Multi-biochemical responses of benthic macroinvertebrate species as a complementary tool to diagnose the cause of community impairment in polluted rivers

Biological indexes, based on benthic macroinvertebrate taxa, are currently used worldwide to measure river ecological quality. These indexes assign a global ecological status of the biotic community, but not necessarily may detect specific effects of water pollutants. Conversely a large set of biochemical markers measured in macroinvertebrate benthic species can detect sublethal effects and inform us about additional environmental factors that are impairing benthic communities. This is especially interesting in moderately polluted sites, where other stressors are already affecting communities but not too strongly to be detected by biotic indexes. Up to ten different markers belonging to distinct metabolic paths and 42 contaminants measured in sample collections of the caddis fly Hydropsyche exocellata were assessed across a polluted gradient in the industrialized Mediterranean River basins of Besós and Llobregat (NE, Spain). Twenty four sample collections were selected to include macroinvertebrate communities representing the five impairment degrees defined by the Spanish Environmental authorities using the biotic metrics. Results evidenced a clear deterioration of the ecological water quality parameters and benthic communities towards downstream reaches. Biochemical responses varied significantly across the studied samples and were able to differentiate samples within communities having a good and deteriorated ecological stage. Principal Component Analyses indicated that salinity was one of the major stresses affecting macroinvertebrate assemblages, whereas antioxidant and metabolizing enzymes responded differently and were closely related to high and presumably toxic levels of accumulated organic pollutants. Therefore these results indicate that the use of multiple -markers sensitive to water pollution may provide complementary information to diagnose environmental factors that are impairing macroinvertebrate communities.     

岩石按劈烈性分级

本文对岩石按劈裂性分级进行了较系统的试验研究,从15个指标中通过分类筛选,挑选出4个指标进行优化组合和可靠性分析,最后选出两组较优组合,再用动态分级法优选其分级档数和分级界限,从而建立起岩石按劈裂性分级标准。     

Diversity and community comparison indices: Assessing macroinvertebrate recovery following a gasoline spill

Diversity and community comparison indices were evaluated to determine their utility in quantifying macroinvertebrate response to a catastrophic gasoline spill into Wolf Lodge Creek, Idaho, U.S.A. The Shannon and Brillouin diversity indices, and the following community comparison indices were analyzed: (1) Jaccard's coefficient of similarity; (2) Renkonen's percentage similarity; (3) Bray-Curtis index; (4) Morisita's similarity index; (5) simplified Morisita index; (6) Canberra metric index; and (7) average χ² index. The Bray-Curtis and average χ² community comparison indices were more effective in quantifying differences in macroinvertebrate composition between gas-impacted and reference areas of Wolf Lodge Creek following the spill. In addition, these indices tracked the progressive spatial recolonization of macroinvertebrates during the 16 month recovery period. All other indices tested failed to adequately quantify macroinvertebrate community response to the gasoline spill.     

路基膨胀土胀缩等级的模糊评判

膨胀土胀缩等级评判是膨胀土地区工程建设的重要工作。本文在分析了现有膨胀土胀缩等级评判方法与标准的基础上,提出了模糊评判模型,涉及到的评判指标包括三项间接反映土的胀缩性能指标,液限、塑性指数Ip 、缩限ws;四项直接相关指标,自由膨胀率Fs,膨胀率Pc,50 kPa 压力下的膨胀率ep50 、胀缩总率eps。特殊情况下允许减少若干评判指标,但间接指标不得少于二项,直接指标不得少于二项,在缺乏间接指标时,直接指标不得少于三项。根据理论分析和大量实测资料建立了每个指标的权重。评判模型已编写了实用的计算机软件,经计算分析和工程检验,证实了本文方法的可靠性     

三峡永久船闸高陡边坡整体稳定性的多因素综合评价

三峡永久船闸高陡边坡工程是1个开放的复杂巨系统,对其整体稳定性的评价需要综合考虑地质资料、数值分析计算成果以及监测数据等多源信息,基于多因素优化融合的思想,采用定性与定量综合集成的方法。基于系统工程的观点,借助可拓学理论,依据菱形思维模式和物元的可拓性,建立了三峡永久船闸高陡边坡工程整体稳定性的多指标分层次综合评价体系。采用物元的概念将研究对象、评价指标和量值结合为一体,应用物元变换建立整体稳定性评价的物元模型,从而实现对三峡永久船闸高陡边坡整体稳定性的质与量的综合描述,并结合其随时间的变化趋势,可以完成对高陡边坡整体稳定性的三维动态评估。另外应用优化理论,进行了评价指标的主、客观组合赋权。经计算得出边坡整体稳定性属1级,特征值为1.86,介于优与良之间。同时,所述方法亦可应用于大坝健康性态整体评价、岩体质量评估、大坝老化评估等其他领域。     

The validity of the Gammarus:Asellus ratio as an index of organic pollution: abiotic and biotic influences.

In freshwaters. Gammarus spp. are more sensitive to organic pollution than Asellus spp. and the relative abundance of the two taxa has been proposed as a pollution index. We tested the validity of this by examining the relationship between the Gammarus: Asellus (G : A) ratio and (1) a suite of physico-chemical variables. (2) established biotic (average score per taxon, ASPT) and richness (species richness (S) and Ephemeroptera, Plecoptera and Trichoptera families richness (EPT family richness)) indices generated from the macroinvertebrate community. In addition, we investigated a suspected biotic interaction, predation, between Gammarus and Asellus. Both univariate and multivariate analyses showed that the G: A ratio was sometimes responsive to changes in parameters linked to organic pollution, such as BOD5 and nitrate levels. However, the G : A ratio also appeared responsive to variables not directly linked to organic pollution, such as conductivity and distance from source. There were significant positive correlations among the G : A ratio and the ASPT, S and EPT, indicating that changes in the relative abundances of Gammarus and Asellus were reflected in changes in the pollution sensitivity and richness of the wider macroinvertebrate community. A laboratory experiment revealed significant predation of Asellus aquaticus juveniles by Gammarus duebeni celticus adults, but no reciprocal predation. We propose that the G: A ratio may be useful as a crude measure of organic pollution that could supplement more complex indices in a multimetric approach to pollution monitoring or be used for monitoring individual sites, where a simple technique is required for monitoring purposes over a period of time. Also, we urge recognition of the possible role of biotic interactions among taxa used in the generation of pollution indices.     

Back-pumping of agricultural runoff into a large shallow lake and concurrent changes in the macroinvertebrate assemblage

Macroinvertebrates were monitored during the summer of 2001 at two paired reference and impact sites, to assess potential effects of agricultural runoff, which was back-pumped upstream into Lake Okeechobee, USA. Monitoring was conducted prior to back-pumping (Pre, April-May), during back-pumping (BP, June-September) and during the following year (Post, April-September, 2002, impact sites only). Prior to back-pumping, the macroinvertebrate communities at both impact sites differed from those at their respective reference sites. During back-pumping, differences in the macroinvertebrate communities were slightly less pronounced among the eastern pair of sites but were more pronounced at the western sites than they were prior to back-pumping. There also were marginal differences in the macroinvertebrate communities at both impact sites between the Pre and BP periods, while very little change was observed in the communities among the same periods at both reference sites. For the Post-Pre and Post-BP period comparisons, there were clear differences between the macroinvertebrate communities at the western impact site, while less pronounced differences were observed at the eastern impact site. This suggests that the Post back-pumping assemblage did not return to that observed prior to back-pumping activity. During BP, several water-quality variables appeared to be different among each of the paired sites and the correlation between water-quality variables and macroinvertebrate community structure was strong at the western sites but weaker at the eastern sites. This suggests that a combination of abiotic variables may have been influencing the community structure at the western sites while back-pumping was occurring. Macroinvertebrates at all sites reflected poor water quality, but more taxonomic changes during back-pumping were observed at the impact sites than at the reference sites. It is not known if these taxonomic changes resulted in impacts among the macroinvertebrate community or to higher-trophic-level predators such as fish. If lake restoration activities result in a shift to a less pollution-tolerant macroinvertebrate community, and the anticipated reduction in future back-pumping activity does not occur, the macroinvertebrate community may return to one that is dominated by pollution-tolerant taxa in affected portions of the lake.     

基于综合赋权和未确知测度的火灾风险评价

为准确评估商场火灾风险,建立了基于综合赋权法的未确知测度评价模型,该模型利用未确知测度建立单指标测度评价矩阵,基于IIAHP、熵、离差平方和最大化计算评价指标的综合权重,从而得到评价对象的综合测度评价向量,最终判定风险等级和排序.利用建立的模型对商场火灾风险进行评价,选取了16个影响商场火灾风险的评价指标,建立了评价指...     

基于模糊综合评价的武汉市居民住宅满意度研究

以满意度理论为基础,构建了包括5个一级指标和14个二级指标的居民住宅满意度评价指标体系,选择合适的隶属函数,运用模糊综合评价对武汉市居民的住宅满意度进行测评,共选取了6个住宅小区作为调查样区,通过调查得到的数据分别对武汉市不同发展阶段住宅的居民进行住宅满意度比较分析,发现武汉住宅发展过程中的问题,以期促进城市住宅健康发展。     

Reliability of the bending resistance of welded beam-to-column joints

This paper deals with the reliability of welded beam-to-column joints designed according to EN 1993-1-8. Based on the set of tests of welded beam-to-column joints, the experimental bending resistance has been obtained. The model’s uncertainty has been evaluated based on the comparison of the theoretical and experimental values of the bending resistance. Limit state equations have been defined for each mode of failure. The reliability index for each component of a joint is evaluated by using FORM, SORM and adaptive sampling. The obtained values of the reliability index of the individual components are discussed, as well as the sensitivity factors of basic variables and sensitivities of the reliability index to the mean value and to standard deviation of basic variables. The probabilistic analysis demonstrated that the component method adopted in EN 1993-1-8 has a high reliability level.     

Modelling aquatic exposure and effects of insecticides--application to south-eastern Australia

Agricultural pesticides are widely used and can affect freshwater organisms. We applied a spatially explicit exposure model, validated for central Europe, to estimate exposure to insecticides through runoff for streams in south-eastern Australia. The model allows the identification of streams potentially affected by insecticide runoff located in 10 × 10 km grid cells. The computation of runoff relies on key environmental factors such as land use, soil texture, slope and precipitation. Additionally, the model predicted the ecological effect of insecticides on the macroinvertebrate community. We predicted insecticide surface runoff that results in a moderate to poor ecological quality for streams in half of the grid cells containing agricultural land. These results are in good accordance with the results obtained by estimating pesticide stress with a biotic index (SPEAR_pesticides) based on macroinvertebrate monitoring data. We conclude that the exposure and effect model can act as an effective and cost-saving tool to identify high risk areas of insecticide exposure and to support stream management.     

Water toxicity assessment and spatial pollution patterns identification in a Mediterranean River Basin District. Tools for water management and risk analysis

In compliance with the requirements of the EU Water Framework Directive, monitoring of the ecological and chemical status of Catalan river basins (NE Spain) is carried out by the Catalan Water Agency.The large amount of data collected and the complex relationships among the environmental variables monitored often mislead data interpretation in terms of toxic impact, especially considering that even pollutants at very low concentrations might contribute to the total toxicity.The total dataset of chemical monitoring carried out between 2007 and 2008 (232 sampling stations and 60 pollutants) has been analyzed using sequential advanced modeling techniques. Data on concentrations of contaminants in water were pre-treated in order to calculate the bioavailable fraction, depending on substance properties and local environmental conditions.The resulting values were used to predict the potential impact of toxic substances in complex mixtures on aquatic biota and to identify hot spots. Exposure assessment with Species Sensitivity Distribution (SSD) and mixture toxicity rules were used to compute the multi-substances Potentially Affected Fraction (msPAF).The combined toxicity of the pollutants analyzed in the Catalan surface waters might potentially impact more than 50% of the species in 10% of the sites.In order to understand and visualize the spatial distribution of the toxic risk, Self Organising Map (SOM), based on the Kohonen's Artificial Neural Network (ANN) algorithm, was applied on the output data of these models. Principal Component Analysis (PCA) was performed on top of Neural Network results in order to identify main influential variables which account for the pollution trends. Finally, predicted toxic impacts on biota have been linked and correlated to field data on biological quality indexes using macroinvertebrate and diatom communities (IBMWP and IPS). The methodology presented could represent a suitable tool for water managers in environmental risk assessment and management.     

A comparison of the macrophyte cover and macroinvertebrate fauna at three sites on the River Kennet in the mid 1970s and late 1990s

In 1974–1976, baseline studies were carried out on the flora and macroinvertebrate fauna of the R. Kennet at two sites downstream of Marlborough (Savernake Upper and Lower) and at one site upstream of Hungerford (Littlecote). Simplified maps of each site, showing the cover of macrophytes, were obtained monthly between April 1974 and April/June 1976, and replicated quantitative samples of the macroinvertebrates were collected on the dominant macrophyte and on gravel in June 1974, and also in June and December 1975. As a consequence of two major droughts and increasing concern over water quality in the Upper Kennet in the 1990s, the studies recommenced in the summer of 1997 using the same sites and methodologies. Maps and macroinvertebrate samples were obtained in early July and December 1997 and in June of both 1998 and 1999. At the Savernake sites, mapping in summer 1997 confirmed what had been apparent for some years. That is, macrophyte cover (both Ranunculus and Schoenoplectus) was much lower than in the 1970s. In contrast, the site downstream at Littlecote retained a relatively high cover of Ranunculus, despite the drought. In late autumn 1997, phosphate stripping commenced at Marlborough Sewage Treatment Works, the drought ended and in addition, the spring of 1998 was unusually wet. Ranunculus recolonised both Savernake sites with remarkable speed by summer 1998 and retained this dominant position in 1999. Quantitative samples of macroinvertebrates collected on gravel and the dominant macrophyte at each of the three study sites indicated that there was no evidence of major loss of family richness between the 1970s and 1990s as a result of the low flows or enrichment. However, at Savernake (but not Littlecote) in summer 1997, the macroinvertebrate assemblage was affected by low flows and/or enrichment. This took the form of changes in the abundance of some families, with lentic forms being favoured in relation to some lotic families. Following the end of the drought, many macroinvertebrate families at Savernake showed a rapid response to the new conditions and the assemblages reverted to those expected in a fast-flowing cretaceous chalk stream. Continued monitoring through the next drought is advisable to provide a greater understanding of the interplay between water quality, the discharge regime, habitat quality (including macrophyte growth) and the response of the macroinvertebrate fauna.     

Towards a monitoring method and a number of multifaceted and hierarchical biodiversity indicators for urban and suburban parks

In this paper we develop a method for the general monitoring of the biodiversity in (sub)urban parks. The method works along two lines, that of habitat diversity and that of species diversity. On the habitat level we measure the diversity in so called ‘habitat units’. These units are divided in planar, linear and punctual elements. For each category we calculate a Shannon–Wiener diversity index and a saturation index. The latter is the ratio of the diversity index compared to the maximum diversity possible. On the species level we use the species number and diversity index of vascular plants, as measured in random sampling plots of 100 m² (for trees and shrubs) and 4 m² (for herbaceous vegetation). In addition, we also use the species number of butterflies, amphibians and breeding birds. These numbers are compared with the total species number in Flanders, resulting in a saturation index per park for butterflies, amphibians and breeding birds. In this way 20 biodiversity indicators are obtained. The proposed method was applied to the municipal park of Loppem (West-Flanders, Belgium), from which the necessary time budget has been calculated. Since it is the first application of a new method and no reference to other parks is available, the proposed bioindicators have been compared with criteria given in the literature on the selection of biodiversity indicators.     

基于模态参数的结构损伤识别指标综述

从指标定义和指标应用的角度,对目前已有的指标进行了综合分析与评价,指出了利用模态参数构造指标来进行损伤识别的优势以及需要进一步解决的问题,以期促进结构损伤检测技术的完善和提高。     

Dynamics of benthic macroinvertebrates in created wetlands receiving wastewater

This paper presents results of a study on the status and dynamics of benthic macroinvertebrates in a wetland constructed for wastewater treatment in Nairobi (Kenya), conducted for 16 weeks during the period between December 1995 and March 1996. Seventeen species of macroinvertebrates were recorded in the wetland. Species richness in the wetland was 9.6 ± 1.3 while species diversity index was 0.466. Mean pH and dissolved oxygen increased gradually from the intake point to the outlet while the BOD₅, suspended solids and free and saline ammonia decreased as the wastewater flowed throughout the wetland. The benthic macroinvertebrate community was poorly developed while microbial community appeared to be well developed. It was evident that the community structure improved with the purification of wastewater along the wetland. As discussed in the paper, aquatic benthos are crucial to wetlands ecosystems function and they are potential indicators of health of these ecosystems.     

不规则岩块点荷载试验的研究

<正> 在现场进行不规则岩块的点荷载试验,是获得强度指标最简单、最有前途的方法,也可以获得岩石的抗拉、抗压强度。 本文通过五种典型形状的岩块(近球体、椭球体、长方体、多棱体和四面体)的有限元计算和分析,探讨了不规则岩块在点荷载作用下的应力分布规律,得到除四面体(极少)以外,其余四种形状的应力分布规律均极为相似。     

百花山自然草甸群落结构与组成分析

为构建自然的混播组合,以百花山草甸的草本植物群落为调查对象,对其进行一个生长季的调查,记录分析草甸的植物组成、垂直结构、季相变化特征。结果表明：共记录野生花卉27科、51属、62种,其中90.32%为多年生植物;将草甸按株高分为3个亚层,各亚层植物平均种数、株数、覆盖度的比例分别约为第一亚层:第二亚层:第三亚层=1:5:4、3:13:4、1:7:2;随时间变化第三亚层Shannon-Wiener指数、Pielou指数、Gleason指数均呈现先降低后升高的趋势,第二亚层3项指数均呈现先升高后降低的趋势,第一亚层3项指标均最低。自然草甸中的植物组成、垂直结构、季相变化特征等是影响草甸的重要因素,基于此可为模拟构建更加自然的混播组合提供参考。     

基于沥青路面功能性能的预防性养护时机指标

路面预防性养护是国内外近年来研究的热点,路面预防性养护对维持良好的路面性能具有重要的意义。预防性养护的成功与否及其效益与进行预防性养护的时机密切相关,然而对于预防性养护的时机目前国内外还没有很好的解决办法。文章从预防性养护的作用出发,结合我国公路事业发展的现状,提出了基于沥青路面功能性能的预防性养护指标体系:路面沥青老化指标、路面渗水系数、路面行车安全性指标、平整度和路面状况指数(PCI) ,以及获取这些指标需要进一步解决的关键问题。     

ANTICIPATED AIR POLLUTION TOLERANCE OF SOME PLANT SPECIES CONSIDERED FOR GREEN BELT DEVELOPMENT IN AND AROUND AN INDUSTRIAL/URBAN AREA IN INDIA: AN OVERVIEW

Vegetation naturally cleanses the atmosphere by absorbing gases and some particulate matter through leaves. Plants have a very large surface area and their leaves function as an efficient pollutant‐trapping device. Some plants have been classified according to their degree of sensitivity and tolerance towards various air pollutants. Sensitive plant species are suggested to act as bio‐indicators. Levels of air pollution tolerance vary from species to species, depending on the capacity of plants to withstand the effect of pollutants without showing any external damage. In this study, the air pollution tolerance index (APTI) of 30 plant species has been evaluated. High values of APTI were recorded in Mangifera indica, Moringa pterydosperma, Cassia renigera and Ailanthus excelsa. The anticipated performance index (API) of 30 plant species has also been evaluated for green belt (GB) development in and around an industrial urban area in India. Using APTI and this performance rating, the most tolerant plants have been identified.