Search Results (14)

A pilot ichthyological index was developed for use within the Water Framework Directive in the area of Central and Eastern Europe for dam reservoirs, which are heavily modified water bodies. This is the first approach to assessing this water body type based on ichthyofauna in Poland. Various fishing gear types were used. The tested dam reservoirs were scattered throughout the country, from lowland to mountainous areas, with very diverse hydrological and morphological characteristics and pressure ranges based on the TSI index. In preliminary work, a correlation matrix with the TSI index’s pressure indicator was tested based on the abundance or biomass of fish species, fish families present, fishing gear used, and fishing depth range for a total of 588 cases. As a result of the tests carried out, the preliminary indicator was based on the ratio of the number of the two families Cyprinidae and Percidae. The correlation between the developed indicator and the pressure index was strong (r = 0.77; p < 0.001). The Percidae family exhibited a strong correlation with the most connections in the matrix. Based on the obtained results, the principle of using already confirmed relationships, such as the ratio between Cyprinidae and Percidae fish families, in the assessment of eutrophication was confirmed to be effective, guaranteeing the effective initial assessment of ecological potential. Full article

Accurate monitoring of water bodies is essential for the management and regulation of water resources. Traditional methods for measuring water quality are always time-consuming and expensive; furthermore, it can be very difficult capture the full spatiotemporal variations across regions. Many studies have shown the possibility of remote-sensing-based water monitoring work in many areas, especially for water quality monitoring. However, the use of optical remotely sensed imagery depends on several factors, including weather, quality of images and the size of water bodies. Hence, in this study, the feasibility of optical remote sensing for water quality monitoring in the Republic of Ireland was investigated. To assess the value of remote sensing for water quality monitoring, it is critical to know how well water bodies and the existing in situ monitoring stations are mapped. In this study, two satellite platforms (Sentinel-2 MSI and Landsat-8 OLI) and four indices for separating water and land pixel (Normalized Difference Vegetation Index—NDVI; Normalized Difference Water Index—NDWI; Modified Normalized Difference Water Index—MNDWI; and Automated Water Extraction Index—AWEI) have been used to create water masks for two scenarios. In the first scenario (Scenario 1), we included all pixels classified as water, while for the second scenario (Scenario 2) accounts for potential land contamination and only used water pixels that were completed surround by other water pixels. The water masks for the different scenarios and combinations of platforms and indices were then compared with the existing water quality monitoring station and to the shapefile of the river network, lakes and coastal and transitional water bodies. We found that both platforms had potential for water quality monitoring in the Republic of Ireland, with Sentinel-2 outperforming Landsat due to its finer spatial resolution. Overall, Sentinel-2 was able to map ~25% of the existing monitoring station, while Landsat-8 could only map ~21%. These percentages were heavily impacted by the large number of river monitoring stations that were difficult to map with either satellite due to their location on smaller rivers. Our results showed the importance of testing several indices. No index performed the best across the different platforms. AWEI_nsh (Automated Water Extraction Index—no shadow) and Sentinel-2 outperformed all other combinations and was able to map over 80% of the area of all non-river water bodies across the Republic of Ireland. While MNDWI was the best index for Landsat-8, it was the worst performer for Sentinel-2. This study showed that optical remote sensing has potential for water monitoring in the Republic of Ireland, especially for larger rivers, lakes and transitional and coastal water bodies. Full article

In surficial sediments of Lake Piediluco, a small, riverine, regulated and heavily modified water body in the Central Italian Apennines, contamination by persistent organochlorine pollutants (POPs) was assessed. During spring and autumn, six representative points were investigated. Reflecting a substantial zonation of pollution within this aquatic ecosystem, concentrations were found to vary from site to site. OCPs, particularly DDT and its metabolites DDE and DDD, were detected at varying frequencies and concentrations from 0.301 to 8.185 ng/g d.w., whilst total PCBs (Σ50 congeners) were from 0.570 to 10.206 ng/g d.w. Although both PCB congener-specific and homolog patterns suggest a prevalent presence of Aroclors 1254 and 1260, a more limited likely contribution of 1248 technical mixture is not to be excluded. In the western area of the lake, affected daily by continuous basin water remixing for hydroelectricity production, major seasonal differences in OCP concentrations were found. Conversely, the eastern area was typified by low seasonal fluctuation and small variation among sites. Regardless of either collection site or seasonality, polychlorinated-p-dioxin and furan (PCDD/Fs) contamination were below 8.3 pg WHO-TEQ/g. In contrast to the present study, POP pollution from PCBs, PCDD/Fs and some DDT-derived pollutants has not been investigated so far. Nevertheless, the concentrations are typical of low-polluted or pristine area lakes and are consistently lower than those of other Italian lakes of greater size and depth (e.g., Como, Garda and Maggiore). The physical and chemical properties of investigated analytes are more consistent with probable diffuse point source contamination originating from the catchment area, rather than from atmospheric depositions by regional or long-range transports. Finally, according to the international sediment quality guidelines (SQGs), Piediluco sediments pose a low risk to sediment-dwelling organisms and, more generally, to the wildlife of such aquatic ecosystems. Full article

Water Framework Directive (WFD) guidance documents from 2019 provide a comprehensive review of methods and guidelines to improve the comparability of heavily modified water bodies (HMWBs) in the European Union. However, there is currently no common, single methodology for monitoring HMWBs and artificial water bodies (AWBs) or for determining maximum (MEP) and good ecological potential (GEP). This study presents the first assessment of hydromorphological conditions of HMWBs and AWBs in Croatia based on type-specific indicators. The typology of HMWBs and AWBs was based on distinct hydromorphological characteristics and modifications in order to be easily related to the uses of the water bodies. The classes of hydromorphological potential were graded from the theoretical MEP, which was determined by the score scale as the tolerated deviation from natural reference conditions, considering potential mitigation measures. The use of the water body and/or the effects on the wider environment were considered while determining MEP and choosing indicators included in monitoring and assessment. In the case of AWBs, the parameters dependent on natural reference conditions, which are non-existent, were omitted from the assessment. Only 27% of HMWBs and 2 out of 51 AWBs achieved good potential for all three hydromorphological elements. The most significant hydromorphological modifications include channelization, straightening, deepening and removal of riparian vegetation due to flood-protection management practices. In order to achieve the environmental objectives set out by the WFD, the Croatian water management system has to start implementing mitigation measures, especially related to natural flood management. Full article

The Water Framework Directive (WFD) is the European legislation on water policy that assesses water quality according to time-consuming metrics and specific taxonomic needs. In this sense, the objective of this study was to evaluate the sensitivity of Daphnia magna feeding rate assays to assess/discriminate the water quality of heavily modified and artificial water bodies. Monthly, for one year, the quality of the Crestuma-Lever reservoir (in two sampling sites: Crestuma and Marina) was assessed using physical, chemical, and biological (concentration of chlorophyll-a) elements proposed by the WFD. Additionally, D. magna was exposed to the collected water samples and the feeding rates were evaluated to include an ecosystem function evaluation in water quality assessment. The WFD metrics showed that, overall, the Crestuma-Lever reservoir has a rating of Good to Moderate Ecological Potential, regardless of site. Feeding rates varied with the sampling site and months, demonstrating that feeding behavior evaluation is a sensitive tool that allows discriminate potential effects indicative of a lower water quality. This finding was recorded by the decrease in the feeding rate (Crestuma: May, Sept; Marina: Nov, Jan, May), despite the WFD classification, and once the organisms are affected by the components present in the water samples. Full article

Stickleback (Gasterosteus aculeatus) is an endangered species in Catalonia. It has disappeared from most of its historical range, including at least five whole basins, and the remaining populations continue to decline. Our monitoring, carried out on most Catalan populations in the north-east of the country, indicates that over the last 15 years there has been a reduction of between 50% and 75% everywhere. Even worse, many of the remaining populations are in heavily modified Mediterranean river stretches, subjected to multiple anthropogenic pressures or highly vulnerable to increasingly drastic droughts due to climate change. In this context, in 2018 we started a project that aims to implement a long-term, low-cost strategy for the conservation of this species in Catalonia. We have opted for a combination of broad-spectrum alternative measures: (1) Strategic restoration of small stretches of river of high interest to the species, mainly intended to ensure the maintenance of flooded pools during extreme droughts. (2) Reintroduction in river stretches with historical presence, firstly in watersheeds with extant populations. (3) Gradually, application of assisted migration to water bodies without historical presence, but with good ecological conditions for a probable successful establishment. (4) Creation of new ex-situ populations in small artificial water bodies, from urban ornamental ponds to small irrigating reservoirs, reaching agreements with the owners, and often carrying out essential previous actions, such as the exotic fish removal. (5) Continuation and extension of regular sampling, in order to implement a permanent monitoring of its trends, and expand the specific knowledge on some key aspects of its ecology. (6) Implementation of a specific environmental awareness and education campaign, as well as environmental volunteering, for the involvement of society in the conservation of this small fish and its habitats. The known genetic differentiation of the remaining populations is being taken into account in the planning of these actions. We will present the results achieved so far, and the plans for the coming years. Full article

Reservoirs are dynamic ecosystems subject to different pressures that influence and compromise their ecological structure. The main objective of this study was to evaluate the potential of using the macroinvertebrate to assess the water quality of four reservoirs (one site in Miranda—M and Pocinho—P; four sites in Aguieira—Ag1 to Ag4; and five sites in Alqueva—Al1 to Al5). The sites were sampled in autumn 2018 (A18), spring and autumn 2019 (S19 and A19) and spring 2020 (S20). In situ physical and chemical parameters were measured and a sample of water and macroinvertebrate were collected for further analyses. Total phosphorus exceeded the allowed concentrations (maximum values recorded: M—0.13 mg/L, P—0.09 mg/L, Ag3—0.22 mg/L and Al5—0.18 mg/L). Total abundance varied between 4 and 3088. Taxonomic richness was always low, between 1 and 12 taxa. The highest Shannon–Wiener value (1.91) was recorded in Ag1_A18 and Al2_A18. Pielou’s evenness varied widely across all reservoirs, from 0.06 to 0.92. Almost all the organisms found were associated with polluted water, according to the index ratings. Organisms tolerant of disturbances (e.g., Chironomidae and Oligochaeta) were associated with sites with the worst water quality, according to the Water Framework Directive (WFD), (M, Ag3, Ag4 and Al5) while organisms with moderate tolerance to disturbances (e.g., Cordullidae and Polycentropodidae) were associated with sites with better water quality (P, Ag1, Ag2 and Al1 to Al4). The macrozoobenthos index (MZB) used proved to be a sensitive tool to Portuguese reservoirs, corroborating most of the results obtained in the remaining analyses, as well as providing a clear ecological potential complementing the analysis carried out by the WFD. Based on this, the macroinvertebrate community appeared to be sensitive and able to characterize the reservoirs’ water quality. Full article

The Water Framework Directive (WFD) is used to evaluate the water quality of aquatic ecosystems. Phytoplankton is the only biological element considered in the reservoirs water quality assessment. In this study, we aimed to assess the use of the bacterioplankton community as an indicator of water quality, using a culture-independent assay (denaturing gradient gel electrophoresis, DGGE). Four Portuguese reservoirs (Miranda, Pocinho, Aguieira and Alqueva) were analysed in four periods (autumn 2018, spring and autumn 2019, and spring 2020). Bacterial total abundance had similar values for Miranda, Pocinho and Aguieira, and generally lower values for Alqueva. Diversity and richness values did not show a clear trend. Negative correlations were observed between some nutrients and the bacterial community. Overall, members of Actinobacteria, Bacteroidetes, Cyanobacteria, Nitrospirae and Proteobacteria were identified in all sampling sites. In Alqueva, no spatial, temporal or water body quality relationships with bacterial community were observed, which may be due to its higher size, low water velocity rate and higher residence times. However, in Miranda, Pocinho and Aguieira, a strong spatial and temporal bacterial community dynamic was observed. Furthermore, the presence of some species (e.g., Acinetobacter sp.) may reflect the poor water quality that was not detected by the WFD approach. Full article

This work intended to assess the adaptability of bioassay with Raphidocelis subcapitata to be used as a complement to the water quality assessment parameters of reservoirs imposed by the European Water Framework Directive (WFD). Thus, water samples of Portuguese reservoirs (Miranda, Pocinho, Aguieira, and Alqueva) were analyzed in three sampling periods (spring and autumn 2019, and spring 2020). A physical and chemical report of waters was also performed. R. subcapitata assay proved to be sensitive, indicating the presence of a potential perturbation that was not always associated with chemical analysis performed. In general, in the spring samplings, the water samples showed more disturbances to R. subcapitata, which in some situations may be associated with the higher content of nutrients and metals. Microalgae assay can be an effective complementary tool to indicate the ecotoxicological potential since they responded quickly to all sample components of water samples, in a wide-ranging variety of water conditions (different sites in several reservoirs). High similarities between the final ecotoxicological and the ecological potentials, according to the WFD parameters, were detected. The ecotoxicological approach based on our results allowed to confirm that bioassays with R. subcapitata are suitable and sensible to detect perturbations. Full article

Fish passes facilitate fish movement in fragmented river systems, yet they can also provide important habitat functions. This study investigated the fish community composition of different constructed habitat types (fluvial habitats, floodplain ponds) within fish passes in relation to habitat characteristics in order to deduce recommendations for fish-friendly designs of such structures. Fish community structures within passes differed significantly from those in the main river, comprising a high number of rheophilic species in fluvial habitats (Thymallus thymallus, Hucho hucho, Salmo trutta, Cottus gobio, Chondrostoma nasus, and Barbus barbus), and of stagnophilic species in floodplain ponds (Rhodeus amarus, Scardinius erythrophthalmus, Misgurnus bipartitus, and Tinca tinca). During summer, floodplain ponds also provided important juvenile habitats for the target species C. nasus and B. barbus. Differences between the two habitat types in fish abundance were mostly explained by differences in macrophyte coverage, gravel, boulders, temperature, and current speed. The findings of this study stress the important habitat functions of fish passes. They also suggest that integration of diverse habitat structures, especially of currently hardly considered constructed floodplain ponds into fish passes, can greatly enhance their fish communities and contribute to the restoration of several declining target species of conservation. Full article

Natural and anthropogenic pressures in inland waters induce molecular response mechanisms in organisms as a defense against such multiple stressors. We studied, for the first time, the expression of the stress proteins, heat shock proteins (HSP) and mitogen-activated proteins kinase (MAPK), in a Daphnia magna natural population as a response to environmental changes in a heavily modified water body (Lake Koronia, Northern Greece). In parallel, the water physicochemical parameters, nutrients’ concentration and phytoplankton abundance were measured. Our results showed fluctuations of the proteins’ levels (HSP70, HSP90, phospho-p38 MAPK, phospho-p44/42 MAPK) providing evidence of their expression in situ. HSP70 showed an increasing tendency while for HSP90, no tendency was recorded. The MAPKs’ members followed a reverse pattern compared to each other. The differential expression of HSP and MAPK members indicates that D. magna in Lake Koronia experienced stressors such as increasing temperature, salinity and increased nutrient concentrations, high pH values and variations in phytoplankton abundance that triggered their activation. These in situ findings suggest that HSP and MAPK expression patterns have the potential to be used as biomarkers of stress factors in D. magna, for effective biomonitoring and setting ecological restoration targets. Full article

Emerging pollutants have aroused an increasing concern due to their ubiquitous presence in the environment and harmful potential. Both emerging (e.g., pharmaceuticals and personal care products) and regulated organic pollutants pose a serious threat to water quality and their presence and spatial distribution are complicated to address as they can derive from several factors: distribution of point and diffuse sources, environmental conditions, hydrogeological features of the region and inherent properties of the considered contaminants. In this study, a ground and surface water monitoring campaign was conducted in the three main detritic groundwater bodies of an extensive and heavily modified river basin in order to draft an initial description of the occurrence and distribution of a wide range of organic contaminants. In total, 63 out of 185 target pollutants were detected. An attempt to understand the importance of different factors governing the distribution of some of the most frequently found pollutants was made. Antibiotics spatial distribution is potentially influenced by the hydrogeological functioning of the basin modified by hydraulic infrastructures (reflected by hydrochemistry and environmental tracers δ²H and δ¹⁸O), not directly related to the distribution of potential sources. The presence of other organic pollutants does not reflect an evident correlation with flow pathways. Differences in contaminant occurrence are potentially attributed to the way pollutants are released into the environment as well as physico-chemical properties. Full article

Reservoirs are formed through the artificial damming of a river valley. Reservoirs, among others, capture polluted load transported by the tributaries in the form of suspended and dissolved sediments and substances. Therefore, reservoirs are treated in the European Union (EU) as “artificial” or “heavily modified” surface water bodies. The reservoirs’ pollutant load depends to a large extent on the degree of anthropogenic impact in the respective river catchment area. The purpose of this paper is to assess the mutual relation between the catchment area and the reservoirs. In particular, we focus on the effects of certain land use/land cover on reservoirs’ water quality. For this study, we selected twenty Polish reservoirs for an in-depth analysis using 2018 CORINE Land Cover data. This analysis allowed the identification of the main triggering factors in terms of water quality of the respective reservoirs. Moreover, our assessment clearly shows that water quality of the analysed dam reservoirs is directly affected by the composition of land use/land cover, both of the entire total reservoir catchment areas and the directly into the reservoir draining sub-catchment areas. Full article

According to the Water Framework Directive, harbours that are classified as heavily modified water bodies must either reach or maintain good ecological potential. Moreover, following the marine spatial planning principles, the effects of port structure changes on water quality must also be considered. To support the sustainable management of harbour waters, we calculated flushing time (FT) through the use of a numerical model within the Civitavecchia port under different scenarios. To assess the effects of the realization of new infrastructure that will significantly alter the port configuration in the coming years, we also developed the flushing efficiency index (FEI). The increase in the harbour basin size due to the embankment extension result in high values of FT, particularly in the inner part of the port, in accordance with the highest values of the enrichment factor of the trace metals found in the sediment. The deterioration of water quality is confirmed by negative FEI values. Otherwise, the index assumes positive values after the realization of a second entrance in the southern part of Civitavecchia port, highlighting a drastic improvement in harbour water renewal. This study provides a low-cost and predictive tool to correctly address environmentally sustainable management of port activities. Full article