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Reconstructing Soil Recovery from Acid Rain in Beech (Fagus sylvatica) Stands of the Vienna Woods as Indicated by Removal of Stemflow and Dendrochemistry
2019
Türtscher, Selina | Grabner, Michael | Berger, Torsten W.
Our goal was to reconstruct soil recovery from Acid Rain based upon removal of stemflow at beech (Fagus sylvatica) stands of known historic and recent soil status. Fourteen beech stands in the Vienna Woods were selected in 1984 and again in 2012 to study changes in soil and foliar chemistry over time. A part of those stands had been strip cut, and to assess reversibility of soil acidification, we analyzed soils around beech stumps from different years of felling, representing the years when acidic stemflow ceased to affect the soil. Furthermore, it was hypothesized that changes of soil chemistry are reflected in the stemwood of beech. Half-decadal samples of tree cores were analyzed for Ca, Mg, K, Mn, Fe, and Al. Soil analyses indicated recovery in the top soil of the stemflow area but recovery was delayed in the between trees areas and deeper soil horizons. Differences in soil pH between proximal and distal area from beech stumps were still detectable after 30 years indicating that soils may not recover fully from acidification or do so at a rather slow rate. Stemwood contents indicated mobilization of base cations during the early 80s followed by a steady decrease thereafter. Backward reconstructions of soil pH and soil nutrients, building on regressions between recent stemwood and soil chemistry, could not be verified by measured soil data in 1984, but matched with declining cation foliar contents from 1984 to 2012. Dendrochemical reconstructions showed highest values in the 1980s, but measured soil exchangeable cation contents were clearly lower in 1984. Hence, we conclude that our reconstructions mimicked soil solution rather than soil exchanger chemistry.
显示更多 [+] 显示较少 [-]Seasonal and Long-Term Dynamics in Stream Water Sodium Chloride Concentrations and the Effectiveness of Road Salt Best Management Practices
2019
Kelly, Victoria R. | Findlay, Stuart E. | Hamilton, Stephen K. | Lovett, Gary M. | Weathers, Kathleen C.
We use a 32-year dataset from a rural, southeastern New York stream to describe the effect of long-term road salt use on concentrations of sodium (Na⁺) and chloride (Cl⁻). Mean annual stream Na⁺ and Cl⁻ concentrations initially increased, reached a plateau, and then increased again. Trends in summer and winter stream concentrations were similar but summer concentrations were higher than winter, indicating that salt entered the stream via groundwater discharge. Seasonal and inter-annual variability in stream Na⁺ and Cl⁻ concentrations and export were high in the latter years of the study and can be explained by increased variability in stream discharge. Stream water Na⁺ and Cl⁻ concentrations were positively correlated with conductivity, and conductivity was negatively correlated with discharge during all seasons (p < 0.001). We used road salt application data from a local agency to examine effects of best management practices. Despite reductions in salt application, there was no commensurate decrease in stream water Na⁺ and Cl⁻ concentrations. We estimate that the legacy of long-term salt accumulation in groundwater and soils may delay a decline in stream water Na⁺ and Cl⁻ concentrations by 20–30 years. Continued research to develop road salt reduction practices is important to mitigate impacts on freshwater ecosystems and drinking water supplies.
显示更多 [+] 显示较少 [-]Urbanized Tributary Causes Loss of Biodiversity in a Neotropical River Segment
2019
da Silva Tronco Johann, Adriana | Mangolin, Loana Priscila | Sanches, Paulo Vanderlei | Sebastién, Nyamien Yahaut | Topan, Dhyego Amilton | Piana, Pitágoras Augusto | Gomes, Benedito Martins
We used the community of benthic macroinvertebrates, alongside physical and chemical characteristics of the water, to verify the influence of an urbanized tributary on a Neotropical river. Specifically, our hypothesis is that urbanized tributaries are potentially able to simplify the biological diversity of the rivers where they flow. The collections were sampled in six sites every 2 weeks from April 2013 to March 2014, using artificial substrates. In conjunction with the benthic macroinvertebrate collections, the temperature, pH, and dissolved oxygen were measured using portable devices, as well as ammonia, total nitrogen, total phosphorus, and biochemical oxygen demand (BOD) in the laboratory. Rainfall values were also obtained. We observed a marked fall in the number of taxa and the values of richness, diversity equitability at the point located below the tributary mouth, with predominance of Chironomidae and Annelida. The high capture rates of a few groups considered tolerant and the high concentrations of total nitrogen, total phosphorus, and BOD confirm the alteration of the quality of the water at the sampling point located below the tributary mouth, leading to a local process of ecological simplification.
显示更多 [+] 显示较少 [-]Phosphorous-doped TiO2 nanoparticles: synthesis, characterization, and visible photocatalytic evaluation on sulfamethazine degradation
2019
Mendiola-Alvarez, Sandra Yadira | Hernández-Ramírez, Ma Aracely | Guzmán-Mar, Jorge Luis | Garza-Tovar, Lorena Leticia | Hinojosa-Reyes, Laura
Mesoporous phosphorous-doped TiO₂ (TP) with different wt% of P (0.5, 1.0, and 1.5) was synthetized by microwave-assisted sol–gel method. The obtained materials were characterized by XRD with cell parameters refinement approach, Raman, BET-specific surface area analysis, SEM, ICP-OES, UV–Vis with diffuse reflectance, photoluminescence, FTIR, and XPS. The photocatalytic activity under visible light was evaluated on the degradation of sulfamethazine (SMTZ) at pH 8. The characterization of the phosphorous materials (TP) showed that incorporation of P in the lattice of TiO₂ stabilizes the anatase crystalline phase, even increasing the annealing temperature. The mesoporous P-doped materials showed higher surface area and lower average crystallite size, band gap, and particle size; besides, more intense bands attributed to O–H bond were observed by FTIR analysis compared with bare TiO₂. The P was substitutionally incorporated in the TiO₂ lattice network as P⁵⁺ replacing Ti⁴⁺ to form Ti–O–P bonds and additionally present as PO₄³⁻ on the TiO₂ surface. All these characteristics explain the observed superior photocatalytic activity on degradation (100%) and mineralization (32%) of SMTZ under visible radiation by TP catalysts, especially for P-doped TiO₂ 1.0 wt% calcined at 450 °C (TP1.0-450). Ammonium, nitrate, and sulfate ions released during the photocatalytic degradation were quantified by ion chromatography; the nitrogen and sulfur mass balance evidenced the partial mineralization of this recalcitrant molecule.
显示更多 [+] 显示较少 [-]How does intensification influence the operational and environmental performance of photo-Fenton processes at acidic and circumneutral pH
2019
Salazar, Luis Miguel | Grisales, Claudia Mildred | Garcia, Dorian Prato
This study evaluates the technical, economical, and environmental impact of sodium persulfate (Na₂S₂O₈) as an enhancing agent in a photo-Fenton process within a solar-pond type reactor (SPR). Photo-Fenton (PF) and photo-Fenton intensified with the addition of persulfate (PFPS) processes decolorize 97% the azo dye direct blue 71 (DB71) and allow producing a highly biodegradable effluent. Intensification with persulfate allowed reducing treatment time in 33% (from 120 to 80 min) and the consumption of chemical auxiliaries needed for pH adjustment. Energy, reagents, and chemical auxiliaries are still and environmental hotspot for PF and PFPS; however, it is worth mentioning that their environmental footprint is lower than that observed for compound parabolic concentrator (CPC)-type reactors. A life-cycle assessment (LCA) confirms that H₂O₂, NaOH, and energy consumption are the variables with the highest impact from an environmental standpoint. The use of persulfate reduced the relative impact in 1.2 to 12% in 12 of the 18 environmental categories studied using the ReCiPe method. The PFPS process emits 1.23 kg CO₂ (CO₂-Eqv/m³ treated water). On the other hand, the PF process emits 1.28 kg CO₂ (CO₂-Eqv/m³ treated water). Process intensification, chemometric techniques, and the use of SPRs minimize the impact of some barriers (reagent and energy consumption, technical complexity of reactors, pressure drops, dirt on the reflecting surfaces, fragility of reactor materials), limiting the application of advanced oxidation systems at an industrial level, and decrease treatment cost as well as potential environmental impacts associated with energy and reagents consumption. Treatment costs for PF processes (US$0.78/m³) and PFPS processes (US$0.63/m³) were 20 times lower than those reported for photo-Fenton processes in CPC-type reactors.
显示更多 [+] 显示较少 [-]CFD modeling of a UV-A LED baffled flat-plate photoreactor for environment applications: a mining wastewater case
2019
Devia-Orjuela, John Steven | Betancourt-Buitrago, Luis Andrés | Machuca-Martinez, Fiderman
The use of ultraviolet light in photoreactors for wastewater treatment has become popular as an alternative of known chemical oxidative substances. UV LED light represents cheaper, robust, and versatile alternative to traditional UV lamps. In this study, it was designed and evaluated a photoreactor with an approach of chemical fluid dynamics (CFD) and experimental validation. The evaluation consisted of (1) CFD velocity profile analysis, (2) characterization of the average light distribution with potassium ferrioxalate actinometry, (3) degradation of a typical recalcitrant metallic cyanocomplex Fe(CN)₆³⁻, and (4) scavenger effect analysis in the photodegradation using potassium persulfate. Actinometrical essay concluded that the system was able to receive 1.93 μE/s. The reactor operated under turbulent regime and best result for Fe(CN)₆³⁻ degradation was obtained at 4 h of operation, using 5-W UV-A LEDs, with pH ~ 7 and 10 mM de S₂O₈²⁻. Baffled photoreactor demonstrated to be useful for this type of illumination and wastewater treatment.
显示更多 [+] 显示较少 [-]How production-based and consumption-based emissions accounting systems change climate policy analysis: the case of CO2 convergence
2019
Karakaya, Etem | Yılmaz, Burcu | Alataş, Sedat
Much of the existing research analyses on emissions and climate policy are dominantly based on emissions data provided by production-based accounting (PBA) system. However, PBA provides an incomplete picture of driving forces behind these emission changes and impact of global trade on emissions, simply by neglecting the environmental impacts of consumption. To remedy this problem, several studies propose to consider national emissions calculated by consumption-based accounting (CBA) systems in greenhouse gas (GHG) assessments for progress and comparisons among the countries. In this article, we question the relevance of PBA’s dominance. To this end, we, firstly, try to assess and compare PBA with CBA adopted in greenhouse gas emissions accounting systems in climate change debates on several issues and to discuss the policy implications of the choice of approach. Secondly, we investigate the convergence patterns in production-based and consumption-based emissions in 35 Annex B countries for the period between 1990 and 2015. This study, for the first time, puts all these arguments together and discusses possible outcomes of convergence analysis by employing both the production- and consumption-based CO₂ per capita emissions data. The empirical results found some important conclusions which challenge most of the existing CO₂ convergence studies.
显示更多 [+] 显示较少 [-]Estimating the spatial distribution of environmental suitability for female lung cancer mortality in China based on a novel statistical method
2019
Han, Xiao | Guo, Yanlong | Gao, Hong | Ma, Jianmin | Sang, Manjie | Zhou, Sheng | Huang, Tao | Mao, Xiaoxuan
Lung cancer as one of the major causes of cancer mortality has been demonstrated to be closely related to the ambient atmospheric environment, but little has been done in the synthetic evaluation of the linkage between cancer mortality and combined impact of ambient air pollution and meteorological conditions. The present study determined the environmental suitability for female lung cancer mortality associated with air contaminants and meteorological variables. A novel fuzzy matter–element method was applied to identify the spatial distribution and regions for the environmental suitability for the female lung cancer mortality across China in 2013. The membership functions between the cancer mortality and 6 environmental factors, including PM₂.₅, NO₂, SO₂, PM₁₀, the annual mean wind speed, and mean temperature, were generated and the weights of each of the environmental factors were established by the maximum entropy (MaxEnt) model. We categorized the environmental suitability combined with GIS spatial analysis into three zones, including low-suitable, medium-suitable, and high-suitable region where the cancer mortality ranging from low to high rate was identified. These three zones were quantified by the MaxEnt model taking different air pollutants and meteorological variables into consideration. We identified that NO₂ was a most significant factor among the 6 environmental factors with the weight of 24.88%, followed by the annual mean wind speed, SO₂, and PM₂.₅. The high-suitable area, mainly in the North China Plain which is a most heavily contaminated region by air pollution in China, covers 1.6195 million square kilometers, accounting for 17.85% of the total area investigated in this study. Identification of the impact of various environmental factors on cancer mortality in the different suitable area provides a scientific basis for the environmental management, risk assessment, and lung cancer control.
显示更多 [+] 显示较少 [-]Assessment of Environmental Quality in the Tamaulipas Laguna Madre, Gulf of Mexico, by Integrated Biomarker Response Using the Cross-Barred Venus Clam Chione elevata
2019
Aguilera, Carlos | Leija, Antonio | Torres, Milton | Mendoza, Roberto
The entire Laguna Madre of Tamaulipas is a natural protected area and a Priority Marine Region of Mexico. However, its important biodiversity and high levels of endemism are threatened by the discharge of different pollutants and activities related to the ocean oil and gas industry. Therefore, the assessment of these effects on this marine ecosystem is of paramount importance. At present, the joint approach of monitoring chemical contaminant levels, alongside the use of pollution biomarkers as surrogate measures of biological impact within the environment, provides the better evaluation of the environmental hazard. Within this context, a biomonitoring study using native Chione elevata mussels sampled from four locations along the Mexican Laguna Madre coasts evaluated whether a battery of select biomarkers was suitable for identifying and quantifying pollution-induced stress in mussels. The levels of acetylcholinesterase (AChE), butyrylcholinesterase (BChE), carboxylesterase (CaE), alkaline phosphatase (ALP), glutathione s-transferase (GST), and the oxygen radical absorbance capacity (ORAC) were measured in soft tissues samples. Different metals (Cd, Pb, Cu, Zn, and Fe) as well as total heavy hydrocarbons were also determined in sediments. Higher concentrations of metals were observed in sampling localities with marine influence possibly related to the presence of marine grass. The concentration of total heavy hydrocarbons, as expected, was higher in sites with intensive fishing activity. The integrated biomarker response (IBR) and the condition index of mussels allowed discriminating between localities of continental and marine influence, revealing that the sampling stations with continental influence were subjected to a greater stress as a result of anthropogenic effects.
显示更多 [+] 显示较少 [-]Epoxiconazole exposure affects terpenoid profiles of oilseed rape plantlets based on a targeted metabolomic approach
2019
Durenne, Bastien | Blondel, Alodie | Druart, Philippe | Fauconnier, Marie-Laure
Epoxiconazole is a broad-spectrum fungicide described as highly persistent in soil and as such can be considered as an abiotic agent like other problematic agrochemicals. Furthermore, the plant phenotyping tool involving non-invasive monitoring of plant-emitted volatile organic compounds (VOCs) may be useful in the identification of metabolic markers for abiotic stress. We therefore decided to profile the VOCs from secondary metabolism of oilseed rape through a dose-response experiment under several epoxiconazole concentrations (0, 0.01, 0.1 and 1 mg L⁻¹). VOC collections of 35-day-old whole plantlets were performed through a dynamic headspace sampling technique under defined and controlled conditions. The plantlets grew freely within a home-made, laboratory and high-throughput glass chamber without any disturbance. Putative metabolic markers were analysed using a targeted metabolomic approach based on TD-GC-MS method coupled with data acquisition in SIM mode in order to focus on terpenes and sulphur-containing volatiles. Chromatograms of emitted terpenes were achieved accurately for the 35-day-old oilseed rape plantlets. We also analysed the presence of sulphur-containing volatiles in samples of shoot and root tissues using an innovative DHS-TD-GC-MS method, but no difference was found between qualitative profiles. Nevertheless, we demonstrated through this experiment that sesquiterpenes such as β-elemene and (E,E)-α-farnesene are involved in epoxiconazole dose-response. In particular, (E,E)-α-farnesene could serve as a metabolic marker of fungicide exposure for oilseed rape plantlets.
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