Applicability of borrowed diatom-based water quality assessment indices in streams around São Carlos-SP,Brazil

Diatom-based indices are increasingly becoming important tools for the assessment of ecological conditions in lotic systems. The applicability of regional and foreign diatom-based water quality assessment indices to streams around São Carlos-SP, Brazil, is discussed. The relationship between measured water quality variables and diatom index scores was assessed. The indices, when compared to chemical analyses, proved useful in providing an indication of the quality of the investigated waters. Though all borrowed indices were applicable to the study area because many widely distributed diatom species have similar environmental tolerances to those recorded for these species elsewhere, ecological requirements of some diatom species from Brazil need to be clarified and incorporated in a diatom-based water quality assessment protocol unique to the region.     

Can diatom-based pollution indices be used for biomonitoring in South Africa? A case study of the Crocodile West and Marico water management area

The inclusion of diatoms into the current suite of biomonitoring tools in use in South Africa, as well as the use of European and other diatom indices in South Africa, and in particular the Crocodile and West Marico water management area, is discussed. The indices, when compared to chemical analyses, proved useful in providing an indication of the quality of the investigated waters. Several widely distributed diatom species were shown to have similar ecological tolerances in South Africa when compared to Europe. Although most of the diatoms encountered in the study were cosmopolitan, several possibly endemic species were recorded. The occurrence of endemic species, not included in existing diatom indices may lead to miscalculations of diatom indices. It is concluded that although diatom indices developed in Europe and elsewhere are useful at the present to indicate water quality, a diatom index unique to South Africa including endemic species will have to be formulated. Handling editor: D. Hamilton     

Development and Applications of Five New Water Quality Indices

Two indices, P₁ and I, employing ranked data and following the beta distribution, are described. These indices, which are true statistical measures of water quality, can be used with any set of parameters. Further, these indices correlate highly with biological and subjective-engineering assessments of water quality. Three indices, employing raw data and based on the chi-square distribution, are described. Two of these, B₁ and B₂, do not have sufficient discrimination to serve as general measures of water quality, although they have use in specific circumstances. The index C has been found to be a measure of excessive variability (at a station), and can be used to quantitatively compare the (data) variability among stations. The five indices described here are evaluated against a set of operational criteria which a mathematically sound index should meet.     

福建南日群岛秋季海洋生态环境诊断与评价

根据2007年9月和10月福建南日岛生态调查资料,从海水水质、海水营养结构与营养水平、生物多样性等3个方面诊断与评价了南日群岛海域环境现状,利用综合质量指数法对海洋生态环境质量进行综合评价,并探讨了不同评价指数的关系及合理性.结果表明:海域的pH、溶解氧(DO)、化学需氧量(COD)、Pb、Cd、Hg、As含量均符合第二类海水水质标准.71%站位的磷酸盐、14%站位的无机氮和7%站位的石油类污染物超第二类海水水质标准.海水水质总体属于较好等级,营养结构表现为氮限制,大部分海域处于富营养化状态,依据浮游生物的多样性指数评价结果为轻污染-清洁水平.生态环境综合质量指数评价结果表明南日群岛海域生态环境总体处于良好水平.利用不同的评价指数对海域环境健康状况进行诊断的结果存在一定差异.在实际评价中应综合运用化学指标和生物指标,才能得到相对客观的结论.     

普者黑岩溶湖泊湿地湖滨带景观格局演变对水质的影响

湖滨带作为湖泊与陆地之间的过渡带,是健康湖泊生态系统的重要组成部分。湖滨带景观格局的演变会对湿地水质产生重要影响,因此探究影响岩溶湿地水质变化的湖滨带关键景观因子,对深入了解景观格局对岩溶湿地水质的影响过程与机制具有重要意义。选择普者黑岩溶湖泊湿地为研究对象,以2005、2007、2009、2011年共4年的Landsat遥感影像及水质监测数据为基础,通过划定湖泊湿地湖滨带缓冲区域,运用秩相关分析和冗余分析研究湖滨带景观格局对普者黑岩溶湖泊湿地水质的影响。结果表明,湖滨带不同缓冲区内景观结构类型比例差异较大;枯水期水质与土地利用类型和景观格局指数的影响大于丰水期;景观格局在不同缓冲区尺度对岩溶湿地的水质具有不同的效应;随着监测点缓冲距离的增加,个别景观指数可较好的揭示湖滨带景观格局演变对岩溶湿地水质的影响,其中,蔓延度指数(CONTAG)、斑块结合度指数(COHSION)、均匀度指数(SHEI)对水质参数的影响较大,边界密度(ED)、聚集度(AI)对水质参数的影响随缓冲距离的增加逐渐减弱,其他景观指数对水质影响差异并不明显,最大斑块指数(LPI)在缓冲距离≤300m的区域内与水质的关系较密切,面积加权平均斑块分维数(AWMPFD)与水质参数有显著负相关性,多样性指数(SHDI)对水质的影响具有不确定性;另外,大部分水质参数与土地利用面积比例有较好的相关性,且湿地面积比例是表征岩溶湖泊湿地水环境质量的主要指标。     

The assessment of water quality in the Artois-Picardie water basin (France) by the use of diatom indices

The performance of six diatom indices to evaluate water quality has been studied in the Artois-Picardie water basin. Results show that all of them satisfactorily assess organic pollution which is the main phenomenon responsible for the degradation of water quality throughout the year. However, only the Specific Pollution Sensitivity Index (SPI), the Generic Diatom Index (GDI) and the Commission of Economical Community Index (CEC) show significant correlations with the ionic strength (expressed by chlorides, sulphates and conductivity) and eutrophication (expressed by chlorophyll and nitrates). Diatom indices do not integrate chemical parameters in the same way. Best correlations are obtained through simultaneous or average chemical analyses whereas for other parameters, best correlations are noted with chemical analyses carried out just before diatom sampling. Tests performed on different chemical data sets show that it is possible to make a realistic estimation of water quality during the summer in the Artois-Picardie water basin by using SPI in September.     

Are diatom-based biotic indices developed in eutrophic,organically enriched waters reliable monitoring metrics in clean waters?

The application of diatom indices developed for organically enriched and eutrophic waters in oligotrophic and relatively pristine streams in the Eastern Highlands of Zimbabwe was investigated based on data collected in May–August 2007. Better suitability of diatom indices in investigating the quality of eutrophic, organically enriched waters compared to oligotrophic waters is demonstrated. More robust data sets on taxonomy and autecology of a great number of diatom species are required to make the indices more powerful tools in monitoring water quality and ecological integrity of streams in the region.     

Implementing landscape indices to predict stream water quality in an agricultural setting: An assessment of the Lake and River Enhancement (LARE) protocol in the Mississinewa River watershed,East-Central Indiana

This study addressed the potential ability to link landscape indices to stream water quality in a predominately agricultural landscape located in the Mississinewa River watershed, East-Central Indiana. A methodology for developing and analyzing landscape indices using a GIS and remotely sensed and geospatial data was applied to 30 Hydrologic Unit Code (HUC) 14-digit subwatersheds. Six indices, three representing natural area extent characteristics and three representing natural area disturbance characteristics were developed. The resulting indices were then tested to determine if they could be linked to water quality variables (Total Phosphorus, Nitrate, E.COLI, and macroinvertebrate [EPT/C] Ephemeroptera, Plecoptera, and Trichoptera/Chironomidae scores). These variables were gathered from a database of diagnostic studies that only called for a single grab sample during a storm event and a base flow. Using this data provided an opportunity to test the quality of using single grab water samples as response variables. Regressions were not found to be significant for any of the four water quality variables. The findings provoked a discussion on the need for managing variation in water quality samples when attempting to develop successful linkages between landscape indices and stream conditions.     

Effects of water stress and rootstocks on fruit phenolic composition and physical/chemical quality in Suncrest peach

The aim of the present work was to evaluate the effects of water stress and different rootstocks on the quality indices and nutritional characteristics of peach fruit, cv. Suncrest. The results show how pre‐harvest factors, such as the type of rootstock and water stress, can influence the quality indices and nutritional properties of peach fruits. Rootstocks type influenced both quality indices such as flesh firmness (FF) and soluble solid content (SSC), but it is unclear how rootstock exerted its influence. Also water stress induced changes in quality indices of peach fruit grafted on GF 677 and Montclar whereas minor effects were recorded when water stress was applied on Penta. The content of hydroxycinnamic acids was similar in control fruits of GF677, Montclar and Penta and it increased significantly only in fruit of trees grafted on GF 677 following water stress. Anthocyanins content in fruit of control plants was higher in Montclar in comparison with the fruit grafted on the other two rootstocks while procyanidin content was higher in fruit of control plants grafted on Penta. Following the water stress an increase in total anthocyanins was observed in GF 677 and Penta whereas no significant differences were found for Montclar. Water stress induced a significant decrease in procyanidin content in Penta. In conclusion in fruits of trees grafted on Penta following water stress quality indices did not show changes but significant variations in some phytochemicals, i.e. anthocyanins and procyanindins were observed. The results suggest that the regulation of water management is an important factor to maintain a good quality of the fruits. In fact, if irrigation stress can induce a higher biosynthesis of phytochemical compounds and an increase of SSC, at the same time, it can change fruit quality traits, such as a lower FW in Montclar, a higher titratable acidity (TA) in GF 677 and Penta and a lower FF in Gf 677 and Montclar.     

Chironomids as water quality indicators in the River Mignone (Central Italy)

Chironomids of the River Mignone (Central Italy) were studied in order to examine their community structure and their relationship to some common biological indices (Biotic Score, Extended Biotic Index, Indice Biotique de Qualité Générale) utilizing the total macroinvertebrate fauna (chironomids generally at family level) for water quality assessment in rivers.A total of 36 taxa belonging to Tanypodinae (2 taxa), Orthocladiinae (22 taxa) and Chironominae (12 taxa) was collected at seven stations four times during a year. The results support the importance of the chironomid identification in water quality assessment studies in rivers, and demonstrate the usefulness of the factorial correspondence analysis as ordination technique based on both qualitative and quantitative chironomid data to determine environmental quality gradients.The value as bioindicator of some taxa was discussed, and chironomid assemblages were related to biological water quality of the river according to functional feeding groups.This study forms part of a larger Research project supported by MPI and CNR grants and is aimed at the biological water quality assessment of the river and at the analysis of the total macrobenthic community.     

Combination of discretization regression with data-driven algorithms for modeling irrigation water quality indices

Forecasting water quality parameters helps plan crop selection and irrigation strategies but is often costly because many parameters are required, particularly in developing nations. Therefore, the current research objective is to estimate the irrigation water quality indices in the Nand Samand catchment by developing machine learning models. To accomplish this objective, six machine learning models (Regression by discretization REGD; Regression by discretization-Bagging, REGD-Bagging; Regression by discretization-Random Subspace, REGD-RSS; Regression by discretization-Additive Regression, REGD-AR; Regression by discretization-M5 Pruned, REGD-M5P; Regression by discretization-Random Forest, REGD-RF) were developed and the accuracy of these model's were checked by ten statistics models and validated for predicting four irrigation water quality indices (soluble sodium percentage, SSP; sodium adsorption ratio, SAR; magnesium hazards, MH; Kelly's ratio, KR). Eleven physicochemical variables were analyzed from 95 open wells of the research area for two different seasons in 2020, pre-monsoon and post-monsoon, respectively. Results revealed that the REGD-M5P model showed the best fit for all irrigation indices based on the correlation coefficient(r) for the SSP, MH, KR, and SAR index (0.947, 0.975, 0.950, and 0.956 during the training phase and 0.868, 0.966, 0.930, and 0.979 during the testing phase, respectively). Similarly, root mean square error (RMSE) values showed the best fit for the REGD-M5P model for all four irrigation indices, i.e., SSP, MH, KR, and SAR (3.696, 3.100, 0.115, and 0.393 in the training phase; 3.446, 3.772, 0.125 and 0.207 in the testing phase, respectively). It may be concluded that machine learning models may improve the parameters of irrigation water quality, and such findings are vital to farmers for crop selection and irrigation application planning. Additionally, the proposed machine learning models in predicting the irrigation water quality index and being fast decision tools for modeling irrigation water quality are also very important.     

Response of diatom indices to simulated water quality improvements in a river

Various diatom indices are routinely used in European countries to monitor water quality in waterways. In order to assess their sensitivities and their integration interval after a sudden and lasting environmental change, epilithic diatom biofilms were transferred from several polluted rivers to an unpolluted stream. To monitor the changes of the index values, the biofilms were sampled in a first experiment 20 and 40 days after transfer, and in a second experiment 30 and 60 days after transfer. Sensitivities of the indices to the water quality improvement were assessed calculating the differences between the index values of the reference and the transferred assemblages. Some indices have intermediate sensitivities (BDI, GDI, ILM, SLA), others higher sensitivities (CEE, EPI, ROT, SPI, TDI). The integration interval of these indices was 40–60 days. Some differences were observed between the indices, but their results were homogeneous when compared to those obtained with other metrics such as Bray-Curtis or Chord distances, used to assess the difference between the transferred and the reference diatom assemblages. These other metrics showed that even after 60 days, the transferred assemblages still differed from the reference. This underlines that metrics do not have the same integration intervals and do not assess the same stresses; the choice of the metric used to assess water quality is of prime importance.     

长江中下游地区若干湖泊水质的多元分析与比较

1996年11月-1998年11月,对鄱阳湖等长江中下游若干浅水湖泊进行了水化学分析,并进行了主要水质指标(包括透明度、pH值、总氮、总磷、氨氮和硝酸盐等)的季节变动规律,并对这些指标进行了方差分析。结果表明:不同利用方式的水体间除硬度、碱度和T-N在几个湖区间的差异较小外,其它各项指标的差异均较显着;季节间除硬度、碱度、Ca、Mg和T-P外,其余各项指标在季节间的差异均较显着,说明其季节变动均不稳定。       

利用浮游生物控制工厂化养鳖水质的机理研究

通过利用浮游生物控制工厂化养鳖池水质养殖与工厂化常规养殖的对照试验及浮游生物、水化学指标、池水细 (霉 )菌含量等各项指标的对照观测 ,发现以隐藻为主体的浮游生物可以控制鳖池水质 ,减少鳖病发生 ,有利于鳖的生长 .鳖的生长速度和产量分别比对照高 52 %和 2 9.3% .减少了水量、能源的消耗 ,显著地降低了生产成本 .同时对隐藻在鳖池整个生态系统中的作用和机理进行了探讨     

Development of pollution indices for the middle section of the Lower Seyhan Basin (Turkey)

Pollution indices aggregate concentrations of several water or air quality parameters into a single quantity to indicate the general status of pollution in a region. Several pollution index models are present in literature. However, their application for different cases may require modifications based on implementation goals and available data. In this study, modified pollution indices were used to evaluate the pollution status in the middle section of the Lower Seyhan River Basin by employing a geographical information system (GIS) software (ArcGIS 9.3) for data processing, estimations and evaluations. Air quality index (AQI) and water quality index (WQI) were utilized to evaluate air and water pollution levels, respectively. Moreover, a composite air–water quality index (AWQI) was developed to perform a general assessment about the overall pollution status. The WQI and AQI were calculated for 2004–2010 and 2007–2010, respectively. The AWQI was developed for the period of 2007–2010. Results indicated that for the available data and time frame considered in the study, air and water qualities were in good conditions (low pollution), in general. Yet, precautions could still be taken for improvement. Results also indicated the need for improvement of monitoring network for better assessment of the environmental quality in the whole basin. In general, GIS tools were very helpful in the development of the indices.     

不同地貌条件下景观对河流水质的影响差异

景观对河流水质的影响在不同地区、不同空间尺度上存在差异。以赤水河流域为研究对象,根据地貌特征将研究区分为喀斯特地貌和非喀斯特地貌,在划分的29个子流域内采集测试水质数据,所选用的水质指标有溶解氧(DO)、电导率(EC)、总氮(TN)和总磷(TP),运用空间分析及数理统计方法,分析流域内不同地貌区景观之间的差异,探究不同空间尺度上景观与水质指标之间的关系。结果表明:(1)流域内景观组成以林地和灌草为主,建设用地和耕地次之,景观组成在不同地貌区各空间尺度上存在差异。建设用地和耕地对水质具有负面影响,且在碳酸盐岩地区更显著;林地对水质具有正面影响;灌草对水质的影响相对复杂。(2)流域内水质表现为碳酸盐岩地区优于碎屑岩地区。景观破碎化指数与总氮(TN)、总磷(TP)呈正相关,是水质变化的重要影响因素;景观聚集度指数与溶解氧(DO)呈正相关;景观破碎化指数和景观聚集度指数与电导率(EC)的关系在两个地区呈相反的结果。(3)不同地貌区景观对河流水质具有不同程度的影响。在两个地区,景观组成对河流水质解释能力最大空间尺度均为河岸带尺度,解释率分别为53.4%和59.1%;景观格局对河流水质解释能力最大...     

Response of epilithic diatom assemblages to urbanization influences

Urbanization has long been recognized to alter the hydrology, water quality and channel form of waterways. Recently, consideration of urban impacts on waterways has expanded to include assessment of the aquatic biota, generally focusing upon the macroinvertebrate fauna. This study compares the impacts of urbanization on the structure of stream benthic diatom communities in 16 first- and second-order streams in the east of Melbourne, Australia. Relationships between the physical elements of urbanization, water quality and diatom communities were examined using multivariate analyses with compositional similarity, and univariate analyses with selected diatom species and indices,. There was a strong negative correlation between urban density and the diatom indices of water quality. The element of urbanization most strongly related to the measured decline in the diatom community was drainage connection. Electrical conductivity was the most influential water quality variable. It is hypothesized that, in addition to increasing electrical conductivity, drainage connection may be impacting the diatom community by increasing the delivery of phosphorus during small storm events. The study suggests that reducing directly piped drainage connection using infiltration and retention is a logical step in the mitigation of urban impacts upon receiving streams. A corollary part of the project indicated strong potential for using overseas diatom indices in studies on water quality in southeastern Australia.     

Using multi-target clustering trees as a tool to predict biological water quality indices based on benthic macroinvertebrates and environmental parameters in the Chaguana watershed (Ecuador)

Macroinvertebrates were sampled in the Chaguana river basin in SW Ecuador in the wet season (March) and the dry season (September) of 2005 and 2006. To assess the robustness of several biological indicators, correlations were calculated between both years and between the wet and the dry season. In addition, it was tested if the indices gave significantly different results for sites with a bad, poor, moderate and good ecological water quality. Composition measures performed poorly in most cases, however, abundance, diversity and richness measures often performed better and tolerance measures, the so-called biotic indices, performed very well, even indices developed for temperate regions. By using pruned multitarget clustering trees, it was possible to predict several well-performing ecological water quality indices simultaneously on the basis of the occurring key macroinvertebrate taxa or, alternatively, on the basis of key environmental variables. In contrast to unpruned trees, which resulted in complex trees that were difficult to interpret and performed inferiorly, pruning resulted in transparent trees. Water quality indices scored high when Hydropsychidae were present and even higher when in addition also Megapodagrionidae were present. When no Hydropsychidae nor Libellulidae were present, the indices reached the lowest scores. However, this model based on key taxa occurrences did not perform well during validation. Water quality indices scored higher with increasing dissolved oxygen concentrations and a strong current velocity. The latter model based on environmental variables also performed well during validation. In the presented study, the ecological water quality could thus be accurately predicted solely on the basis of dissolved oxygen concentration and current velocity. It can therefore be concluded that multitarget clustering trees can be easily used as a practical tool for cost-effective decision support by water quality managers.     

Geographic variation in mangrove flooding and accessibility for fishes and nektonic crustaceans

In the last decade, dozens of indices based on macroinvertebrates were developed to evaluate lotic ecosystems. In contrast, very few of these indices have been applied in lentic ecosystems. Natural wetlands in southern Brazil are increasingly threatened by the expansion of irrigated rice. The main objective of this study was to develop a multimetric index based on macroinvertebrates to evaluate the water quality of natural wetlands and rice fields in southern Brazil. Three samplings were carried out over the rice growth cycle in four conventional and four biodynamic rice fields, and four natural wetlands. The wetlands were considered as reference sites, and the conventional and biodynamic rice crops were considered as manipulated sites at different levels of degradation. Seven metrics were included in the final index after passing though sensitivity and correlation tests. The results indicated that our index has a power to detect a gradient of variation in water quality. Natural wetlands had the best water quality, biodynamic crops had intermediate water quality, and the conventional crops had the lowest water quality. We believe that development of this macroinvertebrate-based multimetric index of water quality could be an important tool for monitoring natural wetlands and rice crops in southern Brazil.