An innovative technique for extracting phosphorus and synthesizing high-purity vivianite from incinerated sewage sludge ash was explored in this investigation, which experienced three principal stages, including leaching with sulfuric acid, purification via resin adsorption, and crystallization through iron electrocoagulation. The optimal conditions for acid leaching of phosphate (PO₄^3-)from incinerated sewage sludge ash were examined by the response surface methodology, and the optimal operational parameters for the iron electrocoagulation process were determined by the Box-Behnken Design. The results indicate that phosphorus extraction efficiency of 92.80% was achieved at a liquid-to-solid ratio of 37.60mL/g, a sulfuric acid concentration of 0.125mol/L, and an acid leaching duration of 90.0min, the metal cations interfering with phosphate precipitation, such as Ca²⁺, Mg²⁺, Al³⁺, and Fe^2+/3+ were efficiently removed by 732cation exchange resin, all phosphorus was removed from the solution successfully during the iron electrocoagulation process at an initial solution pH value of 2.00, a current of 2.00A, and a reaction time of 30.0min, meanwhile, vivianite with a purity of 97.37% were synthesized. The outcomes show that the three-step method facilitates phosphorus recovery from incinerated sewage sludge ash. 61.44% of the phosphorus was retrieved as high-purity vivianite through the three steps; the recovery process costs 14.66yuan per kilogram product of vivianite and yields a profit of 30.68yuan.

This study examined the vertical distribution of herbicide residues in 14 typical dryland soil profiles (0~100cm) from the black soil region of Northeast China. Residues from 57 different herbicides were measured across various soil depths to clarify their vertical distribution characteristics and influencing factors. The findings revealed that herbicide residue characteristics were primarily influenced by the application strategies under different land uses. Notably, nicosulfuron, a commonly used herbicide in cornfields, exhibited significantly higher residue levels in the 0~60cm soil layer compared to other herbicides. A negative correlation was observed between the herbicide's octanol-water partition coefficient (logK_ow) and its distribution ratio in the surface soil (0~20cm)(P<0.001), while a positive correlation was found between the herbicide's degradation period and its distribution ratio in the deep soil(80~100cm) (P<0.05). Additionally, soil pH was negatively correlated with herbicide residues in surface soils (P<0.05), and soil bulk density was negatively correlated with herbicide residues in deep soils (P<0.05). Summer rainfall was found to enhance the vertical migration of herbicides within the soil profile. These results provide crucial data and a scientific foundation for the mitigating, risk control and management of herbicide residues in the agricultural soils of China's black soil region.

This study collected 616 toxicological data of 8 elements on 5 species and 3 microbial processes in 31 Chinese soils through literature collection, attempting to construct a new model for predicting the toxicity of limited elements in soil data—the Quantitative ion characteristic activity relationship (s-QICAR) model. Firstly, based on the normalization method of soil properties, the toxicity values (logEC₁₀; 1.42~3.35) of 8 elements to 5 species and 3 microbial processes were obtained under three soil scenarios of acidic, neutral, and alkaline. On this basis, the relationship between the 23 structural characteristic parameters of elements and their corresponding biological toxicity values was analyzed, and 24s-QICAR models (R²=0.70~0.98; P=0.001~0.023) were established using the covalent radius (CR) of elements. Furthermore, s-QICAR was used to predict the logEC₁₀ (1.44~3.20) of V, As, Se, and Sn for 8species. Combined with the species sensitivity distribution curve, the HC₅values of these four elements protecting 95% of organisms under three scenarios were calculated. After correction, the predicted no-effect concentrations of the four elements in acidic, neutral, and alkaline soil scenarios were V: 13, 16, 17mg/kg; As: 10, 13, 15mg/kg; Se: 4.9, 7.2, 8.4mg/kg; Sn: 42, 44, 45mg/kg, and the ecological risk threshold map for these 4elements was drawn. This study establishes a new method applicable to the ecological risk of soil elements in China, providing scientific basis for soil environmental risk assessment and management.

Microplastics exhibited unique properties and possessed a wide distribution across various environments. The confluence served as a key point for the contamination of microplastics. At present, there was a lack of effective methods to reveal the motion characteristics and accumulation areas of microplastics at the confluence. The motion and fate of microplastics should be accurately captured at the confluence. The three-dimensional hydrodynamic-microplastic transport model for microplastics was established at the confluence. The transport mechanism and fate of microplastics were investigated under varying junction angles and flow ratios through the coupled CFD-DEM method. The results showed that (1) The low velocity zones, including the flow separation, flow stagnation, and downstream of the flow separation, would evolve into regions of microplastic accumulation. (2) Microplastics were primarily influenced by the vortex located in the flow separation, entering the vortex zone from the right bank of the mainstream and gradually forming an elliptical enrichment region. (3) The concentrations of microplastics in the center of the flow separation were positively correlated with the junction angles. (4) There was a linear negative correlation between the concentrations of microplastics and the flow ratios in the center of the flow separation, R²=0.9007. The number of microplastics in the flow separation exhibited a significant negative correlation with the flow ratio at the confluence. The findings of the study would advance the fundamental understanding of microplastic motion in confluences and establish a theoretical framework for precise prevention and control strategies against microplastic pollution.

To have explored the mechanism of the impact of MPs on the nitrogen metabolism function of water bodies, the study had conducted indoor simulation experiments from the perspective of microorganisms. Specifically, it had experimentally tested the impact of traditional polyethylene (PE) microplastics and biodegradable polylactic acid (PLA) microplastics at various concentrations (0, 1, 5, and 10mg/L) on total nitrogen (TN), ammonium (NH₄⁺-N), nitrite (NO₂^--N), and nitrate (NO₃^--N) levels. Furthermore, it had analyzed the effects on nitrogen-metabolizing microbial communities and their functional genes. The results had shown that both PE and PLA microplastics had contribute to nitrogen accumulation in water. PE microplastics increased TN concentrations by 53.77% to 94.76%, while PLA microplastics had caused an increase of 24.04% to 48.74% compared to the control. The impact on different nitrogen forms had varied according to the type and concentration of microplastics. Notably, PE microplastics had been negatively correlated with nitrogen-fixing bacteria, such as Cyanobacteria, whereas PLA microplastics had exhibited a positive correlation with bacteria involved in inorganic nitrogen processes, such as Actinobacteria. It had further shown that both PE and PLA microplastics had significantly affected genes responsible for nitrogen fixation, nitrate reduction, and denitrification. This research had highlightsed the complex effects of microplastics on nitrogen cycling in aquatic systems, with the same particle size but different types and concentrations of MPs leading to varied outcomes on microbial community structure and nitrogen metabolism functions.

This study investigated the susceptibility of karst groundwater from surface pollution. A typical karst spring system (the Chaoshuidong in Yichang, Hubei Province of China) was selected to analyze the contamination characteristics, sources, and transport processes of organochlorine pesticides (OCPs). Water, soil, and sediment samples were collected in four seasons for OCP analysis. The results showed that the average concentrations of OCPs in surface water, spring water, soil and sediment samples from Chaoshuidong system were 8.25ng/L, 5.11ng/L, 15.9ng/g and 12.6ng/g, respectively. OCPs concentrations in the Chaoshuidong system were relatively lower than in other regions, with seasonal fluctuations closely correlated to hydrogeological conditions and OCPs transport dynamics. Composition analysis of hexachlorocyclohexanes (HCHs) and dichlorodiphenyltrichloroethanes (DDTs)indicated that HCHs were primarily from agricultural inputs of Lindane(γ-HCH) in the water and sediments, while the technical HCH dominated in the soils. DDTs were mainly a mixture of inputs from technical DDT and dicofol pesticide in all three media. The contribution of OCPs from the soils in the recharge area to the upstream surface water and to the spring water was 87.8% and 58.3%, respectively, and the contribution of OCPs from the spring water in the discharge area to the spring sediments was 64.2%. This study demonstrated that OCPs can be rapidly transported from recharge area to discharge area through two primary pathways: surface transport and underground transport, subsequently contaminating water bodies.

The degradation efficiency of various emerging pollutants by potassium ferrate (Fe(VI)) catalysed through magnetic biochar (MC) prepared using hydrothermal-calcination method was investigated. The reactive species in M-BC/Fe(VI) system and the effects of the dosage of M-BC, Fe(VI), pH value and natural organic matters on the degradation efficiency of sulfamethoxazole(SMX) were studied. The results indicated that the removal of SMX by alone M-BC (50mg/L) and Fe(VI) (50µmol/L) were 3.5% and 54.1% during 20min, respectively, while the M-BC/Fe(VI) system achieved an SMX degradation rate of 89.6%. Experiments with probe compounds and inhibitors confirmed that the primary reactive species in the system were intermediate valence iron(Fe(V)/Fe(IV)). Fourier-transform infrared spectroscopy analysis revealed that the main active sites on M-BC were surface phenolic hydroxyl groups. Under pH conditions of 8, increasing the dosages of Fe(VI) and M-BC enhanced the removal of SMX by the M-BC/Fe(VI) system. Compared to the alone Fe(VI) system, the degradation of SMX in the M-BC/Fe(VI) system was increased by 114%, 63.6%, 300%, and 350% at pH 7, 8, 9, and 10, respectively. Low concentrations of natural organic matter (1mg/L) promoted the degradation of SMX by the M-BC/Fe(VI) system, but high concentrations of natural organic matter (5~10mg/L) competed with SMX for Fe(VI) and Fe(V)/Fe(IV) , leading to a decrease in the degradation efficiency of SMX. Additionally, the M-BC/Fe(VI) system achieved SMX degradation of 100% and 83.7% in spring and Yellow River water, highlighting its potential for practical application in water treatment process.

A composite photocatalyst of bismuth oxybromide with oxygen vacancies covered by biochar (BC/OV-BiOBr, BOVB)was developed by hydrothermal method. Its photocatalytic performance was investigated with tetracycline (TC) as the target pollutant, and the catalytic effect was verified by dye pollutants. The results showed that 99.8% of tetracycline (TC) and 100% Rhodamine B(RhB) could be decomposed within 60min or 40min under visible light, of which degradation rates were 8.92 times and 9.82 times that of pure BiOBr, respectively. The degradation process of pollutants had strong resistance to pH change and low concentration co-existing ions. The results of phase characterization and photoelectrochemical performance test showed that the morphology was changed from flake to flower and the concentration of oxygen vacancies was increased after adding biochar, which were beneficial to improve the photoresponse and accelerate the charge transfer. Due to the synergistic effect between biochar and oxygen vacancies in driving the free radical chain reaction, the concentration of superoxide free radical (·O₂^-) in the system was increased, which was further transformed it into hydroxyl free radical (·OH), providing abundant strong oxidizing active species for pollutant degradation. In addition, good cyclic stability was certified by 5consecutive degradation experiments.

To evaluate the association and combined effects of perfluoroalkyl and polyfluoroalkyl substances (PFAS) and mixtures on hyperuricemia (HUA) and identify key components, this study analyzed data from 2,564 subjects in the National Health and Nutrition Examination Survey (NHANES) from 2013 to 2016 using logistic regression, weighted quantile sum regression, and Bayesian kernel machine regression. Higher levels of perfluorononanoic acid (PFNA), n-perfluorooctane sulfonic acid (n-PFOA), and perfluoromethylheptane sulfonic acid isomers (Sm-PFOS) were positively associated with HUA when PFAS was exposed as a single source (P<0.05). When considered as mixture exposure, PFAS mixtures were positively associated with HUA overall, with a 39.6% increase in the risk of HUA for each quartile increase in PFAS mixtures (WQS index) (OR=1.396,95%CI: 1.180~1.651, P<0.001), and this association was only observed in the female population. n-PFOA and Sm-PFOS were identified as key components, while linear perfluorooctane sulfonic acid (n-PFOS) and perfluorohexane sulfonic acid (PFHxS) may be negatively associated with HUA in the mixture. Potential interactions between various PFAS were also observed. The research findings can provide the latest epidemiological evidence for the study of the association between PFAS exposure and the risk of hyperuricemia, offering a basis for screening key populations.

Pollen allergy is a global health problem which also has attracted much attention in China, and the incidence is increasing in the northern area. The data of daily airborne pollen concentration, meteorological conditions, vegetation growth and allergic patient were analyzed from 2017 to 2022 in Hohhot of Inner Mongolia Autonomous Region. There were two peaks of pollen dissemination every year. The first peak was in early April, which was a greater proportion of woody plant pollen, with a short duration. The second peak was from August to September, mainly composed of herbaceous plants pollen such as Artemisia of Compositae pollen, with a long duration and had much more serious sensitization effect. The results showed that the effective accumulated temperature of ≥5℃ from January to June was significantly negatively correlated with the start date of the peak pollen dispersal period, while the cumulative precipitation and cumulative sunshine hours from the early stage to the flowering period were significantly positively correlated with the end date of the peak pollen dispersal period. The higher the accumulated temperature was, the earlier the peak period of pollen dispersal started. The end date of peak period would be delayed by the large amount of precipitation and light hours, meanwhile the number of pollen dispersal would increase. There were statistically significant or significant positive correlation between the cumulative value of each meteorological factor or the vegetation index and the monthly average pollen concentration. Appropriate light hours and precipitation, the vegetation would grown well, which would promote pollen dispersal and stimulate an increase in concentration. The number of Allergic Rhinitis patients was consistent with the variation of pollen concentration, and was reaching a peak in August. When the pollen concentration exceeds 100 grains/1000mm², there was a lag period of 0~4days in the peak of AR treatment, among which the most obvious incremental effect was after 2 days. The number of patients was exponentially related to the pollen concentration in a ten-day time range. The above results would provide some practical reference for pollen concentration meteorological forecasting services and the prevention and treatment of AR caused by pollen allergy.