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A multi-scale approach to modelling spatial and dynamic ecological patterns for reservoir's water quality management 总被引:1,自引:0,他引:1
Edna Cabecinha Martinho Loureno Joo Paulo Moura Miguel ngelo Pardal Joo Alexandre Cabral 《Ecological modelling》2009,220(19):2559-2569
With growing levels of urbanization and agriculture throughout the world, it is increasingly important that both research and management efforts take into account the effects of this widespread landscape alteration and its consequences for natural systems. Freshwater ecosystems, namely reservoirs, are particularly sensitive to land use changes. In this context, modelling can be very useful, for decision support, as an investigative tool to forecast the outcome of various scenarios, to guide current management in order to meet future targets and to develop integrated frameworks for management accordingly to the Water Framework Directive (WFD). The present paper examined the applicability of a holistic Stochastic-Dynamic Methodology (StDM), coupled with a Cellular Automata (CA) model, in capturing how expected changes at land use level will alter the ecological status of lentic ecosystems, namely at physicochemical and biological levels. The methodology was applied to Portuguese reservoirs located in the Douro's basin and illustrated with a series of stochastic-dynamic and spatial outputs taking into account expected scenarios regarding land use changes. Overall, the simulation results are encouraging since they seem to demonstrate the tool reliability in capturing the stochastic environmental dynamics of the selected metrics facing spatial explicit scenarios. The ultimate goal was to couple monitoring assessment and the described modelling techniques to ease management and decision making regarding the practical implementation of the WFD, both at the scale of the reservoir body and at the scale of the respective river watershed dynamics. 相似文献
115.
The possibility of transforming waste plastics into valuable hydrocarbons via catalytic cracking and reforming is attracting
increasing interest. Pyrolysis coupled with Gas Chromatographic separation and Mass Spectrometry detection (Py-GC/MS) has
been used in this work to study the product selectivity of various catalysts in the conversion of pure and residual polyethylene
samples into hydrocarbon products. Five acid solids of comparable aluminium contents but different textural and acid properties
were tested as catalysts, including three zeolites (standard ZSM-5, nanocrystalline n-ZSM-5 and Beta) and two mesostructured
solids (Al-MCM-41 and Al-SBA-15). Thermal cracking of the pure and residual polymers generated a similar range of products
to each other, with a high proportion of linear paraffins and olefins of varying lengths. The presence of zeolitic materials
resulted in complete elimination of heavy linear products, an increase in the light hydrocarbon fraction and a marked selectivity
towards the formation of single-ring aromatic species, particularly benzene, toluene and xylene. Aromatic formation was particularly
notable with the small crystal size n-ZSM-5 (aromatic selectivity up to 53.9%) and less marked in the case of standard ZSM-5
(up to 36.4%) and Beta zeolite (up to 35.0%). Mesostructured catalysts like Al-MCM-41 and Al-SBA-15 favoured the production
of light C2–C5 hydrocarbons (up to 57.9%) while the formation of aromatic products was significantly lower than with zeolitic materials.
The paper examines the extent and the causes for this product selectivity and discusses its connection with the acid and textural
properties of each catalyst. It was also observed that, under the experimental conditions employed, the products generated
were not significantly affected by the nature and origin of the polymers employed. 相似文献
116.
Rodrigo A. Medellín ‡ Miguel Equihua † and Miguel A. Amin 《Conservation biology》2000,14(6):1666-1675
Abstract: Evaluating the degree of disturbance of any region to determine its relative importance for conservation purposes requires procedures that are relatively inexpensive and that yield accurate results fast. Because bats are abundant, diverse, and easy to sample, especially in the Neotropical rainforest, they fulfill several of the requirements of indicator species as identified in the literature. For 10 months we sampled bat communities in the Selva Lacandona in Chiapas, Mexico, at 15 sites representing five habitats. We also measured 10 variables representing vegetation structure and diversity at each site. With fuzzy-set techniques we produced a gradient classification of disturbance for the 15 sites based on the vegetation data. We explored the relationship between vegetation conditions, described as the membership degrees in the construct "fuzzy forest set" (the complementary fuzzy set of "disturbance"), and four bat community variables. Bat species richness, number of rare bat species, and the bat diversity index were positively correlated with the vegetation scores, and relative abundance of the most abundant bat species was negatively correlated with vegetation scores. A high number of phyllostomine species in a community is a good indicator of low levels of disturbance. Although a single indicator group will probably not be sufficient for decision-making processes in conservation, evaluating bat populations may be a good first step in assessing an area's conservation value, especially in rainforest regions. 相似文献
117.
Angélique San Miguel Peter Schröder Rudolf Harpaintner Thierry Gaude Patrick Ravanel Muriel Raveton 《Environmental science and pollution research international》2013,20(5):3464-3471
Mixed pollution is a characteristic of many industrial sites and constructed wetlands. Plants possessing an enzymatic detoxifying system that is able to handle xenobiotics seems to be a viable option for the removal of mixed persistent contaminants such organochlorines (OCs: monochlorobenzene (MCB), 1,4-dichlorobenzene (DCB), 1,2,4-trichlorobenzene (TCB), γ-hexachlorocyclohexane (HCH)). In this study, Phragmites australis plants were exposed to sub-lethal concentrations of OCs (7 days), in single-exposure (0.8 to 10 mg?l?1) and in mixture of OCs (0.2 mg?l?1 MCB?+?0.2 mg?l?1 DCB?+?2.5 mg?l?1 TCB?+?0.175 mg?l?1 HCH). Studies were conducted on the detoxification phase II enzymes; glutathione S-transferases (GST), and glucosyltransferases (UGT). Measurements of GST and UGT activities revealed that OCs may be buffered by glutathione and glucose conjugation. There appeared to be a correlation between the effects on phase II enzymes and the degree of chlorination of the benzene ring with, for example, the greatest effects being obtained for HCH exposure. In the case of mixed pollution, the induction of some GST isoenzymes (CDNB, 35 % non-significant) and UGT (118 %) in leaves and the inhibition of phase II enzymes in the other organs were measured. UGTs appear to be key enzymes in the detoxification of OCs. 相似文献
118.
Edumar Ramos Cabral Coelho Lorena Frasson Loureiro Miguel Angelo Schettino Jr. Jair Carlos Checon de Freitas 《Journal of environmental science and health. Part. B》2020,55(4):361-375
AbstractActivated carbons are well-known porous materials as an effective adsorbent used for the removal of emerging contaminants, such as herbicides, which are increasingly present in water bodies. Most water treatment plants, specially in Brazil, are unable to completely remove such contaminants by the conventional process and advanced treatment using activated carbons is required. The aim of this paper was to verify the influence of the activated carbons granulometry and specific surface area on the 2,4-dichlorophenoxyacetic acid (2,4-D) herbicide removal efficiency using distilled-deionized water and filtered water collected from a conventional Water Treatment Plant. Commercial activated carbons samples used in this work were obtained from two different manufacturers. Activated carbons were analyzed by the specific surface area, pore size and volume distribution, nuclear magnetic resonance, infrared and x-ray spectroscopy, moisture, volatile matter and ash contents. Batch adsorption isotherms experiments were used and performed by Langmuir and Freundlich models. Granular and powdered activated carbons removed over 99% of 2,4-D in distilled water and near to 99% using filtered water. The activated carbons evaluated in this work presented high performance and played a key role in water treatment by removing 2,4-D herbicide, ensuring the protection of human health and the ecosystem. 相似文献
119.
Cormenzana JL García-Gutiérrez M Missana T Junghanns A 《Journal of contaminant hydrology》2003,61(1-4):63-72
Effective diffusion coefficients (D(e)) are usually measured by means of "through-diffusion" experiments in which steady state is reached, and the "time-lag" methods are used to estimate the apparent diffusion coefficient (D(a)). For sorbing radionuclides (as caesium), the time needed to reach steady-state conditions is very large, and the precision in D(a) determinations is not satisfactory. In this paper, a method that allows determining simultaneously effective and apparent diffusion coefficients in compacted bentonite without reaching steady-state conditions is described. Basically, this method consists of an "in-diffusion" experiment in which the concentration profile in the bentonite sample is used to estimate D(a), and the temporal evolution of the solute concentration in the reservoir is used to estimate D(e). This method has several advantages over the typical "through-diffusion" experiments, in particular: (a) experiment duration is significantly shorter, (b) D(a) values are measured with greater precision and (c) it is not necessary to maintain a constant solute concentration in the reservoir. This new method has been used to estimate the effective and apparent diffusion coefficients for caesium in FEBEX bentonite and in order to validate it, the results have been compared with results previously obtained with standard methods. Experimental results have been satisfactorily modelled using a simple model of diffusion in porewater and the measured value of D(e)(Cs) is very similar to D(e)(HTO) in the same bentonite. There is no evidence of "surface diffusion" in FEBEX bentonite for caesium. 相似文献
120.
San Miguel EG Pérez-Moreno JP Bolívar JP García-Tenorio R 《Environmental pollution (Barking, Essex : 1987)》2003,123(1):125-130
This paper aims to show the usefulness of 226Ra/228Ra activity ratios and confirm the possibility of using 230Th/232Th activity ratios as chronological markers in sediment cores from an estuarine system strongly contaminated by discharges from non-nuclear industries (fertiliser plants). The validation was carried out using an independent, well-established dating technique based on the analysis of the 137Cs fallout profile, which comprises the same time interval as that covered by both isotope ratios. The advantage of using the 226Ra/228Ra activity ratio profile instead of the Th-isotope profile is that determination can be accomplished with a non-destructive, simpler and less time-consuming technique, because both Ra isotopes can be determined by gamma-ray spectrometry. 相似文献