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17341. 题目: Comparison of acetaminophen degradation in UV-LED-based advance oxidation processes: Reaction kinetics, radicals contribution, degradation pathways and acute toxicity assessment
文章编号: N20032712
期刊: Science of The Total Environment
作者: Boqiang Li, Xiaoyan Ma, Jing Deng, Qingsong Li, Weizhu Chen, Guoxin Li, Guoyuan Chen, Jiping Wang
更新时间: 2020-03-27
摘要: Ultraviolet light emitting diode (UV-LED)-based advanced oxidation processes (AOPs) including UV-LED/chloramine (UV-LED/NH2Cl), UV-LED/hydrogen peroxide (UV-LED/H2O2) and UV-LED/persulfate (UV-LED/PS), were adopted for acetaminophen (AAP) removal. Results showed that AAP could be effectively degraded by the hybrid processes compared to solely using with UV irradiation and oxidants. The AAP degradation in the three UV-LED-based AOPs were in the order of UV-LED/PS > UV-LED/H2O2 > UV-LED/NH2Cl and followed a pseudo-first-order kinetics. The degradation rate constant (kobs) increased with increasing oxidant dosage, whereas overdosing lowered the AAP degradation. The second-order rate constants of HO, SO4−, and Cl with AAP were calculated as 5.15 × 109, 7.66 × 109 and 1.08 × 1010 M−1 s−1, respectively. Under neutral conditions, the contributions of UV-LED, HO, and Cl to AAP degradation were 4.21%, 60.15% and 35.64% in the UV-LED/NH2Cl system, whereas the respective contributions of UV-LED, HO and SO4− to AAP degradation were 2.09%, 22.84% and 75.07% in UV-LED/PS system, respectively. Meanwhile, the corresponding contributions of the involved reactive species were found to be pH-dependence. The natural organic materials (NOM) inhibited the AAP degradation, and the presence of Cl−, HCO3−, and NO3− had different effects on AAP degradation in the three hybrid processes. The AAP degradation was significantly inhibited in the three UV-LED-based AOPs in real water. In addition, the intermediate products were also identified, and possible degradation pathways were proposed in the three UV-LED-based AOPs. The acute toxicity bioassay using bacterium Vibrio fischeri suggested that the UV-LED/PS process was more effective than the UV-LED/H2O2 and UV-LED/NH2Cl processes in reducing the acute toxicity of the reacted AAP solution. Among the three UV-LED-based AOPs, the UV-LED/PS was found to be the most efficient process for AAP degradation.

17342. 题目: Effects of pyrolysis conditions on migration and distribution of biochar nitrogen in the soil-plant-atmosphere system
文章编号: N20032711
期刊: Science of The Total Environment
作者: Zhixiong Ye, Liyun Liu, Zhongxin Tan, Limei Zhang, Qiaoyun Huang
更新时间: 2020-03-27
摘要: The use of biochar to amend soil has been gaining increasing attention in recent years. In this study, the 15N tracer technique was used together with elemental analysis-stable isotope ratio analysis and gas isotope mass spectrometry to characterise biochar, soil, plant, and gas samples in order to explore the nitrogen transport mechanisms in the biochar-soil-plant-atmosphere system during the process of returning biochar to the soil (RBS). The results showed that the nitrogen retention rate of biochar was negatively correlated with the pyrolysis temperature during the preparation process, but was less affected by the pyrolysis atmosphere. In the RBS process, the migration of biochar nitrogen to plants was significantly greater than that of straw nitrogen, and it showed an overall decreasing trend with the increase in pyrolysis temperature, but was less influenced by the pyrolysis atmosphere. At temperatures of 300–500 °C, the pyrolysis atmosphere had a slightly smaller effect on the migration of biochar nitrogen to the air, plant, and soil system, and the pyrolysis temperature was much more important. However, the activation with CO2 gas at a higher temperature (600 °C) significantly enhanced the pore structure of biochar, particularly the structure of small pores; therefore, biochar prepared under a CO2 atmosphere at 600 °C reduces gaseous nitrogen emissions better than that under a N2 atmosphere. In the future, more pyrolysis conditions should be examined and their optimal combination should be further explored to reduce gaseous nitrogen emissions.

17343. 题目: Soil properties of apple orchards on China's Loess Plateau
文章编号: N20032710
期刊: Science of The Total Environment
作者: Min Yang, Shaofei Wang, Xining Zhao, Xiaodong Gao, Shuai Liu
更新时间: 2020-03-27
摘要: There are many apple orchards on the Loess Plateau because of their economic value and aggressive expansion is planned. However, little is known about their ecological impact in deep soil water, soil organic carbon (SOC) and soil aggregation. An accurate evaluation of the soil properties of apple orchards is crucial to ensure the establishment of sustainable ecosystems. We, therefore, measured the soil water content variation in deep layers (200–800 cm), SOC content and density (0–800 cm) and, soil aggregate stability (0–40 cm) in apple (Malus pumila) orchards, black locust (Robinia pesudoacacia) and korshinsk peashrub (Caragana korshinskii). We found that (1) there was generally less soil water in deep soil under apple orchards (13.29%), black locust (12.4%) and korshinsk peashrub (13.46%) than under arable land (18.35%) (p < 0.05). This implies that plantations caused intense reductions in soil water compared with arable land, leading to severe soil desiccation. (2) Apple orchards (1.85 to 5.49 g kg−1) had significantly (p < 0.05) lower SOC density (SOCD) than ecological plantations (2.15 to 8.95 g kg−1). It suggests that apple orchards have a low value for SOC sequestration because their clean cultivation management increases the risk of SOC loss by soil erosion. (3) soil aggregate stability (mean weight diameter, MWD) in apple orchards (0.26–0.63 mm) was significantly (p < 0.05) lower than under black locust (0.63–2.97 mm) and korshinsk peashrub (0.72–2.13 mm) plantations in the 0–40 cm layers, which means that apple orchards have low anti-erodibility. Our results suggest apple orchards and ecological plantations both consumed large amounts of deep soil water, but the ecological benefits (e.g., SOC sequestration, soil and water conservation) delivered by ecological plantations are much higher than those of apple orchards. In the interest of sustainable development in the region, apple cultivation should be undertaken with caution, especially in semiarid regions.

17344. 题目: Wild boar grubbing causes organic carbon loss from both top- and sub-soil in an oak forest in central China
文章编号: N20032709
期刊: Forest Ecology and Management
作者: Yanchun Liu, Xiaojing Liu, Zhongling Yang, Guoyong Li, Shirong Liu
更新时间: 2020-03-27
摘要: Soil disturbances by large animals are known to affect soil carbon (C) storage and thus have the potential to change ecosystem functioning in forests. However, little is known about the effects of wild boar grubbing on soil CO2 emission in forest ecosystems. Here we investigated soil respiration and soil physico-chemical properties of top- (0–10 cm) and sub-soil (10–20 cm) on the paired grubbed and non-grubbed plots in an oak forest for a 2-year period. Wild boar grubbing substantially increased soil respiration by 69.5% in 2015 and 32.9% in 2016, respectively. Wild boar disturbance considerably elevated soil basal respiration but showed no effect on its temperature sensitivity. In addition, we found that the grubbing-induced increases in soil organic carbon and microbial biomass activity from both top- and sub-soil contributed to the stimulated soil respiration after the disturbance. Our 2-year experiment indicates that soil bioturbation could lead to a strong positive effect on soil CO2 emission in oak forest ecosystems, but the stimulation tends to reduce with recovery time. The finding also highlights the importance of soil depth and time effect while quantifying the effect of wild boar grubbing on soil C storage in forest ecosystems.

17345. 题目: Temporal effects of thinning on soil organic carbon pools, basal respiration and enzyme activities in a Mediterranean Holm oak forest
文章编号: N20032708
期刊: Forest Ecology and Management
作者: Cristina Lull, Inmaculada Bautista, Antonio Lidón, Antonio D. del Campo, María González-Sanchis, Alberto García-Prats
更新时间: 2020-03-27
摘要: Soil organic carbon pools have an important role in the maintenance of ecosystems as a source of energy for soil microorganisms. Soil biological and biochemical properties are essential for the decomposition of organic matter. These soil properties can be affected by thinning, which is considered sustainable when the soil properties are maintained or improved. We studied the effects of selective thinning and shrub clearing, performed with an ecohydrological approach, in a marginal Holm oak forest in a semiarid area on soil properties. The effects of thinning (T) were compared with an untreated area (control, C). Fine woody debris was ground into mulch onto the thinned area. Forest floor and mineral soil properties were analyzed between five months and seven years after the thinning. In the forest floor, gravimetric water content (GWCff) and water soluble organic carbon (WSOCff) were analyzed and compared between T and C. In mineral soil, GWCms, soil organic carbon (SOC), WSOCms, soil basal respiration (BR), soil microbial biomass carbon (MBC) and soil enzymes (acid phosphatase (Acid PA) and urease (URE)) were analyzed. In the early stage, the results showed slightly higher SOC and WSOCms in T likely due to fine woody debris left on the forest floor. However, seven years after the thinning the effects of the thinning on all the studied variables were negligible. All variables showed high spatial-temporal variability. Our results suggest that selective thinning and shrub clearing in the studied site do not affect negatively soil properties when woody debris is left on the forest floor.

17346. 题目: Implications of bromate depression from H2O2 addition during ozonation of different bromide-bearing source waters
文章编号: N20032707
期刊: Chemosphere
作者: Jianwei Yu, Yongjing Wang, Qi Wang, Zheng Wang, Dong Zhang, Min Yang
更新时间: 2020-03-27
摘要: Minimizing bromate formation by adding H2O2 is one major option for bromide-containing source water when applying ozone in drinking water. However, difference in background water quality can have a significant influence on bromate depression. In this study, three bromide-bearing source waters (YZ, HR and HP) were selected to investigate bromate depression during the H2O2-ozonation process. The results showed that there was strong correlation between bromate formation and molecular ozone consumption during ozonation process for the three waters. Compared to YZ and HR, ozone was consumed quickly within about 10 min for HP water, inducing lower bromate formation during ozonation process. In the initial step of bromide oxidation, molecular ozone oxidation was responsible for more than 80% of oxidation, much higher than that by hydroxyl radicals. Specifically, 94% of the oxidation of bromide occurred with ozone for YZ water, which might be attributed to the low concentration of organic matter in the water. The residual molecular ozone would be a restrictive factor and affect the bromate formation significantly. For YZ and HP water, as H2O2/O3 (g/g) increased to 0.5, the ozone decomposition rate increased 61 times and 7.2 times respectively, which resulted in difference in bromate depression performance when applying H2O2. Humic acid and tyrosine in water were confirmed to have effects on bromate formation and depression after H2O2 addition. This study could elucidate the different bromate depression effects occurring in different source waters when adding H2O2, which will provide an informative guide for bromate control in drinking water treatment.

17347. 题目: Analog synthesis of artificial humic substances for efficient removal of mercury
文章编号: N20032706
期刊: Chemosphere
作者: Shuaishuai Zhang, Jingpeng Song, Qing Du, Kui Cheng, Fan Yang
更新时间: 2020-03-27
摘要: A cost-effective artificial humic substances (humic acid-modified biochar, HA-BCs) is fabricated by using conventional hydrothermal-assisted pyrolysis technique, and then is considered as a promising adsorbent material for removing mercury ions from aqueous solution. Artificial humic acid (A-HA), humic acid-modified biochar (HA-BCs) are analyzed by using SEM, EA, XRD, FTIR, XPS, and BET techniques. The removal efficiency of mercury ions was greater than 95% after reaching the adsorption equilibrium. Meanwhile, the adsorption kinetics coincided with the pseudo-second-order model and the isotherms for mercury ion sorption can be best interpreted using Freundlich isotherm model, with high regression coefficients (R2 = 0.967–0.990). Furthermore, the surface properties of HA-BCs before and after mercury adsorption are compared and evaluated, realizing that the mechanisms of removal of mercury ions on HA-BCs mainly include surface complexation with oxygen/nitrogen functional groups (-OH, –COOH and –NH2) and formation of precipitation with CO32− and OH−. Furthermore, the used HA-BCs can be regenerated via 0.05 mol/L KI solution and the adsorption capacity of mercury still reaches at 32.57 mg/g after four cyclic utilization.

17348. 题目: Biochar technology in wastewater treatment: A critical review
文章编号: N20032705
期刊: Chemosphere
作者: Wei Xiang, Xueyang Zhang, Jianjun Chen, Weixin Zou, Feng He, Xin Hu, Daniel C.W. Tsang, Yong Sik Ok, Bin Gao
更新时间: 2020-03-27
摘要: Biochar is a promising agent for wastewater treatment, soil remediation, and gas storage and separation. This review summarizes recent research development on biochar production and applications with a focus on the application of biochar technology in wastewater treatment. Different technologies for biochar production, with an emphasis on pre-treatment of feedstock and post treatment, are succinctly summarized. Biochar has been extensively used as an adsorbent to remove toxic metals, organic pollutants, and nutrients from wastewater. Compared to pristine biochar, engineered/designer biochar generally has larger surface area, stronger adsorption capacity, or more abundant surface functional groups (SFG), which represents a new type of carbon material with great application prospects in various wastewater treatments. As the first of its kind, this critical review emphasizes the promising prospects of biochar technology in the treatment of various wastewater including industrial wastewater (dye, battery manufacture, and dairy wastewater), municipal wastewater, agricultural wastewater, and stormwater. Future research on engineered/designer biochar production and its field-scale application is discussed. Based on the review, it can be concluded that biochar technology represents a new, cost effective, and environmentally-friendly solution for the treatment of wastewater.

17349. 题目: Tracking variation of fluorescent dissolved organic matter during full-scale printing and dyeing wastewater treatment
文章编号: N20032704
期刊: Chemosphere
作者: Cheng Cheng, Bo Liu, Chuanyang Liu, Jian Shen, Juldez Nurlan, Muhammad Farooq Saleem Khan, Zhenrong Huang, Yuting Qian, Fei Shen, Jing Wu
更新时间: 2020-03-27
摘要: In this study, fluorescent dissolved organic matter (FDOM) in real printing and dyeing wastewater (PDW) during full-scale two-stage treatment was characterized using excitation-emission matrix (EEM), apparent molecular weight (AMW) cutoff by centrifugal ultrafiltration and high-performance liquid chromatography with fluorescence detector (HPLC-FLD). EEMs of PDW during treatment were relatively invariable with two typical and dominant peaks (P1, 275/320 nm and P2, 230/340 nm). The removal rates of P1 intensity and P2 intensity were both lower than those of DOC or UVA254 during the 1st stage and 2nd stage treatment. The <3 kDa fraction made major contribution to DOC, UVA254, P1 and P2 intensity. The DOM fractions with different AMW exhibited different removal behaviors during the 1st stage and 2nd stage treatment. The <3 kDa fraction of FDOM was poorly removed by biological treatment alone. The HPLC-FLD multi-emission scan results indicated that the major part of FDOM clusters were hydrophilic and they were more difficult to remove than the transphilic and hydrophobic FDOM clusters. According to the physicochemical properties of FDOM in PDW, selective adsorption and advanced oxidation process could be prior options for PDW advanced treatment.

17350. 题目: Dynamics of fungal and bacterial groups and their carbon sources during the growing season of maize in a long-term experiment
文章编号: N20032703
期刊: Biology and Fertility of Soils
作者: Muhammad Shahbaz, Thomas Kätterer, Barry Thornton, Gunnar Börjesson
更新时间: 2020-03-27
摘要: The relative contribution of different microbial groups to soil organic matter (SOM) turnover and utilisation of rhizodeposits during a cropping season has remained largely unknown. We used a long-term field experiment (started in 1956), in which C3 crops were replaced with C4 silage maize in 2000, to investigate dynamics of fungi and bacterial groups and their utilisation of 'young-C4' and 'old-C3' SOM-derived resource every second week during the cropping season (June–Oct). Treatments include bare fallow, unfertilised, fertilised with mineral N and fertilised with farmyard manure (FYM) addition. Extracted soil phospholipid fatty acids (PLFAs) were pooled into Gram-positive, Gram-negative bacteria and fungi (18:2ω6,9) groups and their δ13C values determined. Total PLFAs amount correlated to the SOM contents (highest in FYM) and increased over the cropping season in N-fertilised and FYM treatments. As a result of a peak in plant growth during a period with frequent rain events in August, δ13C of total PLFAs significantly increased from − 23.8 to − 21.6‰ and − 26.1 to − 24.7‰, in N-fertilised and FYM addition, respectively. This clearly indicated a shift in microbial utilisation from old to young SOM sources, which was linked to increased soil moisture contents and fungal biomass. The abundance of Gram-positive increased and that of Gram-negative bacteria decreased until August and vice versa thereafter. The mean δ13C values of individual microbial groups were highest in fungi (corresponding to their seasonal biomass variation) followed by Gram-positive and Gram-negative bacteria. The results clearly demonstrated that irrespective of fertilisation type, fungi were the main players in seasonal SOM dynamics and were strongly influenced by soil moisture and phenological stage of the maize (i.e. rhizodeposition). Disentangling these microbial controls on C resources utilisation will be crucial for understanding C cycling during a cropping season or on an ecosystem scale.

17351. 题目: Is litter decomposition enhanced in species mixtures? A meta-analysis
文章编号: N20032702
期刊: Soil Biology and Biochemistry
作者: Rima J. Porre, Wopke van der Werf, Gerlinde B. De Deyn, Tjeerd Jan Stomph, Ellis Hoffland
更新时间: 2020-03-27
摘要: Litter decomposition is a key process in the carbon balance of soils. Commonly, plant litters occur in mixtures where the species differ in quality traits such as the nutrient concentration and organic carbon quality. Many studies explored if mixing litters retards or speeds up litter decomposition compared to species decomposing alone, with varying results. To identify consistent trends with an overarching quantitative synthesis, we test in a meta-analysis whether on average across studies, the mass loss of mixed litters of two plant species is faster than the average mass loss of single litters. We hypothesise that larger trait divergence of the litter quality of the species in a mixture results in a faster mass loss of the mixture than expected based on the single species. Furthermore we hypothesise that part of the variation in litter mixture mass loss can be explained by experimental design and environmental factors. Explanatory variables used were chemical litter trait dissimilarity in the C, N, P, lignin, cellulose, phenolics concentration as well as soil properties, ecosystem, climate, the duration of litter decomposition and the experimental design. Interactions were studied if supported by mechanistic hypotheses. In the majority of studies and on average, we found that the mass loss of mixed litters is equal to the weighted average of the mass loss of the constituent single litters. None of the hypothesised explanatory variables was consistently associated with litter mixture effects on the mass loss and explained variation in mass loss of significant models was invariably only a few percent of all variation. While further data exploration might elucidate further, interactive, patterns, many of these could not be explored due to lacking data. This meta-analysis therefore refutes the notion that mixing litters in general enhances rates of decomposition. We conclude that the effects of litter mixing are in many cases predictable from the decomposition rates of the individual species. According to our results, any interactive effects (positive or negative) between litter species are contextual, and cannot be generalized and predicted beyond the context in which the results were obtained.

17352. 题目: Insight into the mechanisms of biochar addition on pollutant removal enhancement and nitrous oxide emission reduction in subsurface flow constructed wetlands: Microbial community structure, functional genes and enzyme activity
文章编号: N20032701
期刊: Bioresource Technology
作者: Yinkun Liang, Qinghua Wang, Lei Huang, Maolin Liu, Ning Wang, Yucheng Chen
更新时间: 2020-03-27
摘要: A set of constructed wetlands (CWs) under different biochar addition ratios (0%, 10%, 20%, and 30%) was established to analyze the pollutant removal performance enhancement and nitrous oxide (N2O) emission reduction from various angles, including microbial community structure, functional genes and enzyme activity. Results revealed that the average removal efficiencies of ammonium (NH4+-N) and total nitrogen (TN) were improved by 2.6%–5.2% and 2.5%–7.0%. Meanwhile, N2O emissions were reduced by 56.0%–67.5% after biochar addition. Increased nitrogen removal efficiency and decreased N2O emissions resulted from the increase of biochar addition ratio. Biochar addition changed the microbial community diversity and similarity. The relative abundance of functional microorganisms such as Nitrosomonas, Nitrospira, Thauera and Pseudomonas, increased due to biochar addition, which promoted the nitrogen cycle and N2O emission reduction. High gene copy number and enzyme activity involved in nitrification and denitrification process were obtained in biochar CWs, moderating N2O emission.

17353. 题目: Biochar application for the improvement of water-soil environments and carbon emissions under freeze-thaw conditions: An in-situ field trial
文章编号: N20032604
期刊: Science of The Total Environment
作者: Yu Gao, Tianxiao Li, Qiang Fu, Heng Li, Dong Liu, Yi Ji, Qinglin Li, Yanpeng Cai
更新时间: 2020-03-26
摘要: There are few studies about biochar application in seasonally frozen soil areas. The regulatory mechanism of biochar on the water-soil environment and carbon emissions in seasonally frozen soil areas is unclear, which affects the study of nutrient migration and spring cropping systems under the control of biochar. For this purpose, we monitored the soil temperature (Ts), soil liquid moisture content (Ms) and soil respiration (Rs) rate during the freeze-thaw period under different application amounts of corn stover biochar (0 t∙ha−1, 15 t∙ha−1, 30 t∙ha−1, 45 t∙ha−1 and 60 t∙ha−1). The results showed that biochar can reduce the thermal conductivity of soil, thus improving the thermal insulation effect of frozen thawed soil, and Ts increased by 1.8–5.7 °C. The Ts and Ms were more sensitive to the high biochar application amount than to the low application amount. At the same time, biochar changed the soil aggregate distribution, and Pearson correlation analysis indicated that the soil water retention capacity increased by increasing the macroaggregate content (>0.25 mm), and the Ms increased by 3.7–6.1%. Principal component regression (PCR) analysis showed that biochar can promote soil carbon emission, and Rs of soil treated with biochar was 0.01–0.58 μmol m−2 s−1 higher than that of the control. The Ms and Ts were the most important factors promoting the carbon emissions of freeze-thaw soil under the synergistic effect of biochar and freeze-thaw conditions. However, biochar may promote soil CO2 emissions by affecting the water-soil environment. Considering the soil moisture, seed germination and growth conditions in spring, the suitable biochar application amount was determined to be 44–51 t∙ha−1. This study provides theoretical support for determining reasonable and effective biochar control measures and improving the soil productivity of farmland soil in seasonally frozen soil areas.

17354. 题目: Simultaneous desalination and nutrient recovery during municipal wastewater treatment using microbial electrolysis desalination cell
文章编号: N20032603
期刊: Journal of Cleaner Production
作者: Jiahuan Li, Rudong Liu, Shan Zhao, Shuguang Wang, Yunkun Wang
更新时间: 2020-03-26
摘要: The removal of organics and saline while simultaneously recovering nutrients in municipal wastewater was achieved in a microbial electrolysis desalination cell (MEDC). System performance in terms of organics removal, desalination, and nitrogen and phosphate recovery was investigated under different ion exchange membrane (IEM) pairs and applied voltages. Compared with single-IEM stack MEDC, the MEDC with multi-IEM pairs proved to be able to perform an effective performance for chemical oxygen demand (COD) removal, desalination, and nutrient recovery. The energy consumption for netrient separation and recovery was 0.12 kWh/m3 with 3-IEM stacks at applied voltage of 2 V. The MEDC system with 3-IEM stacks showed 75.5 ± 1.4% COD removal and 8.5 ± 1.1% Coulombic efficiency. The conductivity in effluent decreased to 545 μS/cm (lower than the single-IEM stack, 934 μS/cm), while conductivity in the product chamber was concentrated to 2160 μS/cm (higher than the single-IEM stack, 998.5 μS/cm). Moreover, the recovery efficiencies of nitrogen and phosphate reached 66 ± 5.3% and 66.7 ± 4.7%, respectively. Furthermore, the CV curve and microbial community structure showed that electrical stimulation increased the abundances of electrogenic bacteria (Rhodocyclaceae and Geobacter), which enhanced COD removal and electron transfer. These results clearly demonstrate that the MEDC is an energy efficient technology for the treatment of municipal wastewater, while simultaneously recovering nitrogen and phosphate resources.

17355. 题目: Long-term impact of diversified crop rotations and nutrient management practices on soil microbial functions and soil enzymes activity
文章编号: N20032602
期刊: Ecological Indicators
作者: D.N. Borase, C.P. Nath, K.K. Hazra, M. Senthilkumar, S.S. Singh, C.S. Praharaj, U. Singh, N. Kumar
更新时间: 2020-03-26
摘要: The long-term effect of pulse crops such as pigeonpea (Cajanus cajan L.), chickpea (Cicer arietinum L.) and mungbean (Vigna radiata L.) in crop rotation and nutrient management on soil microbial functions and enzymes activity was studied. We presumed that pulse-inclusive crop rotations and integrated nutrient management would have higher soil enzymes activity and microbial biomass carbon compared with continuous maize (Zea mays L.) - wheat (Triticum aestivum L.) rotation. We used a thirteen years old experiment in Typic Ustochrept soil of Kanpur, India. The treatments consisted of four crop rotations such as maize-wheat (MW), maize-wheat-mungbean (MWMb), maize-wheat-maize-chickpea (MWMC, two years rotation), and pigeonpea-wheat (PW) each with three levels of nutrient management treatments such as without fertilizers (control: CT), integrated nutrient management (INM), and recommended inorganic fertilizers (RDF). Crop rotations with legume in each year (PW and MWMb rotations) increased soil organic carbon (SOC), soil microbial biomass carbon (SMBC) and soil microbial biomass nitrogen (SMBN) compared with those of MWMC and MW (p ≤ 0.05). The PW, MWMb, and MWMC rotations increased the activity of alkaline phosphatase (20–80%), arylsulfatase (16–35%), β-glucosidase (9–16%), dehydrogenase (52–79%) and protease (5–51%) than that of MW rotation. In general, nutrient management treatments followed the order of INM > RDF ≥ CT (p ≤ 0.05) for most of the studied soil parameters. Notably, the activity of acid phosphatase, arylsulfatase and dehydrogenase enzymes was comparable in CT and RDF after thirteen years. It indicated that long-term use of chemical fertilizers could not increase these enzymes activity and warranted the need for organic amendments addition. The increased SOC and enzymes activity (particularly acid/alkaline phosphatase, β-glucosidase and arylsulfatase) in pulse-inclusive rotations were directly reflected in base-crop (wheat) productivity. The effect of crop rotations and nutrient management was mostly additive and thus an oversized increase in soil enzymes activity, SMBC and SOC was noticed in PW and MWMb with INM over the remaining crop rotations × nutrient management combinations. Thus, inclusion of pulses in crop rotation and addition of organic amendments (farmyard manure/crop residue) could be the long-term sustainable strategy to ensure optimum biological functioning of the tropical soils. The study further suggested that continuous addition of inorganic fertilizers could be detrimental to the soil enzymes activity and soil biological health in the long-run.

17356. 题目: Tying up Loose Ends of Microplastic Pollution in the Arctic: Distribution from the Sea Surface through the Water Column to Deep-Sea Sediments at the HAUSGARTEN Observatory
文章编号: N20032601
期刊: Environmental Science & Technology
作者: Mine B. Tekman, Claudia Wekerle, Claudia Lorenz, Sebastian Primpke, Christiane Hasemann, Gunnar Gerdts, Melanie Bergmann
更新时间: 2020-03-26
摘要: Recent studies have shown that despite its remoteness, the Arctic region harbors some of the highest microplastic (MP) concentrations worldwide. Here, we present the results of a sampling campaign to assess the vertical distribution of MP particles (>11 μm) at five stations of the HAUSGARTEN observatory. Water column samples were taken with large volume pumps by filtering 218–561 L of seawater at two to four depth strata (near-surface, ∼300 m, ∼1000 m, and above seafloor), and sediment samples were taken with a multiple corer. MP concentrations in the water column ranged between 0 and 1287 N m–3 and in the sediment from 239 to 13 331 N kg–1. Fourier transform infrared spectroscopy (FTIR) imaging with automated data analysis showed that polyamide (39%) and ethylene-propylene-diene rubber (23%) were the most abundant polymers within the water samples and polyethylene-chlorinated (31%) in sediments. MPs ≤ 25 μm accounted for more than half of the synthetic particles in every sample. The largest MP particle recorded was in the 200 μm size class. The concentrations of fibers were not reported, as fiber detection by FTIR imaging was not available at the time of analyses. Two- and three-dimensional simulations of particle transport trajectories suggest different pathways for certain polymer types. A positive correlation between MP size composition and particulate organic carbon indicates interactions with biological processes in the water column.

17357. 题目: Restoration of soil quality using biochar and brown coal waste: A review
文章编号: N20032511
期刊: Science of The Total Environment
作者: Collins Amoah-Antwi, Jolanta Kwiatkowska-Malina, Steven F. Thornton, Owen Fenton, Grzegorz Malina, Ewa Szara
更新时间: 2020-03-25
摘要: Soils in intensively farmed areas of the world are prone to degradation. Amendment of such soils with organic waste materials attempts to restore soil quality. Organic amendments are heterogeneous media, which are a source of soil organic matter (SOM) and maintain or restore chemical, physical, biological and ecological functionality. More specifically, an increase in SOM can influence the soil microclimate, microbial community structure, biomass turnover and mineralisation of nutrients. The search is on-going for locally sourced alternatives as many forms may be costly or geographically limiting. The present review focuses on a heterogeneous group of amendments i.e. biochar and brown coal waste (BCW). Both biochar (made from a variety of feedstocks at various temperatures) and BCW (mined extensively) are options that have worldwide applicability. These materials have very high C contents and soil stability, therefore can be used for long-term C sequestration to abate greenhouse gas emissions and as conditioners to improve soil quality. However, biochar is costly for large-scale applications and BCW may have inherently high moisture and pollutant contents. Future studies should focus on the long-term application of these amendments and determine the physicochemical properties of the soil, bioavailability of soil contaminants, diversity of soil communities and productivity of selected crops. Furthermore, the development of in situ technologies to lower production and processing costs of biochar and BCW would improve their economic feasibility for large-scale application.

17358. 题目: Surface modification induced cuprous oxide nanoparticle toxicity to duckweed at sub-toxic metal concentrations
文章编号: N20032510
期刊: Science of The Total Environment
作者: Devin A. Rippner, Jennifer Lien, Hagr Balla, Ting Guo, Peter G. Green, Thomas M. Young, Sanjai J. Parikh
更新时间: 2020-03-25
摘要: Nanoparticle capping agents are critical for controlling the growth, oxidation state, and final particle size during aqueous synthesis. However, despite the known phytotoxicity of cetyltrimethylammonium bromide (CTAB) to plants, it is used to synthesize metal oxide nanoparticles of uniform size and with mesoporous structure. Among the few studies that have investigated how CTAB influences nanoparticle toxicity, CTAB has never been identified as the primary cause of nanoparticle toxicity in environmental systems; rather nanoparticle surface charge or morphology was identified as the driver of toxicity in environmentally relevant systems. In the current study, CTAB release from CTAB surface modified Cu2O nanoparticles (SM-Cu2O NPs) inhibited duckweed (Landoltia punctata) growth, even when administered at subtoxic Cu concentrations. Organic ligands, such as humic acid (HA) and ethylenediaminetetraacetic acid (EDTA), lessened growth inhibition associated with exposure to SM-Cu2O NPs, likely through electrostatic and hydrophobic interactions with CTAB. Such results highlight the need for a more holistic approach to nanoparticle surface modification and improved communication between toxicologists and synthetic chemists to develop green alternatives for nanoparticle synthesis.

17359. 题目: Cohesive strength changes of sewer sediments during and after ultrasonic treatment: The significance of bound extracellular polymeric substance and microbial community
文章编号: N20032509
期刊: Science of The Total Environment
作者: Daizong Meng, Wei Jin, Keli Chen, Chen Zhang, Yingjie Zhu, Huaizheng Li
更新时间: 2020-03-25
摘要: Sewer flushing is widely used to remove sewer sediment from drainage systems; however, its performance and cleaning efficiency are limited by the cohesive strength of sewer sediment. To address this, ultrasound, as a clean technology, is proposed to reduce the cohesive strength of sewer sediment. This study investigated the variations in the cohesive strength, extracellular polymeric substances (EPSs), and microbial community of sewer sediment with ultrasonic treatment. During ultrasonic conditioning, the degradation process of the cohesive strength followed the first-order kinetic model and was positively related to the degradation of bound-EPSs. Field emission scanning electron microscopy, particle diameter, and three-dimensional excitation emission analyses suggested that ultrasound reduced the cohesive strength by decreasing the bound-EPS concentration, which reduced the particle size of sewer sediment, and by destroying the structure of tryptophan proteins, which impaired the stability of agglomerated particles. Following ultrasonic treatment, the cohesive strength of the treated sediment was reduced to 69.3% of that of the raw sewer sediment after storage for 21 days; this result could be ascribed to the improvements in polysaccharide transport, amino acid transport, and the cell wall biogenesis functions of the microbial community, as indicated by PICRUSt. Furthermore, next-generation sequencing studies suggest that the proportions of Syntrophomonadaceae, Bacteroidetes_vadinHA17, Synergistaceae, and Syntrophaceae, which are associated with anaerobic digestion and methane production in sediment, improved conspicuously after ultrasonic conditioning.

17360. 题目: Efficient Phosphorus Recycling and Heavy Metal Removal from Wastewater Sludge by a Novel Hydrothermal Humification-Technique
文章编号: N20032508
期刊: Chemical Engineering Journal
作者: Shuaishuai Zhang, Qing Du, Kui Cheng, Markus Antonietti, Fan Yang
更新时间: 2020-03-25
摘要: This publication presents a simple and low-cost hydrothermal humification (HTH) treatment of sewage sludge (SS) together with alkali ash (AA) and biomass for simultaneous implementation of heavy metal removal, nutrient recovery (P) and ash refining. The H/C and O/C atomic ratio plots obtained from elemental analysis demonstrate that dehydration and decarboxylation under hydrothermal conditions are elemental reactions leading to sludge/biomass decomposition and artificial humic matter formation. Introduction of plant biomass into sludge-derived samples and adjustment of KOH or alkali ash (AA) mass effectively improve the recovery of P element, realizing high contents of dissolved phosphorus (DP) (from 7045 to 10075 mg/L) at appropriate pH values (6.5 to 7.7). ICP-AES results indicate the drop of Cr and Cd content below detection limit together with a sharp decrease of the elements Cu (from 0.07 to 0.46 mg/g), Zn (from 0.15 to 0.98 mg/g) and Pb (from 0.067 to 0.142 mg/g) after HTH treatment in sludge-derived liquid products and the heavy metal elements enriched in sludge-derived solids can be recovered into industrial salts by subsequent treatment. Pot planting experiments are conducted to investigate the P-availability in both sludge-derived liquids and solids (after treatment of heavy metal recovery) for promotion of plant growth. A higher proportion of shoot-to-root weight (62.1 % versus 46.2 %) and preserved moisture contents (84.7 % versus 83.7 %) when compared to the control groups demonstrate the effect of the presence of more nutrients after addition of sludge-derived liquid products. This work could provide a smart, energy utilization and sustainable fertilization route for planting growth.