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991.
Biola K. Badmos Ademola A. Adenle Sampson K. Agodzo Grace B. Villamor Daniel K. Asare-Kyei Laouali M. Amadou Samuel N. Odai 《Environment, Development and Sustainability》2018,20(5):2261-2279
This study determined the social vulnerability index (SoVI) of households to climate change impacts for three identified locations (upper, mid and lower) in the Vea catchment, semi-arid Ghana. This study adapted the social, economic and demographic indicator approach. The data used were obtained from a survey of 186 randomly sampled farm households and direct field measurements of 738 farm plots belonging to the same sampled farm households. Information from the literature, expert judgement and principal component analysis were useful for computing and analysing the SoVI. The variables were normalized, weighted and subsequently recombined to determine the index of the three locations towards climate change. Although the SoVI to climate change was highest (0.77) for the upper part of the catchment, the mid- and lower parts of the catchment show a high SoVI of 0.72 each. The overall SoVI for the catchment is 0.73. The study re-emphasizes the high vulnerability level of dry areas to climate change. Moreover, it shows there is variability at micro-scale. There is a need to put appropriate measures to address the vulnerability of households to climate change in the semi-arid areas of West Africa. Factors aggravating dry land’s vulnerability towards climate change should be prevented with implementable policies. Furthermore, it is important to identify conditions that have made some areas less vulnerable to climate change, and then, we can work out the possibility of adapting such to the vulnerable places. 相似文献
992.
Archetypical patterns and trajectories of land systems in Europe 总被引:1,自引:0,他引:1
Levers Christian Müller Daniel Erb Karlheinz Haberl Helmut Jepsen Martin Rudbeck Metzger Marc J. Meyfroidt Patrick Plieninger Tobias Plutzar Christoph Stürck Julia Verburg Peter H. Verkerk Pieter J. Kuemmerle Tobias 《Regional Environmental Change》2018,18(3):715-732
Regional Environmental Change - Assessments of land-system change have dominantly focused on conversions among broad land-use categories, whereas intensity changes within these categories have... 相似文献
993.
Impact of Length of Dataset on Streamflow Calibration Parameters and Performance of APEX Model 下载免费PDF全文
Amanda M. Nelson Daniel N. Moriasi Mansour Talebizadeh Jean L. Steiner Remegio B. Confesor Prasanna H. Gowda Patrick J. Starks Haile Tadesse 《Journal of the American Water Resources Association》2017,53(5):1164-1177
Due to resource constraints, long‐term monitoring data for calibration and validation of hydrologic and water quality models are rare. As a result, most models are calibrated and, if possible, validated using limited measured data. However, little research has been done to determine the impact of length of available calibration data on model parameterization and performance. The main objective of this study was to evaluate the impact of length of calibration data (LCD) on parameterization and performance of the Agricultural Policy Environmental eXtender model for predicting daily, monthly, and annual streamflow. Long‐term (1984‐2015) measured daily streamflow data from Rock Creek watershed, an agricultural watershed in northern Ohio, were used for this study. Data were divided into five Short (5‐year), two Medium (15‐year), and one Long (25‐year) streamflow calibration data scenarios. All LCD scenarios were calibrated and validated at three time steps: daily, monthly, and annual. Results showed LCD affected the ability of the model to accurately capture temporal variability in simulated streamflow. However, overall average streamflow, water budgets, and crop yields were simulated reasonably well for all LCD scenarios. 相似文献
994.
van Soesbergen Arnout Arnell Andrew P. Sassen Marieke Stuch Benjamin Schaldach Rüdiger Göpel Jan Vervoort Joost Mason-D’Croz Daniel Islam Shahnila Palazzo Amanda 《Regional Environmental Change》2017,17(5):1409-1420
Regional Environmental Change - Competition for land is increasing as a consequence of the growing demands for food and other commodities and the need to conserve biodiversity and ecosystem... 相似文献
995.
Weihua Zhang Xinchen Huang Yanming Jia Frederic Rees Daniel C. W. Tsang Rongliang Qiu Hong Wang 《Environmental geochemistry and health》2017,39(2):379-389
Pyrolyzing sludge into biochar is a potentially promising recycling/disposal solution for municipal wastewater sludge, and the sludge-derived biochar (SDBC) presents an excellent sorbent for metal immobilization. As SDBC is composed of both mineral oxides and carbonized organic compartment, this study therefore compared the sorption behaviour of Pb and Zn on SDBC to those of individual and mixture of activated carbon (AC) and amorphous aluminium oxide (Al2O3). Batch experiments were conducted at 25 and 45 °C, and the metal-loaded sorbents were artificially aged in the atmosphere for 1–60 days followed by additional sorption experiments. The Pb sorption was generally higher than Zn sorption, and the co-presence of Pb reduced Zn sorption on each studied sorbent. Higher sorption capacities were observed at 45 °C than 25 °C for SDBC and AC, while the opposite was shown for Al2O3, indicating the significance of temperature-dependent diffusion processes in SDBC and AC. Nevertheless, metal sorption was more selective on Al2O3 that showed a greater affinity towards Pb over Zn under competition, correlating with the reducible fraction of sequential extraction. Furthermore, significant amounts of Pb and Zn were additionally sorbed on SDBC following 30-day ageing. The X-ray diffraction revealed the formation of metal-phosphate precipitates, while the X-ray photoelectron spectroscopy showed a larger quantity of metal–oxygen bonding after 30-day ageing of metal-loaded SDBC. The results may imply favourable long-term transformation and additional sorption capacity of SDBC. In conclusion, SDBC resembles the sorption characteristics of both organic and mineral sorbents in different aspects, presenting an appropriate material for metal immobilization during soil amendment. 相似文献
996.
Battle?Karimi Pierre?Alain?Maron Nicolas?Chemidlin-Prevost Boure Nadine?Bernard Daniel?Gilbert Lionel?RanjardEmail author 《Environmental Chemistry Letters》2017,15(2):265-281
Evaluating the quality of ecosystems in terms of biological patrimony and functioning is of critical importance in the actual context of intensified human activities. Microbial diversity is commonly used as a bioindicator of ecosystems functioning. However, there is a lack of sensitivity of microbial diversity indicators in the case of moderate and chronic environmental degradation, such as atmospheric deposition of pollutants, agricultural practices, diffuse pollution by wastewater and climate change. As a consequence, there is a need for alternative bioindicators of soils and water quality. Here, we discuss the interest of adopting a more integrative approach based on biotic interaction networks beyond the simple diversity indicators. We review how the various biotic interactions can be integrated in the various microbial networks such as trophic, mutualistic and co-occurrence networks. Then we discuss the efficiency of microbial networks and associated metrics to detect changes in microbial communities. We conclude that the connectance, the number of links and the average degree of co-occurrence networks could vary from 10 to 50% in response to minor perturbations when microbial diversity parameters remain stable. Finally, we analyze studies that aimed at linking microbial networks and activity to evaluate the potential of such networks for providing simple and operational indicators of ecosystem quality and functioning. 相似文献
997.
Timothy I. Marjoribanks Richard J. Hardy Stuart N. Lane Daniel R. Parsons 《Environmental Fluid Mechanics》2017,17(2):277-301
Vegetation is a characteristic feature of shallow aquatic flows such as rivers, lakes and coastal waters. Flow through and above aquatic vegetation canopies is commonly described using a canopy mixing layer analogy which provides a canonical framework for assessing key hydraulic characteristics such as velocity profiles, large-scale coherent turbulent structures and mixing and transport processes for solutes and sediments. This theory is well developed for the case of semi-rigid terrestrial vegetation and has more recently been applied to the case of aquatic vegetation. However, aquatic vegetation often displays key differences in morphology and biomechanics to terrestrial vegetation due to the different environment it inhabits. Here we investigate the effect of plant morphology and biomechanical properties on flow–vegetation interactions through the application of a coupled LES-biomechanical model. We present results from two simulations of aquatic vegetated flows: one assuming a semi-rigid canopy and the other a highly flexible canopy and provide a comparison of the associated flow regimes. Our results show that while both cases display canopy mixing layers, there are also clear differences in the shear layer characteristics and turbulent processes between the two, suggesting that the semi-rigid approximation may not provide a complete representation of flow–vegetation interactions. 相似文献
998.
The chemistry of Pb in urban soil must be understood in order to limit human exposure to Pb in soil and produce and to implement remediation schemes. In inner-city gardens where Pb contamination is prevalent and financial resources are limited, it is critical to identify the variables that control Pb bioavailability. Field-portable X-ray fluorescence was used to measure Pb in 103 urban gardens in Roxbury and Dorchester, MA, and 88% were found to contain Pb above the USEPA reportable limit of 400 mug g(-1). Phosphorus, iron, loss on ignition, and pH data were collected, Pb-bearing phases were identified by X-ray diffraction, and Pb isotopes were measured using inductively coupled plasma mass spectrometry. Four test crops were grown both in situ and in Roxbury soil in a greenhouse, and plant tissue was analyzed for Pb uptake by polarized energy-dispersive X-ray fluorescence. Variation at the neighborhood scale in soil mineralogical and chemical characteristics suggests that the bioavailable fraction of Pb in gardens is site specific. Based on Pb isotope analysis, two historical Pb sources appear to dominate the inventory of Pb in Roxbury gardens: leaded gasoline ((207) Pb/(206) Pb = 0.827) and Pb-based paint ((207)Pb/(206) Pb = 0.867). Nearly 70% of the samples analyzed can be isotopically described by mixing these two end members, with Pb-based paint contributing 40 to 80% of the mass balance. A simplified urban human exposure model suggests that the consumption of produce from urban gardens is equivalent to approximately 10 to 25% of children's daily exposure from tap water. Furthermore, analysis of over 60 samples of plant tissue from the four test species suggests that in these urban gardens unamended phytoremediation is an inadequate tool for decreasing soil Pb. 相似文献
999.
Differences in particle size distribution between runoff standards and unknown samples affect the accuracy of estimation of total suspended solids (TSS) concentration using the nephelometric turbidity (NTU) method. The objective was to quantify the effects of a sucrose solution as suspending medium and contrasting particle size distribution on nephelometric turbidity and accuracy of TSS estimation. Nineteen benchmark soils varying in texture and color were divided into particle size distribution of <250 and <2000 microm. Soils from these two aggregate classes were then made into suspension ranging from 0.2 to 15 g L-1 using distilled deionized water. Runoff suspensions ranging from 0.2 to 21 g L-1 were also collected from different watersheds. Turbidity of soil and runoff suspensions was measured in sucrose solution and in distilled deionized water. The sucrose solution density ranged from 1.10 to 1.30 kg L-1. Increasing sucrose solution density decreased turbidity. The TSS concentration was most sensitive to changes in turbidity with the 1.30 kg L-1 sucrose solution. Using the 1.30 kg L-1 sucrose solution, particle size bias and error of TSS estimates were decreased by at least 20% compared to distilled deionized water. Reduction in refraction index differences between the suspended particles and sucrose solution combined with reduced particle settling and reduced Brownian motion resulted in dampening the effects of particle size distribution. We propose a sucrose solution of 1.30 kg L-1 as a better suspending medium to dampen the effect of particle size distribution and thus improve suspension TSS concentration estimation. 相似文献
1000.
Due to variations in soil physicochemical properties, species physiology, and contaminant speciation, Pb toxicity is difficult to evaluate without conducting in vivo dose-response studies. Such tests, however, are expensive and time consuming, making them impractical to use in assessment and management of contaminated environments. One possible alternative is to develop a physiologically based extraction test (PBET) that can be used to measure relative bioaccessibility. We developed and correlated a PBET designed to measure the bioaccessibility of Pb to waterfowl (W-PBET) in mine-impacted soils located in the Coeur d'Alene River Basin, Idaho. The W-PBET was also used to evaluate the impact of P amendments on Pb bioavailability. The W-PBET results were correlated to waterfowl-tissue Pb levels from a mallard duck [Anas platyrhynchos (L.)] feeding study. The W-PBET Pb concentrations were significantly less in the P-amended soils than in the unamended soils. Results from this study show that the W-PBET can be used to assess relative changes in Pb bioaccessibility to waterfowl in these mine-impacted soils, and therefore will be a valuable test to help manage and remediate contaminated soils. 相似文献