显示样式:     当前期刊: Science of the Total Environment    加入关注       排序: 导出
我的关注
我的收藏
您暂时未登录!
登录
  • Brewery wastewater treatment and resource recovery through long term continuous-mode operation in pilot photosynthetic bacteria-membrane bioreactor
    Sci. Total Environ. (IF 4.61) Pub Date : 2018-07-20
    Haifeng Lu, Meng Peng, Guangming Zhang, Baoming Li, Yuanyuan Li

    Photosynthetic bacteria (PSB) are considered ideal for high COD wastewater treatment and resource recovery. This work is the first continuous-mode long-term (440 days) pilot study (240 L) by using PSB-membrane (PSB-MBR) system for such purpose. Results showed that the system started-up in 27 days for brewery wastewater and then stably operated under various temperature, initial COD and pH conditions, which showed fast start-up and strong robustness. Comparing with small-batch PSB-MBR system, the capacity of pollutants treatment degradation rate in the pilot-continuous PSB-MBR system was promoted. The operation parameters for pilot-continuous PSB-MBR system were determined as follows: light-micro aerobic, 72 h hydraulic retention time, 1200 mg L−1 inoculum size and 1.0 g L−1 d−1 organic loading rate, 2.5 F/M. Under these conditions, the COD and NH4+ in effluent were below 80 and 15 mg L−1, respectively. The PSB cell production reached 483.5 mg L−1 d−1 with protein, polysaccharides, carotenoid, bacteriochlorophyll, and coenzyme Q10 of 420.9, 177.6, 2.53, 10.75, 38.6 mg g−1, respectively, showing great potential of resource recovery from organic wastewater. In addition, the collected biomass had no acute toxicity to crucian carps. This work provides a base for the scale-up of this novel technology.

    更新日期:2018-07-21
  • COD removal index — A mechanistic tool for predicting organics removal performance of vermifilters
    Sci. Total Environ. (IF 4.61) Pub Date : 2018-07-20
    Rajneesh Singh, Puspendu Bhunia, Rajesh R. Dash

    The present study was aimed at developing a mathematical COD removal index (CRI) based on the key variables of vermifiltration such as hydraulic retention time (HRT), organic concentration and earthworm density (EWD). In the maiden attempt of framing such an index, many experimental runs were conducted by varying the COD strength of the wastewater from 2.0–4.0 kg/m3, EWD and HLR were from 0 to 10,000 earthworms/m3 and 1.8–4.5 m3/m2·d, respectively. The sensitivity analysis of the developed CRI reveals that the EWD, bedding volume, concentration of organics and the flow applied to the vermifilter can immensely affect the model response. However, flow applied to the system is observed to be the most sensitive among other parameters incorporated in the model. In addition, from the sensitivity analysis, it was also revealed that the removal efficiencies were observed to increase with the increase in CRI values in the COD range of 0.2–6.0 kg/m3. In addition, the plot between the reported removals from literatures on vermifiltration of domestic wastewater and CRI values yielded an R2 value of 0.76. Such a high correlation suggests that the developed CRI index can be applied for other wastewaters also. The results of this study indicate that the developed index can successfully be applied in determining and predicting organics removal from vermifiltration of wastewaters.

    更新日期:2018-07-21
  • Single and simultaneous adsorption of pefloxacin and Cu(II) ions from aqueous solutions by oxidized multiwalled carbon nanotube
    Sci. Total Environ. (IF 4.61) Pub Date : 2018-07-20
    Yaoyu Zhou, Yangzhuo He, Yujia Xiang, Sijun Meng, Xiaocheng Liu, Jiangfang Yu, Jian Yang, Jiachao Zhang, Pufeng Qin, Lin Luo

    In this study, the oxidized multiwalled carbon nanotube (O-MWCNTs) was obtained by a simple method, and investigated by various techniques (SEM, TEM, FT-IR, XPS and zeta potential) for the removal of pefloxacin and Cu(II). The mutual effects of their adsorption onto O-MWCNTs were comprehensively clarified with sole and binary systems with adsorption kinetics, sorption thermodynamic and sorption isotherm models. The results indicated that there are site enhancement and competition of pefloxacin and Cu(II) on O-MWCNTs. According to mechanism investigation on the adsorption of pefloxacin and Cu(II) by XPS analysis, pH impact study, electrostatic interaction and π–π interactions, the low concentration of Cu(II)/pefloxacin could act as a bridge between pefloxacin/Cu(II) and O-MWCNTs, which significantly enhances the adsorption of pefloxacin/Cu(II). This study provided effective method and valuable reference for the elimination of pefloxacin/Cu(II) from aquatic environments.

    更新日期:2018-07-21
  • Temperature variability influences urban garden plant richness and gardener water use behavior, but not planting decisions
    Sci. Total Environ. (IF 4.61) Pub Date : 2018-07-20
    Monika H. Egerer, Brenda B. Lin, Caragh G. Threlfall, Dave Kendal

    Urban environments are being subject to increasing temperatures due to the combined effects of global climate change and urban heat. These increased temperatures, coupled with human planting preferences and green space management practices, influence how urban plants grow and survive. Urban community gardens are an increasingly popular land use, and a green space type that is influenced by unique climate-human behavior interactions. Despite ongoing rapid temperature changes in cities, it is unknown how gardeners are adapting to these changes, and to what extent changes influence planting decisions and patterns of urban plant diversity. In this study, we monitored the variation in daily air temperatures and measured plant species richness at the garden and garden plot scale in 11 community gardens in Melbourne, Australia. We surveyed >180 gardeners to better understand the relationships between temperature variation, garden plant species diversity, and gardener management practices. We found that garden scale temperature variability is driven by regional context, and temperatures are more stable in landscapes with higher impervious surface cover. Gardeners agreed that climatic/temperature changes are influencing their watering behavior, but not their plant selection. Instead plant selection is being driven by desired food production. Yet, when comparing two bioregions, temperature did have a measurable relationship with garden plant composition in the region with more temperature variation. Temperature variability negatively related to plant species richness within garden plots, providing evidence that plant survival is related to climate at this scale in such regions. Although gardeners may be able to water more in response to regional climate changes, gardeners are unlikely to be able to completely control the effects of temperature on plant survival in more variable conditions. This suggests the inner city with more stable temperatures (albeit potentially hotter for longer due to heat island) may accommodate more species diverse gardens.

    更新日期:2018-07-21
  • Impacts of water residence time on nitrogen budget of lakes and reservoirs
    Sci. Total Environ. (IF 4.61) Pub Date : 2018-07-20
    Yindong Tong, Jiaqi Li, Miao Qi, Xiaoyan Zhang, Mengzhu Wang, Xueyan Liu, Wei Zhang, Xuejun Wang, Yiren Lu, Yan Lin

    As an important factor related to the self-purification capacity (e.g. denitrification, burial rate, and downstream output) in aquatic systems, water residence time (WRT) has great impacts on the nitrogen (N) dynamics and its removal process in lakes and reservoirs. In this study, we have analysed the impacts of WRT on the change rates of total nitrogen (TN) concentrations in 50 waterbodies (including 33 lakes and 17 reservoirs) in China, with different change trends (e.g. increasing trends and decreasing trends) and TN concentrations during 2012–2016. Based on the annual ecosystem-scale N mass balance, TN input and output flux in the waterbodies are estimated. The results showed that the decreases of TN concentrations usually occur in the waterbodies with the relatively high TN concentrations in 2012, and WRT has significant impacts on the TN change rates in the waterbodies. Longer WRT could slow down the TN increasing rates in the waterbodies acting as N sinks, but could accelerate the removal from the waterbodies acting as N sources. Higher water phosphorus (P) concentrations could also be beneficial for the faster N removal from the waterbodies, which is mediated via the coupled processes regulating the N transfer from water column to anoxic sediments. China has recently issued the “lake-chief” systems, addressing the specific and flexible strategies for water pollution control in different lakes. The self-purification capacity through denitrification and burial rate, which are closely related to WRT, should be taken into consideration when making specific water management plans in the future.

    更新日期:2018-07-21
  • Environmental impact of personal consumption from life cycle perspective – A Czech Republic case study
    Sci. Total Environ. (IF 4.61) Pub Date : 2018-07-20
    Jan Matuštík, Vladimír Kočí

    The impact of human civilization on the environment is now obvious. With the rapidly growing human population, the problem of human consumption becomes more and more urgent. It is therefore necessary to try to change the patterns of human life and find a more sustainable way of living. To achieve the goal of sustainable society efficiently, it is crucial to identify hot spots for possible impact reduction. Even though several tools now exist, such as footprint calculators, they usually have a narrow perspective, calculating impact only on a single environmental problem. In this study, the Life Cycle Assessment (LCA) method was employed, to measure the environmental impact of human consumption across the entire life-cycle as well as a wide range of impact categories. The use of LCA to identify the major problems of personal consumption is presented in a case study of an average inhabitant of the Czech Republic. Data of average personal consumption were collected and an LCA model was created in GaBi 8 software. Characterization results, obtained using ReCiPe 2016 (E) methodology, show the environmentally dominant segments of consumption which are: household energy consumption – where the dominant process is heating; and food consumption – where the dominant processes are meat and dairy production. This study provides a thorough impact analysis and identifies the hots spots, where actions should be taken. The results provide the necessary basic data for policy-makers, so that steps to reduce individual personal environmental impact can be taken.

    更新日期:2018-07-21
  • Preparation, characterization, and application of macroporous activated carbon (MAC) suitable for the BAC water treatment process
    Sci. Total Environ. (IF 4.61) Pub Date : 2018-07-20
    Lihua Dong, Wenjun Liu, Yi Yu, Li'an Hou, Ping Gu, Guanyi Chen

    To address the sharp decrease in efficiency of the biological activated carbon (BAC) process at low temperatures, a new type of activated carbon (AC), macroporous activated carbon (MAC), was developed from bamboo waste scraps via a special compression, carbonation and activation process without the introduction of chemicals. MAC contains not only the micron-level macropores (Vmaco > 0.71 ml/g) sufficient for bacteria to access and multiply, but ensures the developed smaller pores (particularly micropores, Vmicro > 0.41 ml/g) and a higher hardness (>90%). In addition, the desired volume of macropores with an adiabatic function, which will provide livable space environment for bacteria, can be obtained by adjusting the compression ratio (1:5–1:10). Because of the maximum macropore volume (Vmaco = 0.805 ml/g) and the most abundant macropore distribution (particularly diameters>10,000 nm), MAC (1:6) was selected for the parallel experiment in the laboratory, taking three representative commercial ACs (PICABIOL® 2, raw coal AC-1 and briquetting AC-2) as controls, in which the filtration effluent of a water treatment plant was used as the influent and glucose was added to accelerate bacterial growth. The results showed that MAC (1:6) exhibited the highest DOC removal and biological activity at room/low temperatures (4 °C), indicating that the abundant macropores distribution with adiabatic function in MAC (1:6) is conducive to the growth and breeding of microorganisms. It is equivalent to artificially increasing the surface suitable for bacteria attachment. This is coupled with the higher adsorption capacity for pollutants supplied by the developed micropores in MAC, which provided the substrate for bacteria growth, thus forming a benign circle for water treatment by the BAC process. The results provide significant technical support for BAC's application, particularly at cold temperatures.

    更新日期:2018-07-21
  • An exponential model based new approach for correcting aqueous concentrations of hydrophobic organic chemicals measured by polyethylene passive samplers
    Sci. Total Environ. (IF 4.61) Pub Date : 2018-07-20
    Wenjian Lao, Keith A. Maruya, David Tsukada

    Although low density polyethylene (PE) passive samplers show promise for the measurement of aqueous phase hydrophobic organic chemicals (HOCs), the lack of a practical and unsophisticated approach to account for non-equilibrium exposure conditions has impeded widespread acceptance and thus application in situ. The goal of this study was to develop a streamlined approach based on an exponential model and a convection mass transfer principle for correcting aqueous concentrations for HOCs deduced by PE samplers under non-equilibrium conditions. First, uptake rate constants (k1), elimination rate constants (k2), and seawater-PE equilibrium partition coefficients (KPEWs) were determined in laboratory experiments for a diverse suite of HOCs with logKow range of 3.4–8.3. Linear relationships between log k2 and logKow, and between log KPEW and logKow were established. Second, PE samplers pre-loaded with 13C-labeled performance reference compounds (PRCs) were deployed in the ocean to determine their k2in situ. By applying boundary layer and convection mass transfer theories, ratio (C) of k2 values in field and laboratory exposures was estimated. This C value was demonstrated a constant that was only determined by water velocities and widths of PE strips. A generic equation with C and logKow as parameters was eventually established for extrapolation of non-equilibrium correction factors for the water boundary layer-controlled HOCs. Characterizing the hydrodynamic conditions indicated the sampler configuration and mooring mode should aim at sustaining laminar flow on the PE surface for optimal mass transfer. The PE estimates corrected using this novel approach possessed high accuracy and acceptable precision, and can be suited for a broad spectrum of HOCs. The presented method should facilitate routine utilization of the PE samplers.

    更新日期:2018-07-21
  • Microplastic ingestion by riverine macroinvertebrates
    Sci. Total Environ. (IF 4.61) Pub Date : 2018-07-20
    Fredric M. Windsor, Rosie M. Tilley, Charles R. Tyler, Steve J. Ormerod

    Although microplastics are a recognised pollutant in marine environments, less attention has been directed towards freshwater ecosystems despite their greater proximity to possible plastic sources. Here, we quantify the presence of microplastic particles (MPs) in river organisms upstream and downstream of five UK Wastewater Treatment Works (WwTWs). MPs were identified in approximately 50% of macroinvertebrate samples collected (Baetidae, Heptageniidae and Hydropsychidae) at concentrations up to 0.14 MP mg tissue−1 and they occurred at all sites. MP abundance was associated with macroinvertebrate biomass and taxonomic family, but MPs occurred independently of feeding guild and biological traits such as habitat affinity and ecological niche. There was no increase in plastic ingestion downstream of WwTW discharges averaged across sites, but MP abundance in macroinvertebrates marginally increased where effluent discharges contributed more to total runoff and declined with increasing river discharge. The ubiquity of microplastics within macroinvertebrates in this case study reveals a potential risk from MPs entering riverine food webs through at least two pathways, involving detritivory and filter-feeding, and we recommend closer attention to freshwater ecosystems in future research.

    更新日期:2018-07-21
  • Quantification of subsurface hydrologic connectivity in four headwater catchments using graph theory
    Sci. Total Environ. (IF 4.61) Pub Date : 2018-07-20
    G. Zuecco, M. Rinderer, D. Penna, M. Borga, H.J. van Meerveld

    Hillslope-stream connectivity significantly affects streamflow and water quality responses during rainfall and snowmelt events, but is difficult to quantify. One approach to quantify subsurface hillslope-stream connectivity is graph theory, which considers linear connections between groundwater measurement sites. We quantified subsurface connectivity based on surface topography and shallow groundwater data from four small (<14 ha) headwater catchments in the Italian Dolomites and the Swiss pre-Alps, determined the relation between rainfall, antecedent wetness conditions and subsurface connectivity and assessed the sensitivity of the results to changes in the measurement network. Event total stormflow was correlated to maximum subsurface connectivity. Subsurface connectivity increased during rainfall events but maximum connectivity occurred later than peak streamflow, resulting in anti-clockwise hysteretic relations between the two. Maximum subsurface connectivity was related to the sum of total rainfall plus antecedent rainfall for the Dolomitic catchments, but these relations were less clear for the pre-alpine catchments. Subsurface connectivity was positively correlated to rainfall amount. For the pre-alpine catchments, the fractions of time that the groundwater monitoring sites were connected to the stream were significantly correlated to the upslope site characteristics, such as the Topographic Wetness Index. For the Dolomitic catchments, the fractions of time that the monitoring sites were connected to the stream were correlated to the topographic characteristics of the upslope contributing area for the catchment with the small riparian zone, and with the distance to the nearest stream for the catchment with the large riparian zone. The leave-one-out sensitivity analysis showed that changes in the structure of the groundwater monitoring networks had a limited influence on the results, suggesting that graph-theory approaches can be used to describe subsurface hydrologic connectivity. However, the proposed graph-theory approach should be verified in other catchments with different groundwater monitoring networks.

    更新日期:2018-07-21
  • Manganese-mediated immobilization of arsenic by calcifying macro-algae, Chara braunii
    Sci. Total Environ. (IF 4.61) Pub Date : 2018-07-20
    Shahram Amirnia, Takashi Asaeda, Chihiro Takeuchi, Yasuko Kaneko

    The restoration capability of charophyte Chara braunii was studied in arsenic-polluted water in the context of biogenic calcium and manganese depositions on the plant. In addition to calcite encrustation, formation of craterlike shape deposits of manganese oxides (MnOx) with diameters of 5–10 μm was detected on the cell walls of the plants grown in Mn-rich media. Relative proportions of arsenic taken up by the plant biomass to those incorporated into the calcium and manganese biominerals were determined using a modified sequential chemical extraction method. The mean total arsenic recovery from water reached its highest value at 375 mg kg−1 in treatment with HCO3− and high concentrations of Ca and Mn (40 and 2 mg L−1, respectively). The percentage of arsenic associated with the manganese deposits in the plants exposed to 0.5 mg L−1 As(III) increased from 16.3% to 51.7% of the total arsenic accumulation at low and high Mn levels (<0.05 and 2 mg L−1, respectively), that accounted for the highest Mn-bound arsenic contribution. Surface oxidation of As(III) by MnOx and subsequent precipitation-adsorption of the formed As(V) onto the evolving structure of MnOx could be a plausible mechanism for arsenic removal. The presence, and in some cases dominance of arsenic bound to the biogenic Ca and Mn deposits on the studied aquatic plant may contribute to preservation of arsenic in sediments in a less bioavailable form upon its senescence and decomposition.

    更新日期:2018-07-21
  • Metals and metalloids in blood and feathers of common moorhens (Gallinula chloropus) from wetlands that receive treated wastewater
    Sci. Total Environ. (IF 4.61) Pub Date : 2018-07-20
    Jhon J. López-Perea, Celia Laguna, María Jiménez-Moreno, Rosa C. Rodríguez Martín-Doimeadios, Jordi Feliu, Rafael Mateo

    We addressed the hypothesis that birds in eutrophic wetlands receiving wastewater treatment plant (WWTP) effluents are exposed to high levels of metals and metalloids and this may drive an ecological trap in some species attracted to these highly productive ecosystems. Levels of metals and metalloids were determined in sediment and in blood and feathers of common moorhens (Gallinula chloropus) from two wetlands in Central Spain: Navaseca Pond, which receives directly the effluent of a WWTP; and Tablas de Daimiel National Park, which is a floodplain less affected by urban discharges. Sediment concentrations of Cr, Mn, Fe, Co, Ni, Cu, Zn, Cd and Pb were higher in Navaseca Pond than in TDNP; only Se was higher in Tablas de Daimiel than in Navaseca. Blood levels of Hg and Se were higher in moorhens from Tablas de Daimiel than those from Navaseca. In the case of Hg these levels were below the threshold of adverse effect, but Se levels in 24% of moorhens from Tablas de Daimiel were above the threshold value associated with Se toxicity in birds (1000 ng/mL). In feathers, Hg, Se, Mn, Cu and As levels were higher in Tablas de Daimiel than in Navaseca. Body condition of moorhens was negatively associated with blood Se levels in the moorhens from Tablas de Daimiel than in Navaseca. We can reject the hypothesis of a higher accumulation of metals and metalloids in birds associated with the WWTP effluent, but Se levels may need further research considering the nature of the floodplain of Tablas de Daimiel National Park.

    更新日期:2018-07-21
  • High stoichiometric food quality increases moulting organism vulnerability to pollutant impacts: An experimental test with Gammarus fossarum (Crustacea: Amphipoda)
    Sci. Total Environ. (IF 4.61) Pub Date : 2018-07-20
    Julio Arce-Funck, Clément Crenier, Michael Danger, Elise Billoir, Philippe Usseglio-Polatera, Vincent Felten

    Headwater organisms are most often simultaneously faced with multiple stressors such as low resource quality and pollutants. Higher food quality has been hypothesized to enhance the tolerance of organisms to pollutants, but the interactive effects of food quality and pollutants on species and ecosystems remain poorly studied. To better understand these interactive effects, we experimentally manipulated the phosphorus (P) content of two leaf litters with contrasted carbon quality (alder and maple). During four weeks, individuals of the detritivorous crustacean Gammarus fossarum were exposed to low levels of cadmium ([Cd] = 0, 0.35 or 0.70 μg L−1) while being fed with one of the leaf P treatments. When organisms were not exposed to Cd, their high survival rate was more driven by the carbon quality of the resource (litter species) than by its stoichiometric quality. In contrast, their number of moults and growth rates were primarily increased by the P content of resources. When exposed to Cd, G. fossarum survival rate was reduced, but this effect was largely magnified by a higher P level in resources. Our results showed that despite positive effects of resource stoichiometric quality on organism life history traits (growth, survival), a resource of high stoichiometric quality might be detrimental for organisms exposed to low and environmentally realistic levels of pollutants. Two non-exclusive hypotheses are proposed to explain these results. First, organisms fed on the highest quality resource exhibited the highest moulting frequencies (moults being the most critical life cycle step of arthropods), which could have rendered them more sensitive to pollutants. Secondly, the metabolism of organisms fed on higher quality resources was potentially enhanced, increasing the uptake of dissolved Cd by gammarids. This study suggests that species sensitivity to pollutants might be underestimated in ecosystems facing both nutrient constraint and pollutants. Capsule High stoichiometric food quality increases moulting organism sensitivity to pollutants.

    更新日期:2018-07-21
  • Contamination of polybrominated diphenyl ethers (PBDEs) in urban mangroves of Southern China
    Sci. Total Environ. (IF 4.61) Pub Date : 2018-07-20
    Minwei Chai, Ruili Li, Cong Shi, Xiaoxue Shen, Rongyu Li, Qijie Zan

    Mangroves are threatened due to urban development and human activities in coastal regions. Four urban mangroves in Shenzhen (rapidly developing city of China) were selected according to urban functional zoning, namely, Shajing mangrove (SJM) and Xixiang mangrove (XXM) featured with industry district, Futian mangrove (FTM) and Baguang mangrove (BGM) featured with central business district and ecological preserve. Eight BDE congeners (BDE-28, -47, -99, -100, -153, -154, -183, and -209) in mangrove sediments and leaves were determined. The highest level of BDE-209 in SJM was proximate to areas of point-source discharges of Dongbao River in Pearl River Estuary, China. Total organic carbon (TOC) was influential in BDE-209 accumulations in SJM, XXM, and FTM. Multiple variate analysis implied that PBDEs in SJM, XXM and FTM mainly composed of penta-, octa-, and deca-BDEs, with surface runoff to be the main contamination sources; while BGM was contaminated by penta- and octa-BDEs. Ecological risk of BDE-209 was high in SJM, with medium/negligible risk in the other urban mangroves. The transfers of BDE-209 from sediment to leaf were weak (BGM and FTM), improved (XXM), and restricted (SJM), respectively. This is the first reports of spatial distribution and bioaccumulation of PBDEs in urban mangroves featured with different urban functional zonings. More attention is required to reduce emission of PBDEs into the environment and manage PBDEs contamination in urban mangroves.

    更新日期:2018-07-21
  • Impact of brackish groundwater and treated wastewater on soil chemical and mineralogical properties
    Sci. Total Environ. (IF 4.61) Pub Date : 2018-07-20
    Jeffry Tahtouh, Rabi Mohtar, Amjad Assi, Paul Schwab, Anish Jantrania, Youjun Deng, Clyde Munster

    The long-term effect of using treated wastewater is not clearly defined: some researchers argue that it is better than freshwater for the soil health; others disapprove, claiming that irrigation with unconventional water resources causes soil degradation. This study assesses the impact of irrigation with non-traditional water on the chemical and mineralogical properties of a calcareous clayey soil from West Texas. The exponential rise in population and the realities of climate change contribute to the global increase in freshwater scarcity: non-conventional water sources, such as treated wastewater (TWW) and brackish groundwater (BGW), offer potentially attractive alternative water resources for irrigated agriculture. For this research, the differences between TWW and BGW were addressed by collecting and analyzing water samples for salt and nutrient content. Soil samples from three horizons (Ap, A, and B) were obtained from three different fields: Rainfed (RF), BGW irrigated, and TWW irrigated. Soil was analyzed for texture, salinity, sodicity, and carbon content. Clay mineralogy of the three different fields was analyzed using the B-horizons. The outcomes from the analysis showed that the BGW from the Lipan aquifer has higher salinity and is harder compared to TWW. Although the exchangeable sodium percentage (ESP), sodium adsorption ratio (SAR), and electroconductivity (EC) increased marginally compared to the control soil (RF), the soils were in good health, all the values of interest (SAR < 13, ESP < 15, pH < 8.5, and EC < 4) were low, indicating no sodicity or salinity problems. Smectite, illite, and kaolinite were identified in the three B-horizon samples using bulk X-ray diffraction (XRD). Overall, no major changes were observed in the soil. Thus, TWW and BGW are viable replacements for freshwater irrigation in arid and semi-arid regions.

    更新日期:2018-07-21
  • Development of stripping coil-ion chromatograph method and intercomparison with CEAS and LOPAP to measure atmospheric HONO
    Sci. Total Environ. (IF 4.61) Pub Date : 2018-07-20
    Chaoyang Xue, Can Ye, Zhuobiao Ma, Pengfei Liu, Yuanyuan Zhang, Chenglong Zhang, Ke Tang, Wenqian Zhang, Xiaoxi Zhao, Yuzheng Wang, Min Song, Junfeng Liu, Jun Duan, Min Qin, Shengrui Tong, Maofa Ge, Yujing Mu

    Nitrous acid (HONO) is the major precursor of OH radicals in polluted areas. Accurate measurement of HONO provides vital evidence for exploring the formation of secondary pollution. Stripping coil (SC) equipped with ion chromatograph (IC) or spectrograph as one of wet chemical methods has been already used to measure HONO. The reliability of the method mainly depends on the collection efficiency and the interference from other species. In this study, a SC-IC method was set up to measure HONO. The performance of the method was assessed in the chamber using two kinds of absorption solutions i.e. ultrapure water and 25 μM Na2CO3 solution under different concentrations of SO2. Results indicated that HONO concentrations absorbed by ultrapure water and Na2CO3 solution were almost identical in the absence of SO2 in the chamber and both the collection efficiencies were >99%. However, the collection efficiency of ultrapure water decreased with the increase of SO2, indicating that the presence of SO2 resulted in the penetration of HONO. The collection efficiency kept >90% when the concentration of SO2 was no >23 ppbv. Comparing with the situation without SO2, HONO performed a remarkable increase with the presence of SO2 when using Na2CO3 absorption solution, indicating that the extra generation of HONO from the reaction between SO2 and NO2 in alkaline solution. Consequently, ultrapure water as the absorption solution could provide a high collection efficiency and avoid the interferences from SO2 when the concentration of SO2 was below 23 ppbv. High correlations (slope = 0.94–1.06, r2 > 0.90) were found during the intercomparisons between SC-IC and other three techniques, suggesting the SC-IC method developed in this study was able to measure atmospheric HONO in the field campaigns.

    更新日期:2018-07-21
  • A fluorescence-based assessment of the fate of organic matter in water treated using crude/purified Hibiscus seeds as coagulant in drinking water treatment
    Sci. Total Environ. (IF 4.61) Pub Date : 2018-07-20
    Alfred Ndahi Jones, John Bridgeman

    This study used fluorescence excitation-emission matrices (EEMs) analysis to investigate the characteristics of natural organic matter (NOM) in treated water using okra crude extract (OCE), sabdariffa crude extract (SCE) and kenaf crude extract (KCE) as coagulants. In addition, an assessment of the impact of purified okra protein (POP), purified sabdariffa protein (PSP) and purified kenaf protein (PKP) was undertaken. The performance evaluation of these coagulants in terms of increase or decrease in dissolved organic carbon (DOC) was compared with Peak T fluorescence intensity observed at excitation wavelength 220–230 nm, and emission wavelength 340–360 nm. Fluorescence analysis of water treated with the crude extracts identified the removal of DOC in peaks A and C region whereas the increase in DOC from the protein was predominantly found in peaks T and B region. Furthermore, it was observed that the purified proteins were noted to be capable of reducing the DOC concentration in raw water where all fluorophores were not detected. The application of OCE, SCE and KCE yielded an increase in DOC of 65, 61 and 55% respectively, corresponding to increases of 65, 29 and 54% in peak T fluorescence intensities, at 100 mg/l dose. Furthermore, DOC concentration was reduced by 25, 24 and 18% using POP, PSP and PKP respectively as coagulants with corresponding decreases in fluorescence intensity of 46%, 44 and 36% in POP, PSP and PKP, at a lower dose of 0.1 mg/l. Therefore, it is clear that Peak T fluorescence intensity could be used to characterise organic matter in treated water using natural extracts to assess final water quality.

    更新日期:2018-07-21
  • Nitrogen loading and natural pressures on the water quality of a shallow Mediterranean lake
    Sci. Total Environ. (IF 4.61) Pub Date : 2018-07-20
    A. Mentzafou, E. Dimitriou

    The water quality of Koumoundourou Lake, a heavily modified, peri-urban, brackish and shallow lake near Athens, Greece, is under multiple stressors due to the industrial activities in the catchment area and natural pollution pressures. Although the broader area has undergone significant land use changes since the beginning of the 20th century converting it from rural to heavily industrialized, Koumoundourou Lake remained as one of the few habitats in Attica Region, for large numbers of aquatic birds. The water quality of the lake has been recently improved, which contributed to the increase of aquatic birds' population in the area and to the higher, in relation to the past, nitrogen inputs from natural sources. Therefore, a monitoring program has been implemented to assess the pollution pressure factors in the lake. A water quality model has been also used to simulate the lake's processes and estimate the nutrient mass budget focusing on the various nitrogen loading mechanisms (natural and anthropogenic). Based on the model output, the main polluting factor of the lake is the groundwater inflows. Aquatic birds affect slightly the lake's water quality, while the dry and wet atmospheric deposition contributes insignificantly to the total nitrogen loading.

    更新日期:2018-07-21
  • Brominated and organophosphate flame retardants along a sediment transect encompassing the Guiyu, China e-waste recycling zone
    Sci. Total Environ. (IF 4.61) Pub Date : 2018-07-20
    Huiru Li, Mark J. La Guardia, Hehuan Liu, Robert C. Hale, T. Matteson Mainor, Ellen Harvey, Guoying Sheng, Jiamo Fu, Ping'an Peng

    e-Waste recycling using crude techniques releases a complex, yet incompletely characterized mixture of hazardous materials, including flame retardants (FRs), to the environment. Their migration downstream and the associated risks also remain undocumented. We examined 26 FRs (18 brominated (BFRs: 12 polybrominated diphenyl ether (PBDE) congeners, plus 6 alternatives) and 8 organophosphate esters (OPEs)) in surficial sediments of the Lian River. Sampling encompassed the river's origin, through the Guiyu e-waste recycling zone, to its mouth, as well as associated tributaries. OPE exceeded BFR concentrations in most sediments, despite their far greater water solubilities. Among OPEs, tris(1-chloro-2-propyl) phosphate dominated upstream, but shifted to triphenyl phosphate in Guiyu and downstream sediments. For PBDEs, Deca-BDE dominated upstream, but Penta-BDE prevailed in Guiyu and at many downstream sites. Among emerging alternative BFRs, decabromodiphenyl ethane dominated upstream, transitioning to 1,2-bis(2,4,6,-tribromophenoxy)ethane in Guiyu sediments. Penta-BDE (BDE-47 + -99, 668–204,000 ng g−1, ∑PBDEs 2280–287,000 ng g−1), tetrabromobisphenol A (2,720–41,200 ng g−1), 1,2-bis(2,4,6,-tribromophenoxy)ethane (222–9870 ng g−1) and triphenyl phosphate (4260–1,710,000 ng g−1, OPEs 6010–2,120,000 ng g−1) concentrations in Guiyu sediments were among the highest reported in the world to date. The continuing dominance of these e-waste indicative FRs in sediments downstream of Guiyu suggested that FR migration from Guiyu occurred. Hazard quotients >1.0 indicated that the extreme sediment concentrations of individual FRs posed ecological risks in most Guiyu reach and downstream areas. Simultaneous exposure to multiple FRs likely increased risks. However, risks may be mediated if FRs were associated with strong sorbents, e.g. carbon black from burned debris, hydrophobic polymer fragments, or resided as additives within polymer fragments.

    更新日期:2018-07-21
  • Field tests of in-well electrolysis removal of arsenic from high phosphate and iron groundwater
    Sci. Total Environ. (IF 4.61) Pub Date : 2018-07-20
    Songhu Yuan, Shiwei Xie, Kangyu Zhao, Yiqun Gan, Yanxin Wang

    Subsurface arsenic (As) removal has been proposed for in situ immobilizing As in aquifers at a low cost and without post-disposal of As-containing wastes. However, the results reported for field tests are very limited, particularly when high As, phosphate (P) and iron (Fe) coexist in the groundwater. Herein the performance of single- and multiple-well operations was evaluated for in situ removing groundwater As in Jianghan Plain, central China. To enhance groundwater oxygenation, in-well electrolysis was employed in both operation modes. The groundwater in confined aquifer in Jianghan Plain contains elevated concentrations of As (272–606 μg/L), Fe2+ (4.7–14.3 mg/L) and P (0.90–1.58 mg/L). In the single-well operation with cycles of injection and abstraction, groundwater Fe2+ was completely removed but As cannot be reduced to below the World Health Organization guideline (10 μg/L) due to the high concentration and the competition of coexisting P. In-well electrolysis is cost-effective for boosting dissolved oxygen (DO) and Fe2+ removal in single-well operations. In the multiple-well operation with one abstraction well surrounded by 6 in-well electrolysis wells, removals of groundwater As, Fe, P and Mn were not sufficient because of clogging of treatment wells and incomplete capture of groundwater flowing to the abstraction well. In comparison, single-well operation is more simple and efficient for in situ treatment of groundwater As and Fe than multiple-well operation. This study provides a field example of in situ removing high As in groundwater by both single- and multiple-well operations, and underscores the difficulty in treating the groundwater with coexistence of elevated As and P.

    更新日期:2018-07-21
  • Economic, social, and environmental evaluation of energy development in the Eagle Ford Shale Play
    Sci. Total Environ. (IF 4.61) Pub Date : 2018-07-20
    Rabi H. Mohtar, Hamid Shafiezadeh, John Blake, Bassel Daher

    This research investigates the relation between water, energy, and transportation systems, using the growing hydraulic fracturing activity in the Eagle Ford shale play region of southwest Texas in which the local water systems and road infrastructure were not designed for the frequent transport of water into the production site and of produced gas and oil from the site as are often required for hydraulic fracturing. The research: 1) quantifies the interconnections between water, energy, and transportation systems specific to the Eagle Ford shale region; 2) identifies and quantifies the economic, social, and environmental indicators to evaluate scenarios of oil and gas production; and 3) develops a framework for analysis of the economic, societal, and long term sustainability of the sectors and 4) an assessment tool (WET Tool) that estimates several economic indicators: oil and natural gas production, direct and indirect tax revenues, and average wages for each scenario facilitates the holistic assessment of oil and gas production scenarios and their associated trade-offs between them. Additionally, the Tool evaluates these social and environmental indices, (water demand, emissions, water tanker traffic, accidents, road deterioration, and expected average employment times). Scale of production is derived from the price of oil and gas; government revenues from production fluctuations in relation to rise and fall of the oil and gas market prices. While the economic benefits are straightforward, the social costs of shale development (water consumption, carbon emissions, and transportation/infrastructure factors), are difficult to quantify. The tool quantifies and assesses potential scenario outcomes, providing an aid to decision makers in the public and private sectors that allows increased understanding of the implications of each scenario for each sector by summarizing projected outcomes to allow evaluation of the scenarios and comparison of choices and facilitate the essential dialogue between these sectors.

    更新日期:2018-07-21
  • Effect of zirconium-modified zeolite addition on phosphorus mobilization in sediments
    Sci. Total Environ. (IF 4.61) Pub Date : 2018-07-20
    Jianwei Lin, Siqi He, Honghua Zhang, Yanhui Zhan, Zhibin Zhang

    There is generally a significant heterogeneity in the vertical distribution of mobile phosphorus (P) in sediments, but the previous studies concerning the effect of zirconium-modified zeolite (ZrMZ) addition on the mobilization of P in sediments neglected this feature. In this study, microcosm experiments were conducted to investigate the effect of ZrMZ addition on the mobilization of P in river surface sediments at different depths. A high-resolution diffusive gradients in thin films technology (DGT) were used to measure the concentration of labile P in the overlying water-sediment profiles at a submillimeter vertical resolution. Results showed that the ZrMZ amendment not only could reduce the concentration of soluble reactive P (SRP) in the overlying water, but also could decrease the concentrations of SRP in the pore water at different depths. Furthermore, the ZrMZ amendment resulted in the reduction of both the releasing flux of SRP from sediments to the overlying water and the diffusion flux of SRP from the pore water to the overlying water. After the addition of ZrMZ into the top sediment, the static layer with low DGT-liable P (DGT-P) concentration was observed in the upper sediment. The addition of ZrMZ into the upper sediment resulted in the reduction of mobile P (Pm) in the upper and lower sediments via the transformation of Pm to more stable NaOH-extractable P (NaOH-rP) and residual P (Res-P). In addition, the contents of bioavailable P (BAP) including water-soluble P (WSP), readily desorbable P (RDP) and iron oxide paper extractable P (FeO-P) in the upper sediment were greatly reduced by the ZrMZ addition. Results of this study show that the immobilization of pore water SRP, DGT-P, sediment Pm and sediment BAP by ZrMZ played a very important role in the control of P release from sediments to the overlying water by the ZrMZ amendment.

    更新日期:2018-07-21
  • Assessing plant-available glyphosate in contrasting soils by diffusive gradient in thin-films technique (DGT)
    Sci. Total Environ. (IF 4.61) Pub Date : 2018-07-20
    Zhe Weng, Michael Rose, Ehsan Tavakkoli, Lukas Van Zwieten, Gavin Styles, William Bennett, Enzo Lombi

    Glyphosate represents one quarter of global herbicide sales, with growing interest in both its fate in soils and potential to cause non-target phytotoxicity to plants. However, assessing glyphosate bioavailability to plants from soil residues remains challenging. Here we demonstrate that the diffusive gradient in thin-films technique (DGT) can effectively measure available glyphosate across boundary conditions typical of the soil environment: pH 4–9, P concentrations of 20–300 μg P L−1 and NaHCO3 concentrations of 10–1800 mg L−1. In this study, four soils with different glyphosate sorption properties were dosed with up to 16 mg kg−1 of glyphosate and phytotoxicity to wheat and lupin was measured against the DGT-glyphosate concentrations. An improved dose response curve was obtained for root elongation of wheat and lupin across soil types when DGT-glyphosate was used instead of alkaline-extractable (i.e., total extractable) glyphosate. Total extractable glyphosate concentrations of 2.6 and 5.0 mg glyphosate kg−1 in the sandy Tenosol, equivalent to 2.9 and 6.5 μg L−1 DGT-extractable glyphosate, reduced the root length of lupins (but not wheat) were by 32–36% compared with the untreated control. DGT is therefore a promising method for assessing phytotoxic levels of glyphosate across different soils.

    更新日期:2018-07-21
  • How can we improve understanding of faecal indicator dynamics in karst systems under changing climatic, population, and land use stressors? – Research opportunities in SW China
    Sci. Total Environ. (IF 4.61) Pub Date : 2018-07-21
    Sarah J. Buckerfield, Susan Waldron, Richard S. Quilliam, Larissa Naylor, Siliang Li, David M. Oliver

    Human exposure to water contaminated with faeces is a leading cause of worldwide ill-health. Contaminated water can be transmitted rapidly in karst terrain as a result of the connectivity of surface and groundwater systems, high transmissivity of aquifers over large areas, and well-developed underground conduit systems. Faecal indicator organisms (FIOs) are the most widely-used indicator of faecal contamination and microbial water quality; however, the conceptualisation of FIO risk and associated sources, pathways, and survival dynamics of FIOs in karst landscapes requires a degree of modification from traditional conceptual models of FIO fate and transfer in non-karst systems. While a number of reviews have provided detailed accounts of the state-of-the-science concerning FIO dynamics in catchments, specific reference to the uniqueness of karst and its influence on FIO fate and transfer is a common omission. In response, we use a mixed methods approach of critical review combined with a quantitative survey of 372 residents of a typical karst catchment in the southwest China karst region (SWCKR) to identify emerging research needs in an area where much of the population lives in poverty and is groundwater dependent. We found that the key research needs are to understand: 1) overland and subsurface FIO export pathways in karst hydrology under varying flow conditions; 2) urban and agricultural sources and loading in mixed land-use paddy farming catchments; 3) FIO survival in paddy farming systems and environmental matrices in karst terrain; 4) sediment-FIO interactions and legacy risk in karst terrain; and 5) key needs for improved hydrological modelling and risk assessment in karst landscapes. Improved knowledge of these research themes will enable the development of evidence-based faecal contamination mitigation strategies for managing land and water resources in the SWCKR, which is highly vulnerable to climate change impacts on water supply and quality of water resources.

    更新日期:2018-07-21
  • Application potential of biochar in environment: Insight from degradation of biochar-derived DOM and complexation of DOM with heavy metals
    Sci. Total Environ. (IF 4.61) Pub Date : 2018-07-21
    Mei Huang, Zhongwu Li, Ninglin Luo, Ren Yang, Jiajun Wen, Bin Huang, Guangming Zeng

    Biochar-derived dissolved organic matter (DOM) is important for determining the application potential of biochar in soil remediation. However, little is known about the degradation behavior of biochar-derived DOM and its interaction with heavy metals. Here, incubation experiments combined with quenching titration experiments, which analyzed by spectroscopic technology and chemometric method, were conducted to reveal such behaviors and mechanisms. Ultraviolet–visible (UV–Vis) spectra showed that high aromatic and hydrophobic fractions were enriched in biochar-derived DOM and enhanced during the cultivation process, thus the biochar-derived DOM may retain a high aromaticity, stability, and resistance. However, the environmental risk of Cu caused by the increase of DOM hydrophobicity cannot be overlooked while applying biochar to polluted soil. One fulvic-like (C1), one protein-like (C2) and two humic-like (C3, C4) substances were identified from biochar-derived DOM by using parallel factor analysis of excitation-emission matrix. Additionally, the fluorescence intensity variations of these components in DOM offered an additional interpretation for the observations from UV–Vis spectra. Two-dimensional correlation spectroscopy revealed that Cd binding to biochar-derived DOM first occurred in the protein- and fulvic-like fraction while protein- and humic-like substances had a stronger affinity for Cu. Furthermore, both phenolic and carboxyl groups firstly participated in the binding process of Cd with biochar-derived DOM, while polysaccharide gave the fastest response to Cu binding. These results clearly demonstrated the differences in specific heavy metal binding features of individual fluorescent substances and functional groups in biochar-derived DOM and contribute to improving the application effect of biochar in a multi-heavy metal polluted soil system.

    更新日期:2018-07-21
  • Mitigating greenhouse gas emissions in subsurface-drained field using RZWQM2
    Sci. Total Environ. (IF 4.61) Pub Date : 2018-07-21
    Qianjing Jiang, Zhiming Qi, Chandra A. Madramootoo, Cynthia Crézé

    Greenhouse gas (GHG) emissions from agricultural soils are affected by various environmental factors and agronomic practices. The impact of inorganic nitrogen (N) fertilization rates and timing, and water table management practices on N2O and CO2 emissions were investigated to propose mitigation and adaptation efforts based on simulated results founded on field data. Drawing on 2012–2015 data measured on a subsurface-drained corn (Zea mays L.) field in Southern Quebec, the Root Zone Water Quality Model 2 (RZWQM2) was calibrated and validated for the estimation of N2O and CO2 emissions under free drainage (FD) and controlled drainage with sub-irrigation (CD-SI). Long term simulation from 1971 to 2000 suggested that the optimal N fertilization should be in the range of 125 to 175 kg N ha−1 to obtain higher NUE (nitrogen use efficiency, 7–14%) and lower N2O emission (8–22%), compared to 200 kg N ha−1 for corn-soybean rotation (CS). While remaining crop yields, splitting N application would potentially decrease total N2O emissions by 11.0%. Due to higher soil moisture and lower soil O2 under CD-SI, CO2 emissions declined by 6% while N2O emissions increased by 21% compared to FD. The CS system reduced CO2 and N2O emissions by 18.8% and 20.7%, respectively, when compared with continuous corn production. This study concludes that RZWQM2 model is capable of predicting GHG emissions, and GHG emissions from agriculture can be mitigated using agronomic management.

    更新日期:2018-07-21
  • Energy consumption, CO2 emissions and costs related to baths water consumption depending on the temperature and the use of flow reducing valves
    Sci. Total Environ. (IF 4.61) Pub Date : 2018-07-21
    C. Matos, I. Bentes, S. Pereira, D. Faria, A. Briga-Sá

    In the domestic segment, various appliances and processes consume great amount of water and, consequently, energy. In this context, the main aim of this study is to analyse the impact of water temperature, flow and bath duration in water and energy consumptions. The impact on CO2 emissions and a simple costs analysis were also carried out. It included a monitoring plan of 197 baths taken under different scenarios of water temperature and flow. It was concluded that increasing water consumption leads to an increase on energy consumption and that both resources consumptions increase with bath duration. Bath temperature had influence not only on energy consumption, as expected, but also in water consumption, what may be explained by the user's satisfaction during baths with higher temperatures. The use of a flow reducing valve is not a guarantee of water saving which can also be related to the user's satisfaction patterns, given that the introduction of a flow reducing valve can lead to a bath duration increase. In what concerns to the CO2 emissions, it was concluded, as expected, that higher values are obtained for baths with higher temperatures given their relation with higher energy consumptions patterns. A simple costs analysis revealed that having flow reducing valves, with a bath temperature of 75 °C, increased the costs with electricity and water in 119% and 32%, respectively, when compared with a temperature of 60 °C.

    更新日期:2018-07-21
  • Short-term effects of reduced graphene oxide on the anammox biomass activity at low temperatures
    Sci. Total Environ. (IF 4.61) Pub Date : 2018-07-21
    Mariusz Tomaszewski, Grzegorz Cema, Aleksandra Ziembińska-Buczyńska

    Anaerobic ammonium oxidation (anammox) is an efficient process for nitrogen removal from wastewater, but its common use is limited by its relatively high optimal temperature (30 °C). One of the major bottlenecks of the implementation of mainstream PN/A process is the low activity of the anammox bacteria at low temperature. Due to this reason over the past years, numerous researchers have attempted to overcome this limitation. Recently it was shown that the reduced graphene oxide (RGO) can accelerate the anammox bacteria activity. However all these studies were performed at high temperatures (over 30 °C). Thus, in this study, supporting the anammox process at low temperatures (10–30 °C) by the RGO was investigated for the first time. The statistical analysis confirmed that RGO significantly affects the anammox activity. The stimulation effect of RGO on the anammox bacteria activity is of particular importance at low temperatures, when drastic decrease in process activity is observed at temperatures below 15 °C. The short-term experimental results demonstrated stimulation of the anammox activity at 13 °C, up to 28% by 15 mg RGO/L, but concentrations above 40 mg RGO/L caused the process inhibition, up to 30% with 50 mg RGO/L. However, the effect of RGO probably depends on the nanomaterial dose per biomass unit and the optimal range of this value was evaluated as 20 to 45 mg RGO/g VSS (volatile suspended solids).

    更新日期:2018-07-21
  • Irrigation reduces the negative effect of global warming on winter wheat yield and greenhouse gas intensity
    Sci. Total Environ. (IF 4.61) Pub Date : 2018-07-21
    Jiazhen Li, Wenxu Dong, Oene Oenema, Tuo Chen, Chunsheng Hu, Haijing Yuan, Liying Zhao

    Global warming may exacerbate drought, decrease crop yield and affect greenhouse gas (GHG) emissions in semi-arid regions. However, the interactive effects of increases in temperature and water availability on winter wheat yield and GHG emissions in semi-arid climates are not well-understood. Here, we report on a two-year field experiment that examined the effects of a mean soil temperature increase of ~2 °C (at 5 cm depth) with and without additional irrigation on wheat yield and GHG emissions. Infrared heaters were placed above the crop canopy at a height of 1.8 m to simulate warming. Fluxes of CH4, CO2 and N2O were measured using closed static chamber technique once per week during the wheat growing seasons. Warming decreased wheat yield by 28% in the relatively dry year of 2015, while supplemental irrigation nullified the warming effect completely. Warming did not alter the wheat yield significantly in the relatively wet year of 2016, but supplemental irrigation with no warming decreased the wheat yield by 25%. Warming increased CO2 emissions by 28% and CH4 uptake by 24% and tended to decrease N2O emissions. Supplemental irrigation increased N2O emissions but had little effect on CO2 emissions and CH4 uptake. Evidently, warming and supplemental irrigation had interactive effects on wheat yield, GHG emissions and GHG emissions intensity. Precision irrigation appears to be a means of simultaneously increasing wheat yield and reducing GHG emissions under warming conditions in semi-arid areas.

    更新日期:2018-07-21
  • Effects of ionic strength on removal of toxic pollutants from aqueous media with multifarious adsorbents: A review
    Sci. Total Environ. (IF 4.61) Pub Date : 2018-07-21
    Yanhong Zhang, Changqing Zhu, Fuqiang Liu, Yuan Yuan, Haide Wu, Aimin Li

    Adsorption is one of the most widely used and effective wastewater treatment methods. The role of ionic strength (IS) in shaping the adsorption performances is much necessary due to the ubiquity of electrolyte ions in water body and industrial effluents. The influences of IS on adsorption are rather complex, because electrolyte ions affect both adsorption kinetics and thermodynamics by changing the basic characteristics of adsorbents and adsorbates. For a given adsorption system, multiple or even contradictory effects of IS may coexist under identical experimental conditions, rendering the dominant mechanism recognition and net effect prediction complicated. We herein reviewed the key advancement on the interaction and mechanisms of IS, including change in number of active sites for adsorbents, ion pair for metal ions, molecular aggregation and salting-out effect for organic compounds, site competition for both inorganic and organic adsorbates, and charge compensation for adsorbent-adsorbate reciprocal interactions. The corresponding fundamental theory was thoroughly described, and the efforts made by various researchers were explicated. The structural optimization of adsorbents affected by IS was detailed, also highlighting polyamine materials with exciting “salt-promotion” effects on heavy metal removal from high salinity wastewater. In addition, the research trends and prospects were briefly discussed.

    更新日期:2018-07-21
  • The impacts of land conversion and management measures on the grassland net primary productivity over the Loess Plateau, Northern China
    Sci. Total Environ. (IF 4.61) Pub Date : 2018-07-19
    Chengcheng Gang, Wei Zhao, Ting Zhao, Yi Zhang, Xuerui Gao, Zhongming Wen

    In the 1990s, the Chinese government began implementation of a series of national-scale restoration programs to combat environmental degradation. As one of most important arid and semiarid regions of China, the Loess Plateau has attracted attention related to the effectiveness of these initiatives. The present study analyzed land use and cover change (LUCC) of the grassland in the Loess Plateau and the consequent change in net primary productivity (NPP) based on a consecutive land use data derived from the European Space Agency Climate Change Initiative land cover maps and the CASA (Carnegie-Ames-Stanford Approach) model driven by MODIS-NDVI data. The contributions of climate variation and human activities (including land conversion and management measures) to these changes were also quantitatively differentiated. The results indicated that the area of the Loess Plateau grassland experienced a net increase of 0.43 × 104 km2 over the study period. The total NPP of the Loess Plateau grassland increased by 11,325.13 Gg C·yr−1, of which the human activities and climate variation were responsible for 78.45% and 21.55%, respectively. The land conversion reduced the grassland NPP by 308.60 Gg C·yr−1, whereas management measures increased the NPP by 9197.97 Gg C·yr−1 in the otherwise unmodified grassland. Overall, ecological restoration programs have effectively increased grassland NPP in the Loess Plateau. However, human activities played both positive and negative impacts in this process.

    更新日期:2018-07-20
  • Potential and environmental control of carbon sequestration in major ecosystems across arid and semi-arid regions in China
    Sci. Total Environ. (IF 4.61) Pub Date : 2018-07-19
    Qing Gu, Jin Wei, Shuchang Luo, Mingguo Ma, Xuguang Tang

    With the continuous expansion of drylands in the context of global climate change, governments have implemented a series of greening policies such as afforestation, to reduce ecological degradation. However, owing to historical conditions and technical constraints, few attempts have been made to quantitatively assess the differences in carbon sequestration capacity and the associated environmental controls among major ecosystems in the arid and semi-arid areas. Based on six flux towers located in northwestern China measuring the carbon fluxes in a maize (Zea mays L.) cropland, alpine meadow, wetland, swamp meadow, Tamarix, and gobi desert, this work revealed that all ecosystems sequestered CO2 at various magnitudes. The cropland had the highest carbon uptake, followed by the alpine meadow, swamp meadow, wetland and Tamarix, respectively. Distinct seasonal dynamics in carbon sequestration were observed across these ecosystems with the peak values in summertime, whereas the gobi desert exhibited as a weak carbon sink with considerable fluctuations around the year. In this water-limited region, soil water content instead of rainfall, is expected to be the primary environmental control on the land–atmosphere carbon fluxes, and regarded as a key linkage between hydrologic and ecologic processes. Therefore, not only the appropriate vegetation types, but also the water availability controlled by the local climatic constraints and soil characteristics, should be addressed in order to identify management strategies for ecological restoration in the dry areas.

    更新日期:2018-07-20
  • Experimental study of destruction of acetone in exhaust gas using microwave-induced metal discharge
    Sci. Total Environ. (IF 4.61) Pub Date : 2018-07-19
    Yukun Feng, Wenlong Wang, Yican Wang, Jing Sun, Chao Zhang, Qamar Shahzad, Yanpeng Mao, Xiqiang Zhao, Zhanlong Song

    Volatile organic compounds (VOCs) are air pollutants that pose a major concern, and novel treatment technologies must be continuously explored and developed. In this study, microwave-induced metal discharge was applied to investigate the destruction of acetone as a representative model VOC compound. Results revealed that metal discharge intensity largely depended on microwave output power and the number of metal strips. Microwave metal discharge exerted the distinct combined effects of intense heat, strong light, and plasma. In the case of MW without metal discharge, the decrease in acetone at 200 ppm was remarkably limited (approximately 5.5% (mol/mol)). By contrast, in the case of microwave-induced metal discharge, a considerably high destruction efficiency of up to 65% (mol/mol) was obtained at low concentrations. This finding highlights the potential of microwave-induced discharge for VOC removal. Initial assessment indicated that energy consumption can be acceptable.

    更新日期:2018-07-20
  • Nationwide screening of surface water toxicity to algae
    Sci. Total Environ. (IF 4.61) Pub Date : 2018-07-19
    M.L. de Baat, D.A. Bas, S.A.M. van Beusekom, S.T.J. Droge, F. van der Meer, M. de Vries, P.F.M. Verdonschot, M.H.S. Kraak

    According to the European Water Framework Directive (WFD), chemical water quality is assessed by monitoring 45 priority substances. However, observed toxic effects can often not be attributed to these priority substances, and therefore there is an urgent need for an effect-based monitoring strategy that employs bioassays to identify environmental risk. Algal photosynthesis is a sensitive process that can be applied to identify the presence of hazardous herbicides in surface water. Therefore, the aim of this study was to employ an algal photosynthesis bioassay to assess surface water toxicity to algae and to identify the compounds causing the observed effects. To this purpose, Raphidocelis subcapitata was exposed to surface water samples and after 4.5 h photosynthetic efficiency was determined using PAM fluorometry. In this rapid high throughput bioassay, algal photosynthesis was affected by surface water from only one of 39 locations. Single compounds toxicity confirmation elucidated that the observed effect could be solely attributed to the herbicide linuron, which occurred at 110 times the EQS concentration and which is not included in the WFD priority substances list. In conclusion, applying the algal photosynthesis bioassay enables more efficient and effective assessment of toxicity to primary producers because it: (i) identifies the presence of herbicides that would be overlooked by routine chemical WFD monitoring, and (ii) avoids redundant chemical analyses by focusing only on (non-)target screening in samples with demonstrated effects.

    更新日期:2018-07-20
  • Reduced colonization by soil invertebrates to irradiated decomposing wood in Chernobyl
    Sci. Total Environ. (IF 4.61) Pub Date : 2018-07-19
    A.P. Møller, T.A. Mousseau

    Soil is inhabited by a range of microbes, invertebrates and vertebrates that disintegrate and decompose dead wood and leaf litter. These communities can be perturbed by ionizing radiation from natural radiation sources or from radiation originating from nuclear accidents such as those at Chernobyl, Fukushima and Three Mile Island. We used experimental manipulations of wood quality due to differences in exposure to ionizing radiation among tree trunks and ambient radiation levels of the soil to test the hypothesis that radioactively contaminated wood would result in a negative correlation between the abundance of soil invertebrates colonizing slices of wood and level of radioactive contamination. We extracted soil invertebrates underneath decomposing wood using mustard powder diluted in water. The abundance of soil invertebrates extracted was highly repeatable at study sites and decreased with increasing ambient radiation and total dose measured with thermoluminescent dosimeters (TLDs). Four 10 cm thick slices of ca. 70-year old Scots pines (Pinus sylvestris) were deposited at 20 sites and the invertebrate taxa and their colonization and their abundance was assessed annually during 2014–2017. There were more soil invertebrates under uncontaminated than contaminated slices of wood. In addition, there were more soil invertebrates in areas with less ambient radioactivity, and there was an interaction effect between contamination of wood and ambient radiation implying that the role of contamination differed among slices. Finally, there was an increase in the abundance of soil invertebrates under wood slices during 2013–2017 implying that the abundance of soil invertebrates increased over time. These findings imply that the abundance of soil animals colonizing wood slices was dependent on background radiation, radioactive contamination of wood and the interaction between contamination of wood and ambient radiation.

    更新日期:2018-07-20
  • Trace metal enrichment during the Industrial Period recorded across an altitudinal transect in the Southern Central Pyrenees
    Sci. Total Environ. (IF 4.61) Pub Date : 2018-07-19
    J.P. Corella, A. Saiz-Lopez, M.J. Sierra, M.P. Mata, R. Millán, M. Morellón, C.A. Cuevas, A. Moreno, B.L. Valero-Garcés

    The study of three lacustrine sedimentary archives along an altitudinal transect in the Southern Central Pyrenees - lakes Estanya, Basa and Marboré- has provided a unique record of changes in anthropogenic trace metal concentrations over the last six centuries in NE Iberian Peninsula. Although site-specific processes influence metals enrichments in each lacustrine system, significant enrichments of Hg and Pb and minor to moderate enrichments of Cu, Cd, and Zn with respect to baseline (Pre-industrial) concentrations highlight intensive release of anthropogenic trace metals with the advent of the Industrial Revolution leading to maximum values during the 20th century. The largest trace metal pollution occurred between 1840s and 1920s CE mainly derived from the increasing demand of ore resources in Southern Europe during the Industrialization. A second, less distinct pollution phase occurred between 1950s and 1990s, associated with the “Great Acceleration” and increased trace metal emissions related to road-transport, use of fertilizers in agriculture and the global boost of the Chemical Industry. Enrichment of mercury during the Industrial Period correlates well with Hg production in Spanish Almadén mines and global emission inventories. Local mining in the Pyrenees and regional smelting activities in Spain and Southern France may explain the enrichment of lead (and associated by-products cadmium and zinc) during the first pollution phase while the use of leaded gasoline since the mid-20th century drives the higher Pb enrichment factor found till the late 20th century. This investigation demonstrates that environmental regulations controlling emissions of hazardous metals during the last decades have greatly contributed to a significant reduction of these anthropogenic trace metals enrichments in natural ecosystems although they still double pre-industrial levels. This study also exemplifies the different sensitiveness of lacustrine systems to record past atmospheric pollution phases and highlights the need of multi-archive studies to conduct regional (rather than local) pollution reconstructions.

    更新日期:2018-07-20
  • Effects of soil conservation techniques on water erosion control: A global analysis
    Sci. Total Environ. (IF 4.61) Pub Date : 2018-07-19
    Muqi Xiong, Ranhao Sun, Liding Chen

    Water erosion control is one of the most important ecosystem services provided by soil conservation techniques (SCTs), which are being widely used to alter soil and water processes and improve ecosystem services. But few studies have focused on providing this service using various techniques across the world. Here, a comprehensive review was conducted to compare the effects of SCTs on water erosion control. We conducted a meta-analysis consisting of 1589 sample plots in 22 countries to identify SCTs, which we classified into three groups: biological techniques (BTs, such as afforestation and grain for green), soil management techniques (STs, such as no tillage and soil amendment), and engineering techniques (ETs, such as terraces and contour bunds). Our results were as follows: (1) The SCTs had significant positive effects on water erosion control, and they were generally more effective at reducing annual soil loss (84%) than at reducing annual runoff (53%). (2) The BTs (e.g., 88% for soil and 55% for runoff) were generally more effective at reducing soil and water loss than ETs (e.g., 86% for soil and 44% for runoff) and STs (e.g., 59% for soil and 48% for runoff). (3) On bare lands, the efficiency of water erosion control decreased as the terrain slope increased, but this value increased as the slope increased on croplands and orchards. Furthermore, the effects of SCTs on runoff and soil loss reduction were most efficient on 25°–40° slopes in croplands and on 20°–25° slopes in orchards. (4) The SCTs were more efficient on croplands and orchards in temperate climate zone (CZ), while those on bare lands were more effective in tropical CZ. (5) The SCTs in Brazil and Tanzania were more effective at reducing runoff and soil loss than those in the USA, China and Europe.

    更新日期:2018-07-20
  • Chemical-, site-, and taxa-dependent benthic community health in coastal areas of the Bohai Sea and northern Yellow Sea: A sediment quality triad approach
    Sci. Total Environ. (IF 4.61) Pub Date : 2018-07-19
    Jong Seong Khim, Jinsoon Park, Sung Joon Song, Seo Joon Yoon, Junsung Noh, Seongjin Hong, Bong-Oh Kwon, Jongseong Ryu, Xiaowei Zhang, Tieyu Wang, Yonglong Lu, John P. Giesy

    To investigate benthic ecological quality associated with coastal pollution in the Bohai Sea and northern Yellow Sea, a sediment quality triad (SQT) approach was applied. Chemical (six groups of persistent toxic substances (PTSs) and 8 metals and metalloids), toxicological (AhR-mediated potency), and ecological (bacterial and meiofaunal communities) elements were selected and used in an integrated sediment assessment. The benthic meiofaunal community was newly analyzed and used as an additional component of the infaunal community during the SQT. Concentrations of chemicals and potential toxicity in sediments both indicated moderate to severe pollution in the study area, characterized by site-specific and land-uses. In particular, As, DDTs, and bioassay-derived dioxin equivalents exceeded corresponding sediment quality guidelines at nearly all locations. Limited occurrences of meiofaunal taxa (mean = 5.2) and relatively low species diversity, mainly comprised of nematodes (75.3%) and copepods (14.6%), among locations was generally consistent with pollution. The benthic community was consistent with compound-specific responses to gradients of contamination, particularly for As. Densities of two taxa, Nematoda and Nemertea exhibited strong negative correlations with concentrations of As. Compound-, site-, and taxa-specific variability of pollution of sediments was further supported by results of cluster analysis (CA) and nonmetric multidimensional scaling (NMDS). Finally, assessment integrating five benthic quality elements, including: 1) PTSs; 2) metals and metalloids; 3) sediment toxicity; 4) sediment microbiome; and 5) benthic meiofaunal community, explained contamination of sediments associated with land-uses, locality, or habitat. Status of the benthic community could not be explained by single component and their associations were not quantitative. Results of the integrated assessment, considering multiple benthic quality elements were useful to address overall quality of sediment, and were consistent with chemical-, species-, or site-dependent pollution of sediments in the Bohai and Yellow Seas.

    更新日期:2018-07-20
  • Does foliar nutrient resorption regulate the coupled relationship between nitrogen and phosphorus in plant leaves in response to nitrogen deposition?
    Sci. Total Environ. (IF 4.61) Pub Date : 2018-07-19
    Chengming You, Fuzhong Wu, Wanqin Yang, Zhenfeng Xu, Bo Tan, Li Zhang, Kai Yue, Xiangyin Ni, Han Li, Chenhui Chang, Changkun Fu

    Nutrient resorption from senescing leaves is an important process of internal nutrient cycling in plants, but the patterns of nutrient resorption and the coupled relationship between nitrogen (N) and phosphorus (P) in plant leaves as affected by N deposition remain unclear. We analysed the effects of N addition on the nutrient resorption and coupled relationship between N and P in plant leaves under different nutrient-limited conditions based on a global meta-analysis. Globally, the mean N resorption efficiency (NRE) and P resorption efficiency (PRE) under natural conditions were 47.4% and 53.6%, respectively, which were significantly regulated by geographical and climatic factors as well as plant characteristics. Furthermore, N addition significantly decreased the NRE by 13.3% but slightly affected the PRE on a global scale, and N addition rates and latitude directly and negatively affected the effects of N addition on NRE. Specifically, N addition significantly decreased the NRE under all nutrient-limited conditions, while it had negative, positive, and neutral effects on the PRE under N-limited, P-limited, and N and P-co-limited conditions, respectively. Moreover, the relationships between N and P in green and senesced leaves were tightly coupled under different nutrient-limited conditions in natural ecosystems. However, N addition significantly weakened the relationships between N and P concentrations in green leaves but slightly affected the relationship in senesced leaves, which were mainly modulated by the effects of N addition on nutrient resorption efficiency, especially NRE. These results highlight that nutrient-limited conditions determine the response of nutrient resorption to N deposition and emphasize the effect of nutrient resorption regulation on the coupling of N and P responses to N enrichment. The findings are important for understanding plant nutrient use strategies and the mechanisms underlying the stoichiometric coupling of N and P in response to climate change, and can be used in global biogeochemical models.

    更新日期:2018-07-20
  • Inoculation of Brevibacterium linens RS16 in Oryza sativa genotypes enhanced salinity resistance: Impacts on photosynthetic traits and foliar volatile emissions
    Sci. Total Environ. (IF 4.61) Pub Date : 2018-07-19
    Poulami Chatterjee, Arooran Kanagendran, Sandipan Samaddar, Leila Pazouki, Tong-Min Sa, Ülo Niinemets

    The emission of volatiles in response to salt stress in rice cultivars has not been studied much to date. Studies addressing the regulation of stress induced volatile emission by halotolerant plant growth promoting bacteria containing ACC (1-aminocyclopropane-1-carboxylate) deaminase are also limited. The objective of the present study was to investigate the salt alleviation potential of bacteria by regulating photosynthetic characteristics and volatile emissions in rice cultivars, and to compare the effects of the bacteria inoculation and salt responses between two rice genotypes. The interactive effects of soil salinity (0, 50, and 100 mM NaCl) and inoculation with Brevibacterium linens RS16 on ACC accumulation, ACC oxidase activity, carbon assimilation and stress volatile emissions after stress application were studied in the moderately salt resistant (FL478) and the salt-sensitive (IR29) rice (Oryza sativa L.) cultivars. It was observed that salt stress reduced foliage photosynthetic rate, but induced foliage ACC accumulation, foliage ACC oxidase activity, and the emissions of all the major classes of volatile organic compounds (VOCs) including the lipoxygenase pathway volatiles, light-weight oxygenated volatiles, long-chained saturated aldehydes, benzenoids, geranylgeranyl diphosphate pathway products, and mono- and sesquiterpenes. All these characteristics scaled up quantitatively with increasing salt stress. The effects of salt stress were more pronounced in the salt-sensitive genotype IR29 compared to the moderately salt resistant FL478 genotype. However, the bacterial inoculation significantly enhanced photosynthesis, and decreased ACC accumulation and the ACC oxidase activity, and VOC emissions both in control and salt-treated plants. Taken together, these results suggested that the ACC deaminase-containing Brevibacterium linens RS16 reduces the temporal regulation of VOC emissions and increases the plant physiological activity by reducing the availability of ethylene precursor ACC and the ACC oxidase activity under salt stress.

    更新日期:2018-07-20
  • Study of the exceptional meteorological conditions, trace gases and particulate matter measured during the 2017 forest fire in Doñana Natural Park, Spain
    Sci. Total Environ. (IF 4.61) Pub Date : 2018-07-19
    J.A. Adame, L. Lope, P.J. Hidalgo, M. Sorribas, I. Gutiérrez-Álvarez, A. del Águila, A. Saiz-Lopez, M. Yela

    In late June 2017, a forest fire occurred in Doñana Natural Park, which is located in southwestern Europe. Many animal and plant species, some of which are threatened, suffered from the impact of this fire, and important ecosystems in the European Union were seriously affected. This forest fire occurred under exceptional weather conditions. The meteorological situation was studied at both the synoptic scale and the local scale using meteorological fields in the ERA-Interim global model from ECMWF (European Centre for Medium Range Weather Forecasts), the WRF (Weather Research and Forecasting) mesoscale model and ground observations collected at El Arenosillo observatory. Anomalies were obtained using records (observations and simulations) over the last two decades (1996–2016). An anticyclonic system dominated the synoptic meteorological conditions, but a strong pressure gradient was present; positive high pressure anomalies and negative low pressure anomalies resulted in intense NW flows. At the surface, wind gusts of 80 km h−1, temperatures up to 35 °C and relative humidity values <20% were observed. In terms of anomalies, these observations corresponded to positive temperature anomalies (differences of 12 °C), positive wind speed anomalies (>29 km h−1) and negative relative humidity anomalies (differences of 40%). The forest fire reached El Arenosillo observatory approximately 8 h after it began. When the fire started, record-setting maximum values were measured for all gases monitored at this site (specifically, peaks of 99,995 μg m−3 for CO, 951 μg m−3 for O3, 478 μg m−3 for NO2, 116 μg m−3 for SO2 and 1000 μg m−3 for PM10). According to the temporal evolution patterns of these species, the atmosphere over a burnt area can recover to initial atmospheric levels between 48 and 96 h after an event. The impact of the Doñana plume was studied using hourly forward trajectories computed with the HYSPLIT (Hybrid Single-Particle Lagrangian Integrated Trajectory) model to analyse the emission source for the burnt area. The Doñana fire plume affected large metropolitan areas near the Mediterranean coast. Air quality stations located in the cities of Seville and Cadiz registered the arrival of the plume based on increases in CO and PM10. Using CO as a tracer, measurements from the AIRS and MOPITT instruments allowed us to observe the transport of the Doñana plume from the Strait of Gibraltar to the Mediterranean. Finally, after two days, the Doñana forest fire plume reached the western Mediterranean basin.

    更新日期:2018-07-20
  • Effect of modified coconut shell biochar on availability of heavy metals and biochemical characteristics of soil in multiple heavy metals contaminated soil
    Sci. Total Environ. (IF 4.61) Pub Date : 2018-07-19
    Huakang Liu, Fei Xu, Yanluo Xie, Can Wang, Akang Zhang, Lingling Li, Heng Xu

    On account of the potential in immobilizing metals and improving soil environment, various biochar materials have been extensively applied in environmental remediation. The purpose of this experiment was to evaluate the effect of modified coconut shell biochar (MCSB) on the availability of metals and soil biological activity in multi-metals (cadmium (Cd), nickel (Ni) and zinc (Zn)) contaminated soil. MCSB was obtained from coconut shell biochar (CSB) by hydrochloric acid pickling and ultrasonication, which has significantly improved its surface functional groups and microcosmic pore structure. Sandy soil samples were incubated at 25 °C amended with MCSB or CSB by 0%, 2.5% and 5% addition for 63 days, respectively. The results showed that the acid soluble Cd, Ni and Zn decreased by 30.1%, 57.2% and 12.7%, respectively, in groups with 5% MCSB addition, which indicated MCSB had a better effect on immobilizing metals compared with CSB. In addition, higher soil biological activities were detected in different treatments compared with control (CK). Especially, the maximum bacterial number was found in 5% MCSB treatment, which increased by 149.43% compared with CK. Accordingly, our results suggested that MCSB could be used as an ameliorant to immobilize heavy metals in contaminated soils and improve soil physicochemical and biological properties.

    更新日期:2018-07-20
  • Spatiotemporal evolution of carbon sequestration vulnerability and its relationship with urbanization in China's coastal zone
    Sci. Total Environ. (IF 4.61) Pub Date : 2018-07-19
    Jiansheng Wu, Bikai Chen, Jiaying Mao, Zhe Feng

    Carbon sequestration plays a vital role in maintaining the stability of global climate and the carbon cycle, but is undergoing significant changes due to urbanization. This study proposes the concept of carbon sequestration vulnerability (CSV), and explores the spatiotemporal evolution of CSV and its relationship between urbanization in China's coastal zone from 2000 to 2010. The study results provide a scientific basis for government management and policy-making. The results showed that the average amount of CSV in 2000 and 2010 was 0.301 and 0.279, respectively, in China's coastal zone and exhibited obvious spatial heterogeneity. Land urbanization had better interpretation strength for CSV than population and economic urbanization indexes, and could explain the 10-year change in CSV well in China's coastal zone. In China's coastal zone from 2000 to 2010, CSV response to land urbanization was proven to be positive and linearly increasing, and the slope of the linear relationship was 0.4214, cities with high land urbanization level have higher CSV; likewise, the change in land urbanization level had a significant positive and linear relationship with the change in CSV, and the slope of the linear relationship was 0.5031. When the city's land urbanization level increased by <6.8% over ten years, the CSV declined, and conversely, the CSV rose. For the goal of reduce CSV of cities, government and policy-makers should focus on land urbanization and it is possible to realize the goal by controlling land urbanization below 6.8% every ten years.

    更新日期:2018-07-20
  • The effect of ambient temperature on the activity of influenza and influenza like illness in Jiangsu Province, China
    Sci. Total Environ. (IF 4.61) Pub Date : 2018-07-19
    Qigang Dai, Wang Ma, Haodi Huang, Ke Xu, Xian Qi, Huiyan Yu, Fei Deng, Changjun Bao, Xiang Huo

    ObjectiveWe aimed to evaluate and quantify the association between ambient temperature and activity of influenza like illness (ILI) and influenza in Jiangsu Province, China.MethodDaily data of meteorology, influenza-like illness and detected influenza virus from 1 April 2013 to 27 March 2016 were collected. Distributed lag non-linear model (DLNM) was used to quantify the exposure-lag-response of ILI and influenza activity to daily average temperature.ResultInfluenza A virus (Flu-A) circulated throughout the year with two peaks at −4 °C and 28 °C respectively, while influenza B (Flu-B) viruses were usually tested positive in winter or early spring and peaked at 5 °C. The lag-response curves revealed that the RR of ILI increased with time and peaked 1 day later at low temperature (3 °C), however, the maximum RR of ILI caused by high temperature (26 °C) appeared immediately on day 0, the similar phenomena of immediate effect to ILI at high temperature were also observed in the lag-response curve for Flu-A or Flu-B.ConclusionILI and Flu-A experienced two peaks of circulates at both low and high temperature in Jiangsu. The influenza viruses activity did drive up the rising of ILI%, particularly the activity of Flu-A which circulated throughout the year played a crucial role. Regional homogeneity was the relatively mainstream in aspects of cumulative association between influenza activity and temperature in Jiangsu Province.

    更新日期:2018-07-20
  • Optimization of integrated ultrasonic-Fenton system for metal removal and dewatering of anaerobically digested sludge by Box-Behnken design
    Sci. Total Environ. (IF 4.61) Pub Date : 2018-07-19
    Jannatul Rumky, Mohamed Chaker Ncibi, Rutely C. Burgos-Castillo, Anjan Deb, Mika Sillanpää

    This study reveals the optimization of ultrasonic-Fenton process for the treatment of sludge taken from a local municipal wastewater treatment plant after anaerobic digestion. Box-Behnken design (BBD), a common approach of response surface methodology (RSM), was applied to evaluate and optimize the individual and interactive effects of three process variables, namely Fe2+ dose, H2O2 amount and sonication time for Fenton-ultrasonication method. Five dependent parameters including total organic carbon (TOC), extracellular polymeric substances (EPS), as LB-EPS and TB-EPS, and metals such as Zn and Cu were considered as the responses to investigate. According to the results of analysis of variances (ANOVA), five modelling equations are proposed that can be used to operate the design space with high regression coefficient R2. Modelling results suggest that Fenton parameters, such as: H2O2 and Fe2+ dosage had the significant effects on the overall removal of TOC; whereas, sonication improved the metal removal from the sludge sample. Based on response surface methodology, best performance is achievable under the following conditions: 36 mM of Fe2+, 320 mM H2O2 with 30 min of sonication respectively for all of the responses.

    更新日期:2018-07-20
  • Analytical assessment to develop innovative nanostructured BPA-free epoxy-silica resins as multifunctional stone conservation materials
    Sci. Total Environ. (IF 4.61) Pub Date : 2018-07-19
    Olivia Gómez-Laserna, Paola Lanzafame, Georgia Papanikolaou, María Ángeles Olazabal, Sandra Lo Schiavo, Paola Cardiano

    Bisphenol A (BPA)-free epoxy resins, synthesized from low molecular weight cycloaliphatic compounds, may represents promising materials for stone conservation due to their very appealing and tunable physico-chemical properties, such as viscosity, curing rate and penetration ability, being also easy to apply and handle. Furthermore, alkoxysilanes have been widely employed as inorganic strengtheners since they are easily hydrolysed inside lithic substrates affording SiO linkages with the stone matrix. Taking into account the advantages of these two classes of materials, this work has been focused on the development of innovative conservation materials, based on hybrid epoxy-silica BPA-free resins obtained by reaction of 1,4-cycloexanedimethanol diglycidylether (CHDM-DGE) with various siloxane precursors, i.e. glycidoxypropylmethyldiethoxysilane (GPTMS), tetraethyl orthosilicate (TEOS) and isobutyltrimethoxysilane (iBuTMS), using the 1,8-diaminooctane (DAO) as epoxy hardener. Thanks to Raman spectroscopy the synthesis processes have been successfully monitored, allowing the identification of oxirane rings opening as well as the formation of the cross-linked organic-inorganic networks. In accordance with the spectroscopic data, the thermal studies carried out by TGA and DSC techniques have pointed that GPTMS is a suitable siloxane precursor to synthesize the most stable samples against temperature degradation. GPTMS-containing resins have also shown good performances in the dynamic mechanical analysis (DMA) and in contact angle investigations, with values indicating considerable hydrophobic properties. SEM analyses have highlighted a great homogeneity over the entire observed areas, without formations of clusters and/or aggregates bigger than 45 μm, for the cited materials, confirming the efficiency of GPTMS as coupling agent to enhance the organic/inorganic interphase bonding. The variations provided by the incorporation of nanostructured titania, specifically synthesized, inside the epoxy-silica hybrids have been also evaluated. According to all the collected results, the hybrid materials here reported have proven to be promising multifunctional products for potential application in the field of stone conservation.

    更新日期:2018-07-20
  • Life Cycle Assessment of a shale gas exploration and exploitation project in the province of Burgos, Spain
    Sci. Total Environ. (IF 4.61) Pub Date : 2018-07-17
    D. Costa, B. Neto, A.S. Danko, A. Fiúza

    Natural gas (NG) from shale formations (or shale gas) is an unconventional energy resource whose potential environmental impacts are still not adequately assessed. Hence, this study performs a Life Cycle Assessment (LCA) of shale gas considering a gas well under appraisal in Burgos, Spain. An attributional model was developed, considering the NG pre-production and production phases in the system boundaries, considering 1 MJ of processed NG as a functional unit. Results were obtained through the CML-IA baseline method (developed by the Center of Environmental Science of Leiden University) and showed that well design, drilling and casing, hydraulic fracturing, NG production, gathering, and processing are critical processes. To better address the environmental impacts, a comparison with similar studies was carried out, as well as a sensitivity and an uncertainty analysis using Monte Carlo simulation (MCS). The model was found to be particularly sensitive to water usage in hydraulic fracturing and to the number of workovers with hydraulic fracturing. Limited data availability for shale gas exploration still poses a challenge for an accurate LCA. Even though shale gas remains controversial, it still can be considered as a strategic energy resource, requiring a precautionary approach when considering its exploitation and exploration.

    更新日期:2018-07-19
  • The dynamic links between CO2 emissions, energy consumption and economic development in the countries along “the Belt and Road”
    Sci. Total Environ. (IF 4.61) Pub Date : 2018-07-18
    Yunyang Liu, Yu Hao

    China has proposed the Belt and Road Initiative to promote the cooperation of energy production and trade between the relevant countries. This paper investigates the relationship between the energy consumption and economic growth of the countries along the Belt and Road using a panel of data for 69 countries during the period between 1970 and 2013. Both of the renewable and traditional fossil energy consumptions are investigated in this study. By employing vector error correction model (VECM), fully modified OLS (FMOLS) and dynamic OLS (DOLS) approaches, the estimation results indicate that the nexuses of the energy consumption and economic developments vary across different subgroups. For the entire group, there is evidence of long−run bidirectional causalities among carbon emissions, energy use, industry value added and GDP per capita. For the energy−importing countries along the Belt and Road, there exists unidirectional short−run causality running from GDP to renewable energy and long−run causality in the reverse direction. In contrast, for the energy−exporting countries, there is a bidirectional causality between the energy use and GDP per capita in the long run. These findings suggest significant cooperation potential in the economies and trades of China and the Belt and Road countries.

    更新日期:2018-07-19
  • Artificial neural networks: Modeling tree survival and mortality in the Atlantic Forest biome in Brazil
    Sci. Total Environ. (IF 4.61) Pub Date : 2018-07-18
    Samuel José Silva Soares da Rocha, Carlos Moreira Miquelino Eleto Torres, Laércio Antônio Gonçalves Jacovine, Helio Garcia Leite, Eduardo Monteiro Gelcer, Karina Milagres Neves, Bruno Leão Said Schettini, Paulo Henrique Villanova, Liniker Fernandes da Silva, Leonardo Pequeno Reis, José Cola Zanuncio

    Models to predict tree survival and mortality can help to understand vegetation dynamics and to predict effects of climate change on native forests. The objective of the present study was to use Artificial Neural Networks, based on the competition index and climatic and categorical variables, to predict tree survival and mortality in Semideciduous Seasonal Forests in the Atlantic Forest biome. Numerical and categorical trees variables, in permanent plots, were used. The Agricultural Reference Index for Drought (ARID) and the distance-dependent competition index were the variables used. The overall efficiency of classification by ANNs was higher than 92% and 93% in the training and test, respectively. The accuracy for classification and number of surviving trees was above 99% in the test and in training for all ANNs. The classification accuracy of the number of dead trees was low. The mortality accuracy rate (10.96% for training and 13.76% for the test) was higher with the ANN 4, which considers the climatic variable and the competition index. The individual tree-level model integrates dendrometric and meteorological variables, representing a new step for modeling tree survival in the Atlantic Forest biome.

    更新日期:2018-07-19
  • Delving the environmental impact of roundwood production from poplar plantations
    Sci. Total Environ. (IF 4.61) Pub Date : 2018-07-18
    Daniela Lovarelli, Alessandra Fusi, Roberto Pretolani, Jacopo Bacenetti

    The environmental impact of timber production from poplar plantation was evaluated by means of Life Cycle Assessment (LCA) using an attributional approach. A comparison was performed between a baseline scenario and an alternative one in which different harvesting operations were identified. An economic allocation was adopted to solve the multi-functionality of the studied process, by taking into account the price of the main product and of co-products. Sensitivity analysis was performed on alternative mass allocation and yield variations that derive from using high sustainability plants or from climate stress. A different characterization method was also analyzed. Among the different field operations, crop management involves a higher impact respect to field preparation-planting and harvesting-soil restoring. Emissions related to fertilizers' applications are the main responsible for acidification, eutrophications and particular matter formation. The results show that the modelling of the environmental impact of timber production is robust. The alternative scenario resulted better than baseline for all impact categories (impact reduction ranging from 0.1% to 12.4%), except for HT-noc (+12.2%) and POF (+20.6%), due to fuel and oil consumption in the chainsaw used for harvesting. In the next years, introducing high-sustainability clones (characterized by higher yield and higher resistance to pests and drought) could be an effective way for reducing the environmental impact of poplar roundwood production.

    更新日期:2018-07-19
  • Rainfall isotope variations over the Australian continent – Implications for hydrology and isoscape applications
    Sci. Total Environ. (IF 4.61) Pub Date : 2018-07-18
    Suzanne E. Hollins, Catherine E. Hughes, Jagoda Crawford, Dioni I. Cendón, Karina M. Meredith

    This paper presents a continental scale interpretation of δ2H and δ18O in Australian precipitation, incorporating historical GNIP data at seven sites (1962–2002) and 8–12 years of new monthly data from 15 sites from 2003 to 2014. The more than doubling of stations and the significant time series duration allow for an improved analysis of Australian precipitation isotopes. Local meteoric water lines were developed for each site, and for the Australian continent. When the annual precipitation weighted values were used, the Australian meteoric water line was δ2H = 8.3 δ18O + 14.1‰. Precipitation amount was found to be a stronger driver of precipitation isotopes than temperature at most sites, particularly those affected by tropical cyclones and the monsoon. Latitude, elevation and distance from the coast were found to be stronger drivers of spatial variability than temperature or rainfall amount. Annual isoscapes of δ2H, δ18O and deuterium excess were developed, providing an improved tool to estimate precipitation isotope inputs to hydrological systems. Because of the complex climate, weather and oceanic moisture sources affecting Australia, regional groupings were used instead of the climate zone approach and additional data was included to improve the coverage in data poor regions. Regression equations for the isoscape were derived using latitude, altitude and distance from the coast as predictor variables. We demonstrate how this isoscape can be used as a tool for interpreting groundwater recharge processes using examples from across Queensland and New South Wales, including the Murray Darling Basin. Groundwater isotopes at sites where direct local recharge occurs are similar to rainfall, but for inland sites, which are often arid or semi-arid, a disconnect between shallow groundwater and local rainfall is observed; the departure in deuterium excess for these sites increases with aridity and distance from the headwaters where flooding originates.

    更新日期:2018-07-19
  • Tree species diversity promotes soil carbon stability by depressing the temperature sensitivity of soil respiration in temperate forests
    Sci. Total Environ. (IF 4.61) Pub Date : 2018-07-18
    Junwei Luan, Shirong Liu, Jingxin Wang, Scott X. Chang, Xiaojing Liu, Haibo Lu, Yi Wang

    The diversity-stability interrelationship suggests that high diversity can buffer fluctuations in environmental conditions such as temperature; we thus hypothesize that tree species diversity will lower the temperature sensitivity of soil respiration (Rs), known as Q10 value. Our hypothesis was tested in a deciduous broad-leaf and a coniferous-broad-leaf mixedwood stand in the warm temperate region in China. We measured soil respiration and indices of tree species diversity including species richness (S), the Berger-Parker index (d), the Simpson index (λ), the Shannon index (He′), and the Pielou evenness index (Je). Our results generally confirm our hypothesis that Q10 was positively correlated to λ, but negatively related to He′, d, and Je, and independent of S, in both stands. However, Rs was independent of the diversity indices. These findings imply that tree species diversity promotes soil carbon stability by depressing the Q10. Furthermore, different biotic and abiotic variables explained the variations of species diversity and Q10 in the broad-leaf and mixedwood forests, suggesting that the mechanisms underlining the effects of tree species diversity on Q10 are different between the two forest types. We conclude that sustainable forest management that improves tree species diversity will increase soil carbon stability and benefit our efforts to mitigate climate change.

    更新日期:2018-07-19
  • Microhabitat change alters abundances of competing species and decreases species richness under ocean acidification
    Sci. Total Environ. (IF 4.61) Pub Date : 2018-07-18
    Ivan Nagelkerken, Silvan U. Goldenberg, Ericka O.C. Coni, Sean D. Connell

    Niche segregation allows competing species to capture resources in contrasting ways so they can co-exist and maintain diversity, yet global change is simplifying ecosystems and associated niche diversity. Whether climate perturbations alter niche occupancy among co-occurring species and affect species diversity is a key, but unanswered question. Using CO2 vents as natural analogues of ocean acidification, we show that competing fish species with overlapping diets are partially segregated across microhabitat niches and differently-orientated substrata under ambient CO2 conditions. Under elevated CO2, benthic microhabitats experienced a significant increase in non-calcifying turf and fleshy algae but a sharp reduction in calcareous algae. The increased availability of turf and fleshy algae supported increased densities of a competitively dominant species, whilst the reduction in calcifying algal microhabitats decreased densities of several subordinate species. The change in microhabitat availability also drove an increased overlap in microhabitat use among competing fishes at the vents, associated with a reduced fish species richness on horizontal substrates. We conclude that loss of preferred microhabitat niches, exacerbated by population proliferation of competitively dominant species, can drive population losses of less common and subordinate species, and reduce local species richness. The indirect effects of ocean acidification on microhabitat availability can therefore impair maintenance of species populations, and drive changes in local community and biodiversity patterns.

    更新日期:2018-07-19
  • Late Quaternary environmental dynamics in Lenin Peak area (Pamir Mountains, Kyrgyzstan)
    Sci. Total Environ. (IF 4.61) Pub Date : 2018-07-18
    M. Oliva, J. Ruiz-Fernández

    The Pamir Mountains include peaks exceeding 7000 m, such as Lenin Peak (7134 m) in the northern Zaalai Range. Here, we examine the distribution of soils and geomorphological processes and landforms in its northern slope, from the highest glaciated environments until Alai valley floor. We present the first geomorphological map of the study area as well as an accurate description the main geomorphological units in order to reconstruct landscape dynamics in the area from Quaternary cold stages until present-day. Five main units are distributed: (1) valley floor (2900–3040 m), an area that must have been ice-free during Quaternary glaciations and is currently being reshaped by glaciofluvial processes, with a large alluvial fan reworked by aeolian activity; (2) hummocky terrain (3040–3500 m) including two moraine systems left by a piedmont glacier during the Last Glaciation as well as hilly deposits originated by a catastrophic rockfall event; (3) U-shaped glacial valley (3500–3800 m), including some moraine ridges as well as a sedimentary cover composed of glacial till that is being eroded by fluvial and mass-wasting processes; (4) high mountain valleys (up to 4600–4800 m) adjacent to the main valley floor with small cirque and alpine glaciers and widespread periglacial processes in ice-free environments; (5) glaciers flowing from the Lenin Peak summit until the foot of the mountain, where they form a debris-covered (surge-type) glacier. The existence of abundant glacial, periglacial and rockfall deposits (moraines, till, erratic boulders) allows inferring five different environmental stages since the Last Glaciation. The latest glacial advances took place during the 20th century and the Little Ice Age and deposited two moraine systems near the glacial front. The occurrence of active rock glaciers and protalus lobes indicates that the limit of permafrost conditions is now located at 3400–3500 m, with seasonal frozen ground in lower areas.

    更新日期:2018-07-19
  • Occurrence and distribution of perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS) in natural forest soils: A nationwide study in China
    Sci. Total Environ. (IF 4.61) Pub Date : 2018-07-18
    Qi Wang, Zhen Zhao, Yuefei Ruan, Jun Li, Hongwen Sun, Gan Zhang

    Forests serve as the primary reservoir for organic carbon above ground. Previous studies have revealed that forest soils play key roles in the retention of persistent organic pollutants (POPs). In this study, the occurrence and distribution of perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS) were investigated in 54 surface soil samples from 28 natural forested mountain sites across China between 2012 and 2013. The detection frequency of PFOA (70%) was significantly higher than that of PFOS (4%). PFOA levels ranged from <0.9 to 9.0 pg·g−1 dry weight (dw). Levels of PFOA and PFOS in forest soils were significantly lower than those in agricultural, urban and rural areas in China. Relatively high levels of PFOA were detected in Hubei Province (Jiugong Mountain, average: 3.4 pg·g−1 dw) and Jiangxi Province (Wugong Mountain, average: 4.4 pg·g−1 dw), where many domestic fluoropolymer manufacturers are located. PFOS was only detected in these two provinces (2.2 pg·g−1 dw and 2.7 pg·g−1 dw, respectively). From most of the surveyed mountains, the concentrations of PFOA increased with elevation. The lower temperature and greater precipitation probably made PFOA and its precursors available to transport and degrade more readily at higher altitude sites. A relatively higher level (1.9 ± 1.3 pg·g−1 dw) of PFOA was found in the broadleaf evergreen forest area, mainly due to the high industrial emissions, plant retention, and precipitation rate in this area. Source were the dominant factor controlling the spatial distribution of PFOA in natural forest soils in China.

    更新日期:2018-07-19
  • Temporalis, a generic method and tool for dynamic Life Cycle Assessment
    Sci. Total Environ. (IF 4.61) Pub Date : 2018-07-18
    Giuseppe Cardellini, Christopher L. Mutel, Estelle Vial, Bart Muys

    The limitations of the static nature of Life Cycle Assessment (LCA) are well known. To overcome the loss of temporal information due to the aggregation of flows in the Life Cycle Inventory (LCI), several dynamic LCA methodologies have been proposed. In this paper we present a new generic and operational methodology for dynamic LCA that allows for the introduction of temporal information in both in the inventory and the Life Cycle Impact Assessment (LCIA) phases. The method makes use of graph traversal and convolution to calculate the temporally differentiated inventory, and makes it possible to use several types of dynamic impact assessment. We describe our method and apply it to a cradle-to-grave dynamic LCA of a glued laminated timber (glulam) product. We also test the sensitivity of the global warming results to temporal explicit LCI data. There is a considerable difference in outcome between the static and dynamic approaches. We have implemented our framework in the free and open source software Temporalis that is fully operational and can be used with existing LCA databases.

    更新日期:2018-07-19
  • Treatment of oil sands produced water using combined electrocoagulation and chemical coagulation techniques
    Sci. Total Environ. (IF 4.61) Pub Date : 2018-07-18
    Laleh Shamaei, Behnam Khorshidi, Basil Perdicakis, Mohtada Sadrzadeh

    Hybrid electrocoagulation-chemical coagulation (EC-CC) process has attracted a growing attention for the removal of various types of wastewaters contaminants. In this paper, the feasibility of EC-CC technique as an alternative to conventional chemical processes for the treatment of steam assisted gravity drainage (SAGD) produced water has been systematically studied. Eight parameters, namely electrode material, cell configuration, pH and temperature of the solution, chemical coagulant dosage, intensity of the electrical current, mixing rate, and treatment time were studied. To explore the synergistic effect of the design parameters, the experimental trials were arranged using Taguchi method. Analysis of variance (ANOVA) was performed to evaluate the effect of each design parameter on the organic matter removal from the SAGD produced water. It was found that all parameters except the electrode arrangement had a significant effect on the removal efficiency of the EC-CC process. Among these parameters, the chemical coagulant and the treatment time had the most significant contribution to the efficiency by 40% and 26%, respectively. The optimum condition for the highest TOC removal efficiency (39.8%) was obtained by applying 0.34 A to Al electrode in a bipolar (BP) configuration when the pH, temperature, coagulant concentration, mixing rate, and reaction time were set to 8, 60 °C, 200 mg/L, 700 rpm, and 90 min, respectively. Moreover, a second-order polynomial regression model was proposed to predict the removal efficiency in terms of design parameters. An excellent agreement between the model predictions and experimental data was obtained with the adjusted R2 of about 99%.

    更新日期:2018-07-19
  • Synergistically enhancing Fenton-like degradation of organics by in situ transformation from Fe3O4 microspheres to mesoporous Fe, N-dual doped carbon
    Sci. Total Environ. (IF 4.61) Pub Date : 2018-07-18
    Tao Zeng, Shuqi Li, Jianan Hua, Zhiqiao He, Xiaole Zhang, Hongru Feng, Shuang Song

    Nanocarbon materials are emerging as alternative activators of peroxymonosulfate (PMS) for organics decomposition. However, the relatively low activity and complex syntheses hindered their practical application and innovation with respect to rational design of carbocatalysts is highly desired. Herein, an in situ replication and transformation strategy was employed to facilely convert porous Fe3O4 microspheres into novel Fe/N codoped large-pore mesoporous carbon spheres (M‑Fe/NC) as Fenton-like catalysts for PMS activation. Benefiting from the abundance of active sites induced by dual heteroatom doping, the enhanced active site exposure due to the unique mesoporous structure, and the high stability of carbon component, the derived M‑Fe/NC was superior to the pristine Fe3O4 for PMS activation to degrade various organics and was efficient over a wide pH range (2–9). Compared with the proposed mechanisms of previous reports, both radical (surface-bound SO4− and OH) and nonradical (1O2 and direct oxidation) pathways are involved in the M‑Fe/NC/PMS system. Furthermore, experimental observations in combination with DFT calculations reveal that graphitic N and FeN4 sites serve as dual reaction centers in the catalysis. This research opened an avenue for development of novel multi-doped carbocatalysts used to activate PMS for sustainable remediation.

    更新日期:2018-07-19
  • Effects of sublethal herbicides on offspring germination and seedling growth: Redroot pigweed (Amaranthus retroflexus) vs. velvetleaf (Abutilon theophrasti)
    Sci. Total Environ. (IF 4.61) Pub Date : 2018-07-18
    Yue Qi, Junsheng Li, Gang Fu, Caiyun Zhao, Xiao Guan, Bing Yan, Mengyun Ren

    The effects of sublethal doses of herbicides on plants cannot be ignored, yet little is known about the effects of sublethal doses of herbicides on the F1 generation of plants. Seed germination and seedling growth of native and invasive plants following the sublethal exposure of parent plants to herbicides were comparatively analyzed in this study. Sublethal atrazine and tribenuron-methyl had carry-over effects on the germination and seedling growth of the F1 generation of invasive redroot pigweed (Amaranthus retroflexus L.) and native velvetleaf (Abutilon theophrasti Medicus), both of which had different responses to the carry-over effects of sublethal herbicide. The germination percentage of the F1 redroot pigweed (decreased) was greater than that of the F1 velvetleaf (increased or not significantly changed) following parental exposure to atrazine or tribenuron-methyl. Atrazine reduced the radical growth of 7-day-old velvetleaf seedlings and decreased the difference in seedling length between velvetleaf and redroot pigweed, while tribenuron-methyl had no significant effects on the growth of 7-day-old velvetleaf seedlings. The herbicide inhibition effect on the germination and growth of F1 velvetleaf and redroot pigweed did not increase as the sublethal dose increased. This study suggests that carry-over effects of sublethal herbicides weaken the growth advantage of the F1 velvetleaf at the seedling stage and may have a more negative influence on progeny population development of native velvetleaf compared with invasive redroot pigweed.

    更新日期:2018-07-19
  • Valorisation of olive agro-industrial by-products as a source of bioactive compounds
    Sci. Total Environ. (IF 4.61) Pub Date : 2018-07-18
    Beatriz Gullón, Patricia Gullón, Gemma Eibes, Cristóbal Cara, Antonia De Torres, Juan Carlos López-Linares, Encarnación Ruiz, Eulogio Castro

    A large amount of olive-derived biomass is generated yearly in Spain, which could be used as a potential source of bioactive compounds. The present work evaluates the recovery of natural antioxidants from olive tree pruning (OTP) and olive mill leaves (OML). For this purpose, the effect of different solvents on the total phenolic content (TPC), total flavonoid content (TFC), and antioxidant activity was evaluated. The solvent was found to have a significant effect (p < 0.05) on the TPC, TFC, and the DPPH, ABTS, and FRAP activity, affording similar results for the extracts from the two by-products. The extracts obtained using 50% ethanol showed high TPC (23.85 and 27.54 mg GAE/gdw for OTP and OML, respectively) and TFC (52.82 and 52.39 mg RE/gdw for OTP and OML, respectively). Also, the OTP and OML extracts exhibited notable antioxidant activity as measured by the ABTS method (45.96 and 42.71 mg TE/gdw, respectively). Using pyrolysis-gas chromatography/mass spectrometry, 30 bioactive compounds were detected in both extracts. Additionally, UPLC-DAD-ESI-MS allowed the identification of 15 compounds in the samples. Furthermore, the antioxidant extracts were found to inhibit the growth of several food pathogenic bacteria. This research demonstrates that these by-products from olive grove farming are a good source of antioxidant compounds with antibacterial properties, which have potential applications in the food and pharmaceutical industries.

    更新日期:2018-07-19
Some contents have been Reproduced with permission of the American Chemical Society.
Some contents have been Reproduced by permission of The Royal Society of Chemistry.
化学 • 材料 期刊列表