Ecological Status Of Surface Waters Research Articles

Fuzzy logic as a novel approach to predict biological condition gradient of various streams in Ceyhan River Basin (Turkey)

Creating a method to categorize the ecological status of streams according to their biological conditions and establishing scientifically defensible nutrient criteria to protect their biotic integrity poses significant challenges. Biomonitoring of least disturbed areas is an important issue to accurately assess the ecological status of surface waters and ensure their sustainability. The fuzzy logic as a novel approach was firstly applied to evaluate the biological condition gradient of 44 sampled streams in the Ceyhan River Basin, utilizing two diatom indices, total phosphorus (TP), electrical conductivity (EC), and CORINE data. The fuzzy logic was employed to examine variations in the diatom compositions and land cover based on biological condition gradients (BCGs) of various streams and to assess the suitability of BCG in evaluating the health of studied stream systems. A three-layer fuzzy logic was constructed to predict BCGs of steams based on input data, with diatom metrics, TP, and EC representing BCGdia and land cover variables contributing to BCGland. The effects of operating variables were studied to optimize BCG results. The highest BCG score (0.85) was determined in Aksu Spring Brook in the spring, whereas the lowest value (0.05) was calculated in Erkenez Stream3 in the summer. BCGs showed strong relationships with nutrients, altitude, and EC. Results of BCGs indicated that sampling stations have various ecological statuses ranging from bad to high in the Ceyhan River Basin. The BCGdia and BCGland made important contributions to determine the ecological status of streams in the Ceyhan River Basin. Results showed that the BCG approach allows a more reliable way to determine the ecological status of streams in the Ceyhan River Basin by combining biological and chemical assessments for the sustainability of the environment. It is recommended that the BCG will be applied and evaluated in future research studies across various river basins, both within and outside of Turkey.

Use of random forest for assessing the effect of water quality parameters on the biological status of surface waters

The Water Framework Directive aims to reach good status in European surface waters by 2027. Despite the efforts taken already, the ecological status of surface waters has hardly improved during the last decades. In order to find efficient measures, there is an urgent need to improve our knowledge in understanding the linkage between the anthropogenic factors and the indicators of the ecological status assessment. Due to the complexity of the ecosystems, basic statistical methods (such as linear regression) cannot help in finding relationships between the biological quality elements and the supporting water chemistry parameters. The paper demonstrates that in these cases a machine learning data-driven method can be a promising tool for supporting biological classification. With random forest, the Gini index was used for ranking physico-chemical variables based on their influence on biological elements. Variables that have the biggest Gini index were selected for predicting the biological status of phytoplankton, phytobenthos and macrophytes. Binary classification and predictions were performed on a five-class scale. Predictions tended to be fairly good (errors varied within 8–60%, median 33.3%). A comparative analysis was also made with logistic regression, however, in some cases it led to slightly worse or slightly better predictions. We concluded that due to significant errors, the biological status assessment cannot be replaced completely by model predictions, but the method is sufficient to fill in certain gaps in the data and can help in the planning of biological monitoring systems. The evaluation was performed with Hungarian river and water quality database.

The goby fish Sicydium spp. as valuable sentinel species towards the chemical stress in freshwater bodies of West Indies

Implementation of the European Water Framework Directive in tropical areas such as the French West Indies (FWI) requires to select relevant aquatic sentinel species for investigating the ecological status of surface waters. The present work aimed to study the biological response of the widespread fish Sicydium spp. towards river chemical quality in Guadeloupe island through a set of proper biomarkers. During a 2-year survey, the hepatic EROD activity, the micronucleus formation and the level of primary DNA strand breaks in erythrocytes were measured respectively as an enzymatic biomarker of exposure and genotoxicity endpoints in fish living upstream and downstream of two chemically-contrasted rivers. Hepatic EROD activity was shown to be variable along the time but always significantly higher in fish from the most contaminated river (Rivière aux Herbes) compared to the low contaminated one (Grande Rivière de Vieux-Habitants). Fish size did not influence EROD activity. Female fish exhibited a lower EROD activity compared to males depending on the catching period. We observed significant temporal variation in micronucleus frequency and primary DNA damage level measured in fish erythrocytes that did not depend on the fish size. Micronucleus frequency and to a lesser extent DNA damage were significantly higher in fish from the Rivière aux Herbes compared to the Grande Rivière de Vieux-Habitants. Our results argue for the interest of using Sicydium spp. as sentinel species to assess river quality and chemical pressures in FWI.

Using diatom indices to estimate the ecological status of minimally disturbed rivers of the Sakarya River Basin (Türkiye)

AbstractIn order to determine the ecological status of surface waters of different types in a particular ecoregion, the reference conditions for each type should be identified to compare with observed conditions, as suggested by the Water Framework Directive (WFD). In this study, 36 candidate reference river sites of the Sakarya Basin (Türkiye) were sampled three times in 2018, and the biological assessment of these sites was evaluated using 18 different diatom indices. In addition, nine different environmental variables were also sampled combined with epilithic diatoms. Based on the canonical correspondence analysis (CCA), alkalinity and pH were determined as the most significant environmental variables for diatom assemblages. Among the diatom indices, Biological Diatom Index (IBD), Artois‐Picardie Diatom Index (IDAP), Descy's Index (DES) and Sládeček's Index (SLA) showed significant correlations with alkalinity and pH according to multiple linear regression (MLR) results. IBD index showed the highest response to the pressures and indicated high or good ecological status of the sampling sites. Moreover, rivers with high water quality status have a high correlation with alkalinity, pH and pollution‐sensitive species. On the other hand, good water quality rivers were highly correlated with total phosphorus and intermediate pollution‐sensitive or pollution‐tolerant species. The 13 reference sites established in this study can be used to assess the ecological status by comparison with the same types of river bodies for further studies in the basins of Türkiye.

River Macrophyte Index for ecological status assessment of the non-karst and Dinaric karst waters

Assessing the ecological status of surface waters is essential for evaluating the ecosystem health and for defining of river basin management strategy. River Macrophyte Index (RMI) is uniformly used for assessing the trophic status of rivers and was intercalibrated for Mediterranean and Eastern-Continental lowland rivers in European Union but not for Dinaric karst rivers. Karst rivers are specific due to extreme water level fluctuations that might reflect in macrophyte communities' response. We built a composite stressor gradient as a proxy for trophic status, classified 85 plant species in the ecological indicator groups using large, representative data set, separately examined sites from karst and non-karst rivers and validated updated River Macrophyte Index (RMIup) with the independent data set. We found the differences in the response of macrophyte communities of karst and non-karst waters to the composite stressor gradient what resulted in type-specific boundary values. RMI reference values were significantly higher for karst waters in comparison to non-karst waters, but the normalised boundary values were similar for both water types indicating that key shifts in macrophyte communities occur at similar deviations along the stressor gradient. Boundary values of the updated RMI differed from those from the original RMI version as lower normalised RMI values were observed using the updated RMI version, but only at high to moderate ecological status sites. The updated RMI is showing a good relationship with the composite stressor gradient using the development and validation dataset and provides us with an effective assessment system and river management tool.

Estimated nutrient leakage from arable land in different bioeconomy scenarios for two areas in central Sweden, determined using a leaching coefficient method

Knowledge of future developments in agriculture and how these will affect nutrient leakage from arable land is important in efforts to achieve good ecological status of surface waters. This study assessed the impact of five scenarios for a bioresource-based economy, involving use of renewable biological resources from land and sea, on nitrogen (N) and phosphorus (P) leakage from arable land to surface-waters and groundwater. The scenarios (developed in an earlier study) were applied to two areas in central Sweden, leaching region LR-6 (5350 km2) and catchment C6 (19 km2). Using the NLeCCS calculation system to produce leakage coefficients, we evaluated the changes in total N and total P leakage from arable soil. The leakage coefficients described agricultural management practices and climate conditions representing the leaching region LR-6 in Sweden and the baseline year was 2016. The scenarios varied from a baseline in terms of crop combination (relative area of different crops) and extent of mitigation measures (e.g. delayed tillage date, buffer zone width and relative area, and catch crop). Expected consumption of meat varied in the scenarios, with lower consumption meaning fewer cattle and consequently less grass ley. The scenarios was supplemented with calculations of introducing mitigation measures up to their maximum potential.In leaching region LR-6, calculated baseline leakages was 10.5 kg N ha−1 year−1 and 0.87 kg P ha−1 year−1, values that varied in the scenarios by −4% to 5% (N) and −6% to 19% (P). In catchment C6 calculated baseline leakages was 7.1 kg N ha−1 year−1 and 1.11 kg P ha−1 year−1, and the values in the scenarios varied by −15% to 2% (N) and −5% to 5% (P). Assuming maximum potential of the mitigation measures decreased leakage further, by up to −19%.Crop combination had a major impact on total N and P leakage in the scenarios. Leakage increased when the amount of grass ley in the rotation decreased, but remained relatively unchanged when the crop combination change only involved annual crops. Frequency of the mitigation measures increased in all scenarios, with associated decreases in N and P leakage that counteracted the increased leakage caused by changes in crop combination. The most effective mitigation measure was catch crop for N leakage and delayed soil tillage for P leakage.

Weighted risk assessment of critical source areas for soil phosphorus losses through surface runoff mechanisms

In intensive livestock areas, soils commonly contain elevated nutrients above the agronomic optimum which increases the risk of nutrient losses and contributing to poor ecological status waterbodies. Large within-field variability in soil nutrient content exists, and at-risk phosphorus (P) hotspots are rarely quantified due to sub-optimal soil sampling regimes. This study aims to address this issue by developing and evaluating an improved classification of P transfer risk at a sub-field scale through a weighted risk assessment model that combines gridded soil sampling data with modelled in-field surface runoff pathways. Within-field soil P variability was quantified at six field-scale sites in Northern Ireland using two different sampling techniques; traditional bulked field soil sampling (i.e. bulk analysis of W pattern sampling) and gridded sampling (at 35 m resolution) alongside interpolation. Results show that traditional bulked sampling failed to account for the sub-field scale spatial variability in soil P content. This may contribute to the poor chemical and ecological status of surface waters by frequently under-predicting soil nutrient content, and failing to identify potential contributing sources of soil P losses. In contrast, higher intensity gridded sampling and interpolation revealed wide in-field spatial variability in soil P content, facilitating the identification of contributing sources of P losses to poor water quality and aiding in the characterisation of risk for nutrient losses to waterways. Hydrological modelling of in-field runoff pathways indicated several P sources potentially contributing to runoff-based P losses. Our weighted risk assessment model was successful in identifying P hotspots and transfer potential to water courses, illustrating that a similar approach could be applied anywhere in the world where excess P poses a problem for water quality. Model validation took place using instream water quality sampling data, which showed that higher risk weighting model results correlated to poorer water quality conditions. This methodology could be a useful management tool to help countries meet their national water quality targets.

STRUCTURAL CHANGES OF RIVER ECOSYSTEMS’ BIOLOGICAL QUALITY ELEMENTS UNDER CONDITIONS OF MINERAL WATER FLUX

The Government of the Republic of Armenia strives to ensure a better management of surface water resources by establishing regular hydrobiological monitoring system in accordance with the EU WFD requirements. However, there is a very limited use of biological quality elements in monitoring of the ecological status of surface waters due in part to a lack of studies on their reflection towards different stressors. Thus, the aim of the study was to estimate the structural changes of benthic macroinvertebrates and macrophytes under the influence of the mineral water flux. The hyperlocal studies have been conducted in the area where the single stressor is mineral water. The results have shown that benthic macro invertebrates are more sensitive towards mineral water flux than macrophytes which allowed also to conclude on the higher efficiency of use of macrophytes in the estimation of water trophic status in case of mixed effects of organic pollution and mineral waters.

Key Factors for the Findability of Fish Passes in Large Epipotamal Rivers: The Case of the River Drava

Restoring the longitudinal connectivity of rivers through fish passes is of great importance for achieving good ecological status of surface waters. However, the key stimuli determining the findability of the entrance of these structures is still subject to debate. In this article, the influence of water temperature, light and acoustic stimuli in addition to flow parameters on fish movement is assessed. Analyses are based on a comprehensive dataset of 40,000 fish migrations covering time accurate recording of ascending individuals during the observation periods from 2015 to 2020 in various fish passes on the river Drava in Carinthia, Austria. The data are assessed by technical, fish ecological and statistical methods. Results indicate that the effect of the water temperature gradient between the fish pass and the main river has most impact on the ascent rates, whereas the two factors of light and acoustic, as well as most of the flow parameters, have no or negligible effect on the findability. A favourable thermal environment can be important to ensure efficient upstream migration and thus facilitate the findability of fish passes.

Assessment of the environmental status of the water object by hydrochemical indicators

The problem of surface water is one of the key challenges of humanity. In accordance with the goals of research and analysis of the environmental status of water bodies are of great practical importance, as their condition further affects the quality of drinking water. The purpose of the work is to assess the environmental status of the water body. The originality of the obtained results is a comprehensive assessment based on the analysis of time monitoring data on the ecological status of water of the water body, taking into account the weighting factors of pollution indices. The study of the ecological state was carried out taking into account the integrated hydrochemical indicators. Microsoft Excel software was used to conduct the study. Google Maps was used to find places on maps and build the maps you needed to work. Microsoft Excel was used to perform calculations and build graphics. The ecological status of a water body is determined on the basis of pollution index calculations. The method of assessing the ecological status of surface waters by relevant categories has been improved through the use of weights. The assessment method is universal and can be used to study the ecological status of any water body. However, the selection of hydrochemical indicators took into account only the content of major pollutants, namely chlorides, sulfates, phosphates, suspended solids, petroleum products, compounds of copper and zinc violated. The obtained research results can be used in the development of water management plans and measures to improve their condition.

Phytoplankton Composition and Ecological Status of Lakes with Cyanobacteria Dominance.

Phytoplankton is one of the five biological quality elements used in the assessment of the ecological status of surface waters according to the European Water Framework Directive established in 2000. In this study, we determined the ecological status of three small and shallow lakes in the Polesie Plain, Eastern Poland, by using indices based on phytoplankton assemblages. The predominant phytoplankton of all three lakes were filamentous cyanobacteria, both heterocystous and non-heterocystous, represented by the genera Aphanizomenon, Planktothrix, Limnothrix, and Planktolyngbya. We used the Hungarian Q index, German PSI (Phyto-See-Index), and recently developed PMPL (Phytoplankton Metrics for Polish Lakes) for Polish lakes. We compared the results from the calculation of the indices to physicochemical data obtained from the lake water and Carlson’s Trophy State Index (TSI). On the basis of TSI, Gumienek and Glinki lakes were classified as advanced eutrophic, whereas Czarne Lake had a better score and was classified as slightly eutrophic. The trophic state was generally confirmed by the ecological status based on phytoplankton indices and also showed the diverse ecological situation in the lakes studied. Based on the Polish PMPL, Gumienek Lake was classified as having bad status (ecological quality ratio (EQR) = 0.05), whereas Glinki and Czarne lakes were classified within the poor status range (EQR = 0.25 and 0.35, respectively). However, based on the German PSI, the lakes were classified in a different manner: the status of Gumienek and Czarne lakes was better, but unsatisfactory, because they were still below the boundary for the good status category recommended by the European Commission. The best ecological status for the studied lakes was obtained using the Q index: Gumienek Lake with EQR = 0.42 had a moderate status, and Czarne Lake with EQR = 0.62 obtained a good status. However, Glinki Lake, with EQR = 0.40, was classified at the boundary for poor and moderate status. Based on our study, it seems that the best index for ecological status assessment based on phytoplankton that can be used for small lakes is the Polish (PMPL) index.

Statistical approaches to explore the linkages between physicochemical parameters and BQEs, and set river nutrient threshold concentrations in Hungary

Abstract The objective of the Water Framework Directive (WFD) is to achieve good ecological status in surface waters by 2027. To make a proper evaluation of the ecological status of watercourses, it is necessary to harmonize class boundaries for chemical and biological quality elements (BQEs). This paper aims to explore the linkages between physicochemical parameters and BQEs and set river nutrient threshold concentrations that support good ecological status. Regression and mismatch methods were applied to find the relationship between phytoplankton (PP) and phytobenthos (PB) ecological quality ratio and mean total phosphorus (TP) and total nitrogen (TN) concentrations. Nutrient thresholds have been suggested for several water types, which are varied in the case of highland rivers 1.8–6.2 mg TN/l, 180–400 μg TP/l; in the case of lowland rivers 1.4–5.0 mg TN/l, and 100–350 μg TP/l. These values are similar to what other studies found, but the relationship between biology and nutrients was weaker. Besides nutrients, additional data of measured dissolved organic carbon, 5-day biochemical oxygen demand, chemical oxygen demand with potassium permanganate method, and information about hydromorphological features were involved in the analysis. The research demonstrates that random forest can be used as a nonlinear, multiparametric model for predicting biological class from five variables with 35–81% error for PP and with 18–47% error for PB.

Water quality assessment of the rivers of the Southern Buh Basin within Vinnytsia Region as per integral indicator of pollution

Vinnytsia Region is a region of Ukraine that attracts people by its nature from ancient times to the present day and is subject to various active economic development efforts. Natural water (aquatic) objects such rivers, lakes, as well as their floodplains and watersheds, are among the ones that are intensively affected by human activities. Therefore, the author chose the basin of the Southern Buh River within Vinnytsia Region for establishing a degree of anthropogenic transformation in the river itself and for determining the state of its left tributaries.
 The paper highlights the results of field and laboratory studies of chemical and organoleptic state of water of the Southern Buh and its tributaries. The study of the Southern Buh Basin was conducted within Vinnytsia Region, as it is a region of early agricultural development and it has a large number of enterprises of various industries on its territory. Since the basin occupies a large area of Vinnytsia Region, it was reasonable to explore the main tributaries of the Southern Buh flowing through the main localities, and to identify the required sampling points.
 Currently, the problem of ensuring rational use of water resources is severe because of such factors as growth of water consumption, irrational use of natural resources, excessive and uncontrolled economic activity. All these factors lead to disruption of relations within geosystems, degradation of natural components and decrease of natural resources productivity. Therefore, the study of a degree of anthropogenic transformation of landscape complexes, including geosystems, allows identification of a possibility to reverse anthropogenic changes and display intensity and tendencies of natural processes after transformation of the complexes, as well as display of ability of natural components of the landscape to self-restore. All these components are necessary for field researches and form a basis for the author's research.
 The aim of the research is to conduct an assessment of the ecological status of surface waters, which serves as one of components of the general status of water bodies, as well as to determine their chemical status based on concentrations of high-priority hazardous pollutants. It establishes the fact that the quality of surface waters of the basin depends on a degree of pollution of water bodies that are subject to economic activity affecting the transformation of the basin system.

Eco-assessment of least disturbed areas of the Antalya River basin: application of diatom indices from different ecoregions.

Biomonitoring of least disturbed areas is a crucial issue to accurately assess the ecological status of surface waters and ensure their sustainability. Diatom metrics are important tools for the assessment of environmental conditions of lotic ecosystems to achieve environmental sustainability. The present study was aimed to evaluate the ecological status of least disturbed areas in the Antalya River basin (Turkey) using diatom indices developed from different ecoregion. Diatom species such as Cymbella excisa, Achnanthidium minutissimum, Cocconeis euglypta, and Cocconeis placentula were the most contributing species to the dissimilarity of sampling stations between rainy and dry seasons. The first two axes of canonical correspondence analysis (CCA) elucidated a strong (86%) correlation between diatom taxa and stressors. Results of the Monte Carlo permutation test indicated that total phosphorus (TP), water temperature, Tin (Sn), total organic carbon, zinc, and pH are significantly influential ecological factors on the distribution of diatom taxa among sampling stations. The Spearman correlation rank test indicated that diatom indices had significant positive and negative correlations with TP gradient. Results revealed that diatom indices developed from different ecoregions have different scores for the eco-assessment of similar sampling stations. European diatom indices mostly showed similar behavior in the bioassessment of the ecological status of rivers in the Antalya region compared to the different ecoregion. Among European diatom indices, TIT was more competitive and could give better results in the bio-evaluation of rivers in the Antalya River basin. Using diatom indices developed from different ecoregions may lead to an erroneous assessment of water quality. Accordingly, ecoregional specific diatom metrics are needed to accurately determine the surface water quality. Eco-assessment of least disturbed areas of the Antalya River basin: application of diatom indices from different ecoregions: Abuzer Çelekli, Ömer Lekesiz, Tolga Çetin.

Do investments in water quality and habitat restoration programs pay off? An analysis of the chemical and biological water quality of a lowland stream in the Zwalm River basin (Belgium)

Early nineties of previous century aquatic biodiversity was low in many West-European countries as a consequence of pollution, hydromorphological degradation and a lack of sound environmental legislation. Since the early 2000s and the implementation of the European Water Framework Directive a big step forward has been made to achieve a good ecological status of surface waters in Europe. However, to date little is known about the response of biological life in small lowland streams on improving conditions for both water quality and habitat diversity. In this study, we assessed possible relationships between chemical water quality and aquatic biodiversity of the Zwalm River basin (Belgium) using a dataset of long-term measurements of the chemical and biological water quality. Specifically, we wanted to know 1) the evolution in chemical and biological water quality over the last three decades and 2) if an improvement in chemical water quality was reflected in the macroinvertebrate and fish diversity. We found that there was indeed a significant improvement in the chemical water quality thanks to the installation of wastewater treatment plants and river basin management plans. Shortly after this improvement in chemical water quality, an increase in the number and abundance of pollution sensitive macroinvertebrate taxa was observed, which was consequently also seen in the biotic index score, based on macroinvertebrates. Despite a limited change in community composition observed for fish, no significant increase in diversity, or in the biotic index score of fish could be found. Currently, a stagnation of the improving water quality is observed. Hydromorphological restoration and free fish migration remain important key factors to improve diversity of macroinvertebrates and fish species. Based on the results of this study, we provide guidelines (for example restoration of spawning beds, decrease diffuse pollution from agriculture) to optimize the investments made in river restoration and to achieve the good ecological status by 2027 as defined by the European Water Framework Directive.

Nutrient load compensation as a means of maintaining the good ecological status of surface waters

We examine how nutrient load compensation could help a firm expand its production when production is a source of nutrient loads, threatening the ecological status of a water body. We ask whether compensation is technically feasible and whether it can be made in an ecologically sustainable way. Credits for compensation may be provided by point or nonpoint sources. We apply our approach to the case of Finnish Lake Kallavesi, where the Supreme Administrative Court, based on the Water Framework Directive, refused an environmental permit for a plan to build a large pulp mill. We employ a lake nutrient response model to determine water quality using probabilistic analysis of the ecological status of the lake. The supply potential of phosphorus credits from point sources was too low to keep the lake in good ecological status with at least 80% probability and must be complemented by credits from agricultural nonpoint sources. Using a trade ratio of 1:1.2 to reflect uncertainty on credits from nonpoint sources suggests that the reduction in agricultural phosphorus loading would suffice on its own to ensure the good ecological status by 90% probability. The cost of buying nutrient reduction credits would be at most 2% of the investment.

Multiple stressors determine river ecological status at the European scale: Towards an integrated understanding of river status deterioration.

The biota of European rivers are affected by a wide range of stressors impairing water quality and hydro-morphology. Only about 40% of Europe's rivers reach 'good ecological status', a target set by the European Water Framework Directive (WFD) and indicated by the biota. It is yet unknown how the different stressors in concert impact ecological status and how the relationship between stressors and status differs between river types. We linked the intensity of seven stressors to recently measured ecological status data for more than 50,000 sub-catchment units (covering almost 80% of Europe's surface area), which were distributed among 12 broad river types. Stressor data were either derived from remote sensing data (extent of urban and agricultural land use in the riparian zone) or modelled (alteration of mean annual flow and of base flow, total phosphorous load, total nitrogen load and mixture toxic pressure, a composite metric for toxic substances), while data on ecological status were taken from national statutory reporting of the second WFD River Basin Management Plans for the years 2010-2015. We used Boosted Regression Trees to link ecological status to stressor intensities. The stressors explained on average 61% of deviance in ecological status for the 12 individual river types, with all seven stressors contributing considerably to this explanation. On average, 39.4% of the deviance was explained by altered hydro-morphology (morphology: 23.2%; hydrology: 16.2%), 34.4% by nutrient enrichment and 26.2% by toxic substances. More than half of the total deviance was explained by stressor interaction, with nutrient enrichment and toxic substances interacting most frequently and strongly. Our results underline that the biota of all European river types are determined by co-occurring and interacting multiple stressors, lending support to the conclusion that fundamental management strategies at the catchment scale are required to reach the ambitious objective of good ecological status of surface waters.

Benthic Diatoms in River Biomonitoring—Present and Future Perspectives within the Water Framework Directive

The European Water Framework Directive 2000/60/EC (WFD) has been implemented over the past 20 years, using physicochemical, biological and hydromorphological elements to assess the ecological status of surface waters. Benthic diatoms (i.e., phytobenthos) are one of the most common biological quality elements (BQEs) used in surface water monitoring and are particularly successful in detecting eutrophication, organic pollution and acidification. Herein, we reviewed their implementation in river biomonitoring for the purposes of the WFD, highlighting their advantages and disadvantages over other BQEs, and we discuss recent advances that could be applied in future biomonitoring. Until now, phytobenthos have been intercalibrated by the vast majority (26 out of 28) of EU Member States (MS) in 54% of the total water bodies assessed and was the most commonly used BQE after benthic invertebrates (85% of water bodies), followed by fish (53%), macrophytes (27%) and phytoplankton (4%). To meet the WFD demands, numerous taxonomy-based quality indices have been developed among MS, presenting, however, uncertainties possibly related to species biogeography. Recent development of different types of quality indices (trait-based, DNA sequencing and predictive modeling) could provide more accurate results in biomonitoring, but should be validated and intercalibrated among MS before their wide application in water quality assessments.

Assessing the Ecological Status of European Rivers and Lakes Using Benthic Invertebrate Communities: A Practical Catalogue of Metrics and Methods

The Water Framework Directive requires that the ecological status of surface waters be monitored and managed if necessary. A central function in ecological status assessment has the Biological Quality Elements—organisms inhabiting surface waters—by indicating human impact on their habitat. For benthic invertebrates, a wide array of national methods are used, but to date no comprehensive summary of metrics and methods is available. In this study, we summarize the benthic invertebrate community metrics used in national systems to assess the ecological status of rivers, (very) large rivers, and lakes. Currently, benthic invertebrate assemblages are used in 26 national assessment systems for rivers, 13 assessment systems for very large rivers, and 21 assessment systems for lakes in the EU. In the majority of systems, the same metrics and modules are used. In the Red Queen’s race of ecosystem management this may be a disadvantage as these same metrics and module likely depict the same stressors but there is growing evidence that aquatic ecosystems are subject to highly differentiated, complex multiple stressor impacts. Method development should be fostered to identify and rank impacts in multi-stressor environments. DNA-based biomonitoring 2.0 offers to detect stressors with greater accuracy—if new tools are calibrated.

Use of Biotesting Methods for Assessing the Ecological Condition of Surface Waters

Purpose. Analysis of national and foreign experience in solving the problem of chemical pollution of surface waters and its economic consequences in accordance with the provisions of European legislation. Methods. System analysis. Results. Selection of the optimal set of biotesting methods for assessing the environmental consequences of chemical pollution of surface waters; study of the system of environmental liability, which operates in European and other foreign countries, and national regulations on the recovery of damages for violations of water legislation. The analysis of foreign and national sources on the use of biotesting techniques to assess the ecological status of surface waters and determine the toxic properties of water and chemicals. In world practice, a biotesting method is used to obtain data on the effects of hazardous toxic chemicals on aquatic ecosystems. Biotests are available and cheap (when using specially designed modifications for practical needs), do not require special training of performers and can be easily mastered in practical laboratories. Conclusions. To assess and control the quality of surface waters and their sources of pollution in accordance with the recommendations of the Water Framework Directive 2000/60 / EC, biotesting techniques are used using a "basic set of taxa" - algae, crustaceans and fish.