城市空气质量模糊评价新方法

在权广义距离概念的基础上提出一种新的城市空气质量模糊评价方法,评价过程能充分利用实际数据所包含的各种信息.与模糊综合评判模型的同一应用实例结果进行比较,表明文章提出的评价方法更为有效.     

A probabilistic water quality index for river water quality assessment: a case study

Available water quality indices have some limitations such as incorporating a limited number of water quality variables and providing deterministic outputs. This paper presents a hybrid probabilistic water quality index by utilizing fuzzy inference systems (FIS), Bayesian networks (BNs), and probabilistic neural networks (PNNs). The outputs of two traditional water quality indices, namely the indices proposed by the National Sanitation Foundation and the Canadian Council of Ministers of the Environment, are selected as inputs of the FIS. The FIS is trained based on the opinions of several water quality experts. Then the trained FIS is used in a Monte Carlo analysis to provide the required input-output data for training both the BN and PNN. The trained BN and PNN can be used for probabilistic water quality assessment using water quality monitoring data. The efficiency and applicability of the proposed methodology is evaluated using water quality data obtained from water quality monitoring system of the Jajrood River in Iran.     

A new four-step hierarchy method for combined assessment of groundwater quality and pollution

A new four-step hierarchy method was constructed and applied to evaluate the groundwater quality and pollution of the Dagujia River Basin. The assessment index system is divided into four types: field test indices, common inorganic chemical indices, inorganic toxicology indices, and trace organic indices. Background values of common inorganic chemical indices and inorganic toxicology indices were estimated with the cumulative-probability curve method, and the results showed that the background values of Mg²⁺ (51.1 mg L^?1), total hardness (TH) (509.4 mg L^?1), and NO₃ ^? (182.4 mg L^?1) are all higher than the corresponding grade III values of Quality Standard for Groundwater, indicating that they were poor indicators and therefore were not included in the groundwater quality assessment. The quality assessment results displayed that the field test indices were mainly classified as grade II, accounting for 60.87% of wells sampled. The indices of common inorganic chemical and inorganic toxicology were both mostly in the range of grade III, whereas the trace organic indices were predominantly classified as grade I. The variabilities and excess ratios of the indices were also calculated and evaluated. Spatial distributions showed that the groundwater with poor quality indices was mainly located in the northeast of the basin, which was well-connected with seawater intrusion. Additionally, the pollution assessment revealed that groundwater in well 44 was classified as “moderately polluted,” wells 5 and 8 were “lightly polluted,” and other wells were classified as “unpolluted.”     

水环境质量综合评价的新模型

为检验已订的水环境质量评价标准的合理性,解决各单项水质指标的评估结果的不相容性问题,提高水质等级模型的分辨率,提出了一种新的水质评价模型-逻辑斯谛曲线(LOG)模型,它的水质等级是连续的实数值;根据LOG模型的参数值可以分析各水质指标值对水质等级的影响程度,从而检验原订水质等级标准的合理性;并给出了基于实码遗传算法的LOG建模的实施方案.实例研究说明,这套方案是实用的和通用的,在其它环境质量综合评价中也具有广泛的应用价值.     

城市空气质量综合评价的可拓方法

可拓方法是从定性和定量两个角度去处理现实世界中矛盾问题的一种新方法 ,它能较完整地反映事物的综合质量水平。本文介绍了可拓评价方法的基本原理 ,并探讨了该方法在城市空气质量综合评价中的应用 ,结果表明是合理可行的     

A method for monitoring ground water quality near waste storage facilities

A practical optimization approach developed in this paper derives effective monitoring configurations for detecting contaminants in ground water. The approach integrates numerical simulation of contaminant transport and mathematical programming. Well sites identified by the methodology can be monitored to establish the occurrence of a contaminant release before a plume migrates to a regulatory compliance boundary. Monitoring sites are established along several horizons located between the downgradient margin of a contaminant source and a compliance boundary. A horizon can form an effective line of defense against contaminant migration to the compliance boundary if it is spanned (covered) by a sufficient number of sites to yield a well spacing that is equal to or less than a maximum value established by numerical modeling. The objective function of the integer programming model formulation expresses the goals of: (1) covering a maximum number of siting horizons, and (2) allocating wells to the single most effective horizon. The latter is determined from well spacing requirements and the width of the zone of potential contaminant migration traversed by the horizon. The methodology employs a highly tractable linear programming model formulation, and the user is not required to predefine a set of potential well sites. These attributes can facilitate its implementation in practice.     

Quantitative assessment of eutrophication: A scoring system for characterising water quality in coastal marine ecosystems

A scoring system based on nutrient concentrations was developed to assess coastal water quality according to the trophic level. Three nutrient data sets from eutrophic, mesotrophic and oligotrophic waters were used as the reference information for setting up a semi quantitative water quality scale (from 0 to 5) to express different nutrient loadings. The validity and sensitivity of the method was applied to a number of stations spaced out along the coastal area of Rhodes (Greece). A score for each nutrient/sampling site was calculated and the scorecard formed, was the data matrix used for numerical classification of the stations. The results showed (a) good discrimination between cutrophic, mesotrophic and oligotrophic waters (b) nitrate among the nutrients showed the maximum sensitivity in characterising pollution levels. The reference data sets used for assessing eutrophication levels ensured the objectivity of the method. The proposed method is described step-by-step and it is suggested that the method can be further adapted to describe other forms of pollution becoming a useful quantitative technique in coastal management practices.     

改进的模糊综合评价法在太湖水质类别判定中的应用

水质判别是一个多参数多级别的模糊概念,基础的模糊综合评价法存在局限性,对基础模糊数学法中隶属度函数及最大隶属度原则进行改进,建立一种改进的模糊综合评价法。以太湖流域水质判别为实例验证了此方法比传统的方法更有效,且适合在太湖流域应用。     

Application of water quality index for groundwater quality assessment: Thirumanimuttar sub-basin, Tamilnadu, India

An attempt has been made to understand the hydrogeochemical parameters to develop water quality index in Thirumanimuttar sub-basin. A total of 148 groundwater samples were collected and analyzed for major cations and anions. The domination of cations and anions was in the order of Na>Mg>Ca>K for cations and Cl>HCO₃ >SO₄ in anions. The hydrogeochemical facies indicate alkalis (Na and K) exceed alkaline earths (Ca and Mg) and strong acids (Cl and SO₄) exceed weak acid (HCO₃). Water quality index rating was calculated to quantify overall water quality for human consumption. The PRM samples exhibit poor quality in greater percentage when compared with POM due to effective leaching of ions, over exploitation of groundwater, direct discharge of effluents and agricultural impact. The overlay of WQI with chloride and EC correspond to the same locations indicating the poor quality of groundwater in the study area. SAR, Na%, and TH were noted higher during both the seasons indicating most of the groundwater locations not suitable for irrigation purposes.     

A feasible method to assess inaccuracy caused by patchiness in water quality monitoring

Patchiness is a typical property of water quality in lakes. However, in conventional water quality monitoring, patchiness is usually too expensive to take into account, due to the high number of required samples. This study examines a feasible methodology developed for estimating the representativeness of discrete chlorophyll a measurements. Four spatially extensive data sets were collected from the Enonselkä basin of Lake Vesijärvi in Southern Finland, using a flow trough system with a fluorometer in a moving boat. Data sets were used to estimate (1) the spatial representativeness of discrete sampling; (2) the effect of varying sample size on the detected mean chlorophyll a concentration and on the observed proportion of variance. Spatial representativeness was assessed using semivariogram analysis. Results indicate that the spatial representativeness of discrete sampling can remain undesirably low. Furthermore, in monitoring programs involving just one or only a few samples, there is a significant risk of obtaining a false estimate for the mean value and variance of chlorophyll a concentration over the whole monitoring area.     

A new method for environmental site assessment of urban solid waste landfills

Regarding various types of pollutant, waste management requires high attention. Environmental site selection study, prior to landfill operation, and subsequently, monitoring and maintaining of the location, are of foremost points in landfill site selection process. By means of these studies, it is possible to control the undesirable impacts caused by landfills. Study ahead aims at examination of effectiveness of a new method called Monavari 95–2 in landfill site assessment. For this purpose, two landfills Rasht and Andisheh, which are, respectively, located on humid and arid areas, were selected as case studies. Then, the results obtained from both sites were compared with each other to find out the weaknesses and strengths of each site. Compared with others similar methods, much more criteria (53 parameters) can be considered within this method, so the results will be more calculable. According to this method, Rasht landfill (site H) is classified as unacceptable landfill site i.e. there is an urgent need for a new suitable site for landfill, while Andishe Landfill (site D) is ranked as acceptable landfill site but needs environmental management program to handle the existing weaknesses.     

Sensitivity analysis of TOPSIS method in water quality assessment II: sensitivity to the index input data

This is the second part of the study on sensitivity analysis of the technique for order preference by similarity to ideal solution (TOPSIS) method in water quality assessment. In the present study, the sensitivity of the TOPSIS method to the index input data was investigated. The sensitivity was first theoretically analyzed under two major assumptions. One assumption was that one index or more of the samples were perturbed with the same ratio while other indices kept unchanged. The other one was that all indices of a given sample were changed simultaneously with the same ratio, while the indices of other samples were unchanged. Furthermore, a case study under assumption 2 was also carried out in this paper. When the same indices of different water samples are changed simultaneously with the same variation ratio, the final water quality assessment results will not be influenced at all. When the input data of all indices of a given sample are perturbed with the same variation ratio, the assessment values of all samples will be influenced theoretically. However, the case study shows that only the perturbed sample is sensitive to the variation, and a simple linear equation representing the relation between the closeness coefficient (CC) values of the perturbed sample and variation ratios can be derived under the assumption 2. This linear equation can be used for determining the sample orders under various variation ratios.     

Sensitivity analysis of TOPSIS method in water quality assessment: I. Sensitivity to the parameter weights

Sensitivity analysis is becoming increasingly widespread in many fields of engineering and sciences and has become a necessary step to verify the feasibility and reliability of a model or a method. The sensitivity of the Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) method in water quality assessment mainly includes sensitivity to the parameter weights and sensitivity to the index input data. In the present study, the sensitivity of TOPSIS to the parameter weights was discussed in detail. The present study assumed the original parameter weights to be equal to each other, and then each weight was changed separately to see how the assessment results would be affected. Fourteen schemes were designed to investigate the sensitivity to the variation of each weight. The variation ranges that keep the assessment results unchangeable were also derived theoretically. The results show that the final assessment results will change when the weights increase or decrease by ±20 to ±50 %. The feedback of different samples to the variation of a given weight is different, and the feedback of a given sample to the variation of different weights is also different. The final assessment results can keep relatively stable when a given weight is disturbed as long as the initial variation ratios meet one of the eight derived requirements.     

A new assessment method for urbanization environmental impact: urban environment entropy model and its application

The thermodynamic law is one of the most widely used scientific principles. The comparability between the environmental impact of urbanization and the thermodynamic entropy was systematically analyzed. Consequently, the concept "Urban Environment Entropy" was brought forward and the "Urban Environment Entropy" model was established for urbanization environmental impact assessment in this study. The model was then utilized in a case study for the assessment of river water quality in the Pearl River Delta Economic Zone. The results indicated that the assessing results of the model are consistent to that of the equalized synthetic pollution index method. Therefore, it can be concluded that the Urban Environment Entropy model has high reliability and can be applied widely in urbanization environmental assessment research using many different environmental parameters.     

WPI指数在地表水环境质量评价中的运用

在地表水环境质量评价中提出了 WPI指数 ,并对其使用方法作了详细说明 ,提供了计算 API指数和判定水质类别的 wpix( data,bh,lx)函数     

Risk assessment for salmon from water quality changes following timber harvesting

Land use activities may affect surface water quantity and quality. Water quality changes (concentration increases) from land use activities that are above background but below the water quality standard or criteria have always been considered benign. Increased public interest and recent legislation and management regarding threatened, or endangered, salmon populations suggest that environmental influences on these populations need to be reevaluated.As one approach, we developed a risk assessment (toxicity and exposure) for salmon from water quality changes following timber harvesting. Toxicity relationships for nitrate-nitrogen (as an LC₅₀) using chloride, suspended sediment, and exposure were developed from the literature and data from the Alsea Watershed Study in the Oregon Coast Range. These relationships were used to predict the probable risk to coho salmon (Oncorhynchus kisutch) to nitrate-nitrogen exposure.The control or reference catchment, Flynn Creek, had higher nitrate-nitrogen concentrations, but showed little likelihood of risk to salmon because of lower suspended sediment concentrations. The treated catchment, Needle Branch (harvested 27 years ago), had lower nitrate-nitrogen concentrations and was expected to have less risk to salmon. However, the risk assessment relationship exhibited sensitivity to suspended sediment concentrations. This smaller catchment had higher suspended sediment transport and thus a higher risk of nitrate-nitrogen exposure to salmon. The suspended sediment transport functions were based on post-treatment monitoring (1966–1973) and are not considered to represent the current situation. These findings are not meant to be categorical, but merely illustrative of this risk assessment application.     

A new nanosilver-based spectrophotometric method for monitoring Eriochrome black T in river water

In this paper, a new spectrophotometric method is reported for the determination of nanomolar levels of Eriochrome black T in environmental samples. The method is based on the catalytic effect of silver nanoparticles on the oxidation of Eriochrome black T by hexacyanoferrate (III) in acetate–acetic acid medium and at 25 °C. The absorbance is measured at 512 nm with the fixed-time method. It relies on the linear relationship between the absorbance difference (?A) and Eriochrome black T amounts in the range of 40–1,250 nM. Under optimum conditions, the sensitivity of the proposed method, i.e., the detection limit corresponding to 80 s, is about 25 nM. The method is featured with good accuracy and reproducibility for Eriochrome black T determination in river water samples without any pre-concentration and separation step.     

System dynamic simulation: A new method in social impact assessment (SIA)

Many complex social questions are difficult to address adequately with conventional methods and techniques, due to the complicated dynamics, and hard to quantify social processes. Despite these difficulties researchers and practitioners have attempted to use conventional methods not only in evaluative modes but also in predictive modes to inform decision making. The effectiveness of SIAs would be increased if they were used to support the project design processes. This requires deliberate use of lessons from retrospective assessments to inform predictive assessments. Social simulations may be a useful tool for developing a predictive SIA method. There have been limited attempts to develop computer simulations that allow social impacts to be explored and understood before implementing development projects. In light of this argument, this paper aims to introduce system dynamic (SD) simulation as a new predictive SIA method in large development projects. We propose the potential value of the SD approach to simulate social impacts of development projects. We use data from the SIA of Gareh-Bygone floodwater spreading project to illustrate the potential of SD simulation in SIA. It was concluded that in comparison to traditional SIA methods SD simulation can integrate quantitative and qualitative inputs from different sources and methods and provides a more effective and dynamic assessment of social impacts for development projects. We recommend future research to investigate the full potential of SD in SIA in comparing different situations and scenarios.     

Indexing method for assessment of pollution potential of leachate from non-engineered landfill sites and its effect on ground water quality

Dumping of solid waste in a non-engineered landfill site often leads to contamination of ground water due to leachate percolation into ground water. The present paper assesses the pollution potential of leachate generated from three non-engineered landfill sites located in the Tricity region (one each in cities of Chandigarh, Mohali and Panchkula) of Northern India and its possible effects of contamination of groundwater. Analysis of physico-chemical properties of leachate from all the three landfill sites and the surrounding groundwater samples from five different downwind distances from each of the landfill sites were collected and tested to determine the leachate pollution index (LPI) and the water quality index (WQI). The Leachate Pollution Index values of 26.1, 27 and 27.8 respectively for landfill sites of Chandigarh (CHD), Mohali (MOH) and Panchkula (PKL) cities showed that the leachate generated are contaminated. The average pH values of the leachate samples over the sampling period (9.2 for CHD, 8.97 for MOH and 8.9 for PKL) show an alkaline nature indicating that all the three landfill sites could be classified as mature to old stage. The WQI calculated over the different downwind distances from the contamination sites showed that the quality of the groundwater improved with an increase in the downwind distance. Principal component analysis (PCA) carried out established major components mainly from natural and anthropogenic sources with cumulative variance of 88% for Chandigarh, 87.1% for Mohali and 87.8% for Panchkula. Hierarchical cluster analysis (HCA) identifies three distinct cluster types for the groundwater samples. These clusters corresponds to a relatively low pollution, moderate pollution and high pollution regions. It is suggested that all the three non-engineered landfill sites be converted to engineered landfill sites to prevent groundwater contamination and also new sites be considered for construction of these engineered landfill sites as the present dumpsites are nearing the end of their lifespan capacity.