Spatiotemporal variations in soil pollution by polycyclic aromatic hydrocarbons over a 20-year economic boom in different districts of a heavy industrial city in North China.

Urbanization-related human activities, such as population aggregation, rapid industrial expansion, and intensified traffic, are key factors that impact local polycyclic aromatic hydrocarbon emissions and their associated health risks. Consequently, regions with varying degrees of urbanization within a megacity may exhibit diverse spatiotemporal patterns in the presence and distribution of soil polycyclic aromatic hydrocarbons, resulting in different levels of ecological risks for local inhabitants following the same period of development. In this study, we measured the concentrations of 16 polycyclic aromatic hydrocarbons in soil samples collected from industrial district and rural district in Tianjin (China) in 2018, and compared with polycyclic aromatic hydrocarbon data in 2001 from a previous study to characterize these regional variations in occurrence, source, and human risk of polycyclic aromatic hydrocarbons induced by urbanization with time and space. The results indicate the 20-year rapid urbanization and industrialization has differentially affected the composition, distribution and sources of polycyclic aromatic hydrocarbons in soils from different economic functional zones in Tianjin. Additionally, its impact on health risks in rural district appeared to be more significant than that in industrial district.

Prediction of the bioaccessibility and accumulation of cadmium in the soil-rice-human system based on optimized DGT and BCR coupled models.

Cadmium, as a typical heavy metal, has the potential to induce soil pollution and threaten human health through the soil-plant-human pathway. The conventional evaluation method based on the total content in soil cannot accurately represent the content migrated from the food chain to plants and the human body. Previous studies focused on the process of plant enrichment of heavy metals in soil, and very few studies directly predicted human exposure or risk through the labile state of Cd in soil. Hence, a relatively accurate and convenient prediction model of Cd release and translocation in the soil-rice-human system was developed. This model utilizes available Cd and soil parameters to predict the bioavailability of Cd in soil, as well as the in vitro bioaccessibility of Cd in cooked rice. The bioavailability of Cd was determined by the Diffusive Gradients in Thin-films technology and BCR sequential extraction procedure, offering in-situ quantification, which presents a significant advantage over traditional monitoring methods and aligns closely with the actual uptake of heavy metals by plants. The experimental results show that the prediction model based on the concentration of heavy metal forms measured by BCR sequential extraction procedure and diffusive gradients in thin-films technique can accurately predict the Cd uptake in rice grains, gastric and gastrointestinal phase (R2=0.712, 0.600 and 0.629). This model accurately predicts Cd bioavailability and bioaccessibility across the soil-rice-human pathway, informing actual human Cd intake, offering scientific support for developing more effective risk assessment methods.

Copper-zinc nanoparticle-decorated nitrogen-doped carbon composite for electrochemical determination of triclosan.

A new sensor based on copper-zinc bimetal embedded and nitrogen-doped carbon-based composites (CuZn@NC) was prepared for triclosan (TCS) detection by pyrolyzing the precursor of Cu-Zn binuclear metal-organic framework (MOF). The performance for detecting TCS was evaluated using linear scanning voltammetry (LSV) and differential pulse voltammetry (DPV), and the proton and electron numbers during TCS oxidation have been proved to be one-to-one. The results indicated that CuZn@NC can present a satisfactory analysis performance for TCS detection. Under the optimized conditions, the linear response range was 0.2-600 µM and the detection limit was 47.9 nM. The sensor presented good stability (signal current dropped only 2.5% after 21 days) and good anti-interference of inorganic salts and small molecular organic acids. The good recovery (97.5-104.1%) for detecting spiked TCS in commercial products (toothpaste and hand sanitizer) suggested its potential for routine determination of TCS in real samples.

Microbial nitrogen transformation regulates pathogenic virulence in soil environment.

Soil nitrogen addition induces the generation and proliferation of some bacterial virulence, yet the interactive mechanisms between the two remain unclear. Here we investigated the variation of virulence genes (VGs) abundance during soil nitrogen transformation, and explored the biological mechanism and key pathways involved in the regulation of VGs by nitrogen transformation. The results showed that the diversity and abundance of virulence genes in soil under high nitrogen input (100 mg/kg) were markedly higher than those under low nitrogen input (50 mg/kg), suggesting a trade-off between the prevalence of virulence genes and nitrogen metabolism. Nutritional/metabolic factor, regulation, immune modulation and motility were the dominant virulence types. Linear regression analysis showed that soil nitrogen mineralization and nitrification rate were closely correlated with the abundance of virulence genes, mainly involving adherence, nutritional/metabolic factors and immune modulation (p < 0.05). Structural equations indicated that microbial community succession associated with nitrogen transformation largely contributed to the changes in VGs abundance. Metagenomic analysis revealed that major virulence genes pilE, pchB, and galE were regulated by nitrogen-functional genes gdh, ureC, and amoC, implying that microbial nitrogen transformation influences immune modulation, nutritional/metabolic factors, and adherence-like virulence. The meta-transcriptome reiterated their co-regulation, and the key pathway may be glutamate/urea> α-ketoglutarate/ammonia > pyruvate/amino acid. The outcome provides strong evidence on the linkage between microbial nitrogen transformation and pathogenic virulence factors development in the soil environment, which will aid in the effective suppression of the prevalence of soil pathogenic virulence.

Spatial Distribution and Bio-accumulation of Cadmium and Lead in Soil, Rice and Vegetables in Typical Pollution Areas, China.

The adverse effects of Cd and Pb on human health have been widely reported. While, there were several typical pollution areas in China which has not been investigated comprehensively and deeply. In this study, 475 soil and 472 plant samples from these pollution areas were analyzed for Cd and Pb with ICP-MS. Here, the pollution levels of different areas were analyzed and compared; the spatial distributions in soil, rice and cabbage samples were illustrated in map; and the relationships of Cd and Pb in soil and rice, soil and cabbage were also discussed. The results showed that Cd pollution still existed in some south, central-south and south-east zones except other three zones located in suburb of Tianjin, north-east and north China which might be explained by the higher background values, soil acidity, Karst landscape and metallurgy industry. Comparatively, the Pb concentrations showed lower over-standard rate. Moreover, the spatial distribution of Cd and Pb in rice and cabbage showed similar trends with those of soil samples. Particularly, the average Cd and Pb concentrations in lettuces were much higher than those in other plants. Cd and Pb concentrations in rice and cabbage showed low linear dependence with the concentrations in soil. The results in this study added basic environmental data and would be helpful to future soil remediation of these areas.

From aggregation-induced to solution emission: a new strategy for designing ratiometric fluorescent probes and its application for in vivo HClO detection.

In this paper, we introduced a new strategy for converting aggregation-induced emission (AIE) to fluorescence emission in solution into the rational design of new fluorescent probes. Two fluorescent probes based on this strategy, namely, PDAM-Lyso and PDAM-Me, have been synthesized and tested both in vitro and in vivo. The fluorophores of the two probes are both phenothiazine molecules, which link to the diaminomaleonitrile (DAMN) moiety through imine bonds. In the presence of imine bonds, the probes emit red fluorescence in an aqueous solution caused by the AIE effect. As the imine bonds are selectively cut-off by HClO, the DAMN moiety gets removed, inducing blue fluorescence of the reaction product. In this way, the selectivity of the DAMN-based probes toward HClO against metal ions and other reactive oxygen species (ROS) was successfully improved. The imaging of endogenous and exogenous HClO with these two probes reveals that lysosome-targeting probes are of great advantage in the detection of natively generated HClO. Furthermore, the imaging of endogenous HClO in zebrafish suggests that PDAM-Lyso is capable of monitoring the generation of HClO in vivo, illustrating that this strategy is of great significance in designing new probes.

In Situ Determination of Bisphenol A in Beverage Using a Molybdenum Selenide/Reduced Graphene Oxide Nanoparticle Composite Modified Glassy Carbon Electrode.

Due to the endocrine disturbing effects of bisphenol A (BPA) on organisms, rapid detection has become one of the most important techniques for monitoring its levels in the aqueous solutions associated with plastics and human beings. In this paper, a glassy carbon electrode (GCE) modified with molybdenum selenide/reduced graphene oxide (MoSe2/rGO) was fabricated for in situ determination of bisphenol A in several beverages. The surface area of the electrode dramatically increases due to the existence of ultra-thin nanosheets in a flower-like structure of MoSe2. Adding phosphotungstic acid in the electrolyte can significantly enhance the repeatability (RSD = 0.4%) and reproducibility (RSD = 2.2%) of the electrode. Under the optimized condition (pH = 6.5), the linear range of BPA was from 0.1 µM⁻100 µM and the detection limit was 0.015 µM (S/N = 3). When using the as-prepared electrode for analyzing BPA in beverage samples without any pretreatments, the recoveries ranged from 98⁻107%, and the concentrations were from below the detection limit to 1.7 µM, indicating its potential prospect for routine analysis of BPA.

Effects of foliar dressing of selenite and silicate alone or combined with different soil ameliorants on the accumulation of As and Cd and antioxidant system in Brassica campestris.

This study was conducted to investigate the possibility of using a combined technology to synchronously reduce As and Cd accumulation in the edible parts of Brassica campestris. The results showed that a foliar application of selenite (Se) and silicon (Si) combined with soil ameliorants (including Ca-Mg-P fertilizer, sodium silicate and red mud) showed limited effects on the growth of B. campestris. The As concentration in the leaves of B. campestris in all treatments was below the Chinese safety standard. When sodium silicate and Ca-Mg-P fertilizer were added to the soil, the additional foliar application of Se and Si could in some cases help further reduce the concentrations of As and Cd in the leaves of B. campestris. However, when red mud was applied to the soil, the foliar application of Se and Si enhanced the Cd concentration in the leaves of B. campestris. In most cases, high levels of soil ameliorants plus foliar application of Se and Si significantly enhanced the As concentrations in both the soil solution and the roots of B. campestris but reduced the soil solution Cd concentration and the leaf As concentration. Most of the treatments reduced the thiobarbituric acid reactive substances (TBARS) concentration in the leaves of B. campestris, and the foliar application of Se and Si helped the soil ameliorants alleviate the oxidative stress resulting from As and Cd exposure. In this study, several treatments significantly increased the activities of superoxide dismutase (SOD) and ascorbate peroxidase (APX). However, the enzymes peroxidase (POD) and catalase (CAT) were not induced by most treatments. In summary, the combined treatment of 1gkg-1 Ca-Mg-P fertilizer plus foliar spraying 2mmolL-1 sodium selenite was most effective in reducing the Cd concentration and a rather strong ability to reduce the As concentration and trigger the activities of SOD and APX in the leaves of B. campestris.

Characteristics of PAHs in farmland soil and rainfall runoff in Tianjin, China.

Rainfall runoff can remove certain amounts of pollutants from contaminated farmland soil and result in a decline in water quality. However, the leaching behaviors of polycyclic aromatic hydrocarbons (PAHs) with rainfall have been rarely reported due to wide variations in the soil compositions, rainfall conditions, and sources of soil PAHs in complex farmland ecosystems. In this paper, the levels, spatial distributions, and composition profiles of PAHs in 30 farmland soil samples and 49 rainfall-runoff samples from the Tianjin region in 2012 were studied to investigate their leaching behaviors caused by rainfall runoff. The contents of the Σ16PAHs ranged from 58.53 to 3137.90 µg/kg in the soil and 146.58 to 3636.59 µg/L in the runoff. In total, most of the soil sampling sites (23 of 30) were contaminated, and biomass and petroleum combustion were proposed as the main sources of the soil PAHs. Both the spatial distributions of the soil and the runoff PAHs show a decreasing trend moving away from the downtown, which suggested that the leaching behaviors of PAHs in a larger region during rainfall may be mainly affected by the compounds themselves. In addition, 4- and 5-ring PAHs are the dominant components in farmland soil and 3- and 4-ring PAHs dominate the runoff. Comparisons of the PAH pairs and enrichment ratios showed that acenaphthylene, acenaphthene, benzo[a]anthracene, chrysene, and fluoranthene were more easily transferred into water systems from soil than benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[ghi]perylene, and indeno[123-cd]pyrene, which indicated that PAHs with low molecular weight are preferentially dissolved due to their higher solubility compared to those with high molecular weight.

Enhanced sinks of polystyrene nanoplastics (PSNPs) in marine sediment compared to freshwater sediment: Influencing factors and mechanisms.

The difference in the transport behaviors of nanoplastics consistently assistant with their toxicities to benthic and other aquatic organisms is still unclear between freshwater and marine sediments. Here, the mobilities of polystyrene nanoplastics (PSNPs) and key environmental factors including salinity and humic acid (HA) were systematically studied. In the sand column experiments, both tested PSNPs in the freshwater system (100 nm NPs (100NPs): 90.15 %; 500 nm NPs (500NPs): 54.22 %) presented much higher penetration ratio than in the marine system (100NPs: 8.09 %; 500NPs: 19.04 %). The addition of marine sediment with a smaller median grain diameter caused a much more apparent decline in NPs mobility (100NPs: from 8.09 % to 1.85 %; 500NPs: from 19.04 % to 3.51 %) than that containing freshwater sediment (100NPs: from 90.15 % to 83.56 %; 500NPs: from 54.22 % to 41.63 %). Interestingly, adding HA obviously led to decreased and slightly increased mobilities for NPs in freshwater systems, but dramatically improved performance for NPs in marine systems. Electrostatic and steric repulsions, corresponding to alteration of zeta potential and hydrodynamic diameter of NPs and sands, as well as minerals owing to adsorption of dissolved organic matter (DOM) and aggregations from varied salinity, are responsible for the mobility difference.

Assessing soil remediation effect of Cr and Pb based on bioavailability using DGT, BCR and standardized determination method.

In the field of soil remediation, the importance of bioavailability of pollutants has not received adequate attention, leading to the excessive application of remediation measures. Therefore, to ensure the safe use of farmland soil, a scientific method is needed to assess labile contaminants and their translocation in plants. To evaluate soil remediation effect based on bioavailability, the concentrations of these heavy metals in soil were analyzed using by the method for total metal content, the Community Bureau of Reference (BCR) extraction, and the diffusive gradients in thin films (DGT) technique. The results reveal that the correlation coefficients between metal concentrations measured by DGT and those accumulated in rice grains are the highest (Cr-R2 = 0.8966, Pb-R2 = 0.9045). However, the capability of method for total metal content to evaluate the remediation effect of heavy metals is very limited. In contrast, although Cr and Pb measured by BCR show a high correlation with HMs in rice plants, the method still falls short in precisely assessing bioavailability. Significantly, DGT proves to be more effective, successfully distinguishing the remediation effects of different treatments. Generally, DGT offers a more accurate and simpler assessment method, underscoring its practical significance for monitoring soil remediation and environmental management.

The effect of anthropogenic activities on the behavior of novel brominated flame retardants in surface soil of Northern China urbanized zone.

Novel brominated flame retardants (NBFRs) have emerged as an alternative to traditional brominated flame retardants (BFRs) and may pose risks to the environment and human health. However, the distribution pattern of NBFRs in urbanized zones and their association with multiple socioeconomic variables have not been adequately explored. Herein, seven NBFRs were investigated in surface soil samples from Tianjin, China, a typical urbanized area. The ∑7NBFRs ranged from n.d. to 101 ng/g, dry weight (dw) (mean: 12.6 ± 17.6 ng/g dw), which exhibited a relatively elevated level compared to NBFRs in soils from other regions worldwide. Decabromodiphenylethane (DBDPE) was the main contaminant, and its concentration ranged from 0.378 to 99 ng/g, dry weight (dw) (mean: 11.4 ± 17.0 ng/g dw), accounting for 81 % of the ∑7NBFRs. Notably, NBFRs exhibited peak concentrations within residential zones, significantly surpassing those recorded in the remaining four regions (green, farmland, water environment and other) (p < 0.05). Furthermore, the concentration of NBFRs in the soil of the Binhai New District within Tianjin was the highest, significantly exceeding that of other administrative areas, which was closely related to the intensive industrial activities in this region. The above results indicate that human activities are a key factor affecting the concentration of NBFRs in the soil. Moreover, a variety of statistical methods were employed to investigate the correlation between socioeconomic variables and the distribution of NBFRs. The concentration of NBFRs showed a significant correlation with population density and the gross domestic product (GDP) (p < 0.05), and the incorporation of administrative regional planning into structural equation models demonstrated an indirect influence on the spatial distribution of NBFRs concentration, mediated by its impact on population density. These results emphasize the association between NBFRs contamination and the degree of urbanization, thereby providing valuable insights for assessing the exposure risk of NBFRs among urban residents.

The weakened physiological functions of human serum albumin in presence of polystyrene nanoplastics.

Due to the widespread presence of nanoplastics (NPs) in daily essentials and drinking water, the potential adverse effects of NPs on human health have become a global concern. Human serum albumin (HSA), the most abundant and multi-functional protein in plasma, has been chosen to understand the biological effects of NPs after entering the blood. The esterase activity and the transport of bisphenol A in the presence of polystyrene nanoplastics (PSNPs) under physiological conditions (pH 4.0 and 7.4) have been investigated to evaluate the possible biological effects. The interactions between PSNPs and HSA have also been systematically studied by multispectral methods and dynamic light scattering techniques. The esterase activity of HSA presented a decreased trend with increasing PSNPs; conversely, higher permeabilities are accompanied by higher amounts of PSNPs. Compared with the unchanged hydrodynamic diameter and weaker interactions at pH 7.4, stronger binding between HSA and PSNPs at pH 4.0 led to a significant increase in the particle size of the PSNPs-HSA complex. The quenching mechanism belonged to the static quenching type. The electrostatic force is proposed to be the dominant factor for PSNPs binding to HSA. The work provides some information about the toxicity of NPs when exposed to humans.

Contamination Status, Environmental Factor and Risk Assessment of Polychlorinated Biphenyls and Hexachlorobutadiene in Greenhouse and Open-Field Agricultural Soils across China.

With the popularization and high-intensity utilization of greenhouse cultivation for crops growth, the pollution of greenhouse soils has been of concern. Therefore, a national-scale survey was conducted to investigate the contamination status, sources, influence factors and the risks of polychlorinated biphenyls (PCBs) and hexachlorobutadiene (HCBD) in greenhouse and nearby open-field soils. Contents of PCBs ranged from 10-6). This study provided a full insight on the contamination status and risks of PCBs and HCBD when guiding greenhouse agriculture activities.

Predictive and estimation model of Cd, Ni, and Zn bioaccumulations in maize based on diffusive gradients in thin films.

Consumption of maize contaminated with heavy metals such as cadmium, nickel, and zinc threaten human health. For situ measuring the bioavailability of heavy metals, the diffusive gradients in thin films (DGT) is superior to other traditional methods. It is also important to find a method for predicting heavy metal enrichment in maize based on the DGT method. In this study, field surveys were conducted in the main maize producing areas of Tianjin, China. Heavy metal concentrations in maize grains were predicted by coupling DGT with traditional extraction methods. The results show that coupling DGT with soil solution can significantly improve prediction accuracy (Cd-R2 = 0.908, Ni-R2 = 0.903, and Zn-R2 = 0.904). This indicated that DGT and soil solution were feasible predictors of heavy metal concentration in maize. The DGT induced fluxes in soil/sediment (DIFS) model was used to simulate the uptake process of heavy metals by DGT, and better reveal the desorption processes of heavy metals in soils. DIFS-based desorption processes were employed to characterize the resupply ability of heavy metals in soils. The coupling of DGT and DIFS parameters provided the best prediction accuracy in this study (Cd-R2 = 0.920, Ni-R2 = 0.928, and Zn-R2 = 0.908). Predictions are slightly weaker for Zn than for Cd and Ni (Cd-P < 0.01, Ni-P < 0.01, and Zn-P < 0.05). The reason is that the average resupply type of Cd and Ni in soil is partially sustained while Zn is resupplied via diffusion only. The desorption rate k-1 can excellently improve the prediction accuracy of DGT, which avoids the disadvantage that soil solution does not consider desorption. The coupling of DGT and DIFS parameters provides an accurate and reliable method for predicting heavy metal enrichment in maize.

Accumulation Characteristics and Pollution Evaluation of Soil Heavy Metals in Different Land Use Types: Study on the Whole Region of Tianjin.

Heavy metal pollution in soil has received much attention in recent decades. Many studies have analyzed the interaction between specific soil quality and soil heavy metal pollution. However, there is little information about the pollution status, spatial distribution and pollution sources of heavy metals in the province of Tianjin. In this paper, the distribution characteristics and pollution sources of heavy metals in soil were studied by means of the surface soil of Tianjin, as the study area and object, conducted in combination with land use types, using multiple data analysis and multivariate statistics, while the pollution levels were evaluated by various indices. The results showed the mean contents of the seven heavy metals of the studied elements followed an increasing order of Cd (0.15 mg/kg) < As (11.9 mg/kg) < Cu (24.3 mg/kg) = Pb (24.3 mg/kg) < Ni (27.9 mg/kg) < Cr (70.7 mg/kg) < Zn (79.1 mg/kg). The median values of Cr and Ni were lower than the background values and did not exceed the screening values at the points, and the median values of Cu, Zn and Pb were close to the background values, while the median contents of As and Cd were higher than the background values. The highest accumulation of heavy metals was found in grassland, and the coefficient of variation of heavy metal contents were higher in garden land, industrial and mining storage land, residential land and transportation land, indicating that the soil heavy metal contents under these land use types were more significantly disturbed by human factors. The evaluation results of the ground accumulation index method showed that the soil in Tianjin was free of pollution, except for Cd, which was at the non-polluted to moderately polluted level. The Nemero integrated pollution index evaluation method and the pollution load index evaluation method together showed that the integrated pollution levels of heavy metals in Tianjin soils were both at no pollution level/safety level. Apart from Cd and As, which were not correlated, the other heavy metals were correlated with each other two by two. Cd, Pb and Zn were the main pollution contributors from traffic, industry and other anthropogenic factors, while Cr and Ni were the main pollution contributors from soil parent material, and Cu was the main pollution contributor from mining and metal smelting. In addition, As was presumed to be the main source of pollution contribution from agriculture and surface runoff.

Distribution and speciation of arsenic in seasonally stratified reservoirs: Implications for biotransformation mechanisms governing interannual variability.

HPLC-ICPMS was used to analyze the spatiotemporal variation of As species in different sections and tributaries of the Aha Reservoir over four seasons, and the migration and transformation mechanisms were clarified by combined analysis of hydrochemical parameters and microbial composition. The results showed that the internal release of As from the reservoir sediments is mainly due to the reduction of iron oxide and the release of adsorbed As(V). The average proportion of As(III) increased from 27.2% in autumn to 46.5% in summer, 68.9% in winter, and up to 70.8% in spring. In spring and summer, the high concentration of As(III) and organic arsenic in the epilimnion under phosphorus restriction was caused by the reductive metabolism of phytoplankton after intake of As(V). The arsenic species in the metalimnion were mainly affected by the oxidation-reduction potential (ORP). In summer and autumn, As-oxidizing bacteria used As(III) as an electron donor, and nitrate played an important role as an electron acceptor, maintaining the dominance of As(V) in the hypolimnion. However, in winter and spring, temperature-controlled ORP was the main process, which was dominated by As(III). In conclusion, As species show annual cycles in different layers of seasonally thermal stratified reservoirs. It provides a systematic mechanism of As species transformation in reservoirs, especially the effect of biological transformation mechanism.

Exploring the Relationship between Ecosystem Services under Different Socio-Economic Driving Degrees.

The large-scale transformation of natural ecosystems to socio-economic development land types under human activities was a primary reason for the decline of regional ecosystem services. It is a key issue for regional ecosystem planning and management to reveal the relationship between ecosystem services of different land use types under different socio-economic driving degrees. However, the current related research was not in-depth. Based on the land use data of Wuhan City in 1980, 1990, 2000, 2010, and 2020, this study classified land use into three categories according to the different degrees of human activities on natural ecosystem development: the land use of a natural ecosystem (LUNE), the land use of a productive ecosystem (LUPE), and the land use of a socio-economic system (LUSE). The InVEST model was used to simulate five ecosystem services (grain yield, water yield, carbon storage, habitat quality, and water purification), and the spatio-temporal distribution and functional transformation of the three land use types were analyzed. Results showed that with the intensified urban expansion in Wuhan, the LUSE types increased to 2.7 times that of the original. However, the natural land types basically maintained a stable area, coupling with the large-scale transformation between the LUPE and LUSE types. Land use change resulted in significant spatial changes of five ecosystem services, especially carbon storage and habitat quality. The correlation analysis indicated that the five kinds of ecosystem services mainly showed a synergistic relationship, meanwhile the LUSE type denoted the most significant correlation with ecosystem services among these three category types. This study indicated that besides the protection of natural ecosystems, the LUSE type would become the key land use type in the planning and management of improving regional ecological function.

Efficient pH-universal degradation of antibiotic tetracycline via Co2P decorated Neosinocalamus affinis biochar.

Considering the complexity of traditional cobalt phosphide (Co2P) loaded biochar synthesis research on a simple and efficient synthesis method has practical significance. In this study, after phosphoric acid activation, Neosinocalamus affinis biochar (NAB) and nanoplate Co3O4 quickly formed a Co2P-NAB composite material with high Co2P crystallinity and was uniformly dispersed on the surface of NAB in a microwave reactor. Co2P-NAB has an excellent catalytic degradation effect in the activation of peroxymonosulfate (PMS) to degrade tetracycline (TC). The optimal TC degradation efficiency was achieved with the addition of 50 mg L-1 TC concentration, 0.2 g L-1 catalysts, 0.406 mM PMS and pH = 6.02. In addition, according to the pseudo-first-order reaction rate constant calculation, the composite of Co2P-NAB and PMS the synergy efficiency is 81.55 %. Compared with Co2P-NAB (10.83 %) and PMS (7.62 %) alone, the Co2P-NAB/PMS system has a significant promotion effect on the degradation of TC molecules. Additionally, the Co2P-NAB/PMS system had a TC mineralization rate of 68 % in 30 min. Furthermore, after a series of characterization, detection and analysis, and influencing factor experiments, we proposed a potential mechanism for the Co2P-NAB/PMS reaction system to degrade TC and found that singlet oxygen (1O2) plays an essential role in the non-radical degradation process. Finally, according to the liquid chromatography-mass spectrometry (LC-MS) detection of TC degradation intermediates, a possible degradation route was proposed. Therefore, this work uses microwave technology to present a novel and simple synthesis method for transition metal phosphides, which provides potential application value for the treatment of actual wastewater with heterogeneous catalysts.

Assessment of pesticide pollution in suburban soil in south Shenyang, China.

In this study, 35 representative farmland soil samples from suburban areas in south Shenyang, the capital city in Liaoning province, China, were collected to evaluate the pollution of 114 pesticides. Surface soil samples were air-dried and sieved. Ultrasonic extraction was used for pesticides preparation prior to analysis with gas chromatography-mass spectrometry. The total concentrations of tested pesticides in the area ranged in 0-51.32 ng/g and the average of concentrations was 6.86 ng/g. Six pesticides, including butachlor(with detect frequency 71.4%), p,p'-DDE (88.6%), p,p'-DDT (77.1%), o,p'-DDD (82.9%), hexachlorobenzene (88.6%) and δ-HCB (77.1%), were detected most frequently. It indicated that DDTs (N.D.-40.25 ng/g) and HCHs (N.D.-42.79 ng/g) were the predominant pesticide pollutants in soil because of their long term persistence. On the contrary, most of organophosphorus pesticides, pyrethroids and carbamates were not detected. Spatial variation of six pesticides with high detection frequency (>70%) in soil was illustrated. Pollution levels, characteristics and the possible sources were also discussed. The data were helpful to figure out the pollution of the pesticides and could be further used to evaluate the health risk associated with food safety.