61. 题目: Assembly processes of abundant and rare microbial communities in orchard soil under a cover crop at different periods
作者: Zhiyuan Zhao, Yanting Ma, Tianyu Feng, Xu Kong, Zhaohui Wang, Wei Zheng, Bingnian Zhai
摘要: Soil microorganisms play key roles in agricultural ecosystems. However, little is known about their dynamic diversity patterns and community assembly processes, especially in the rare microbial biosphere in agriculture systems. In this study, we determined the responses of diversities and assembly processes of abundant and rare bacterial and fungal subcommunities to agricultural practice (i.e. cover crop) in a semiarid orchard soil by using 16S and ITS rRNA gene sequencing. We found that the community structures of abundant and rare taxa exhibited a similar response to cover crop or growth periods. Growth periods significantly changed the bacterial and fungal subcommunities structure. Only the fungal subcommunities structure was affected by cover crop. The community assembly of abundant and rare fungi was respectively dominated by stochastic process and deterministic process and less affected by cover crop and growth period. For abundant bacteria, the assembly process was dominated by heterogeneous and undominated processes, and the importance of heterogeneous selection process was increased by cover crop at setting and maturing period. The assembly process of rare bacterial community was dominated by a homogeneous selection and the relative importance of dispersal limitation was increased at maturing period. We also found that the assembly processes of abundant taxa were significantly related to the soil DON, NH4+-N, NO3–-N and pH, while the assembly processes of rare taxa were significantly related to the soil DOC, AP and SOC. Our results provide new insights into the formation of the microbial community in orchard soil under a cover crop, especially the seasonal succession of abundant and rare bacterial and fungal subcommunities.
62. 题目: Humic acid enhanced pyrene degradation by Mycobacterium sp. NJS-1
作者: Xiaoning Li, Hailong Liu, Weiben Yang, Hongjie Sheng, Fang Wang, Jean Damascene Harindintwali, H.M.S.K. Herath, Yinping Zhang
摘要: The search for nature-based tools to enhance bioremediation is essential for the sustainable restoration of contaminated ecosystems. Humic acid (HA) is an important component of organic matter in soil and water, but its effect on the microbial degradation of organic pollutants remains unclear. In this study, the biodegradation of pyrene by Mycobacterium sp. NJS-1 with and without HA was investigated. Only around 10.5% of pyrene was biodegraded in the pyrene treatment alone, whereas the addition of HA significantly enhanced biodegradation to the point where over 90% of pyrene was biodegraded. The production of 4,5-dihydropyrene-4,5-diol and phenanthrene-3,4-diol indicated the metabolic pathway via attacking of 4,5-positions of pyrene. Interestingly, 1,2-dimethoxypyrene was detected with the addition of HA, suggesting that HA induced a new ring-opening pathway involving the attack on the 1,2-positions of pyrene. The addition of HA first induced protein self-cleavage behavior with a significant increase in phenylalanine, tyrosine, and tryptophan containing large numbers of COO− groups. Furthermore, it altered the intracellular and extracellular ultrastructure of bacterial cells, promoting their growth in size and number as well as reducing the space between them. Overall, HA increased the ring-opening positions of pyrene and facilitated its interaction with bacterial cells, thus improving its biodegradability. Building upon the findings of this study to further research is conducive to the sustainable solution of environmental pollution.
63. 题目: Preferential removal of benzene, toluene, ethylbenzene, and xylene (BTEX) by persulfate in ethanol-containing aquifer materials
期刊: Environmental Science and Pollution Research
作者: Huan Wang, Yudao Chen, Wei Meng, Yaping Jiang, Yaping Cheng
摘要: The effective approaches to eliminate impacts of ethanol on the biodegradation of benzene, toluene, ethylbenzene, and xylene (BTEX) are concerned in the bioremediation of groundwater contaminated with ethanol-blended gasoline. In situ chemical oxidation (ISCO) is a common technique widely used for the remediation of contaminated groundwater. However, the selectivity of ISCO for BTEX and ethanol removal is poorly understood. Therefore, a batch experiment was performed with different aquifer materials, including calcareous soil, basalt soil, granite soil, dolomite, and sand. Gasoline was used to provide dissolved BTEX and ethanol reagent was used as additive to improve the quality of gasoline and to reduce the possibility of air pollution caused by gasoline. Persulfate (PS) was used as a chemical oxidant to oxidize organic contaminants. The target concentrations of BTEX and ethanol were 20 mg/L and 1000 mg/L, respectively. The results showed that ethanol could be preferentially degraded in the absence of PS and inhibit BTEX biodegradation. However, BTEX could be preferentially removed prior to ethanol in all aquifer materials used at ambient temperature, when PS was added at a PS/BTEX molar ratio of 150. Over 94% BTEX in sand, dolomite, and granite soil was preferentially removed with the first-order decay rate constants of 0.890–2.703 day−1 within the first ~ 10 days, followed by calcareous and basalt soil at the constants of 0.123–0.371 day−1. Ethanol could compete with BTEX for sulfate radical at the first-order decay rate constants of 0.005–0.060 day−1 for the first 25 days, which was slower than that of BTEX. The pH quickly decreased to < 2.5 in dolomite, sand, and granite soil, but maintained > 6.2 in calcareous soil. Rich organic matter in calcareous and basalt soil had an inhibition effect on BTEX oxidation by PS. The pH buffer in calcareous soil may imply the potential of PS oxidation combined with bioremediation in carbonate rock regions.
64. 题目: Characteristics of Dissolved Organic Matter and Dissolved Lignin Phenols in Tropical Forest Soil Solutions during Rainy Seasons and Their Responses to Nitrogen Deposition
期刊: ACS Earth and Space Chemistry
作者: Mengke Wang, Ziting Zhang, Yinghui Wang, Xiaohan Mo, Qiang Zhang, Peng Zhang, Gege Yin, Liping Li, Senhao Wang, Jiangming Mo, Wei Zhang, Jun-Jian Wang
摘要: Dissolved organic matter (DOM) in soils plays a crucial role in biogeochemical cycles during rainy seasons in forest systems. However, spatiotemporal variations in DOM characteristics in forest soil solutions during the rainy season and their responses to increased nitrogen deposition are unclear. Using optical spectroscopy, dissolved lignin phenol analysis, and stable carbon isotope analysis, we characterized DOM in soil solutions collected in May, July, and September at different soil depths (20 and 40 cm) from two tropical plantations with three N addition levels (0, 50, and 100 kg N ha–1 yr–1). Although the dissolved organic carbon (DOC) concentration did not significantly differ between depths, the aromaticity and δ13C values of DOM and dissolved lignin phenol levels were lower at 40 cm than at 20 cm, which could be attributed to the preferential mineral adsorption or microbial consumption of dissolved lignin and light carbon isotopes in the layer between 20 and 40 cm. The DOC concentration decreased and DOM aromaticity (indicated by specific ultraviolet absorbance at 254 nm) increased from May to September, possibly due to increasing consumption of nonaromatic DOM and dilution of DOC in the middle and late rainy seasons. However, 8 years of nitrogen addition did not significantly alter the DOM concentrations or characteristics in the soil solution. These findings enhanced our understanding of the dynamics of DOM quantity and quality in tropical plantations and their drivers under global environmental change.
65. 题目: Quantifying importance of macrobenthos for benthic‐pelagic coupling in a temperate coastal shelf sea
期刊: Journal of Geophysical Research: Oceans
作者: Wenyan Zhang, Andreas Neumann, Ute Daewel, Kai Wirtz, Justus E.E. Beusekom, Annika Eisele, Mengyao Ma, Corinna Schrum
摘要: Benthic oxygen fluxes consist mostly of advective and diffusive terms. Both terms in the German Bight exhibit a prominent annual cycle but with opposite variation patterns. To understand the driving mechanisms quantitatively, a novel 3-D benthic-pelagic coupled model resolving interactions among macrobenthos, bioturbation, oxygen consumption, and carbon early diagenesis was applied to reconstruct the benthic states. Simulation results show a satisfactory agreement with field data and reveal that the benthic oxygen flux is determined by not only pelagic drivers but also by internal dynamics associated with the interaction between organic carbon and macrobenthos, and bedform morphodynamics. Variation of advective flux, characterized by summer-low and winter-high, is mainly driven by hydrodynamics and bedform morphodynamics, while variation of diffusive flux, featured by summer-high and winter-low, is a compound effect of pelagic and benthic drivers with a dominant control by macrobenthos through bioturbation. The role of bioturbation in benthic oxygen consumption is twofold: (a) on the one hand, it alters the particulate organic carbon (POC) distribution in surface sediments, thereby changing the availability of POC to oxygen consumption; (b) on the other hand, it mixes oxygen down into sediments, thereby facilitating oxygen consumption. Our results indicate that the first role prevails in sandy seafloor characterized by energetic hydrodynamics, while the second role becomes increasingly important along with a weakening of bottom currents. We found that bioturbation contributes up to 87% ￼ 4% and 55% ￼ 8% of the total benthic oxygen fluxes in muddy seabed and at a regional scale (the German Bight), respectively.
66. 题目: Insights into the removal of Cd and Pb from aqueous solutions by NaOH-EtOH-modified biochar
期刊: Environmental Technology & Innovation
作者: Tong Cai, Huihui Du, Xiaoli Liu, Baiqing Tie, Zhaoxia Zeng
摘要: The enhancement of surface functional groups on biochar is essential to improving its toxic metals adsorption capacity. In this study, we used two solutions: NaOH(aq) and NaOH dissolved in absolute ethanol (C2H5OH) to dope the surface of powdered oiltea camellia shell. Then, the shells were pyrolyzed at 500 °C for 120 min to obtain NaOH-modified biochar (SBC), NaOH-C2H5OH-modified biochar (EBC), and the undoped sample (BC). After modification, the special surface area, O-containing functional groups, especially C=C were improved. The specific surface area of EBC and SBC (91.76 and 56.83 m2g−1, respectively) were superior to that of the BC (36.98 m2g−1). With NaOH-C2H5OH, more C=C groups were introduced via elimination reaction, enhancing its adsorption properties. EBC consistently showed higher adsorption efficiency than BC for Cd(II) and Pb(II). Moreover, the spectroscopic analysis revealed that Cd(II)-π, Pb(II)-π interactions were the predominant mechanisms for the toxic metals’ collection on the EBC, each contributing 75.45% and 58.60%, respectively. Besides, the O-functional groups onto EBC surface bonded easily to Pb(II) than Cd(II) in the mixture solution. Therefore, EBC produced in the NaOH-C2H5OH system, as efficient and cost-effective biochar, is promising for toxic metals adsorption.
67. 题目: Degradation of Naproxen by UV-irradiation in the presence of nitrate: Efficiency, mechanism, products, and toxicity change
期刊: Chemical Engineering Journal
作者: Sicheng Gong, Chao Ding, Jia Liu, Kun Fu, Yishuai Pan, Jun Shi, Huiping Deng
摘要: Nitrate photolysis can produce reactive species that may affect the fate of coexisting micropollutants in the aquatic environment. In this study, the photo-degradation of naproxen (NPX) in the presence of nitrate was investigated. The observed pseudo-first-order rate constant (kobs) increased linearly with the nitrate dosage increasing from 1 mM to 10 mM. According to the EPR analysis and the quenching experiments, hydroxyl radicals (HO•) and reactive nitrogen species (RNS, mainly NO2•) were found to play major roles in NPX degradation at pH 7.0 with the contribution of 34.3% and 40.7%, respectively. The kobs decreased with increasing pH due to the lower contribution of HO• and RNS. Moreover, water matrix components impacted the kinetics of NPX decomposition differently. Natural organic matter (NOM) had an inhibitory effect on the degradation of NPX, while bicarbonate and chloride ions slightly promoted the degradation. Furthermore, the degradation products in the system were identified by UPLC Q-TOF-MS analysis, and the transformation of NPX was shown to be mainly side-chain cleavage, hydroxylation, ring-opening, and nitration, indicating the role of HO• as well as RNS. According to the cytotoxicity assay and the toxicity of identified products predicted by ECOSAR program, the formation of several toxic products with aldehyde and nitro groups led to the increased toxicity during NPX degradation. Our study provides insights into the transformation mechanisms and the toxicity evolution of NPX in the photolysis system.
68. 题目: Degradation of 17 Benzodiazepines by the UV/H2O2 Treatment
期刊: Frontiers in Environmental Science
作者: Wen-Dan You, Pu Ye, Bin Yang, Xin Luo, Jie Fang, Zi-Tian Mai, Jian-Liang Sun
摘要: Benzodiazepines are one group of psychoactive drugs widely detected in water environments, and their persistence during conventional wastewater treatment has raised great concerns. Here we investigated the degradation of 17 benzodiazepines in water by UV/H 2 O 2 treatment. The results showed that the UV/H 2 O 2 treatment significantly increased the degradation of 17 benzodiazepines in phosphate buffer solutions at pH 7.0. This can be attributed to the high reactivity of hydroxyl radicals (·OH) towards benzodiazepines with second-order rate constants of 3.48 × 10 9 M −1 s −1 –2.44 × 10 10 M −1 s −1 . The degradation of alprazolam, a typical benzodiazepine, during the UV/H 2 O 2 treatment was increased with the increasing H 2 O 2 dosage. The solution pH influenced the alprazolam degradation significantly, with the highest degradation at pH 7.0. Water matrix, such as anions (Cl − , HCO 3 − , NO 3 − ) and humic acid, decreased the degradation of alprazolam by UV/H 2 O 2 treatment. Based on the degradation products identified using quadrupole time-of-flight mass spectrometer, the degradation mechanisms of alprazolam by UV/H 2 O 2 treatment were proposed, and hydroxylation induced by ·OH was the main reaction pathway. The degradation of 17 benzodiazepines by UV/H 2 O 2 treatment in wastewater treatment plant effluent and river water was lower than that in phosphate buffer solutions. The results showed that the benzodiazepine psychoactive drugs in natural water can be effectively removed by the UV/H 2 O 2 treatment.
69. 题目: Preliminary evaluation of the operation variables and degradation pathway in the alkali-catalyzed hydrothermal oxidation of triclosan
期刊: Journal of Cleaner Production
作者: Rong Zhang, Rui Shi, Nengmin Zhu, Zhiyong Han, Hongjun Luo, Yushuang Chen, Xinshou Li
摘要: Due to the lack of green treatment technologies for chlorinated organic contaminant detoxification, in this study, the effect of non-hazardous alkali-catalyzed hydrothermal oxidation (HTO) on triclosan (TCS) was investigated. The optimal parameters determined by single-factor experiments were: a H2O2/TCS (H/T) ratio of 2.5 mL/mg, a temperature of 180 °C, a residence time of 120 min. Using these parameters, the final dechlorination efficiency (DE) of 99.69% was obtained. Response surface methodology (RSM) was employed to further determine the optimal conditions under multi-factor interactions. The optimal parameters were an H/T ratio of 2.5 mL/mg, a temperature of 187 °C, and a residence time of 150 min. The determined DE was 99.47%. The results of three-dimensional excitation-emission matrix (3D-EEM) fluorescence spectroscopy showed that the degradation of TCS generated humic acid-like organics with aromatic ring and phenolic hydroxyl functional groups. Furthermore, fluorescence spectroscopy analysis showed that the residence time increased from 30 to 120 min, and the fluorescence intensity difference increased from 100.5 to 218 au, which confirmed that •OH participated in the alkali-catalyzed HTO process. There were two different reaction pathways: (1) Cleavage of the C–O bond between the two benzene rings, followed by the opening and dechlorination of the benzene ring via oxidation; (2) The benzene rings were directly hydroxylated, opened, and dechlorinated through oxidation. The intermediate products were further oxidized to non-Cl-containing organics, achieving the harmless degradation of TCS. Further analysis showed that the total organic carbon (TOC) removal efficiency was about 80% at a residence time of 140 min, indicating that TCS was almost completely mineralized. This study provides a green and environmentally benign approach for the detoxification of chlorinated organic contaminants.
70. 题目: Effect of mixed primary and secondary sludge for two-stage anaerobic digestion (AD)
期刊: Bioresource Technology
作者: Cheng Sun, Liang Guo, Yongkang Zheng, Dan Yu, Chunji Jin, Yangguo Zhao, Zhiwen Yao, Mengchun Gao, Zonglian She
摘要: As an energy-efficient and eco-friendly sludge treatment process, two-stage anaerobic digestion (AD) is widely employed to recovery biomass energy from waste sludge. However, the effect of primary and secondary sludge for two-stage AD was not clear. In this study, two-stage AD of mixed sludge in different volume ratio was investigated. The maximum cumulative H2 yield (100.5 ml) and CH4 yield (2643.6 ml) were obtained in volume ratio of 1:3 (primary sludge: secondary sludge). In two-phase AD, mixed sludge could induce positive effect on both organics releasing in extracellular polymeric substances (EPS) and the utilization of volatile fatty acids (VFAs). By investigating the compositional characteristics of dissolved organic matters (DOM) through excitation-emission matrix (EEM) coupling with fluorescence regional integration (FRI), it revealed more degradable substances utilization in mixture of sludge. Results from this work suggest that two-phase AD with mixed sludge is efficient for renewable energy recovery.
71. 题目: Kinetics and mechanisms of diniconazole degradation by α-MnO2 activated peroxymonosulfate
期刊: Separation and Purification Technology
作者: Mengjiu Zhao, Ruishuang Xu, Zhengqiang Chen, Zhihong Gao, Shengrun Zheng, Haiyan Song
摘要: As one of the high-efficiency triazole fungicides, diniconazole (DIN) has been used on a large scale in agricultural production. Due to its high stability and toxicity, DIN is usually persisted in soil and water and has been demonstrated to be a potential threat to environment and humans. In this study, the degradation kinetics, mechanisms, and degradation products of DIN by peroxymonosulfate (PMS) activated with α-MnO2 were systematically studied. The results showed that DIN was rapidly degraded in α-MnO2 activated PMS system, and the degradation kinetics of DIN in this reaction system could be described by the pseudo-first-order kinetic model. The degradation of DIN was affected by environmental conditions. Acidic condition was beneficial to the degradation of DIN, whereas co-existing anions (HPO42-, Cl- and HCO3-) and humic acid inhibited the degradation of DIN in MnO2 activated PMS system. SO4￼- and HO￼ generating from PMS activated by α-MnO2 were confirmed as the major active species in degradation of DIN. The potential sites attacked in the DIN structure might be 11Cl, 10Cl, 14C and 17C based on the DFT calculation. Moreover, the degradation pathways of DIN were proposed, including hydroxylation, hydroxyl addition, cleavage of 14C-15N and intramolecular cyclization.
72. 题目: Climate change mitigation potential of biochar from forestry residues under boreal condition
期刊: Science of The Total Environment
作者: Andreas Hagenbo, Clara Antón-Fernández, Ryan M. Bright, Daniel Rasse, Rasmus Astrup
摘要: Forest harvest residue is a low-competitive biomass feedstock that is usually left to decay on site after forestry operations. Its removal and pyrolytic conversion to biochar is seen as an opportunity to reduce terrestrial CO2 emissions and mitigate climate change. The mitigation effect of biochar is, however, ultimately dependent on the availability of the biomass feedstock, thus CO2 removal of biochar needs to be assessed in relation to the capacity to supply biochar systems with biomass feedstocks over prolonged time scales, relevant for climate mitigation. In the present study we used an assembly of empirical models to forecast the effects of harvest residue removal on soil C storage and the technical capacity of biochar to mitigate national-scale emissions over the century, using Norway as a case study for boreal conditions. We estimate the mitigation potential to vary between 0.41 and 0.78 Tg CO2 equivalents yr−1, of which 79% could be attributed to increased soil C stock, and 21% to the coproduction of bioenergy. These values correspond to 9–17% of the emissions of the Norwegian agricultural sector and to 0.8–1.5% of the total national emission. This illustrates that deployment of biochar from forest harvest residues in countries with a large forestry sector, relative to economy and population size, is likely to have a relatively small contribution to national emission reduction targets but may have a large effect on agricultural emission and commitments. Strategies for biochar deployment need to consider that biochar's mitigation effect is limited by the feedstock supply which needs to be critically assessed.
73. 题目: Degradation of sulfamethazine in UV/monochloramine process: Kinetics, by-products formation, and toxicity evaluation
期刊: Chemical Engineering Journal
作者: Huiming Xiang, Naiyun Gao, Xian Lu, Yuanquan Xiang, Wenhai Chu
摘要: Ultraviolet combined monochloramine (UV/NH2Cl) process is a promising advanced oxidation process (AOP) to remove organic micropollutants effectively through the generation of various reactive species e.g., hydroxyl radicals (HO•), reactive chlorine species (RCS), and reactive nitrogen species (RNS). This study investigated the kinetics, transformation pathways, DBPs formation, and toxicity alternation in the degradation of sulfamethazine (SMT). Based on the calculation of degradation kinetic models, RNS was proved to be the most important reactive species in the degradation of SMT in UV/NH2Cl. The contribution of RNS, HO• and RCS were approximately 56.6%, 38.8%, and 4.5%, respectively. With the NH2Cl dosage increased from 100 to 800 µmol L-1, degradation rate increased from 37% to 73% in 10 min. Significantly alternation was not observed with the changing of pH. Natural organic matter (NOM) remarkably inhibited the degradation rate to 48.6% and 32.8% in the presence of 1 and 2 mg L-1 NOM. Degradation reactions of SMT in UV/NH2Cl system primarily comprised of hydroxylation, nitrosation, and ring opening reactions. The total theoretical toxicity of degradation system increased in the first 20 min and decreased eventually. Comparing with UV/free chlorine (UV/Cl2) process, less disinfection by-products (DBPs) generated in UV/NH2Cl treatment. Thus, the theoretical toxicity of DBPs formed in UV/NH2Cl was much lower than UV/Cl2. Within 40 min degradation, the theoretical toxicity value reached maximum at pH 7.1 due to the mass production of dicloroacetonitrile (DCAN). Bromide ions (10µmol L-1) significantly promoted the formation of brominated DBPs especially dibromoacetonitrile (DBAN). This study provided insight into the important role of RNS in the SAs’ transformation in UV/NH2Cl process and reference to benefits and disadvantages when selecting the process for disinfection in drinking water treatment.
74. 题目: Methane emission is independent from silicon availability in warm-temperate Chamaecyparis obtusa forest soils from diverse topographic positions
作者: Ryosuke Nakamura, Ayaka Sakabe, Kenshi Takahashi
摘要: It has been recently reported that silicon (Si) increases methane (CH4) emission from peats through mobilizing phosphorus and organic carbon bound to iron minerals and stimulating microbial activities. However, it is unknown whether this effect of Si applies in other environments, such as warm temperate forest soils that function primarily as a CH4 sink but occasionally as a CH4 source. We tested our hypothesis that CH4 emission should increase with Si availability in warm temperate forest soils under anaerobic conditions, by incubating four soil samples collected from a variety of topographic positions in the Kiryu Experimental Watershed, in Shiga, Japan. The soil characteristics including soil pH and total phosphorus and iron contents varied among the soils. Much greater CH4 emission was observed in the soils from the riparian wetland areas than in those from the upland areas. The onset of methanogenesis was not accelerated by Si addition during the incubation. At the end of the incubation, the Si addition did not increase total CH4 production from the soils. A lack of the Si effects would be due to low quantities of phosphorus retained by iron minerals in the entire area of this watershed and high abundance of more potent electron acceptors in the upland. Overall, our results suggest that increasing Si availability exerts little influence on CH4 emissions from warm temperate forest soils under the used experimental conditions in this watershed.
75. 题目: Activation of persulfate by swine bone derived biochar: Insight into the specific role of different active sites and the toxicity of acetaminophen degradation pathways
期刊: Science of The Total Environment
作者: Xuerong Zhou, Cui Lai, Shiyu Liu, Bisheng Li, Lei Qin, Xigui Liu, Huan Yi, Yukui Fu, Ling Li, Mingming Zhang, Huchuan Yan, Jing Wang, Ming Chen, Guangming Zeng
摘要: Recently, persulfate (PS) activation system has grown up as a primary branch of advanced oxidation processes, and biochar has been recognized as a potential nonmetal material in this field. However, few studies have focused on the corresponding relationship between actives sites on biochar and active species in AOPs. To pave this way, similar biochar (obtained from different pyrolysis temperature) with different functional structures were involved. In this study, biochar derived from swine bone (BBC) was applied in PS activation system to degrade acetaminophen (ACT). The results showed that both radical and non-radical pathway worked in the PS/BBCs systems, and the degradation rate (from 0.1042 to 0.4364 min−1) climbed with the increase of pyrolysis temperature (from 700 to 900 °C). To probe into the corresponding relationship between functional structure and active species, the effect of pyrolysis temperature on functional structure was analyzed. It came out that 1) defects could act as active sites for various active species; 2) persistent free radicals could do favor to the generation of 1O2 and O2￼−; 3) hydroxyapatite in swine bone only served as hard templet for the porous structure. ACT degradation process was measured by Liquid chromatograph-mass spectrometer, and Scendesmus obliquus was applied to investigate the toxicity of PS/BBCs system. It illustrated that the existence of SO4￼− mainly contributed to the generation of high toxic intermediates (such as biphenyl and diphenyl ether) in the PS/BBCs system. Furthermore, the enhancement of adsorption capacity would mitigate the toxicity of PS/BBCs systems to some extent.
76. 题目: Influence of polyethylene terephthalate microplastic and biochar co-existence on paddy soil bacterial community structure and greenhouse gas emission
期刊: Environmental Pollution
作者: Lanfang Han, Liying Chen, Detian Li, Yang Ji, Yuanyuan Feng, Yanfang Feng, Zhifeng Yang
摘要: Microplastic (MP) contamination is ubiquitous in agricultural soils. As a cost-effective soil amendment, biochar (BC) often coincides with MP exposure. However, little research has been conducted regarding the independent and combined effects of MPs and BC on the soil microbiome and N2O/CH4 emissions. Therefore, in this study, polyethylene terephthalate (PET) and wheat straw-derived BC were used, respectively, as a representative MP and BC during an entire rice growth period. The high-throughput sequencing results showed that PET alone lowered bacterial diversity by 26.7%, while PET and BC co-existence did not induce apparent change. The relative abundances of some microbes (e.g., Cyanobacteria, Verrucomicrobia, and Bacteroidetes) that are associated with C and N cycling were changed at the phylum and class levels by all the treatments. In comparison with the control, the treatment of BC, PET, and their co-existence reduced the cumulative CH4 emissions by 50%, 53%, and 61%, respectively. The higher mitigation by BC + PET may be the result of higher soil Eh and a consequently lower methanogenesis functional gene mcrA abundance in the treated soils. In addition, BC and PET alone, as well as their combined treatment, increased the abundance of nitrification genes, enhancing the soil nitrification process. However, the relative contribution of the nitrification process to N2O emission was possibly lower than that of denitrification, in which the N2O reductase gene nosZ was found to be the primary gene regulating N2O emissions. BC alone increased nosZ abundance by 42.3%, thereby showing the potential in suppressing N2O emission. In contrast, when BC was co-added with PET, the nosZ abundance lowered possibly because of increased soil aeration, and thus its cumulative N2O emission was 38% higher than the BC treatment. Overall, these results demonstrated that BC and PET function differently in soil ecosystems when they coexisted.
77. 题目: Fe(III)-doped activated biochar sorbents trigger mitochondrial dysfunction with oxidative stress on Daphnia magna
作者: Songhee Lee, Sungjong Lee, Eun Hea Jho, Sooim Shin, Chang Min Park
摘要: This study investigates the ecotoxicological effects of the synthesized Fe(III)-doped activated biochar (FeAB) sorbents using Daphnia magna and elucidates the underline mechanism of potential oxidative stress that may be induced by the sorbent. The EC50 value was determined to be 68.8 mg L−1. The superoxide dismutase (SOD) activity of D. magna was generally inhibited and the glutathione (GSH) level was significantly reduced even at the lowest FeAB concentration used (i.e., 0.12 mg L−1). This means that the antioxidant system of D. magna can be significantly inhibited by exposure to even a small amount of FeAB. While the higher reactive oxygen species (ROS)/reactive nitrogen species (RNS) levels in the exposed samples than the control at low FeAB concentrations (i.e., <15.63 mg L−1) suggest the failure of the anti-oxidation mechanism of SOD and GSH, the lower average levels of ROS/RNS in the exposed samples than the control at relatively high concentrations (i.e., 31.25–1000 mg L−1) can be explained by the reduced ROS/RNS production due to cell damage. Furthermore, the mitochondrial complex III activities were significantly inhibited in a FeAB concentration-dependent manner. Overall, the FeAB sorbent down-regulates the antioxidant mechanism, and this, together with the inefficient mitochondria, increases the ROS generation, leading to mitochondrial dysfunction again. The potential oxidative stress of FeAB on D. manga observed in this study suggests that the environmental application of FeAB needs to adopt a method that can minimize the direct contact between FeAB and organisms.
78. 题目: Redox-driven changes in organic C stabilization and Fe mineral transformations in temperate hydromorphic soils
作者: Beatrice Giannetta, Danilo Oliveira de Souza, Giuliana Aquilanti, Luisella Celi, Daniel Said-Pullicino
摘要: Paddy soils experience long-term redox alternations affecting the interactions between the biogeochemical cycling of iron (Fe) and carbon (C). Differences in particle aggregation and soil organic matter (SOM) turnover are likely to both affect and be affected by the trajectory of Fe mineral evolution/crystallinity with redox fluctuations. We hypothesized that the legacy effects of redox cycling under paddy management affects particle aggregation, the distribution and mineralogy of Fe (hydr)oxides between particle-size fractions, and the interaction with SOM stabilization. Moreover, we expected underlying processes to be different in paddy eluvial and illuvial horizons, particularly due to the different inputs and redox conditions these horizons experience. To test these hypotheses, we evaluated the distribution of Fe species and organic C between different aggregate and particle-size fractions in topsoil (eluvial) and subsoil (illuvial) horizons of soils under long-term paddy and non-paddy management in NW Italy, as well as mineralogical changes in Fe phases by Fe K-edge Extended X-ray Adsorption Fine Structure (EXAFS) and X-ray Absorption Near Edge Structure (XANES) spectroscopy. Our findings indicate that although paddy topsoils are depleted in hydrous Fe oxides with respect to non-paddy soils, they can stabilize important amounts of C through mineral associations, particularly with finer particle-size fractions rich in less crystalline Fe phases. We also show that redox cycling can influence microaggregate stability and consequently the distribution of Fe phases and OC between intra and inter-microaggregate fractions. On the other hand, illuvial horizons under paddy management were enriched in short-range ordered hydrous Fe oxides and this contributed to enhanced microaggregate formation and C stabilization with respect to non-paddy subsoils.
79. 题目: Effects of compost-derived humic acid on the bio-dechlorination of pentachlorophenol in high iron content paddy soil
期刊: Ecotoxicology and Environmental Safety
作者: Yu Xiao, Haojie Lu, Wenbing Tan, Jun Tang, Yang Wang, Junxiang Shi, Tingqiao Yu, Ying Yuan
摘要: Pentachlorophenol (PCP) is a common residual organic pollutant in paddy soil, and its harmful effects on soil ecosystems have been confirmed. Humic acid (HA) could act as an electron shuttle to promote the reductive dechlorination of PCP under anaerobic conditions. Humic-like substances produced by composting of kitchen waste were able to facilitate the reductive dechlorination of PCP during Fe(III) oxide reduction by iron-reducing bacteria. However, the effects of compost-derived HAs on reductive dechlorination of PCP in a paddy soil system with a high iron content have not been fully confirmed. The characteristics of HAs from different stages of composting during bio-dechlorination of PCP were still unclear. The functional components of compost-derived HAs, which are responsible for reductive dechlorination of PCP in different stages of composting, also need further investigation. In this study, we conducted a series of experiments on the Guangdong paddy soil system with high iron content (17.5 mg kg−1) to investigate the reductive dechlorination of PCP by HA in the early, middle, and later stages of food waste composting. The results showed that the middle- and late-stages of compost-derived HAs all promoted reductive dechlorination of PCP in the paddy system, but it was opposite in the early-stage. Significant differences were also presented in the components of HAs from different stages of composting. The early-stage compost-derived HAs contain numerous easy degradable components, it would inhibit the dechlorination of PCP by the changes of microbial metabolism in paddy soil. Compost-derived HAs in the middle composting stage showed the best reductive dechlorination effects on PCP. The reason might be that the compost-derived HAs in the middle composting stage could act both as electron donors and transfers. The electron transfer capacities (ETC) of middle-stage compost-derived HAs were significantly higher than those in the early and later composting stages. Compared with the natural HAs in the soil system, compost-derived HAs contained more chlorinated products with lower toxicities after the PCP degradation. This result mainly contributed to the detoxification and mineralization of PCP in the soil. These findings clarified the effects of compost-derived HAs on PCP bio-dechlorination in paddy soil with high iron content, identifying the optimal phase of compost-derived HA and providing a theoretical basis for the utilization of kitchen waste composting as a resource of HA.
80. 题目: Novel bioaugmentation strategy boosted with biochar to alleviate ammonia toxicity in continuous biomethanation
期刊: Bioresource Technology
作者: Yixin Yan, Miao Yan, Giulia Ravenni, Irini Angelidaki, Dafang Fu, Ioannis A. Fotidis
摘要: This study investigated for the first time if ammonia tolerant methanogenic consortia can be stored in gel (biogel) and used in a later time on-demand as bioaugmentation inocula, to efficiently relieve ammonia inhibition in continuous biomethanation systems. Moreover, wood biochar was assessed as a potential enhancer of the novel biogel bioaugmentation process. Three thermophilic (55°C), continuous stirred-tank reactors (RBgel, RChar and RMix), operated at 4.5 g NH4+-N L-1 were exposed to biogel, biochar and mixture of biogel and biochar, respectively, while a fourth reactor (RCtrl) was used as control. The results showed that the methane production yields of RMix, RChar and RBgel increased by 28.6%, 20.2% and 10.7%, respectively compared to RCtrl. The highest methane yield was achieved by the synergistic interaction between biogel and biochar. Additionally, biogel stimulated a rapid recovery of Methanoculleus thermophilus sp. and syntrophic acetate oxidising bacteria populations.