21. 题目: Spatial variation of dissolved organic nitrogen in Wuhan surface waters: Correlation with the occurrence of disinfection byproducts during the COVID-19 pandemic
期刊: Water Research
作者: Leyun Wang, Xian Zhang, Shanshan Chen, Fanbin Meng, Dayi Zhang, Yi Liu, Miao Li, Xiang Liu, Xia Huang, Jiuhui Qu
摘要: Intensified sanitization practices during the recent coronavirus disease-2019 (COVID-19) led to the release of chlorine-based disinfectants in surface water, potentially triggering the formation of disinfection byproducts (DBPs) in the presence of dissolved organic nitrogen (DON). Thus, a comprehensive investigation of DON's spatial distribution and its association with DBP occurrence in the surface water is urgently needed. In this study, a total of 51 water samples were collected from two rivers and four lakes in May 2020 in Wuhan to explore the regional variation of nitrogen (N) species, DON's compositional characteristics, and the three classes of DBP occurrence. In lakes, 53.0% to 86.3% of N existed as DON, with its concentration varying between 0.3–4.0 mg N/L. In contrast, NO3−-N was the dominant N species in rivers. Spectral analysis revealed that DON in the lakes contained higher humic and fulvic materials with higher A254, A253/A203, SUVA254, and PIII+IV/PI+II+V ratios, while rivers had higher levels of hydrophilic compounds. Trihalomethanes (THMs) were the most prevalent DBPs in the surface waters, followed by N-nitrosamines and haloacetonitriles (HANs). The levels of N-nitrosamines (23.1–97.4 ng/L) increased significantly after the outbreak of the COVID-19 pandemic. Excessive DON in the surface waters was responsible for the formation of N-nitrosamines. This study confirmed that the presence of DON in surface water could result in DBP formation, especially N-nitrosamines, when disinfectants were discharged into surface water during the COVID-19 pandemic.
22. 题目: Development of an acidized biochar-supported hydrated Fe(III) oxides for highly efficient cadmium and copper sequestration from water
期刊: Science of The Total Environment
作者: Yan Li, Liangmin Gao, Yu Wang, Shuo Cheng, Guowei Wu, Xuan Yang, Shunli Wan
摘要: Biochar-supported metallic oxides are attractive adsorbents for heavy metal cleanup, but the adsorption performance is still unsatisfactory as a result of the self-aggregation of the incorporated metallic oxides. A new hybrid nano-material was prepared through impregnating hydrated ferric oxide (HFO) nanoparticles within biochar bearing high-density charged oxygen-containing groups (e.g., carboxyl and hydroxyl groups) (ABC) derived from HNO3 treatment. The as-made adsorbent, denoted as HFO-ABC, possesses highly dispersed HFO nanoparticles with typical size lower than 20 nm, and exhibits greater sorption capacity for Cd(II) and Cu(II) than the pristine biochar-supported HFO. It also shows great sorption preference toward Cd(II) and Cu(II) in co-presence of high levels of Ca2+, Mg2+ and humic acid (HA). Such prominent performance is put down to the high-density charged functional groups on the host ABC, which not only promote the dispersion of the immobilized HFO nanoparticles but also generate the potential Donnan membrane effect, i.e., the pre-concentration and permeation of target metals prior to their preferable adsorption by nano-HFO. The predicted effective coefficients of intra-particle diffusion for Cu(II) and Cd(II) are 4.33×10−9 and 3.83 ×10−9 cm2/s, respectively. HFO-ABC exhibits excellent performance for fixed-bed column application, and yields 513 and 990 BV effluents for Cd(II) and Cu(II) to achieve their discharge standards, respectively. The spent HFO-ABC could be in situ regenerated using binary HCl-CaCl2 solution with desorption efficiency higher than 95%. All results manifest that increasing charged functional groups via HNO3 treatment is an effective measure for boosting sorption performance of biochar-based nanocomposites.
23. 题目: Impact of montmorillonite clay on the homo- and heteroaggregation of titanium dioxide nanoparticles (nTiO2) in synthetic and natural waters
期刊: Science of The Total Environment
作者: Junyu Wang, Xiaoli Zhao, Fengchang Wu, Zhi Tang, Tianhui Zhao, Lin Niu, Mengyuan Fang, Hongzhan Wang, Fanfan Wang
摘要: The homoaggregation of titanium dioxide nanoparticles (nTiO2) and their heteroaggregation with ubiquitous natural clay colloids are crucial processes affecting the environmental transport and fate of nTiO2, whereas the latter has received less attention. In this study, the effects of pH, electrolytes, natural organic matter (NOM), and montmorillonite on the homo- and heteroaggregation of nTiO2 were systematically investigated. The isoelectric point of bare nTiO2 was 6.98, whereas TiO2-montmorillonite mixtures remained negative charged due to the reduced particle surface potential by heteroaggregation. Homoaggregation of nTiO2 was mainly affected by anions, whereas heteroaggregation in TiO2-montmorillonite mixtures was mainly affected by cations. Heteroaggregation between nTiO2 and montmorillonite involved the adsorption of C-C/C-H. Intensive aggregation of nTiO2 were observed with 4 mg/L montmorillonite, whereas with 20 mg/L montmorillonite, the aggregation was significantly inhibited by the over-coverage of montmorillonite. NOM was attached to the surface of nTiO2 with the adsorption of functional groups involving C-C/C-H and O-C=O. The addition of NOM effectively reduced the homo- and heteroaggregation of nTiO2, and the stabilizing effect was enhanced with the increased molecular weight and aromatic/aliphatic fraction in NOM. Besides electrostatic repulsion, steric repulsion could also be one of the main stabilization mechanisms of NOM. With Ca2+ in the solutions, the stabilizing effect of NOM was significantly weakened through cation bridging. The addition of montmorillonite could facilitate the aggregation of nTiO2 in the presence of NOM. The homo- and heteroaggregation of nTiO2 were also observed in 7 different types of natural waters. Homoaggregation predominated in waters with high ionic strength and low NOM contents (seawater and groundwater), whereas heteroaggregation predominated in surface freshwater and wastewater systems. The results reflect the instability of nTiO2 in natural aquatic environments and the potential risk they pose to benthic organisms.
24. 题目: Unexpected degradation and deiodination of diatrizoate by the Cu(II)/S(IV) system under anaerobic conditions
期刊: Water Research
作者: Jingxin Yang, Yujie Luo, Xianghui Fu, Zijun Dong, Chuan Wang, Hong Liu, Chengchun Jiang
摘要: Transition metal catalyzed sulfite auto-oxidation is a promising technology used in water and wastewater treatment for the elimination of contaminants. In the literature, this process has been reported to be efficient only in the presence of oxygen. However, in this study, we unexpectedly found that the degradation of diatrizoate (DTZ) by a system based on the combination of copper ion and sulfite (Cu(II)/S(IV)) reached over 95% under anaerobic conditions, but was considerably retarded under aerobic conditions at pH 7. Furthermore, it was found that Cu(I), generated from the cleavage of the CuSO3 complex, was the main reactive species responsible for the degradation of DTZ by the Cu(II)/S(IV) system under anaerobic conditions. In fact, the absence of oxygen promoted the accumulation of Cu(I). The concomitant release of the iodide ion with the degradation of DTZ indicated that the anaerobic degradation of DTZ by the Cu(II)/S(IV) system mainly proceeded through the deiodination pathway, which was also confirmed by the detection of deiodinated products. The anaerobic degradation of DTZ was favored at higher initial concentrations of Cu(II) or sulfite in this system. Since the CuSO3 complex, the precursor of Cu(I), was formed mainly at pH 7, the highest anaerobic degradation of DTZ was achieved at pH 7. An increase in reaction temperature considerably enhanced the degradation of DTZ by the Cu(II)/S(IV) system with an apparent activation energy of 119.4 kJ/mol. The presence of chloride, bicarbonate and humic acid slightly influenced the anaerobic degradation of DTZ. The experiments with real water samples also demonstrated the effectiveness of the degradation of DTZ by the Cu(II)/S(IV) system under anaerobic conditions.
25. 题目: Identification of processes mobilizing organic molecules and arsenic in geothermal confined groundwater from Pliocene aquifers
期刊: Water Research
作者: Wen Qiao, Huaming Guo, Chen He, Quan Shi, Shiping Xing, Zhipeng Gao
摘要: Organic matter (OM) has been accepted as an important trigger fueling Fe(III) oxide reduction and arsenic release in the late Pleistocene-Holocene anoxic aquifers, whereas its fates and roles on arsenic mobility in the Pliocene aquifer are unclear. To fill this gap, groundwaters from a confined Pliocene aquifer (CG) and an unconfined Holocene aquifer (UG) were sampled in the Guide Basin, China, to monitor evolutions of groundwater geochemistry and OM molecular signatures along the groundwater flow path. The outcomes showed that groundwater pH, temperature, and arsenic concentrations in the CG samples generally increased along the groundwater flow path, which were much higher than those in the UG samples. The numbers and intensities of recalcitrant molecules (polycyclic aromatics and polyphenols) in the CG samples remarkably increased along the path, but relatively labile molecules (highly unsaturated and phenolic compounds and aliphatic compounds) showed the opposite trends. The arsenic-poor (<10 μg/L) UG samples contained more labile molecules than the arsenic-rich CG samples. High groundwater pH, temperature, and sediment age in the confined aquifers may be responsible for the selective mobilization of the unique polycyclic aromatics and polyphenols. The mobilized recalcitrant organic molecules may enhance arsenic release via electron shuttling, complexation, and competition. Furthermore, high temperature and pH may also facilitate arsenic desorption. The study provides molecular-scale evidences that the mobilization of recalcitrant organic molecules and arsenic were concurrent in the geothermal confined groundwater.
26. 题目: The decomposition of macrozoobenthos induces large releases of phosphorus from sediments
期刊: Environmental Pollution
作者: Xiaolei Xing, Musong Chen, Yuexia Wu, Yazhou Tang, Cai Li
摘要: Lake eutrophication and algal blooms may result in the mortality of macrozoobenthos. However, it is still not clear how macrozoobenthos decomposition affect phosphorus (P) mobility in sediments. High-resolution dialysis (HR-Peeper) and the diffusive gradients in thin films (DGT) technique were used in this study to assess the dissolved organic matter (DOM), dissolved/DGT-labile iron (Fe), P, and sulfur (S(-II)) profiles at a millimeter resolution. The decomposition of Bellamya aeruginosa significantly increased the internal loading of sediments P. The Fe(III) and sulfate were reduced under anaerobic conditions and promoted P desorption from sediments. This was supported by the significant increase in DGT-labile S(-II) and dissolved/DGT-labile P, Fe(II) and the significant positive correlation between Fe and P on days 8. The simultaneous increase in DOM and soluble reactive phosphorus (SRP) and the significant positive relationship between these factors were observed during the decomposition of B. aeruginosa. This suggested that complexation of DOM with metals may promotes the release of P from sediments.
27. 题目: Mapping soil organic carbon stock by hyperspectral and time-series multispectral remote sensing images in low-relief agricultural areas
作者: Long Guo, Xiaoru Sun, Peng Fu, Tiezhu Shi, Lina Dang, Yiyun Chen, M. Linderman, Ganlin Zhang, Yu Zhang, Qinghu Jiang, Haitao Zhang, Chen Zeng
摘要: High-precision digital soil organic carbon (SOC) stocks mapping is very important for agricultural production management and global carbon cycle. The spatial heterogeneity of farmland SOC is not only influence by the environmental factors of soil formation but also the management practices of tillage, fertilization, and irrigation. However, the traditional modeling covariates of digital soil mapping, such as terrain factors, land use types and climate factors have weak spatial variations in low-relief agricultural areas, and they cannot reflect the large spatial variation of SOC. Thus the time-series multispectral remote sensing images will be used for mapping soil properties in low relief regions in this study, meanwhile a new collaborative verification strategy was put forward to evaluate the spatial distribution characteristics of soil maps. The current study was performed in a nearly flat agricultural region southeast of Iowa (with an area of approximately 385.45 ha), where 195 surface soil samples (0–15 cm) were collected. A hyperspectral image (Headwall-Hyperspec, 380–1700 nm) and the time-series multispectral remote sensing images of Sentinel 2 and Landsat 8 were used to construct the prediction models of SOC stock and its relevant soil properties of SOC and soil bulk density (SBD) through partial least square regression (PLSR) and extreme learning machine (ELM) models. The collected soil samples and evaluation indexes of root mean square error (RMSE), R2, and ratio of performance to interquartile range (RPIQ) were used to evaluate the model performance. Results are as follows: (1) hyperspectral images were successfully used to predict the SOC stock, SOC, and SBD through PLSR and ELM, while ELM (RPIQ = 2.03, 1.97, 1.64) outperformed PLSR (RPIQ = 1.83, 1.97, 1.53); (2) the time-series multispectral remote sensing images of Sentinel 2 and Landsat 8 can reflect the spatial distribution characteristics of the SOC stock, SOC and SBD by PLSR and ELM, but the combination of Sentinel 2 images and ELM obtained the best prediction results (RPIQ = 1.45, 1.25, 1.26); and (3) the differences of the soil maps predicted by the hyperspectral image and time-series multispectral remote sensing images were small, and the largest percentage errors nearly appeared on the edges of the farmland patches owing to mixed pixels. This study further confirmed the good prediction abilities of the time-series multispectral remote sensing images in low relief farmland regions. Lastly, this mapping strategy can provide additional valuable information for agricultural management and carbon cycle.
28. 题目: Mechanical and biological chiseling impacts on soil organic C stocks, root growth, and crop yield in a long-term no-till system
期刊: Soil and Tillage Research
作者: Thiago Massao Inagaki, João Carlos de Moraes Sá, Cássio Antonio Tormena, Andressa Dranski, Amanda Muchalak, Clever Briedis, Ademir de Oliveira Ferreira, Neyde F.B. Giarola, Álvaro Pires da Silva
摘要: Soils under no-till (NT) in Brazil have been aimlessly chiseled mainly due to compaction symptoms. The impacts on soil organic carbon (SOC) of these operations as well as the effects of more sustainable alternatives are still highly unknown. We hypothesized that the use of plants with deep root systems in the crop rotation could be a suitable alternative to mechanical chiseling for no-till fields. Thus, our objective in this study was to evaluate changes in SOC stocks, root development, and crop yield over time caused by mechanical and biological chiseling in a long-term no-till system (i.e., 18 years). The experiment was laid out as randomized blocks with four replicates and the treatments were as follows: 1) No-till system without any mechanical disturbance, cultivated with black oats + vetch in winter, here called “No-till cover crop (NT-CC)”. 2) No-till system with one mechanical disturbance through chiseling, also cultivated with black oats + vetch in winter, here called “No-till Mechanical Chiseling (NT-MC)”. 3) No-till without any mechanical disturbance cultivated with black oats + forage radish (Raphanus Sativus L.) instead of vetch, here called “No-till Biological Chiseling”. Compared to NT-CC, the use of NT-MC depleted the SOC stocks by -0.41 Mg ha−1 year−1. NT-MC also highly depleted proxies for microbial-related C pools such as hot-water and permanganate extractable C. It demonstrates the deleterious effects of the mechanical chiseling operations on the surface depths (0−30 cm depth) of our long-term no-till system and raises concerns about the use of these operations in highly weathered areas. On the other hand, the NT-BC promoted significantly higher sequestration rates of 1.29 Mg ha−1 year−1 (LSD test, p < 0.05). The NT-BC has also promoted significantly higher sequestration rates of proxies of microbial-related organic matter, and soybean and wheat root development (length and mass) than the other managements. For cumulative crop yield and biomass input, both NT-BC and NT-CC promoted significantly higher values than NT-MC during the four years of assessment. The root development of wheat and soybean significantly contributed to the increase of SOC stocks, observed by positive correlations (p < 0.01). The results demonstrated that the use of radish as an intercrop for alleviating soil compaction was a good alternative to replace mechanical chiseling in compacted NT fields due to its superior performance in increasing SOC stocks, promoting higher root development, and crop yield.
29. 题目: Nitrification, denitrification and anammox process coupled to iron redox in wetlands for domestic wastewater treatment
期刊: Journal of Cleaner Production
作者: Yuhui Ma, Xiangyong Zheng, Shengbing He, Min Zhao
摘要: Constructed wetlands (CWs) is widely used in rural areas as low-cost wastewater treatment technology. However, in rural domestic wastewater treatment using subsurface CWs, the lack of oxygen for nitrification and a carbon source for denitrification is often responsible for low removal of nitrogen. As organic carbon addition requires human and financial investment, which is not suitable for long-term utilization in rural areas. Other electron donors become the preferred choice. Compared to granulated iron materials, the iron scraps with fluffy structure could avoid clogging problem and be effective for nitrogen removal simultaneously. In this study, two CWs were constructed using gravel and iron scraps as substrate, respectively. After 6 months of operation, the total nitrogen and ammonia removal in CWs with iron improved to 71.46% and 70.44%, respectively. Enhancement of 24.08% organic nitrogen removal was observed in iron zone of CWs. Autotrophic denitrifying bacteria became the dominant genus in the system. Traditional nitrification-denitrification and anaerobic ammonia oxidation process could be the primary nitrogen removal pathway in CWs with iron. The presence of iron-reducing bacteria (Anaeromyxobacter, Geobacter, and Geothrix) provided the possibility of iron oxide reduction reactions. Electron transfer and products in iron oxidation and reduction processes significantly affected on nitrogen removal to complete the coupling of iron cycle and nitrogen cycle in CWs.
30. 题目: Remodeling of Arctic char ( Salvelinus alpinus ) lipidome under a stimulated scenario of Arctic warming
期刊: Global Change Biology
作者: Chao Wang, Yufeng Gong, Fuchang Deng, Enmin Ding, Jie Tang, Garry Codling, Jonathan K. Challis, Derek Green, Jing Wang, Qiliang Chen, Yuwei Xie, Shu Su, Zilin Yang, Jason Raine, Paul D. Jones, Song Tang, John P. Giesy
摘要: Arctic warming associated with global climate change poses a significant threat to populations of wildlife in the Arctic. Since lipids play a vital role in adaptation of organisms to variations in temperature, high‐resolution mass spectrometry based lipidomics can provide insights into adaptive responses of organisms to a warmer environment in the Arctic and help to illustrate potential novel roles of lipids in the process of thermal adaption. In this study, we studied an ecologically and economically important species–Arctic char (Salvelinus alpinus), with a detailed multi‐tissue analysis of the lipidome in response to chronic shifts in temperature by use of a validated lipidomics workflow. In addition, dynamic alterations in the hepatic lipidome during the time‐course of shifts in temperature were also characterized. Our results showed that early life stages of Arctic char were more susceptible to variations in temperature. One‐year‐old Arctic char responded to chronic increases in temperature with coordinated regulation of lipids, including headgroup‐specific remodeling of acyl chains in glycerophospholipids (GP) and extensive alterations in composition of lipids in membranes, such as less lyso‐GPs, and more ether‐GPs and sphingomyelin (SM). Glycerolipids (e.g., triacylglycerol, TG) also participated in adaptive responses of the lipidome of Arctic char. Eight‐week‐old Arctic char exhibited rapid adaptive alterations of the hepatic lipidome to stepwise decreases in temperature, while showing blunted responses to gradual increases in temperature, implying an inability to adapt rapidly to warmer environments. Three common PEs (PE 36:6|PE 16:1_20:5, PE 38:7|PE 16:1_22:6, and PE 40:7|PE 18:1_22:6) were finally identified as candidate lipid biomarkers for temperature shifts via machine learning approach. Overall, this work provides additional information to a better understanding of underlying regulatory mechanisms of the lipidome of Arctic organisms in the face of near‐future warming.
31. 题目: New insights into the evolution of bacterial community during the domestication of phthalate-degrading consortium
期刊: Journal of Cleaner Production
作者: Xue-Jing Huang, Huan Du, Xiao-Long Deng, Yong-Hong Chen, Lei Xiang, Yan-Wen Li, Hui Li, Ce-Hui Mo, Quan-Ying Cai, Hai-Ming Zhao
摘要: The selective enrichment culture technique is widely used in domestication of pollutant-degrading microorganisms. However, very little information is available regarding the evolution and interaction of microbial communities during the domestication. For the first time, successional variation of bacterial community and metabolism were investigated during the enrichment culture of a phthalate-degrading consortium. Results showed that the content of extracellular polymeric substances (EPS) increased significantly (p<0.05) during the domestication, especially the polysaccharide, playing an important role in protecting the consortium against phthalate toxicity. In contrast, significant (p<0.05) and successional decreases were observed in bacterial richness and diversity with the increasing concentrations of phthalate. Finally, Proteobacteria (60.8%) and Bacteroidetes (12.4%) associated with phthalate tolerance and degradation became the dominant phyla. Actinobacteria and Acidobacteria phyla dominated in the initial activated sludge and then gradually reduced at the late stage of domestication. Microbial interaction networks revealed that the mutualism and competition coexisted among members of the bacterial consortium due to the occupation of different niches. This study would contribute to the optimization and development of enrichment culture techniques for boosting bioremediation on a knowledge-based control.
32. 题目: In situ synthesis of micro-plastics embedded sewage-sludge co-pyrolyzed biochar: Implications for the remediation of Cr and Pb availability and enzymatic activities from the contaminated soil
期刊: Journal of Cleaner Production
作者: Mehr Ahmed Mujtaba Munir, Balal Yousaf, Muhammad Ubaid Ali, Chen Dan, Qumber Abbas, Muhammad Arif, Xiaoe Yang
摘要: Careful designing of biochar (BC) employing biological and industrial waste materials has gained much attention to improve soil health via reducing the bioavailability of heavy metals (HMs) in the contaminated-soil. Herein, a forty-day pot experiment was conducted to explore the influence of micro-plastic (MP) embedded sewage-sludge (SS). The effects of SS and MP dosage ratios (0-15%) on the physicochemical properties of the modified-biochars were also studied with slow-pyrolyzed (SBC-500 °C) and flash-pyrolyzed biochar (FSBC-700 °C). Our investigations found remarkable positive synergistic effects for the SBC-15% involving increased soil pH, CEC, high carbon contents, and alleviation in Cr and Pb leaching than control and FSBC-700 °C. Besides, SBC-15% containing high carbon functional groups can effectively mitigate the Cr and Pb availability stress by intensifying the adsorption or passivation in the amended-soil, thereby, significantly reducing the Cr and Pb EDTA-extractable contents. Chemical fractionation analyses further confirmed that SBC-15% addition was more helpful for Cr and Pb immobilization and ultimately reducing transfer-rate, bioconcentration-factor, and translocation-factor as compared to FSBC-15% and control due to its higher alkalinity, surface area/porosity, and available carbon functional groups. The maize biomass (root and shoot) increased by more than 50%, and the activities of soil enzymes such as urease, alkaline phosphatase, and glucosidase enzyme activities were also enhanced. This ecologically feasible strategy would pave an efficient way to make full use of the SS and MP for the biochar synthesis with excellent soil remediation performance.
33. 题目: Efficient degradation of diclofenac sodium by periodate activation using Fe/cu bimetallic modified sewage sludge biochar/UV system
期刊: Science of The Total Environment
作者: Liuyang He, Lixin Lv, Suresh C. Pillai, Hailong Wang, Jianming Xue, Yongfei Ma, Yanli Liu, Yulin Chen, Li Wu, Zulin Zhang, Lie Yang
摘要: Iron/copper bimetallic nanoparticles based sludge biochar (Fe/Cu-SBC) was prepared by using a modified co-precipitation route. The Fe/Cu-SBC system prepared was subsequently applied to activate periodate (IO4−) to degrade diclofenac sodium (DCF) by using UV light at room temperature (25 °C). The physicochemical properties of both SBC and Fe/Cu-SBC such as morphology, physical properties, crystal structures and functional groups were examined. The type and number of surface functional groups were found to be increased and the catalytic performance was improved by the modification of Fe/Cu bimetallic nanoparticles. The influence of various parameters to evaluate the catalytic efficiency such as periodate (PI) concentration, dosage of catalysts, UV power, initial pH and coexisting anions were investigated. Under the optimized conditions (pH 6.9, UV-power 60 W, PI concentration of 5 mM and 0.1 g Fe/Cu-SBC), it was observed that 99.7% of DCF was degraded with a pseudo-first-order kinetics reaction constant 9.39 × 10−2 min−1. The radical scavenging experiments showed that IO3• radicals were the predominantly reactive oxidants in the Fe/Cu-SBC/UV system. Therefore, this investigation provides a feasible alternative for the degradation of PPCPs in wastewater.
34. 题目: Feasibility of the 4 per 1000 aspirational target for soil carbon: A case study for France
期刊: Global Change Biology
作者: Manuel P. Martin, Bassem Dimassi, Mercedes Román Dobarco, Bertrand Guenet, Dominique Arrouays, Denis A. Angers, Fabrice Blache, Frédéric Huard, Jean‐François Soussana, Sylvain Pellerin
摘要: Increasing soil organic carbon (SOC) stocks is a promising way to mitigate the increase in atmospheric CO2 concentration. Based on a simple ratio between CO2 anthropogenic emissions and SOC stocks worldwide, it has been suggested that a 0.4% (4 per 1000) yearly increase in SOC stocks could compensate for current anthropogenic CO2 emissions. Here, we used a reverse RothC modelling approach to estimate the amount of C inputs to soils required to sustain current SOC stocks and to increase them by 4‰ per year over a period of 30 years. We assessed the feasibility of this aspirational target first by comparing the required C input with net primary productivity (NPP) flowing to the soil, and second by considering the SOC saturation concept. Calculations were performed for mainland France, at a 1 km grid cell resolution. Results showed that a 30%–40% increase in C inputs to soil would be needed to obtain a 4‰ increase per year over a 30‐year period. 88.4% of cropland areas were considered unsaturated in terms of mineral‐associated SOC, but characterized by a below target C balance, that is, less NPP available than required to reach the 4‰ aspirational target. Conversely, 90.4% of unimproved grasslands were characterized by an above target C balance, that is, enough NPP to reach the 4‰ objective, but 59.1% were also saturated. The situation of improved grasslands and forests was more evenly distributed among the four categories (saturated vs. unsaturated and above vs below target C balance). Future data from soil monitoring networks should enable to validate these results. Overall, our results suggest that, for mainland France, priorities should be (1) to increase NPP returns in cropland soils that are unsaturated and have a below target carbon balance and (2) to preserve SOC stocks in other land uses.
35. 题目: Effects of chronic exposure to different sizes and polymers of microplastics on the characteristics of activated sludge
期刊: Science of The Total Environment
作者: Jiankang Xu, Xinying Wang, Zhanao Zhang, Zehua Yan, Yan Zhang
摘要: Wastewater treatment plants (WWTPs) have become an important source of microplastics (MPs) contamination and most MPs remain in the sludge inducing potential impacts on sludge disposal. However, little is known about the influence of MPs on the characteristics of sludge, which is essential for sludge disposal. In this study, the dewaterability of activated sludge in response to chronic exposure (60 days) to MPs of different sizes (213.7 nm ~ 4.2 mm) and polymers (polystyrene, polyethylene, and polyvinyl chloride) were investigated. Overall, different particle sizes caused more evident effects on sludge dewatering than different polymer types did. Millimeter MPs (~4 mm) dramatically reduced the dewaterability of sludge by 29.6% ~ 47.7%. These effects were mainly caused by the physical crushing of MPs on sludge flocs, except polyvinyl chloride (PVC)-MPs, possibly containing additives, induced toxicity on sludge. Moreover, 100 mg/L nano-size MPs (213 nm) also reduced the dewatering performance of sludge. The potential mechanism is that nano-size MPs inhibited sludge activity and decreased the abundance of key microorganisms, which subsequently altered the composition and spatial distribution of extracellular polymeric substances (EPS), and finally impeded sludge dewatering. Our results highlight the impacts of different sizes of MPs on the characteristics of sludge, affecting the final disposal of sludge.
36. 题目: Enhanced diclofenac elimination in Fe(II)/peracetic acid process by promoting Fe(III)/Fe(II) cycle with ABTS as electron shuttle
期刊: Chemical Engineering Journal
作者: Jinbin Lin, Yuye Hu, Junyang Xiao, Yixin Huang, Mengyun Wang, Haoyu Yang, Jing Zou, Baoling Yuan, Jun Ma
摘要: Fe(II)/peracetic acid (Fe(II)/PAA) process exhibits a great potential in abatement of micropollutants because of the fast reaction between Fe(II) and PAA. Similar to Fenton system, the slow reduction from Fe(III) to Fe(II) leads to the high dosage of Fe(II) in Fe(II)/PAA process. This study introduced 2,2’-azino-bis(3-ethylbenz- -othiazoline-6-sulfonate) (ABTS) as electron shuttle to improve the oxidation capacity of Fe(II)/PAA process by accelerating the redox cycle of Fe(III)/Fe(II). ABTS/Fe(II)/PAA process possessed high elimination efficiency of diclofenac in acidic conditions. Alcohols quenching experiments confirmed that ABTS•+ was the primary reactive species responsible for diclofenac elimination, although FeIVO2+ and carbon-centered radicals (R-O•) also existed in ABTS/Fe(II)/PAA process. ABTS•+ was generated via various pathways, including the reactions of ABTS with Fe(III), FeIVO2+ and R-O•. ABTS was not an ideal electron shuttle because R-O• could decompose partial ABTS•+ to sulfoxides and sulfones. Two possible degradation pathways of diclofenac were proposed based on the detected transformation products. ABTS/Fe(II)/PAA process was highly-efficient for diclofenac elimination in underground water and reservoir water, while high concentration of humic acid had inhibition effect on diclofenac degradation. The present study provides a promising way to alleviate the intrinsic drawbacks of Fe(II)/PAA process and might advance its potential application in water treatment.
37. 题目: Highly efficient As(III) removal in water using millimeter-sized porous granular MgO-biochar with high adsorption capacity
期刊: Journal of Hazardous Materials
作者: Tao Chen, Yuanfeng Wei, Weijian Yang, Chengbin Liu
摘要: Biochar adsorbents for removing As(III) suffer from the problems of low adsorption capacity and ineffective removal. Herein, a granular MgO-embedded biochar (g-MgO-Bc) adsorbent is fabricated in the form of millimeter-sized particles through a simple gelation-calcination method using chitosan as biochar sources. High-density MgO nanoparticles are evenly dispersed throughout the biochar matrix and can be fully exposed to As(III) through the rich pores in g-MgO-Bc. These features endow the adsorbent with a high adsorption capacity of 249.1mg/g for As(III). The g-MgO-Bc can efficiently remove As(III) over a wide pH of 3-10. The coexisting carbonate, nitrate, sulfate, silicate, and humic acid exert a negligible influence on As(III) removal. 300μg/L of As(III) can be purified to far below 10μg/L using only 0.3g/L g-MgO-Bc. The spent g-MgO-Bc could be well regenerated by simple calcination. In fixed-bed column experiments, the effective treatment volume of As(III)-spiked groundwater achieves 1500 BV (30L) (3g of adsorbent, solution flow rate of 2.0mL/min, C0 = 50μg/L). The Mg(OH)2 generated in situ in g-MgO-Bc is responsible for the adsorption of As(III) through the inner-sphere complex mechanism. The work would extend the potential applicability of biochar adsorbent for As(III) removal to a great extent.
38. 题目: Photo-induced degradation and toxicity change of decabromobiphenyl ethers (BDE-209) in water: Effects of dissolved organic matter and halide ions
期刊: Journal of Hazardous Materials
作者: Fangyuan Cheng, Jiale He, Chao Li, Ying Lu, Ya-nan Zhang, Jiao Qu
摘要: BDE-209 is a widely used brominated flame retardant that is ubiquitous in the aquatic environment, especially in marine water. However, photodegradation of BDE-209 in seawater is still not fully understood. In this work, the photodegradation kinetics of BDE-209 in water was studied and the effects of seawater dissolved organic matter (S-DOM) and halide ions (Cl−, Br−) were evaluated. S-DOM inhibited the degradation of BDE-209 through dynamic quenching and light shielding effect. However, with the coexistence of S-DOM, Cl− and Br−, the photodegradation of BDE-209 was significantly promoted. The promotional effect is attributed to the generation of excited triplet state S-DOM, singlet oxygen, and reactive halogen radicals. The results of density functional theory calculation showed that •Cl addition reaction on C-Br sites of BDE-209 is the main reaction pathway of BDE-209 with chlorine radical, which leads to the generation of mixed Cl/Br substituted intermediates. The acute toxicity and estrogenic effects of BDE-209 solution were enhanced during simulated sunlight irradiation. These results indicate that the environmental factors in seawater play important roles in the photodegradation of BDE-209, and contribute to the potential ecological risks of PBDEs in the marine environment.
39. 题目: Low mobility of CuO and TiO2 nanoparticles in agricultural soils of contrasting texture and organic matter content
期刊: Science of The Total Environment
作者: Marie SIMONIN, Jean M.F. MARTINS, Gaëlle UZU, Lorenzo SPADINI, Aline NAVEL, Agnès RICHAUME
摘要: The fate of nanoparticles (NPs) in soil under relevant environmental conditions is still poorly understood. In this study, the mobility of two metal-oxide nanoparticles (CuO and TiO2) in contrasting agricultural soils was investigated in water-saturated soil columns. The transport of TiO2 and CuO-NPs were assessed in six soils with three different textures (from sand to clay) and two contrasted organic matter (OM) contents for each texture. TiO2 mobility was very low in all soils, regardless of texture and OM content. Mass recoveries were always less than 5%, probably in relation with the strong homo-aggregation of TiO2-NPs observed in all soil solutions, with apparent sizes 3–6 times larger than their nominal size. This low mobility suggests that TiO2-NPs present a low risk of direct groundwater contamination in contrasted surface soils. Although their retention was also generally high (more than 86%), CuO nanoparticles were found to be mobile in all soils. This is probably related to their smaller apparent size and low capacity of homo-aggregation of CuO-NPs in all soil solutions. No clear influence of neither soil texture or soil total organic matter content could be observed on CuO transport. However, this study shows that in contrasted agricultural soils, CuO-NPs transport is mainly controlled by the solutes dissolved in soil solution (DOC and PO4 species), rather than by the properties of the soil solid phase.
40. 题目: Impact of freeze-thaw cycles on organic carbon and metals in waters of permafrost peatlands
作者: D.A.H.É.D.R.E.Y. PAYANDI-ROLLAND, L.I.U.D.M.I.L.A.S. SHIROKOVA, F.A.B.I.A.N. LABONNE, P.A.S.C.A.L.E. BÉNÉZETH, O.L.E.G.S. POKROVSKY
摘要: Despite the importance of soil and surface waters freezing in permafrost landscapes, the behaviour of dissolved organic carbon (DOC), nutrients and metals during periodic freeze-thaw cycles (FTC) remains poorly known. The on-going climate warming is likely to increase the frequency of FTC in continental aquatic settings, which could modify the chemical composition of waters. In this study, we conducted 9 repetitive cycles of overnight freezing (-20 °C) and 5 hours thawing (4°C) in the laboratory using representative 0.22 μm-filtered waters from NE European permafrost peatland: leachates of vegetation and soil, and natural surface waters (depression, thermokarst lake and river). Only minor (<5% - 15%) changes of DOC concentrations, SUVA254 and molecular weight were observed in all leachates and the depression water. In contrast, several trace elements (Fe, Al, P, Mn, As, and REE) exhibited sizable variations during FTC (>10%). The leachates and the depression water were enriched in trace elements, whereas the thermokarst lake and the river demonstrated a decrease in concentration of Fe (-39 and -94 %, respectively), Al (-9 and -85 %), and Mn (-10 and -79 %) during FTC. Overall, the observations demonstrated an increase in aliphatic low molecular weight organic matter (OM), and the precipitation of Fe, Al hydroxides and organo-mineral particles. Therefore, enhanced of frequency of FTC can favour the release of metals and toxicants from acidic OM-rich surface waters and maintain stable OM-metals-colloids in large lakes and rivers, thus regulating aquatic transport of DOC and metals from soils to the Arctic Ocean.