Comment on “Assessing water quality of five typical reservoirs in lower reaches of Yellow River,China: Using a water quality index method” by Wei Hou,Shaohua Sun,Mingquan Wang,Xiang Li,Nuo Zhang,Xiaodong Xin,Li Sun,Wei Li,and Ruibao Jia (2016) [Ecological Indicators, 61, 309–316]

Hou et al. (2016) recently developed a water quality index (WQI) for assessing water quality of five typical reservoirs. Despite all the merits of the practical WQI, it suffers from lack of uncertainty consideration; a fact that motivated the present discussion focusing on mitigation of uncertainty in water quality assessment. In this regard, superiority of employing fuzzy WQI (FWQI) rather than crisp WQI is emphasized. Due to robustness of FWQI in handling uncertainties surrounding data acquisition, employment of fuzzy concept can improve water quality assessment and monitoring to generate results which are more consistent with real world conditions.     

Investigating the effects of point source and nonpoint source pollution on the water quality of the East River (Dongjiang) in South China

Understanding the physical processes of point source (PS) and nonpoint source (NPS) pollution is critical to evaluate river water quality and identify major pollutant sources in a watershed. In this study, we used the physically-based hydrological/water quality model, Soil and Water Assessment Tool, to investigate the influence of PS and NPS pollution on the water quality of the East River (Dongjiang in Chinese) in southern China. Our results indicate that NPS pollution was the dominant contribution (>94%) to nutrient loads except for mineral phosphorus (50%). A comprehensive Water Quality Index (WQI) computed using eight key water quality variables demonstrates that water quality is better upstream than downstream despite the higher level of ammonium nitrogen found in upstream waters. Also, the temporal (seasonal) and spatial distributions of nutrient loads clearly indicate the critical time period (from late dry season to early wet season) and pollution source areas within the basin (middle and downstream agricultural lands), which resource managers can use to accomplish substantial reduction of NPS pollutant loadings. Overall, this study helps our understanding of the relationship between human activities and pollutant loads and further contributes to decision support for local watershed managers to protect water quality in this region. In particular, the methods presented such as integrating WQI with watershed modeling and identifying the critical time period and pollutions source areas can be valuable for other researchers worldwide.     

两类水质综合评价方法的特点及其在河流水环境管理中的作用

河流水质恶化已成为严峻的环境问题,针对河流开展水质综合评价对河流水环境管理具有重要意义。依据不同的评价目标,选择合理的综合评价的评估标准成为河流水质评价中重要的问题之一。通过基于期望值和阈值的水质健康综合评估法(ETI)和水质质量指数(WQI)两种水质综合评价方法对"引滦入津"工程重要水源地伊逊河水质进行评价,结果显示:1)伊逊河水质ETI评估结果为良好等级,WQI评估结果为一般等级;2)伊逊河采样点水质在ETI评价中分布于4个等级,WQI仅分布于2个等级;3)伊逊河自上游至下游水质显著降低,特别是ETI评估中由优秀等级转变为差等级;4)ETI和WQI评估结果显示极显著相关性(R=0.951,P0.01);5)通过逐步多元回归,ETI评估结果的主导因子是DO、EC、SS、BOD_5和TP(P0.05),WQI评估结果的主导因子是DO、SS、BOD_5、TP、TN和NH_3-N(P0.05)。进一步分析表明伊逊河水质恶化与其流域内土地利用情况密切相关。在河流水环境管理中,ETI作为一种水质相对值评估方法,能更好体现流域内水质差异的区分度,便于管理者迅速定位流域内亟需治理的河流或河段,同时能够根据河流自身特征制定管理目标,可作为河流管理绩效评估的有效手段;而WQI作为一种水质绝对值评估方法,更适用于河流水质时间变化评估,对河流经长期治理后的管理效果评价起到重要作用。     

Relationships between pollutant discharge and water quality in the rivers from “better” to “worse” water quality

The long-term relationship between pollutant discharge and river water quality of biological/biochemical oxygen demand (BOD) in the Yamato-gawa River, Japan, has been found to be similar to perturbation or dynamic equilibrium change of alternative stable states in the ecosystem fields with a linear relationship as a usual condition. Similar relationships have been observed in short-terms for single precipitation events both in the Richmond River, Australia, and in a mountainous watershed in Japan. On the contrary, nutrient concentrations have not changed in a long-term besides nutrient discharge increases in the Richmond River. In this paper, long-term chronological relationships of annual pollutant discharges and water quality in the Brisbane River, Australia, were investigated based on pollutant discharge estimations and water quality monitoring data as a case study in the “better” water quality river. Effects of precipitation variation were taken into account in the pollutant discharge estimations by introducing precipitation variance coefficient (PVC). Total nitrogen (TN) and total phosphorus (TP) concentrations in the river were found to be improved with fluctuations in the lower Brisbane River Catchment during 1975–2012. Long-term dynamic equilibrium alterations of pollutant discharge and water quality were found for TN and TP at the first time in the Brisbane River. The investigated term was found to be divided into two phases, 1975–2001 and 2001–2012 for TN, and 1975–2007 and 2005–2012 for TP. Both pollutant discharges and pollutant concentrations in the river were smaller in Phase 2 than Phase 1. Based on the relationships in the three rivers, a hypothesis on pollutant discharge and water quality from “better” to “worse” river water environment was presented that rapid and/or excess pollutant discharge increases cause perturbation or dynamic equilibrium alterations with the basal relationships as the linear relationships.     

Assessing water quality of five typical reservoirs in lower reaches of Yellow River,China: Using a water quality index method

To assess water quality of reservoirs in lower reaches of Yellow River using the water quality index (WQI) method and try to compare water quality and main contaminations of mountain and Yellow River reservoirs, water samples were carried out over 6 years. Nine water variables were selected to participate WQI calculation by Principal Component Analysis (PCA). WQI values ranged from 17.8 to 77.8 in five reservoirs, which indicated “good” to “very poor” water quality of reservoirs. No significant differences in WQIs were found between mountain and Yellow River reservoirs. A major finding from our study is that mercury was the main contamination in 5 reservoirs, while TP (total phosphorus) and SO₄ were another main contaminations in mountain and Yellow River reservoirs, respectively. Application of the WQI is suggested to be a helpful tool that enables the public and decision makers to evaluate water quality of drinking reservoirs in lower reaches of Yellow River.     

Dynamic successive assessment method of water environment carrying capacity and its application

Water environment carrying capacity (WECC) is an important foundation of sustainable socioeconomic development and may be affected by many factors such as water resources, water quality, economy, population and environmental protection. This article focuses on the temporal and spatial variability of WECC to explore a method of dynamic successive assessment. First, the Pressure-State-Response (PSR) framework is used to develop a systematic and causal indicator system representing the three aspects of water environment pressure carrying capacity (WEPCC), water environment state carrying capacity (WESCC) and water environment response carrying capacity (WERCC). The Variable Fuzzy Pattern Recognition (VFPR) model and an analytic hierarchy process (AHP) model are combined to successively and dynamically assess WEPCC, WESCC and WERCC, and after that the weighting method is used to calculate WECC. Furthermore, WECC is divided into 27 classes on the basis of WEPCC, WESCC and WERCC contributions. The proposed method is applied to the dynamic successive assessment of WECCs in China, including inter-province comparisons. The results show that the dynamic successive WECC assessment method is reasonable, and it can be used not only to accurately understand the changes of WECC through time but also to distinguish qualitative differences masked by similar WECC values.     

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.     

Predicting Water Quality Index (WQI) by feature selection and machine learning: A case study of An Kim Hai irrigation system

A variety of water quality indices have been used to assess the state of waterbodies all over the world. In calculating a Water Quality Index (WQI), traditional methods require the evaluation of many water quality parameters, making them costly and time-consuming. In recent years, machine learning (ML) algorithms have emerged as an effective tool to solve many environmental problems, including water quality management. In this study, we investigate the performance of the ML-based method in calculating the WQI. We apply several feature selection techniques to select the key parameters fed the ML models. Experiments are carried out to evaluate the WQI based on a dataset collected from 2007 to 2020 of An Kim Hai system, one of the most important irrigation systems in the north of Vietnam. The obtained results show that the application of selection methods allows reducing significantly the number of water quality parameters fed the ML models without losing their accuracy. In particular, by using the embedded method, we find out four important parameters, including Coliform, DO, Turbidity, and TSS, that have the greatest impact on water quality. Based on these parameters, the Random Forest model provides the best accuracy in predicting the WQI values from the An Kim Hai system with a Similarity of 0.94. The combination of feature selection and ML methods is then considered an effective alternative for calculating the WQI, leading to a desirable performance and a reduction of input parameters. This makes water quality monitoring less costly, substantial effort, and time.     

A modified drinking water quality index (DWQI) for assessing drinking source water quality in rural communities of Khuzestan Province,Iran

We reconsidered the Canadian Council of Ministers of the Environment Water Quality Index (CCME WQI) to achieve an efficient drinking water quality index (DWQI) for assessment of drinking source water quality in rural communities of Khuzestan Province, Iran in 2009–2013. In contribution with a panel of water quality experts, the CCME WQI was mainly modified by four changes: (1 and 2) assigning weight factors for input parameters and index factors, (3) modifying excursion concept for carcinogens and bioaccumulative pollutants and (4) removing effect of unequal measurements of input parameters. The DWQI characterizes the drinking source water quality through comparing the measured values of input parameters with relevant benchmarks. The DWQI score (from 0 to 100) classifies the water quality in five categories as poor (0–54.9), marginal (55.0–69.9), fair (70.0–84.9), good (85.0–94.9) and excellent (95.0–100). Based on the DWQI, the temporal changes of the rural drinking source water quality were not significant; while the spatial variations of the water quality were considerable across the province, so the DWQI scores in the northern counties were higher than that in the southern ones. At the county level, the highest and lowest average scores of the DWQI (±standard deviation: SD) were observed in Izeh and Shadegan to be 90 ± 5 and 69 ± 10, respectively. Based on the DWQI, proportions of the drinking water sources with the excellent, good, fair, marginal and poor qualities were determined to be 6.7, 59.1, 26.2, 7.8 and 0.1%, respectively. Turbidity and Ryznar Index (RI) were introduced respectively as the health-based and esthetic parameters with the most violations (22.7 and 63.2%, respectively). The results of the case study and sensitivity analysis indicated that the DWQI is a simple, flexible, stable and reliable index and could be used as an effective tool to characterize drinking source water quality.     

Assessment of water quality and health risks for toxic trace elements in urban Phewa and remote Gosainkunda lakes,Nepal

The concentration of 13 metals (Al, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Cd, Pb, and Hg) and their associated health risk assessment was performed for two Himalayan lakes, urban Phewa and remote Gosainkunda, from Nepal. Water Quality Index (WQI), Metal Index (MI), Hazard Quotient (HQ), Hazard Index, and Cancer Risk were calculated in order to evaluate the water quality of these lakes. Correlation analysis revealed that Mn and Fe were derived from natural geological weathering processes and Pb, V, Cr, Co, Ni, Cu, Zn, and Cd might have originated from anthropogenic sources. The results revealed that WQI of the remote lake fell into excellent water quality and urban lake fell into poor water quality, which is also supported by the MI calculation. Moreover, the HQ of Mn in urban lake showed values greater than unity suggesting its health risk to the local inhabitants. The cancer index values indicated “high” risk due to Cr, whereas Cd possesses “very low” cancer risk on local population residing nearby areas. This study provides the useful database and suggests for the regular assessment and policy formulation for safeguarding the natural water bodies in the region.     

Application of modified water quality indices as indicators to assess the spatial and temporal trends of water quality in the Dongjiang River

The Dongjiang River plays an important role in southern China, as a source for irrigation and potable water of Hongkong and the other parts of the Pearl River Delta (PRD). The water quality index (WQI) was calculated to assess the spatial and temporal variability and identify the classification of water quality in the river. In order to simplify the procedure and reduce the analytical costs of the water quality evaluation, a modified WQI (defined as WQI_min) was introduced based on Principal Component Analysis (PCA) and correlations analyses of the water parameters detected in dry and wet seasons during 2011–2012. Compared with the previous index, similar spatial changing trend and classification of the water quality were obtained by WQI_min, which was composed of pH, temperature, total suspended solid, NH₄⁺-N, and NO₃⁻-N. The results showed an excellent water quality in the tributary site near the reservoir, a good water quality in the upstream of the river, and medium water quality in the downstream of the river, which suggested that the urban wastewater originated from increasing population size and industry development in the downstream mainly led to the deterioration of water quality along the river. Moreover, WQI_min could more adequately reflect the seasonal changes of water quality which was slightly worse in dry season than wet season. Our results also suggest that continuous monitoring should be conducted to prevent pollution from industry and anthropogenic activities.     

广东省水质现状及驱动因素

水质现状评估及其驱动因素分析是实现水生态保护、水资源利用和水污染治理的关键,对于水生态系统的可持续发展具有重要意义。以广东省七大流域为研究区,基于2019-2020年间的溶解氧（DO）、透明度（SDD）、悬浮物（SPM）、叶绿素a （Chla）、氨氮（NH₃N）、总氮（TN）、总磷（TP）7个指标的水质监测数据,综合运用单因子指数法（SI）和综合水质指数（WQI）评价方法,分丰水期（N=66）和枯水期（N=54）评估研究区的水质现状,并探讨水质参数与地形、气象、社会经济和土地覆被类型等驱动因素之间的相关关系。SI评估结果显示广东七大流域主要以工业污水、农业面源等造成的Chla和TN浓度超标、部分水体富营养化严重为主,同时伴有溶解氧浓度偏低的问题;WQI评估结果显示研究区有57%以上的采样点属于中等以下水质。Chla、SPM、NH₃N和TP浓度具有显著的季节和驱动因素差异：丰水期的Chla和TP浓度低于枯水期,但SPM和NH₃N浓度高于枯水期。枯水期DO、TN和WQI的显著性影响因子为丰水期的1/3左右;这种季节差异可能是流域内降雨、营养盐负荷和土地覆被类型导致的复杂地表径流及面源污染所致。珠江三角洲河网区、粤西诸河、韩江下游以及粤东诸河练江流域的水质问题突出。未来水生态系统的可持续发展研究可以借助长时间序列、多频次、高分辨率的遥感监测手段和多种数值模拟方法以及常规水质评估模型,探讨气候变化、河岸带产业结构和流域土地利用方式对面源污染的影响,以进一步厘清降雨强度、三产结构和土地利用方式转变对区域水质变化的影响。     

Assessing water quality and classifying trophic status for scientifically based managing the water resources of the Lake Timsah,the lake with salinity stratification along the Suez Canal

Lake Timsah is considered as the biggest water body at Ismailia City with a surface area of 14?km². It is a saline shallow water basin lies approximately mid-way between the south city of Suez and the north city of Port Said at 30^o35′46.55“N and 32^o19′30.54″E. Because it receives water with high and low salinities, salinity stratification is producing in the Lake Timsah, with values of 14–40‰ for the surface water and over 40‰ for the bottom water. The temperature of the lake water decreased to below 19 °C in the winter and rose to above 29?°C in the summer; the concentration of dissolved oxygen ranged between 6.5 and 12.2?l^?1 and the pH fluctuated between 7.9 in its lower value and 8.2 in its higher value. Water transparency was very low as indicated by Secchi disc readings recorded during this study and varied between 0.3 and 2.7?m. The main chemical nutrient (phosphorus) reached its highest levels of 96?µg?l^?1 in winter and their lowest values of 24?µg?l^?1 during summer. This nutrient concentration is high especially by comparing with those of unpolluted marine waters, but is typical of the more eutrophic coastal waters worldwide. The composition and abundance of phytoplankton with dominancy of diatoms and increased population density (20,986 cell l^?1) reflect the eutrophic condition of the lake. The intensive growth of phytoplankton was enriched by high concentration of chlorophyll a with annual values ranged between 6.5 and 56?µg?l^?1. The objective of the present work was quantitative assessment of the quality of the water of the Lake Timsah using different approaches. During the present study, three different approaches were applied for the quantitative assessment of Lake Timsah water quality: the trophic state index (TST); trophic level index (TLI) and water quality index (WQI). Application of the trophic state and trophic level indices (TSI & TLI) revealed that the Lake Timsah has trophic indices of 60 and 5.2 for TSI and TLI, respectively. Both indices reflected the eutrophic condition of the lake waters and confirmed that the eutrophication is a major threat in the Lake Timsah. On the other hand, the WQI calculated for the Lake Timsah during the present study with an average of 49 demonstrated that the water of the Lake Timsah is bad and unsuitable for main and/or several uses. Moreover, WQI allows accounting for several water resource uses and can serve a more robust than TSI and/or TLI and can be used effectively as a comprehensive tool for water quality quantification. In conclusion, the three subjective indices used for the assessment process for the lake water are more suitable and effective for needs of the sustainable water resources protection and management of the Lake Timsah.     

Use of the water quality index and dissolved oxygen deficit as simple indicators of watersheds pollution

The use of the water quality index (WQI) and the dissolved oxygen deficit (D) as simple indicators of the watersheds pollution was investigated and compared in the Municipality of Las Rozas (north-west of Madrid, Spain). The quality of the water in Guadarrama and Manzanares rivers and Paris Park ponds, the main watersheds of this area was investigated during 2 years (from September 2001 to September 2003). It was found that the WQI was very useful for the classification of the waters monitored. The WQI was 70, which corresponds to “good” quality water at the sampling point 1 (entrance of Las Rozas) and decreased to around 64 (medium quality) at the sampling point 6 (outlet of Las Rozas) in the case of Guadarrama River. The WQI was around 65 in the influents of Manzanares River. Finally, in Paris Park the WQI ranged from around 72–55, which corresponded to a classification from “good” to “medium” quality, respectively. A high linear relationship between the WQI and the dissolved oxygen deficit (D) was found. Therefore, a fast determination of WQI may be carried out knowing the values of D, which are easily obtainable by field measurements. It was found an influence of the climate conditions on the values of WQI and D.     

土壤质量与土壤质量指标及其评价

土壤作为一种重要的自然资源可以为人类生产食物和纤维,并维持地球生态系统.土壤也是植物生长的媒介、水、热和化合物的源、水分的过滤器和废物分解的生物介质.土壤与水、气和植物互作并抑制环境的波动.土壤可以调节很多控制水气质量和促进植物生长的生态过程.土壤质量概念的引入使我们更全面地理解土壤,也有助于合理地使用和分配劳力、能源、财政和其它投入.土壤质量也提供了一个通用的概念使得专业人员、生产者和公众明白土壤的重要性.此外,它也是一个评价管理措施和土地利用变化对土壤影响的评价工具.土壤质量由土壤的物理、化学和生物性质组成,MDS已被科学家们提出用于土壤质量评价.国际上比较常用的评价方法主要有多变量指标克立格法、土壤质量动力学方法、土壤质量综合评分法和土壤相对质量法.人类对土地不和谐地利用和管理可以导致全球生物地球化学循环发生改变和加快土壤性质变化的速度,当前世界各地土壤退化相当严重,已日益威胁到人类赖以生存的土地资源.在探讨相关概念的基础上综述了近年来土地利用变化对土壤理化质量和生物质量的影响进展,以引起国内外学者对土地利用变化对土壤质量影响研究的重视,从而为探讨土地利用对土壤质量影响的机理和规律以及退化土地的恢复和区域土地资源管理以及土地的持续利提供理论依据.土壤质量未来的研究应该集中在土壤质量指标与评价方法;土壤质量变化的发生条件、过程、影响因素及其作用机理与时空规律性;尺度问题的研究;土壤质量保持与提高的途径及其关键技术研究.     

The need of hypothesis-driven designs and conceptual models in impact assessment studies: An example from the free-living marine nematodes

The literature on the use of marine nematodes as bioindicators of anthropogenic impact is extensive. Nevertheless, review studies have reported a high degree of variability among results and no consistent overall pattern has so far emerged. This lack of congruence might be partially because hypotheses formulation in environmental assessment studies has been largely inductive or abductive and not deductive or hypothesis-driven. In the present study, we emphasize the need of using hypothesis-driven designs and conceptual models in impact assessment studies. Hypotheses for individual and population level studies can be derived from the dynamic energy budget model (DEB). By means of differential equations, DEB model can infer whether a stressor promotes a shift in energy allocation along the life history of the individuals. For community/assemblage level studies, the predictions of the dynamic equilibrium model (DEM) for species richness is presented and extended for abundance, evenness, taxonomic distinctness, and changes in assemblage structure and sample dispersion. While it is predicted that species richness peaks at intermediate levels of disturbances and enrichment, evenness decreases with increasing disturbances and reducing enrichment/pollutant concentrations. Based on DEM,enrichment and pollutants may promote change in community structure by favoring the tolerant species, while physical disturbances may promote sample dispersion as a result of unselective mortality. Finally, we discuss the benefits of using niche-based models to select the indicator species, instead of using classical ordination methods, twinspan and similarity percentage analysis. The selection of indicator species have to be independent from the other species and must consider the set of environmental conditions. The use of conceptual models to select the best ecological indicators is highly recommended. It allows a logical way of testing for causalities and of scaling the different studies for comparisons.     

基于环境流体动力学模型的浅水草藻型湖泊水质数值模拟

针对内蒙古乌梁素海面临的污染现状,基于三维环境流体动力学模型(EFDC)的计算模式,将其与CE-QUAL-ICM模型耦合,模拟了不同情景下的乌梁素海藻类、总氮、总磷、化学需氧量年际和季节变化规律,模型中不仅考虑了风速和蒸发对模型的影响,也加入了挺水植物密度、高度、直径等形态指标,以此反映水生植物存在的区域中植物吸收降解污染物质、风速对底部应力、流场变化等因素对模型模拟结果的影响。研究结果表明:考虑挺水植物分布的耦合模型能够很好的模拟藻类和污染物质在乌梁素海内的年际、季节变化过程,模拟结果更接近于实际,模拟值与实测值间的相对误差基本控制在30%以内,大部分相对误差已控制在20%以内;降低入湖污染物质负荷直接影响着湖区内水质浓度的变化。另外,对于浅水或挺水植物密集而无法进入取得信息的区域,利用所建耦合模型能够为这些区域湖泊规划、管理、修复提供依据。     

IS TEMPORAL OCCURRENCE OF DIATOMS RELATED TO SPECIES TRAITS,LOCAL ABUNDANCE,AND REGIONAL DISTRIBUTION?1

Water quality in streams typically changes fast, and sensitive biological indicators are crucial for monitoring these changes in water quality. Diatoms are widely used in biological stream quality assessment. However, interannual and intra‐annual variation of diatom population densities is large, often hampering a reliable quality assessment. We studied the importance of different species traits on temporal occurrence of diatom species. We also examined whether temporal occurrence of diatoms is related to species' local abundance or regional distribution using a data set collected in Finnish streams. According to the general linear model (GLM), temporal occurrence of diatoms increased with increasing local abundance and regional distribution. Species that occurred more frequently also had larger niche breadths and nonmarginal niche positions. In addition, cell size and attachment ability were positively related to species temporal occurrence. Our results imply that abundant and widely distributed species with large niches and ability to attach sustain persistent populations in varying environmental conditions typical for streams. We suggest that future studies could concentrate on monitoring these common (abundant) species when detecting the possible changes in the biological state of streams. We advise, however, to consider a relatively large number of species as many of the most common species may have low indicator values.     

Comparative study of ecological indices for assessing human-induced disturbance in coastal wetlands of the Laurentian Great Lakes

Several ecological indices have been developed to evaluate the wetland quality in the Laurentian Great Lakes. One index, the water quality index (WQI) can be widely applied to wetlands and produces accurate measurements of wetland condition. The WQI measures the degree of water quality degradation as a result of nutrient enrichment and road runoff. The wetland fish index (WFI), wetland zooplankton index (WZI), and the wetland macrophyte index (WMI), are all derived from the statistical relationships of biotic communities along a gradient of deteriorating water quality. Compared to the WQI, these indices are less labor-intensive, cost less, and have the potential to produce immediate results. We tested the relative sensitivity of each biotic index for 32 Great Lakes wetlands relative to the WQI and to each other. The WMI (r² = 0.84) and WFI (r² = 0.75) had significant positive relationships (P < 0.0001) with the WQI in a linear and polynomial fashion. Slopes of the WMI and WFI were similar when comparing the polynomial regressions (ANCOVA; P = 0.117) but intercepts were significantly different (P = 0.004). The WZI had a positive relationship with the WQI in degraded wetlands and a negative relationship in minimally impacted wetlands. The strengths and weaknesses of each index can be explained by the interactions among fish, zooplankton, aquatic plants and water chemistry. The distribution of different species indicative of low and high quality in each index provides insight into the relative wetland community composition in different parts of the Great Lakes and helps to explain the differences in index scores when different organisms are used. Our findings suggest that the WMI and WFI produce comparable results but the WZI should not be used in the minimally impacted wetlands without further study.