Enhanced biodegradation of phenol under Cr(VI) stress by microbial collaboration and potential application of machine learning for phenol biodegradation.

Cr(VI) and phenol commonly coexist in wastewater, posing a great threat to the environment and human health. However, it is still a challenge for microorganisms to degrade phenol under high Cr(VI) stress. In this study, the phenol-degrading strain Bacillus cereus ZWB3 was co-cultured with the Cr(VI)-reducing strain Bacillus licheniformis MZ-1 to enhance phenol biodegradation under Cr(Ⅵ) stress. Compared with phenol-degrading strain ZWB3, which has weak tolerance to Cr(Ⅵ), and Cr(Ⅵ)-reducing strain MZ-1, which has no phenol-degrading ability, the co-culture of two strains could significantly increase the degraded rate and capacity of phenol. In addition, the co-cultured strains exhibited phenol degradation ability over a wide pH range (7-10). The reduced content of intracellular proteins and polysaccharides produced by the co-cultured strains contributed to the enhancement of phenol degradation and Cr(Ⅵ) tolerance. The determination coefficients R2, RMSE, and MAPE showed that the BP-ANN model could predict the degradation of phenol under various conditions, which saved time and economic cost. The metabolic pathway of microbial degradation of phenol was deduced by metabolic analysis. This study provides a valuable strategy for wastewater treatment containing Cr(Ⅵ) and phenol.

Biomass hydrothermal carbonization solution-assisted synthesis of intercalation-expanded core-shell structured molybdenum disulfide for efficient adsorption of Cr (VI) in electroplating wastewater treatment.

Cr (VI) is a common heavy metal pollutant in electroplating wastewater. This study introduces the liquid-phase product from the hydrothermal reaction of coffee grounds (CGHCL) into the synthesis process of molybdenum disulfide, assisting in the fabrication of an intercalated, expanded core-shell structured molybdenum disulfide adsorbent (C-MoS2), designed for the adsorption and reduction of Cr (VI) from electroplating wastewater. The addition of CGHCL significantly enhances the adsorption performance of MoS2. Furthermore, C-MoS2 exhibits exceedingly high removal efficiency and excellent regenerative capability for Cr (VI)-containing electroplating wastewater. The core-shell structure effectively minimizes molybdenum leaching to the greatest extent, while the oleophobic interface is unaffected by oily substances in water, and the expanded interlayer structure ensures the long-term stability of C-MoS2 in air (90 days). This study provides a viable pathway for the resource utilization of biomass and the application of molybdenum disulfide-based materials in wastewater treatment.

The association between the urinary chromium and blood pressure: a population-based study.

BACKGROUND AND AIM: The impact of trace elements and heavy metals on human health has attracted widespread attention. However, the correlation between urinary chromium concentrations and blood pressure remains unclear and inadequately reported, and the aim of this study was to investigate the relationship between urinary chromium concentrations and blood pressure in adults in the United States (US). METHODS: We utilized data from the National Health and Nutrition Examination Survey (NHANES) 2017-2018 for this study. Multivariate logistic regression and multivariate linear regression were used to explore the association of urinary chromium concentrations with hypertension and blood pressure. Additionally, we also performed subgroup analysis and restricted cubic splines (RCS). RESULTS: A total of 2958 participants were enrolled in this study. The overall mean systolic blood pressure and diastolic blood pressure were 123.98 ± 0.60, 72.66 ± 0.57 mmHg, respectively. The prevalence of hypertension was found in 41.31% of the whole participants. In the fully adjusted model, we did not observe a correlation between urinary chromium concentrations and the risk of hypertension and systolic blood pressure. However, we found a negative association between urinary chromium concentrations and diastolic blood pressure. In subgroup analysis, we observed a positive association between urinary chromium and the risk of hypertension among participants older than 60 years of age and those who were Non-Hispanic Black. The interaction term highlighted the influence of age and race on this positive association. We also found a negative association of urinary chromium with diastolic blood pressure in male, participants who were current smokers, overweight, and other races, as well as those without alcohol use and anti-hypertensive drug use. However, the interaction term only revealed the influence of alcohol consumption on the negative association. CONCLUSION: Our study suggested that urinary chromium concentrations may show a negative association with diastolic blood pressure and this association was significantly dependent on alcohol consumption. Besides, a positive association between urinary chromium and the risk of hypertension was also found among participants older than 60 years of age and those who were Non-Hispanic Black.

Coprecipitation of Fe/Cr Hydroxides at Organic-Water Interfaces: Functional Group Richness and (De)protonation Control Amounts and Compositions of Coprecipitates.

Iron/chromium hydroxide coprecipitation controls the fate and transport of toxic chromium (Cr) in many natural and engineered systems. Organic coatings on soil and engineered surfaces are ubiquitous; however, mechanistic controls of these organic coatings over Fe/Cr hydroxide coprecipitation are poorly understood. Here, Fe/Cr hydroxide coprecipitation was conducted on model organic coatings of humic acid (HA), sodium alginate (SA), and bovine serum albumin (BSA). The organics bonded with SiO2 through ligand exchange with carboxyl (-COOH), and the adsorbed amounts and pKa values of -COOH controlled surface charges of coatings. The adsorbed organic films also had different complexation capacities with Fe/Cr ions and Fe/Cr hydroxide particles, resulting in significant differences in both the amount (on HA > SA(-COOH) ≫ BSA(-NH2)) and composition (Cr/Fe molar ratio: on BSA(-NH2) ≫ HA > SA(-COOH)) of heterogeneous precipitates. Negatively charged -COOH attracted more Fe ions and oligomers of hydrolyzed Fe/Cr species and subsequently promoted heterogeneous precipitation of Fe/Cr hydroxide nanoparticles. Organic coatings containing -NH2 were positively charged at acidic pH because of the high pKa value of the functional group, limiting cation adsorption and formation of coprecipitates. Meanwhile, the higher local pH near the -NH2 coatings promoted the formation of Cr(OH)3. This study advances fundamental understanding of heterogeneous Fe/Cr hydroxide coprecipitation on organics, which is essential for successful Cr remediation and removal in both natural and engineered settings, as well as the synthesis of Cr-doped iron (oxy)hydroxides for material applications.

Concentrations of Bioelements (Zn, Cu, Fe, Cr, Mg, Mn) in Serum and Bone Tissue of Aging Men Undergoing Hip Arthroplasty: Implications for Erectile Dysfunction.

Background: Erectile dysfunction (ED) stands out as one of the most prevalent sexual disorders in men, with its incidence progressively escalating with age. As delineated by the International Consultation Committee for Sexual Medicine on Definitions/Epidemiology/Risk Factors for Sexual Dysfunction, the prevalence of ED among men under 40 years is estimated to be within the range of 1-10%. The aim of this study was to determine the relationship between the concentration of bioelements (Zn, Cu, Fe, Cr, Mg, and Mn) in the serum and bone tissue and the concentration of selected hormones in men with and without erectile dysfunction. Materials and methods: The retrospective cohort study included 152 men who underwent total hip arthroplasty for hip osteoarthritis at the Department of Orthopaedic Traumatology and Musculoskeletal Oncology at the Pomeranian Medical University in Szczecin. Certain exclusion criteria were applied to ensure the integrity of the study. These included individuals with diabetes, a history of cancer, alcohol abuse, liver or kidney failure, New York Heart Association (NYHA) class III or IV heart failure, and those taking medications that affect bone metabolism, such as mineral supplements, neuroleptics, chemotherapeutic agents, immunosuppressants, corticosteroids, or antidepressants. Patients with hypogonadism or infertility were excluded from the study. Results: The study showed an association between bioT concentrations and Cu concentrations in both patients with and without erectile dysfunction. A correlation between bioactive testosterone and Cr concentrations was also observed in both groups. Patients with erectile dysfunction showed a relationship between bioT concentration and Zn concentration, TT concentration and Mn concentration, FT concentration and Zn concentration, and E2 concentration and Cr concentration. An analysis of elemental concentrations in bone tissue showed an association between FT and Mg and Mn concentrations, but only in patients with erectile dysfunction. In patients without erectile dysfunction, a correlation was observed between FT and Cu concentrations. A correlation was also observed between bioT concentrations and Mg, Mn, and Zn concentrations, but only in patients with erectile dysfunction. In patients without erectile dysfunction, a correlation was observed between bioT and Cu concentrations. Conclusions: Studying the relationship between the concentration of bioelements (Zn, Cu, Fe, Cr, Mg, and Mn) in the serum and bone tissue and the concentration of selected hormones in men may be important in explaining the etiology of the problem. The study of the concentration of Zn and Cu in bone tissue and serum showed that these two elements, regardless of the place of accumulation, may be related to the concentration of androgens in men.

Arthrospira platensis enriched with Cr(III), Mg(II), and Mn(II) ions improves insulin sensitivity and reduces systemic inflammation in equine metabolic affected horses.

Equine metabolic syndrome (EMS) is a critical endocrine condition in horses, characterized by hyperinsulinemia, hyperlipidemia, and insulin resistance, posing a significant threat to their health. This study investigates the efficacy of supplementing EMS-affected horses with Arthrospira platensis enriched with Cr(III), Mg(II), and Mn(II) ions using biosorption process in improving insulin sensitivity and glucose tolerance, reducing inflammation, and mitigating obesity-related fat accumulation. Our results demonstrate that Arthrospira supplementation reduces baseline insulin and glucose levels, contributing to decreased adipose tissue inflammation. Furthermore, Arthrospira supplementation results in a decrease in body weight and improvements in overall body condition scores and cresty neck scores. Additionally, administration of Arthrospira leads to reduced levels of triglycerides and aspartate aminotransferase, indicating a decrease in hepatic adiposity and inflammation. These findings suggest that Arthrospira, enriched with essential micro- and macroelements, can be an advanced feed additive to enhance insulin sensitivity, promote weight reduction, and alleviate inflammatory processes, thereby improving the overall condition of horses affected by EMS. The use of Arthrospira as a feed additive has the potential to complement conventional management strategies for EMS.

Metagenomes from microbial populations beneath a chromium waste tip give insight into the mechanism of Cr (VI) reduction.

Dumped Chromium Ore Processing Residue (COPR) at legacy sites poses a threat to health through leaching of toxic Cr(VI) into groundwater. Previous work implicates microbial activity in reducing Cr(VI) to less mobile and toxic Cr(III), but the mechanism has not been explored. To address this question a combined metagenomic and geochemical study was undertaken. Soil samples from below the COPR waste were used to establish anaerobic microcosms which were challenged with Cr(VI), with or without acetate as an electron donor, and incubated for 70 days. Cr was rapidly reduced in both systems, which also reduced nitrate, nitrite then sulfate, but this sequence was accelerated in the acetate amended microcosms. 16S rRNA gene sequencing revealed that the original soil sample was diverse but both microcosm systems became less diverse by the end of the experiment. A high proportion of 16S rRNA gene reads and metagenome-assembled genomes (MAGs) with high completeness could not be taxonomically classified, highlighting the distinctiveness of these alkaline Cr impacted systems. Examination of the coding capacity revealed widespread capability for metal tolerance and Fe uptake and storage, and both populations possessed metabolic capability to degrade a wide range of organic molecules. The relative abundance of genes for fatty acid degradation was 4× higher in the unamended compared to the acetate amended system, whereas the capacity for dissimilatory sulfate metabolism was 3× higher in the acetate amended system. We demonstrate that naturally occurring in situ bacterial populations have the metabolic capability to couple acetate oxidation to sequential reduction of electron acceptors which can reduce Cr(VI) to less mobile and toxic Cr(III), and that microbially produced sulfide may be important in reductive precipitation of chromate. This capability could be harnessed to create a Cr(VI) trap-zone beneath COPR tips without the need to disturb the waste.

Sustainable leather tanning: Enhanced properties and pollution reduction through crude protease enzyme treatment.

In this study, proteolytic bacteria, particularly Pseudomonas aeruginosa strain SM4 (OQ349573), were isolated from tannery solid waste dumping yard soil and employed to produce extracellular protease enzymes. The bacteria exhibited optimal growth after 30 h of incubation at 37 °C and pH 7. Under conditions of 55 °C, pH 8, and a substrate concentration of 2 %, the crude enzyme displayed its highest activity at 105 UmL-1. Notably, the produced crude enzyme showed no discernible inhibitory effects on detergents, metal salts, or organic solvents. Application of the crude protease at concentrations of 3 % and 2 % in chrome tanning of goatskins (GS) and cowhides (CH), respectively, yielded significant reductions of 35 % and 30 % in chromium and other post-tanning chemicals compared to conventional processes. Despite the 30 to 35 % reduction in tanning and post-tanning chemicals, the uptake of chrome and associated chemicals by crust leather was higher than observed in conventional processes. Chromium content analysis of the effluent revealed an 81 % reduction during piloting in real industrial operations, accompanied by reductions of about 46 % in BOD and COD pollution loads. The finished leather obtained from the enzymatic process exhibited superior mechanical properties, including higher tensile strengths (210 and 195 kg cm-2), stitch tear (92 and 165 kg cm-1), grain crack load (28 and 32 kg), and distension (73 and 62 mm) for GS and CH, respectively, surpassing or closely aligning with standard values and those obtained in conventional processes.

Chromiomics: Chromium detoxification and approaches for engineering tolerance in plants.

Chromium (Cr) is a heavy metal that poses a grave threat to the ecosystem including plants. Chromium is very harmful to plants due to its effects on many physiological and metabolic pathways culminating in a negative impact on plant's growth, development, and ability to take up nutrients. Plants have developed physiological, biochemical, and molecular ways of defense against Cr, such as by augmenting antioxidant potential to reduce reactive oxygen species (ROS). A number of genes have been discovered to play a significant role in the defense mechanisms of plants against Cr, for example, genes associated with the activation of phytochelatins, metallothioneins, and those of enzymes like glutathione-S-transferases. Along with this, a few miRNAs have been found to be associated in alleviating Cr stress and, to augment plant tolerance by controlling transcription factors, HSPs, and the expression of a few proteins and hormones. Defense pathway genes and miRNAs have been used for the generation of transgenic phytoremediator plants. Not only do the transgenic plants have a higher tolerance to Cr, but they also act as hyperaccumulators for Cr and have the potential to remediate other heavy metals. This article describes about environmental Cr contamination, Cr effects on plants, different genes and miRNAs involved in Cr stress mitigation and use of candidate genes, microRNAs for creating transgenic plant systems for phytoremediation, and the applications of CRISPR technology. It is expected that the integration of omics approach and advanced genomics will offer scope for more effective phytoremediation of Chromium in the coming years.

Crucial roles of soil inherent Fe-bearing minerals in enhanced Cr(VI) reduction by biochar: The electronegativity neutralization and electron transfer mediation.

Biochar has been used for soil Cr(VI) remediation in the last decade due to its enriched redox functional groups and good electrochemical properties. However, the role of soil inherent Fe-bearing minerals during the reduction of Cr(VI) has been largely overlooked. In this study, biochar with different electron-donating capacities (EDCs) was produced at 400 °C (BC400) and 700 °C (BC700), and their performance for Cr(VI) reduction in soils with varied properties (e.g., Fe content) was investigated. The addition of BC400 caused around 14.2-36.0 mg g-1 Cr(VI) reduction after two weeks of incubation in red soil, paddy soil, loess soil, and fluvo-aquic soil, while a less Cr(VI) was reduced by BC700 (2.57-16.7 mg g-1) with smaller EDCs. The Cr(VI) reduction by both biochars in different soils was closely related to Fe content (R2 = 0.93-0.98), so red soil with the richest Fe (14.8% > 1.79-3.49%) showed the best reduction capability, and the removal of soil free Fe oxides (e.g., hematite) resulted in 71.9% decrease of Cr(VI) reduction by BC400. On one hand, Fe-bearing minerals could increase the soil acidity, neutralize the surface negative charge of biochar, enhance the contact between Cr(VI) and biochar, and thus facilitate the direct Cr(VI) reduction by biochar in soils. On the other hand, Fe-bearing minerals could also facilitate the indirect Cr(VI) reduction by mediating the electron from biochar to Cr(VI) with the cyclic transformation of Fe(II)/Fe(III). This study demonstrates the key role of soil Fe-bearing minerals in Cr(VI) reduction by biochar, which advances our understanding on the biochar-based remediation mechanism of Cr(VI)-contaminated soils.

Synergistic impact of bioavailable PHEs and alkalinity on microbial diversity and traits in agricultural soil adjacent to chromium-asbestos mines.

Soil microbial communities undergo constant fluctuations, particularly in response to environmental factors. Although the deposition of toxic mine waste is recognized for introducing potentially hazardous elements (PHEs) into the soil, its specific impacts on microbial communities remain unclear. This study aims to explore the combined effects of soil alkalinity and bioavailable PHEs on microbial diversity and traits in agricultural soil adjacent to a chromium-asbestos mining area. By employing a comprehensive analysis, this study indicated that microbiological attributes were reduced in contaminated areas (zone 1), whereas both the levels of bioavailable PHEs (CrWs: 31.08 mg/kg, NiWs: 13.90 mg/kg) and alkalinity indices (CROSS, MCAR, MH) were significantly higher. The spatial distribution of soil alkalinity and bioavailable PHEs, primarily originating from chromium-asbestos mines, has been determined. This study also elucidates the negative relationship between soil stressors (Alkalinity and PHEs) and microbial activities (soil enzymatic activity, microbial respiration, and biomass carbon). The vector's length exhibited a notable difference between zone 1 (0.51) and zone 2 (0.32), indicating a substantial limitation on carbon (C). Also, the investigation of soil bacterial diversity unveiled notable disparities in the prevalence of microbial populations inside zone 1. Proteobacteria constituted 57.18% of the total population indicating a noteworthy prevalence in the contaminated soils. Finally, the random forest (RF) algorithm from machine learning was selected and proven to be a robust choice in Taylor diagrams for predicting the causative stressors responsible for the deterioration of soil microbial health. Therefore, this research offers insights into the health and resilience of soil microbial communities under synergistic stress conditions, which will aid environmentalists in planning future interventions and improving sustainable farming techniques.

Heavy metal association with chronic kidney disease of unknown cause in central India-results from a case-control study.

BACKGROUND: Chronic Kidney Disease of unknown cause (CKDu) a disease of exclusion, and remains unexplained in various parts of the world, including India. Previous studies have reported mixed findings about the role of heavy metals or agrochemicals in CKDu. These studies compared CKDu with healthy controls but lacked subjects with CKD as controls. The purpose of this study was to test the hypothesis whether heavy metals, i.e. Arsenic (As), Cadmium (Cd), Lead (Pb), and Chromium (Cr) are associated with CKDu, in central India. METHODS: The study was conducted in a case-control manner at a tertiary care hospital. CKDu cases (n = 60) were compared with CKD (n = 62) and healthy subjects (n = 54). Blood and urine levels of As, Cd, Pb, and Cr were measured by Inductively Coupled Plasma- Optical Emission Spectrometry. Pesticide use, painkillers, smoking, and alcohol addiction were also evaluated. The median blood and urine metal levels were compared among the groups by the Kruskal-Wallis rank sum test. RESULTS: CKDu had significantly higher pesticide and surface water usage as a source of drinking water. Blood As levels (median, IQR) were significantly higher in CKDu 91.97 (1.3-132.7) µg/L compared to CKD 4.5 (0.0-58.8) µg/L and healthy subjects 39.01 (4.8-67.4) µg/L (p < 0.001) On multinominal regression age and sex adjusted blood As was independently associated with CKDu[ OR 1.013 (95%CI 1.003-1.024) P < .05].Blood and urinary Cd, Pb, and Cr were higher in CKD compared to CKDu (p > .05). Urinary Cd, Pb and Cr were undetectable in healthy subjects and were significantly higher in CKDu and CKD compared to healthy subjects (P = < 0.001). There was a significant correlation of Cd, Pb and Cr in blood and urine with each other in CKDu and CKD subjects as compared to healthy subjects. Surface water use also associated with CKDu [OR 3.178 (95%CI 1.029-9.818) p < .05). CONCLUSION: The study showed an independent association of age and sex adjusted blood As with CKDu in this Indian cohort. Subjects with renal dysfunction (CKDu and CKD) were found to have significantly higher metal burden of Pb, Cd, As, and Cr as compared to healthy controls. CKDu subjects had significantly higher pesticide and surface water usage, which may be the source of differential As exposure in these subjects.