共查询到20条相似文献，搜索用时 15 毫秒
1.
E. Aghaarabi F. Aminravan R. Sadiq M. Hoorfar M. J. Rodriguez H. Najjaran 《Stochastic Environmental Research and Risk Assessment (SERRA)》2014,28(3):655-679
This paper presents the use of two multi-criteria decision-making (MCDM) frameworks based on hierarchical fuzzy inference engines for the purpose of assessing drinking water quality in distribution networks. Incommensurable and uncertain water quality parameters (WQPs) at various sampling locations of the water distribution network (WDN) are monitored. Two classes of WQPs including microbial and physicochemical parameters are considered. Partial, incomplete and subjective information on WQPs introduce uncertainty to the water quality assessment process. Likewise, conflicting WQPs result in a partially reliable assessment of the quality associated with drinking water. The proposed methodology is based on two hierarchical inference engines tuned using historical data on WQPs in the WDN and expert knowledge. Each inference engine acts as a decision-making agent specialized in assessing one aspect of quality associated with drinking water. The MCDM frameworks were developed to assess the microbial and physicochemical aspects of water quality assessment. The MCDM frameworks are based on either fuzzy evidential or fuzzy rule-based inference. Both frameworks can interpret and communicate the relative quality associated with drinking water, while the second is superior in capturing the nonlinear relationships between the WQPs and estimated water quality. More comprehensive rules will have to be generated prior to reliable water quality assessment in real-case situations. The examples presented here serve to demonstrate the proposed frameworks. Both frameworks were tested through historical data available for a WDN, and a comparison was made based on their performance in assessing levels of water quality at various sampling locations of the network. 相似文献
2.
《Ground Water Monitoring & Remediation》1999,19(4):81-89
Robowell is an automated process for monitoring selected ground water quality properties and constituents by pumping a well or multilevel sampler. Robowell was developed and tested to provide a cost-effective monitoring system that meets protocols expected for manual sampling. The process uses commercially available electronics, instrumentation, and hardware, so it can be configured to monitor ground water quality using the equipment, purge protocol, and monitoring well design most appropriate for the monitoring site and the contaminants of interest. A Robowell prototype was installed on a sewage-treatment plant infiltration bed that overlies a well-studied u neon fined sand and gravel aquifer at the Massachusetts Military Reservation, Cape Cod, Massachusetts, during a time when two distinct plumes of constituents were released. The prototype was operated from May 10 to November 13, 1996, and quality-assurance/quality-control measurements demonstrated that the data obtained by the automated method was equivalent to data obtained by manual sampling methods using the same sampling protocols. Water level, specific conductance, pH, water temperature, dissolved oxygen, and dissolved ammonium were monitored by the prototype as the wells were purged according to U.S. Geological Survey (LJSGS) ground water sampling protocols. Remote access to the data record, via phone modem communications, indicated the arrival of each plume over a few days and the subsequent geochemical reactions over the following weeks. Real-time availability of the monitoring record provided the information needed to initiate manual sampling efforts in response to changes in measured ground water quality, which proved the method and characterized the screened portion of the plume in detail through time. The methods and the case study described are presented to document the process for future use. 相似文献
3.
Groundwater quality assessment using data clustering based on hybrid Bayesian networks 总被引：1，自引：1，他引：0
Pedro A. Aguilera Antonio Fernández Rosa F. Ropero Luís Molina 《Stochastic Environmental Research and Risk Assessment (SERRA)》2013,27(2):435-447
Bayesian networks (BNs) have become a standard in the field of Artificial Intelligence as a means of dealing with uncertainty and risk modelling. In recent years, there has been particular interest in the simultaneous use of continuous and discrete domains, obviating the need for discretization, using so-called hybrid BNs. In these hybrid environments, Mixtures of Truncated Exponentials (MTEs) provide a suitable solution for working without any restriction. The objective of this study is the assessment of groundwater quality through the design and application of a probabilistic clustering, based on hybrid Bayesian networks with MTEs. Firstly, the results obtained allows the differentiation of three groups of sampling points, indicating three different classes of groundwater quality. Secondly, the probability that a sampling point belongs to each cluster allows the uncertainty in the clusters to be assessed, as well as the risks associated in terms of water quality management. The methodology developed could be applied to other fields in environmental sciences. 相似文献
4.
A method is described that enables a variety of maps, which indicate the probabilities of deposition, to be constructed in a reproducible manner from the stratigraphie information typically available at well-studied stratovoicanoes. These maps can then be used as a basis for hazard assessment. The sampling of the deposits of previous eruptions is subject to uncertainties due to erosion, sectoral deposition and non-exposure. A model-based, iterative algorithm is used to compensate for the incomplete sampling. For each site, the available evidence from the other sites is used to estimate the probability of deposition for missing deposits. A geographical information system (GIS)-based method that uses Thiessen polygons to represent the presence or absence of deposits, together with simple cartographic rules based on depositional processes, then defines the extent of deposition. The combined operation of these two techniques is presented for Montagne Pelée in Martinique, using the amended stratigraphic record of Smith and Roobol (1990) for the past 6000 years. Three types of maps are created: maps for individual depositional events (the 1902 block-and-ash flow and surge deposits are used to verify the technique); maps for different deposit types aggregated over 6000 years of activity; and scenario maps which, in Montagne Pelée’s case, recognise that during the next Peléean or Plinian eruption a variety of hazards will have to be confronted. 相似文献
5.
Ricardo M. Pinto-Coelho Ludmila S. Brighenti José F. Bezerra-Neto Cid Antônio Morais Jr. Alan Vieira Gonzaga 《Limnologica》2010,40(2):126-133
We investigated the effects of increase in sampling effort (30-1043 sampling points) on the accuracy of assessment of the spatial patterns of surface-water quality in a eutrophic tropical reservoir. The investigation was carried out during the dry season, when previous investigations showed that the spatial heterogeneity is more stable. A multi-parameter Yellow Springs Instruments probe coupled to a TechGeo D-GPS was used. This system is equipped to measure and store in a continuous recording mode, several physical and chemical parameters linked to geographical coordinates obtained with a precision of less than 1 m. We used different geostatistical approaches to determine the optimal number of sampling points required to reflect the real spatial patterns of water quality in the system. This approach was tested in a small tropical reservoir (Ibirité) that receives effluents from an oil refinery (the state-owned REGAP oil refinery, PETROBRAS) located near the city of Belo Horizonte. The study showed not only that the spatial patterns of water quality are significantly affected by sampling effort but also it was demonstrated that the establishment of an adequate sampling program is a critical point for the precise identification of source points of pollution. The results of this investigation enabled us to demonstrate the potential uses and limits of this method for rapid assessment of the water quality of lakes and reservoirs that receive external inputs of water contaminants or nutrients. 相似文献
6.
An assessment of water quality measurements during a long‐lasting low water period in the Elbe River is presented. Weekly samples were taken from May to December 2003 at a sampling site in the middle part of the Elbe River. For multivariate data analysis, 34 parameters of 46 samplings were considered. As a result of this analysis, 78% of the variance of the data set is explained by five factors. They can be assigned to the following latent variables: season (37.5%) > tributaries (12.7%) > re‐suspension (10.4%) > discharge (9.4%) > complexation (8.5%). For the investigated sampling site, two key processes were identified as dominating factors on the water quality during low water conditions. First, seasonal phytoplankton development caused changes in redox conditions with consequences for re‐solution of pollutants from sediments. Second, tributaries have a higher impact on the main stream, due to changes in mixing processes. Therefore, in addition to flood investigations, monitoring strategies, and management plans should be developed in order to survey changes in water quality during low water conditions. 相似文献
7.
Hodge J Longstaff B Steven A Thornton P Ellis P McKelvie I 《Marine pollution bulletin》2005,51(1-4):113-118
We present an overview of a portable underway water quality monitoring system (RUM-Rapid Underway Monitoring), developed by integrating several off-the-shelf water quality instruments to provide rapid, comprehensive, and spatially referenced 'snapshots' of water quality conditions. We demonstrate the utility of the system from studies in the Northern Great Barrier Reef (Daintree River) and the Moreton Bay region. The Brisbane dataset highlights RUM's utility in characterising plumes as well as its ability to identify the smaller scale structure of large areas. RUM is shown to be particularly useful when measuring indicators with large small-scale variability such as turbidity and chlorophyll-a. Additionally, the Daintree dataset shows the ability to integrate other technologies, resulting in a more comprehensive analysis, whilst sampling offshore highlights some of the analytical issues required for sampling low concentration data. RUM is a low cost, highly flexible solution that can be modified for use in any water type, on most vessels and is only limited by the available monitoring technologies. 相似文献
8.
主成分监督分类及其在水质特征遥感图像识别中的应用 总被引：8，自引：0，他引：8
建立了一种水域水质状况图像识别的主成分监督分类方法。首先通过TM水域图像数据的主成分分析，将原有各波段图像的显著且独立的信息集中在数目尽可能少的合成图像中；再依据不同类型水体的光谱特性，分析各主成分图像的构成及其环境生态学含义，由此对整个研究区域内存在的不同标志类型及其分布特征有所了解；在此基础上，选定训练样本集，从而根据具有清楚的环境生态意义的标志类型，应用监督法得到较好的识别分类结果。分析表明，这一方法采用主成分分析确定标志类型，无需大量的现场调查，因而具有非监督聚类成本低的优点，分类结果则优于非监督法，且各类型的生态意义明显，分布特征与环境因子相互吻合，是水域水质环境图像识别的有效而实用的方法。 相似文献
9.
主成分监督分类及其在水质特征遥感图像识别中的应用 总被引：5，自引：1，他引：4
建立了一种水域水质状况图像识别的主成分监督分类方法,首先通过ＴＭ水域图像数据的主成分分析,将原有各波段图谱的显著且独立的信息集中在数目尽可能少的合成图象中,再依据不同类型水体的光谱特征,分析各主成分图像的构成及其环境生态学含义,由此对整个研究区域内存在的不同标志类型及其分布特征有所了解,在此基础上,选定训练样本集,从而人有清楚的环境生态意义的标志类型,应用监督法得到较好的识别分类结果,分析表明,这 相似文献
10.
Casey Bosse Gunther Rosen Marienne Colvin Patrick Earley Robert Santore Ignacio Rivera-Duarte 《Marine pollution bulletin》2014
The bioavailability and toxicity of copper (Cu) in Shelter Island Yacht Basin (SIYB), San Diego, CA, USA, was assessed with simultaneous toxicological, chemical, and modeling approaches. Toxicological measurements included laboratory toxicity testing with Mytilus galloprovincialis (Mediterranean mussel) embryos added to both site water (ambient) and site water spiked with multiple Cu concentrations. Chemical assessment of ambient samples included total and dissolved Cu concentrations, and Cu complexation capacity measurements. Modeling was based on chemical speciation and predictions of bioavailability and toxicity using a marine Biotic Ligand Model (BLM). Cumulatively, these methods assessed the natural buffering capacity of Cu in SIYB during singular wet and dry season sampling events. Overall, the three approaches suggested negligible bioavailability, and isolated observed or predicted toxicity, despite an observed gradient of increasing Cu concentration, both horizontally and vertically within the water body, exceeding current water quality criteria for saltwater. 相似文献
11.
William R. Norman 《Ground Water Monitoring & Remediation》1986,6(2):56-60
Ground water scientists engaged in assessment of contaminant occurrence and migration are faced with a number of practical problems. These problems include, but are not limited to, escalating drilling costs, labor costs for proper sampling of monitoring wells, collection of ground water samples that are representative of aquifer conditions and accurate delineation of hydrogeologic regimes and the areal and vertical distribution of ground water contaminants.
In response to these problems, a number of ground water sampling devices have been developed. One device is a gas-driven ground water sampler developed for multilevel installation. Use of these samplers have been shown to decrease project costs and allow easy collection of high quality samples. However, the currently available samplers are relatively expensive, some of them operate on a closed check valve system, which does not allow determination of piezometric heads in aquifers with fluctuating water tables and they are not adaptable to design changes in the field necessitated by site-specific hydrogeologic conditions.
GHR Engineering Associates Inc. has designed an effective gas-driven sampler, which accomplishes the same objectives as the commercially available models, but is on the average, one-tenth the cost of currently available samplers. It offers the advantages of being more cost-effective than commercially available models, has an open check valve system to allow measurements of water table fluctuation and is easily adaptable in the field to meet site-specific hydrogeologic conditions. 相似文献
In response to these problems, a number of ground water sampling devices have been developed. One device is a gas-driven ground water sampler developed for multilevel installation. Use of these samplers have been shown to decrease project costs and allow easy collection of high quality samples. However, the currently available samplers are relatively expensive, some of them operate on a closed check valve system, which does not allow determination of piezometric heads in aquifers with fluctuating water tables and they are not adaptable to design changes in the field necessitated by site-specific hydrogeologic conditions.
GHR Engineering Associates Inc. has designed an effective gas-driven sampler, which accomplishes the same objectives as the commercially available models, but is on the average, one-tenth the cost of currently available samplers. It offers the advantages of being more cost-effective than commercially available models, has an open check valve system to allow measurements of water table fluctuation and is easily adaptable in the field to meet site-specific hydrogeologic conditions. 相似文献
12.
Ballesteros E Torras X Pinedo S García M Mangialajo L de Torres M 《Marine pollution bulletin》2007,55(1-6):172-180
Macroalgae is a biological key element for the assessment of the ecological status in coastal waters in the frame of the European Water Framework Directive (WFD, 2000/60/EC). Here we propose a methodology for monitoring water quality based on the cartography of littoral and upper-sublittoral rocky-shore communities (CARLIT, in short). With the use of spatial databases, GIS, and available information about the value of rocky-shore communities as indicators of water quality, it is possible to obtain an environmental quality index representative of the ecological status of rocky coasts. This index, which completely fulfils the requirements of the WFD, is expressed as a ratio between the observed values in the sector of shore that is being assessed and the expected value in a reference condition zone with the same substrate and coastal morphology (Ecological Quality Ratio, EQR). The application of this index to the coast of Catalonia (North-Western Mediterranean) is presented. 相似文献
13.
A new index is proposed for water quality assessment in rivers and creeks. The index is similar to the Pantle–Buck saprobity index, but is based on qualitative characteristics and uses macrobenthos families (rarely genera), for which original values of saprobity and indicator weight are given. Data collected at 245 watercourses in the central European Russia are used to study the correlation of the new index with the anthropogenic load onto watercourses, as well as with the watercourse type and size and the type of substrate. The index is shown to be more effective than the Pantle-Buck index modified by Sladecek and the Woodiwiss index and applicable for rapid assessment of watercourse pollution. 相似文献
14.
《Ground Water Monitoring & Remediation》1985,5(2):83-99
The objective of most ground water quality monitoring programs is to obtain samples that are "representative" or that retain the physical and chemical properties of the ground water in an aquifer. Many factors can influence whether or not a particular sample is representative, but perhaps the most critical factor is the method or type of sampling device used to retrieve the sample.
The sampling equipment available today ranges from simple to highly sophisticated, and includes bailers, syringe devices, suction-lift pumps, gas-drive devices, bladder (Middelburg-type) pumps, gear-drive and helical rotor electric submersible pumps and gas-driven piston pumps. New devices are continually being developed for use in small-diameter wells in order to meet the needs of professionals engaged in implementing elaborate ground water monitoring programs.
In selecting a sampling device for a monitoring program, the professional must consider a number of details. Among the considerations are: the outside diameter of the device, the overall impact of the device on ground water sample integrity (including the materials from which the sampling device and associated equipment are made and the method by which the device delivers the sample), the capability of the device to purge the well of stagnant water, the rate and the ability to control the rate at which the sample is delivered, the depth limitations of the device, the ease of operating, cleaning and maintaining the device, the portability of the device and required accessory equipment, the reliability and durability of the device, and the initial and operational cost of the device and accessory equipment. Based on these considerations, each of the devices available for sampling ground water from small-diameter wells has its own unique set of advantages and disadvantages that make it suitable for sampling under specific sets of conditions. No one sampling device is applicable to all sampling situations. 相似文献
The sampling equipment available today ranges from simple to highly sophisticated, and includes bailers, syringe devices, suction-lift pumps, gas-drive devices, bladder (Middelburg-type) pumps, gear-drive and helical rotor electric submersible pumps and gas-driven piston pumps. New devices are continually being developed for use in small-diameter wells in order to meet the needs of professionals engaged in implementing elaborate ground water monitoring programs.
In selecting a sampling device for a monitoring program, the professional must consider a number of details. Among the considerations are: the outside diameter of the device, the overall impact of the device on ground water sample integrity (including the materials from which the sampling device and associated equipment are made and the method by which the device delivers the sample), the capability of the device to purge the well of stagnant water, the rate and the ability to control the rate at which the sample is delivered, the depth limitations of the device, the ease of operating, cleaning and maintaining the device, the portability of the device and required accessory equipment, the reliability and durability of the device, and the initial and operational cost of the device and accessory equipment. Based on these considerations, each of the devices available for sampling ground water from small-diameter wells has its own unique set of advantages and disadvantages that make it suitable for sampling under specific sets of conditions. No one sampling device is applicable to all sampling situations. 相似文献
15.
Eighteen sites in South Carolina under investigation by the Superfund program were sampled to determine ambient ground water quality. Samples from 11 of 15 monitoring wells sampled with a bailer contained either caprolactam or Santowhite® (a registered trademark of the Monsanto Co.) or both organic compounds. A maximum of 540 μg/L of caprolactam and 780 μg/L of Santowhite was observed in the samples from the monitoring wells. None of the samples collected using dedicated submersible pumps at 28 other wells contained either compound.
Caprolactam is used in the manufacturing of nylon cord, and Santowhite is used as an antioxidant in latex gloves. Therefore, it was suspected that the nylon cord used to raise and lower the bailer and the latex gloves that were worn during sampling may have contributed the caprolactam and Santowhite to the sample.
An experiment using pH-adjusted distilled water and private well water revealed that the nylon cord and the latex gloves may contribute contaminants to ground water samples. Research is needed into the potential for caprolactam and Santowhite to interfere with laboratory analyses in addition to the potential for absorption of contaminants by nylon cord. Until additional information is available, alternative materials or sampling techniques should be considered to minimize the potential impact of nylon cord and latex gloves on the quality of bailed samples. 相似文献
Caprolactam is used in the manufacturing of nylon cord, and Santowhite is used as an antioxidant in latex gloves. Therefore, it was suspected that the nylon cord used to raise and lower the bailer and the latex gloves that were worn during sampling may have contributed the caprolactam and Santowhite to the sample.
An experiment using pH-adjusted distilled water and private well water revealed that the nylon cord and the latex gloves may contribute contaminants to ground water samples. Research is needed into the potential for caprolactam and Santowhite to interfere with laboratory analyses in addition to the potential for absorption of contaminants by nylon cord. Until additional information is available, alternative materials or sampling techniques should be considered to minimize the potential impact of nylon cord and latex gloves on the quality of bailed samples. 相似文献
16.
17.
Time series analysis of optical remote sensing data for the mapping of temporary surface water bodies in sub-Saharan western Africa 总被引：2，自引：0，他引：2
A map of temporary small water bodies (TSWB) at 1 km resolution was derived for the arid, semi-arid and dry sub-humid regions of sub-Saharan western Africa where the spatio-temporal distribution of actual surface water occurrence exhibits high inter- and intra-annual variability. Water bodies and humid areas have been mapped and characterized by the analysis of 10 daily small water bodies (SWB) maps based on SPOT VEGETATION (VGT) data spanning the period January 1999–September 2007. Further analysis of the SWB time series provided additional information about the seasonal recurrence of water bodies as well as their hydrological function. A map derived from a continuous time series assures the inclusion of temporary features, a clear advantage compared to other datasets, which are based on several single date observations. The method described in this paper targets at a rapid creation of TSWB maps based on the SWB time series for different time intervals and regions.An accuracy assessment has been carried out with a stratified random sampling approach and a one-stage cluster analysis that relies on high-resolution satellite data to verify the detected water bodies. The overall accuracy, considering only the commission error, is 95.4% for the whole study region, with best results in the arid and semi-arid climate zone. The method to map water bodies delivers satisfactory results, particularly for sparsely vegetated areas as well as flat areas of the study region. In more humid, more vegetated areas and in mountainous areas, the possibility of false detections increases due to surface characteristics. 相似文献
18.
An integrated fuzzy-stochastic modeling approach for assessing health-impact risk from air pollution 总被引：4，自引：4，他引：0
Heng L. Li Guo H. Huang Yun Zou 《Stochastic Environmental Research and Risk Assessment (SERRA)》2008,22(6):789-803
High concentrations of air pollutants in the ambient environment can result in breathing problems with human communities.
Effective assessment of health-impact risk from air pollution is important for supporting decisions of the related detection,
prevention, and correction efforts. However, the quality of information available for environmental/health risk assessment
is often not satisfactory enough to be presented as deterministic numbers. Stochastic method is one of the methods for tackling
those uncertainties, by which uncertain information can be presented as probability distributions. However, if the uncertainties
can not be presented as probabilities, they can then be handled through fuzzy membership functions. In this study, an integrated
fuzzy-stochastic modeling (IFSM) approach is developed for assessing air pollution impacts towards asthma susceptibility.
This development is based on Monte Carlo simulation for the fate of SO2 in the ambient environment, examination of SO2 concentrations based on the simulation results, quantification of evaluation criteria using fuzzy membership functions, and
risk assessment based on the combined fuzzy-stochastic information. The IFSM entails (a) simulation for the fate of pollutants
in ambient environment, with the consideration of source/medium uncertainties, (b) formulation of fuzzy air quality management
criteria under uncertain human-exposure pathways, exposure dynamics, and SPG-response variations, and (c) integrated risk
assessment under complexities of the combined fuzzy/stochastic inputs of contamination level and health effect (i.e., asthma
susceptibility). The developed IFSM is applied to a study of regional air quality management. Reasonable results have been
generated, which are useful for evaluating health risks from air pollution. They also provide support for regional environmental
management and urban planning. 相似文献
19.
《Limnologica》2014
A new multimetric MMI_PL index, which is based on the macroinvertebrate composition and combines six single key metrics, has already been implemented in Poland according to the requirements of the EU Water Framework Directive. The objectives of our survey were to assess the biological water quality using the new multimetric MMI_PL index in both reference and human-impacted streams, to analyze whether the values of the new multimetric index properly reflect the ecological status of the water in upland and mountain streams as well as to determine which environmental factors influence the distribution of benthic macroinvertebrates and the values of the metrics. The study was carried out from 2007 to 2010 in three Ecoregions that were established by the EU WFD. A total of 60 sampling sites: 36 reference sites that were situated in the headwaters of mountain streams at mid- and high-altitudes and 24, human-impacted sampling sites were selected. The benthic macroinvertebrate surveys were supported by both a hydromorphological and macrophyte assessment according to the River Habitat Survey (RHS) and to the Macrophyte Methods for Rivers. Canonical correspondence analysis (CCA) showed that the values of the Habitat Quality Assessment (HQA) index, conductivity, pH and altitude were the parameters most associated (statistically significant) with the distribution of benthic macroinvertebrate taxa and the values of the metrics in both the reference and human-impacted (impaired) sections of the streams in Ecoregions 9, 10 and 14. The new MMI_PL index was useful for biological water quality assessment and was also important for separating both the reference and impaired sections of streams. The MMI_PL index and some key metrics performed contrary to what was expected in relation to the reference high-altitude siliceous streams (the High Tatra Mts., Ecoregion 10). Low values of multimetric index and key metrics did not properly reflect their high ecological status and pristine character as reflected by the hydromorphological (RHS) and macrophyte surveys or the physical and chemical parameters of the water. 相似文献
20.
The European Water Framework Directive (WFD) establishes a framework for the protection and improvement of estuarine and coastal waters, trying to achieve 'good surface water status at the latest 15 years after the date of entry into force of this Directive'. One of the biological elements that should be analysed is the benthos and, as such, the WFD normative definitions describe the aspects of the benthic communities that must be included in the ecological status assessment of a water body. Therefore, it is essential to include, in the assessment, the different metrics that address those parameters identified in the normative definitions for each of the ecological status classes. In this contribution the use of the AMBI, richness and diversity, combined with the use, in a further development, of factor analysis together with discriminant analysis, is presented as an objective tool (named here M-AMBI) in assessing ecological quality status. This assessment requires previous classification of water bodies and typologies, together with the definition of reference conditions; this is undertaken in this contribution using historical data, expert judgement and multivariate analysis. The study has been undertaken by examining changes in benthic communities in the Basque Country, over the last decade, as a case-study, to demonstrate the accuracy and potential of these methodologies. 相似文献