A novel iron-based phosphate cement (IPC), derived from iron-rich smelting slag (ISS), was developed as a sustainable and efficient binder for the stabilization/solidification of trivalent chromium (Cr3+). The mechanical properties, hydration behavior, microstructure, leaching toxicity, chromium chemical forms, and environmental safety of chromium-stabilized iron phosphate cement (CIPC) were thoroughly evaluated. The results showed that, with a mass ratio of ISS to ammonium dihydrogen phosphate (ADP) of 2.0, and even with the addition of 20 % chromium nitrate nonahydrate (CN), the compressive strength of CIPC reached 4.2 MPa after curing for 28 d. Furthermore, chromium leaching was well below 1 mg/L, significantly lower than the GB 5085.3-2007 standard limit of 15 mg/L, demonstrating the effective encapsulation of Cr3+ due to IPC's high early strength. In the IPC system, Cr3+ was primarily stabilized by forming CrPO4 and CrxFe1-x(OH)3 co-precipitates, which were further solidified through the physical encapsulation of IPC hydration products, such as (NH4)2Fe(PO3OH)2 center dot 4H2O, (NH4) (Mg,Ca)PO4 center dot H2O, and FePO4. This process resulted in a solidification efficiency of up to 99 %. BCR analysis confirmed that more than 98 % of the chromium in the CIPC remained in a stable residual form. Finally, the ecological risk index (PERT) was found to be 23.52, far below the safety threshold of 150, indicating the solidified material's long-term environmental safety. This study provides an innovative approach for the reutilization of ISS while effectively stabilizing/solidifying chromium.

To reveal the engineering properties of Zn-contaminated soil solidified with a new cementitious material, namely phosphate rock powder-MgO-cement (PMC), several series of solidified soil characterization tests including moisture content, dry density, pH value, unconfined compressive strength, and stress-strain curve were conducted. The traditional Portland cement was selected for a comparison purpose. The effects of curing time and Zn2 + concentration on these property indexes were investigated to explore the inhibition mechanism of heavy metal Zn2+ on the stabilization process. In addition, the correlations of unconfined compressive strength with three physical property indexes were analyzed. The results indicated that the PMC stabilizer was far superior to the cement for stabilizing Zn-contaminated soil in terms of mechanical properties and environmental impacts. The normalized moisture content of PMC stabilized soil was greater than the cement stabilized soil, indicating a more complete hydration reaction. A small amount of Zn2+ can promote the hydration reaction, but when the Zn2+ concentration exceeded 0.5 %, the hydration reaction was significantly hindered. The dry density of PMC stabilized soil was about 6 % more than cement stabilized soil under the same conditions. The pH values of PMC stabilized samples were much lower than the cement stabilized soil samples and distributed in 8.0-9.5. The stress-strain characteristic of PMC stabilized soil was softening type and the heavy metal Zn2+ was solidified by adsorption, which could make the stress-strain curve of cement stabilized sample change from brittle type to ductile type.

In this essay, by summarizing the research progress and achievements of various scholars at home and abroad in recent years on the material properties and corrosion resistance of magnesium phosphate cement (MPC), we review the factors influencing on the properties of MPC, and analyze the effects of raw materials, retarders, and admixtures on the properties of MPC. Two different hydration mechanisms of MPC are discussed, and finally the research progress of MPC in the field of anti-corrosion coatings for steel and ordinary concrete (OPC) is highlighted, and suggestions and prospects are given.

Eutrophication and ecosystem damage result from phosphate pollution. Competing ions make extracting trace phosphate under 2.0 mg/L from treated wastewater difficult. However, if the phosphate could be sustainably recovered or reused in agriculture, considerable savings in fertilizer could be made. On the other hand, agricultural waste, which is a menace, contains a significant amount of cellulose that finds interesting applications as a biodegradable material. This study synthesized a cellulose-based adsorbent with iron hydroxide nanoparticles from nano-fibrillated cellulose (CNF) from agricultural waste and carboxymethyl cellulose (CMC). It selectively removed phosphate from secondary treated wastewater. Fe(OH)3@CNF/CMC (FCC) removed 3 mg/g phosphate. The hydrogel-like material quickly absorbed 40 g/g of water and slowly released it for a week when dry. Soil burial test indicates microorganisms biodegraded 80 % of the hydrogel in 3 months. After these findings, we delivered plant nutrients using the phosphate-rich exhausted FCC adsorbent. Results showed that phosphate-rich FCC improved seed germination and plant growth. Phosphate-loaded FCC adsorbent promoted better plant growth than single super-phosphate and control samples. This study creates a circular economy-based slowrelease fertilizer from agricultural waste and secondary-treated wastewater. This approach uses the 3 R rule-recycle, recover, and reuse-to benefit society ecologically and economically.

Pesticide contamination has become a major environmental concern with organophosphates such as chlorpyrifos emerging as major pollutants posing significant risks to both ecosystems and human health. Chlorpyrifos is widely used in agriculture to control pests, however due to its persistence, its accumulation in soils can lead to long-term environmental damage. The objective of this study was to isolate and characterize chlorpyrifos-degrading bacteria from a tobacco field exposed to intensive pesticide use in T & uuml;rkiye. To achieve this, a selective enrichment strategy was employed to promote the growth of chlorpyrifos-degrading microorganisms. Two distinct experimental setups were established to target both normally growing and slower-growing bacteria: the first involved a 4-week incubation with weekly subculturing as described in the literature, while the second applied an 8-week incubation with biweekly subculturing. At the end of the enrichment period, bacterial loads were compared between the two groups. Four of the nine bacterial isolates were obtained from the newly tested long-term setup. Among all isolates, members of the genus Pseudomonas exhibited the best adaptation to the prolonged enrichment conditions. Additionally, isolates belonging to the genera Klebsiella, Sphingobacterium, and Peribacillus were isolated from the normally growing group. Two isolates (AB4 & AB15), identified as Sphingobacterium thalpophilum, were determined to be novel chlorpyrifos degraders. This is the first reported study from T & uuml;rkiye focusing on the biodegradation of chlorpyrifos by native soil bacteria. The findings revealed that various ecological areas, constitute potential sources for new microbial metabolic processes and these bacterial strains can be used in bioremediation studies.

Organophosphate pesticides, widely used in agriculture, are effective in pest control but pose environmental and health risks through soil, water, and air contamination. Exposure to these chemicals is linked to adverse human health effects, underscoring the need for environmentally sustainable practices. This study aimed to assess urinary organophosphate metabolites and examine the relationship between GSTM1 and GSTT1 gene polymorphisms with biomarkers of oxidative stress among farmers in Himachal Pradesh exposed to pesticides. We collected urine samples (50 mL) from the exposed group to detect organophosphate metabolites using GC-MS. Blood samples (5 mL) were also obtained for GSTM1 and GSTT1 genotyping and assessment of antioxidant enzyme activities. The results showed decreased enzymatic activity of SOD (2.92 +/- 1.07) and catalase (12.60 +/- 3.15) in the exposed group, with increased MDA levels (4.14 +/- 1.36), compared with the unexposed group (SOD: 7.04 +/- 1.34, catalase: 25.75 +/- 2.20, MDA: 1.15 +/- 0.18). No significant associations (p > .05) were found between GSTM1 or GSTT1 genotypes and SOD, catalase, or MDA activities. The study concluded that prolonged pesticide exposure induces oxidative stress linked to specific genetic variations, suggesting directions for further research into the toxicogenetics of pesticide exposure and its health implications.

Magnesium phosphate cement (MPC), renowned for its rapid hardening, low water demand, low-temperature hydration capability, and excellent wear resistance, is an ideal construction material for the extreme lunar environment, characterized by high vacuum, low gravity, and severe temperature fluctuations. In this study, by-product B-MgO from lithium extraction in salt lakes was utilized to develop four types of phosphate cement systems: ammonium magnesium phosphate cement (MAPC), sodium magnesium phosphate cement (MSPC), calcium magnesium phosphate cement (MCPC), and potassium magnesium phosphate cement (MKPC). Through a comparative analysis of the physical and mechanical properties of these systems at varying calcination temperatures of MgO, MKPC was identified as the most suitable for lunar construction. Further investigations examined the influence of the water-to-binder ratio (W/B) and the mass ratio of raw materials (M/P) on MKPC performance, alongside a detailed analysis of its phase composition and microstructure. The results revealed that the optimal MKPC performance is achieved at an MgO calcination temperature of 1000 degrees C, an M/P ratio of 1:1 to 2:1, and a W/B ratio of 0.2 to 0.25. Additionally, MKPC was employed as a cementitious material to produce MKPC-simulated lunar regolith concrete with regolith contents of 30 %, 53 %, and 70 %. The fabricated concrete met the required mechanical properties and 3D printability standards under lunar environmental conditions. Even at high regolith content, the concrete maintained satisfactory mechanical performance. These findings provide an efficient and reliable material solution for lunar infrastructure construction. (c) 2024 Published by Elsevier B.V. on behalf of COSPAR.

To minimize environmental damage, conserve global diminishing fertilizer reserves, all while maximizing food production, it is essential that farmers apply phosphate fertilizers at the optimal rate. The purpose of this study is to assess grower attitudes and behavior, with respect to proper application of phosphorus, and to investigate how certain exogenous factors might influence such applications. Data were analyzed from a survey conducted in North Carolina, USA, with 122 farmer participants. The findings reveal that annual phosphorus applications consistently exceed recommendations, which indicates overapplication, leading to economic inefficiency and environmental concerns. Overapplication is neither due to knowledge gaps in nutrient concentrations in the soil nor the lack of interest in soil sampling, as 99% of farmers submit soil tests as frequently or more frequently than every two years. Only 36% of growers indicated that they would not apply phosphorus if their soil report indicated that levels were sufficient, and that none was required. Additionally, overapplication is not strongly influenced by price effects, as only nine percent of growers abandoned applications in 2021, following a dramatic spike doubling fertilizer prices. The adoption of reduced phosphate fertilization will depend on strong local trusted technical assistance and continued extension education.

Cadmium (Cd) is a toxic, non-essential heavy metal, with significant stress to plants such as soybean (Glycine max). High Cd concentration in the soil inhibits various stages of soybean growth, including seed germination, vegetative growth, and the reproduction stage. Phosphate, a vital macronutrient, has been shown to alleviate Cd-induced stress; however, the molecular mechanisms remain poorly understood. This study aimed to explore the interactive effects of Cd and phosphate on soybeans at the physiological, transcriptomic, and metabolic levels using a multi-omics approach. Experiments were conducted where soybean plants were treated with different concentrations of Cd and phosphate. The results indicated that Cd stress significantly reduced plant height, photosynthetic rate, and transpiration rate, while phosphorus application mitigated these effects, reducing Cd absorption in both roots and shoots. Furthermore, antioxidant enzyme activities (superoxide dismutase, catalase, and peroxidase) were significantly enhanced by phosphate under Cd stress, which scavenged reactive oxygen species (ROS) generated by cadmium, thereby protecting cells from oxidative stress damage. Transcriptome and metabolome analyses revealed substantial changes in gene expression and metabolite profiles in response to Cd and phosphate treatments. Notably, phosphorus treatment induced the up-regulation of genes involved in stress response, root development, and metal transport, while altering metabolic pathways related to phenolic acids, flavonoids, and lipids. This research provided new insights into the molecular mechanism by which phosphorus enhanced the activity of antioxidant enzymes, thereby improving the plant's antioxidant defense capacity and reducing the toxic effects of cadmium in soybeans, offering potential strategies for enhancing crop resilience against heavy metal contamination.

Phosphorus and potassium are essential macronutrients, and potassium dihydrogen phosphate, a compound containing both, plays a vital role in plant growth and reproduction. However, its rapid leaching poses significant environmental concerns, lessening its practical utility. To overcome this issue, a biodegradable hydrogel based on amla was synthesized through graft polymerization and evaluated as a water-retaining material for agricultural applications, specifically for the controlled release of fertilizers. The synthesized hydrogel was characterized using FTIR, SEM, XRD, and TGA. Its swelling properties, water retention capacity, porosity, and density were also examined. The biodegradable nature of the synthesized hydrogel was confirmed via soil burial and composting techniques, with FTIR used to validate the degradation. The hydrogel degraded almost entirely within 64 days in compost soil and 72 days in burial soil. Finally, potassium dihydrogen phosphate release studies were conducted, and the data were analyzed using Fick's law of diffusion and various kinetic models (zero order, first order, Higuchi, and Korsemers Peppas). The release pattern was measured via UV spectrophotometry over 45,000 min, demonstrating controlled nutrient delivery. These findings suggested that the synthesized hydrogel matrix has strong potential as an effective water retention system and for regulated nutrient release.