Quality Of Aquatic Ecosystems Research Articles

Modeling Fecal Indicator Bacteria in Urban Waterways Using Artificial Neural Networks

AbstractFecal indicator bacteria (FIB) are used as proxies to measure the microbial water quality of aquatic ecosystems. Methods of modeling FIB have evolved in order to provide accurate and timely...

Evaluation of the anthropogenic impact in Suat Ugurlu Dam lake using multivariate statistical techniques

Sediments play an important role in the quality of aquatic ecosystems in the Dam Lake where they can either be a sink or a source of contaminants, depending on the management. This purpose of this study is to identify the sediment quality in order to find out the causes for the malodor and the eutrophication that is causing a bad scenario. Solutions for improving the dam are proposed. Multivariate statistical techniques, such as a principal component analysis (PCA) and cluster analysis (CA), were applied to the data regarding sediment quality in relation to anthropogenic impact in Suat Ugurlu Dam Lake. This data was generated during 2014-2015, with monitoring at four sites for 11 parameters. A PCA and CA were used in the study of the samples. The total variance of 84.1%, 74.3%, 87.4% and 91.5% suggest 4, 3, 3 and 4 principle components (PCs) in the four locations: LC1, LC2, LC3 and LC4, respectively. Also, a CA was applied to both the variables and the observations. Some variables and observations showed a high similarity based on the results of variables in the CA. Also, the similarity ratio of temperature-mercury (Hg) and oxidation reduction potential (ORP) was high and generally, the cluster number of variables was 5, according to the selected similarity level.

Parasites and pollution: the effectiveness of tiny organisms in assessing the quality of aquatic ecosystems, with a focus on Africa.

The aquatic environment represents the final repository for many human-generated pollutants associated with anthropogenic activities. The quality of natural freshwater systems is easily disrupted by the introduction of pollutants from urban, industrial and agricultural processes. To assess the extent of chemical perturbation and associated environmental degradation, physico-chemical parameters have been monitored in conjunction with biota in numerous biological monitoring protocols. Most studies incorporating organisms into such approaches have focussed on fish and macroinvertebrates. More recently, interest in the ecology of parasites in relation to environmental monitoring has indicated that these organisms are sensitive towards the quality of the macroenvironment. Variable responses towards exposure to pollution have been identified at the population and component community level of a number of parasites. Furthermore, such responses have been found to differ with the type of pollutant and the lifestyle of the parasite. Generally, endoparasite infection levels have been shown to become elevated in relation to poorer water quality conditions, while ectoparasites are more sensitive, and exposure to contaminated environments resulted in a decline in ectoparasite infections. Furthermore, endoparasites have been found to be suitable accumulation indicators for monitoring levels of several trace elements and metals in the environment. The ability of these organisms to accumulate metals has further been observed to be of benefit to the host, resulting in decreased somatic metal levels in infected hosts. These trends have similarly been found for host-parasite models in African freshwater environments, but such analyses are comparatively sparse compared to other countries. Recently, studies on diplozoids from two freshwater systems have indicated that exposure to poorer water quality resulted in decreased infections. In the Vaal River, the poor water quality resulted in the extinction of the parasite from a site below the Vaal River Barrage. Laboratory exposures have further indicated that oncomiracidia of Paradiplozoon ichthyoxanthon are sensitive to exposure to dissolved aluminium. Overall, parasites from African freshwater and marine ecosystems have merit as effect and accumulation indicators; however, more research is required to detail the effects of exposure on sensitive biological processes within these organisms.

Assessment of water quality in Iran’s Anzali Wetland, using qualitative indices from 1985, 2007, and 2014

In the present study, the water quality of the Anzali Wetland, located southwest of the Caspian Sea in Iran, was compared for the years 1985, 2007, and 2014, using a weighted arithmetic mean function (National Sanitation Foundation Water Quality Index: NSFWQIa), a weighted geometric mean function (NSFWQIm), and the Oregon Water Quality Index (OWQI). To that end, nine water quality parameters [pH, turbidity (TURB), temperature (T), dissolved oxygen (DO), nitrate (NO3), total solids (TS), phosphate (PO4), biological oxygen demand (BOD5), and fecal coliforms (FC)] were analyzed at eight selected stations. According to the proposed classification for water quality indices (higher value (0–100), better water quality), the Wetland water quality was classified as the mean values of the three indices for the three sampled years, as follows: NSFWQIa (13.72, 12.81, 12.07); NSFWQIm (63.049, 52.388, 49.108); and OWQI (26.867, 14.477, 15.53). The values of NSFWQIa, NSFWQIm, and OWQI for the western stations were better than for the other stations in the region over the 29-year span of investigation; however, the remainders of the stations’ values were very poor. Because wastewaters discharged from industrial and agricultural areas are more concentrated in the eastern part of the Anzali Wetland, the eastern stations of the Wetland showed lower water quality compared to the central and western stations. The water of the Anzali Wetland has different quality classes according to the aggregation methods employed. It is concluded that when evaluating water quality of aquatic ecosystems, several indices should be used to obtain more comprehensive results.

Fluctuating Asymmetry in Two Common Freshwater Fishes as a Biological Indicator of Urbanization and Environmental Stress within the Middle Chattahoochee Watershed

Deviations in bilateral symmetry or fluctuating asymmetry of an organism may result under environmental stressors that reduce developmental homeostasis and stability. Anthropogenic stressors such as increased urbanization can negatively impact environmental quality of aquatic ecosystems. Researchers have stressed the value in finding easy, accurate and inexpensive methods for assessing potential stress within ecosystems. Here we use fluctuating asymmetry (FA) as a useful quantitative tool in assessing the environmental quality and potential urban-based stressors within eight creeks of the Bull and Upatoi Creeks Watershed within the larger watershed of the Middle Chattahoochee. Using Geographic Information System (GIS), we characterize land-use patterns and a decreasing urbanization gradient as related to each creek’s eastward position from Columbus, Georgia. We collected two common fishes (redbreast sunfish; Lepomis auritus and bluegill; Lepomis macrochirus), measured both metric and meristic traits and investigated if the degree of FA in these two common fishes correlated with the urbanization gradient across creeks. We found significant differences in FA among creeks with one of the highest FA measures for the most urban creek. Principal component analysis (PCA) scores of urbanization and water chemistry were regressed against FA scores. We found no significant relationship between urbanization and FA nor environmental water chemistry and FA among creeks. We comment on the use of FA as a potential response variable and biological indicator of environmental stress within this watershed.

Macrophyte response to the protection and restoration measures of four water bodies

Macrophytes are a good long-term indicator of quality of aquatic ecosystems and are essential for the proper functioning of the entire lake ecosystem. Submerged vegetation is considered to be indicative of an improvement of the ecological status of these lakes. Here, we analyzed the distribution, structure, and diversity of vegetation communities in four eutrophic water bodies (postglacial lakes: Slawskie and Uzarzewskie and man-made lakes: Maltanski Reservoir and Turawa Średnia Reservoir) after the application of restauration and protections measures. The restoration measures included biomanipulation, phosphorus inactivation, hypolimnion aeration, or injection of nitrate-rich waters to the hypolimnion. All of them were sustainable and did not cause drastic changes in the ecosystem. Between 9 and 17 macrophyte communities were found in the examined water bodies. The largest effects were observed after the simultaneous use of three lake restoration techniques which led to the appearance of 17% charophytes. Pronounced effects leading to the higher contribution of elodeids to the macrophyte community were achieved in the lake in which two methods were applied. Least effective was the method focused on hypolimnion restoration in a small lake, which did not cause the reappearance of submerged vegetation. Spontaneous recovery achieving good status is also possible in a large lake in case of applying the thorough conservation measures. An intensive growth and diversity of macrophytes was a result of the improvement in the water quality as a consequence of undertaken protective activities and/or restoration measures. However, the re-colonization of submerged macrophytes during restoration process is not obvious and the feed-back mechanisms may delay a response of the ecosystem. The vegetation of the studied lakes was unstable, showing high variability in individual years of research, which indicates that these ecosystems are still under reconstruction and not reach equilibrium state yet.

Diversity of Phytoplankton Communities in a Tropical River Basin, Nigeria

Biological assessment is a useful alternative for understanding the ecological quality of aquatic ecosystems because biological communities integrate the environmental effects of water. This work investigates the diversity and abundance of phytoplankton in the Upper Jebba Basin of the Niger River in Nigeria. We sampled phytoplanktons by dragging plankton nets at three stations from March to May 2015 for qualitative and quantitative samples. Qualitative plankton samples were collected by towing 55μm mesh hydrobios plankton nets just below the water surface for five minutes at each sampling station. Quantitative samples, on the other hand, were collected by filtering 100 litres of water fetched with a bucket through a 55μm mesh hydrobios net. Both samples were preserved separately in a 4% buffered formalin solution. A total of 3160 cells/ml of phytoplanktons from taxa were identified in the study. High dominance of Oscillatoria sp., Microcystis sp., Chlorella sp., Pediastrum sp. and Synendra indicate that this lake has high amount of organic waste, polluted predominantly by upstream concerns (i.e., mining, agricultural, and domestic) and should be monitored strictly by relevant agencies in order to additional reduced health hazards caused by these pollutants.HYDRO Nepal JournalJournal of Water, Energy and EnvironmentIssue: 19Page: 52-56

Explaining ecological quality by using variable vegetation densities in hydrological modelling

Interactions between vegetation density, water flow distribution and nutrient availability might explain spatial and temporal variability in ecological quality of aquatic ecosystems. We analysed these interactions by simulating a variable vegetation density in hydrodynamic and ecological models. Simulation results of two vegetation density scenarios were compared and related to ecological quality, determined by ecological tools and based on plant species abundance. Our results show that vegetation density is an important factor in determining the water flow distribution. It further shows that water and nutrient distribution influences the vegetation density. Interactions between vegetation density, water and nutrient distribution continue in a positive feedback loop. With this study we showed that explaining ecological quality with hydrological models is improved when variable vegetation densities are included.

Patterns and multi-scale drivers of phytoplankton species richness in temperate peri-urban lakes

Local species richness (SR) is a key characteristic affecting ecosystem functioning. Yet, the mechanisms regulating phytoplankton diversity in freshwater ecosystems are not fully understood, especially in peri-urban environments where anthropogenic pressures strongly impact the quality of aquatic ecosystems. To address this issue, we sampled the phytoplankton communities of 50 lakes in the Paris area (France) characterized by a large gradient of physico-chemical and catchment-scale characteristics. We used large phytoplankton datasets to describe phytoplankton diversity patterns and applied a machine-learning algorithm to test the degree to which species richness patterns are potentially controlled by environmental factors. Selected environmental factors were studied at two scales: the lake-scale (e.g. nutrients concentrations, water temperature, lake depth) and the catchment-scale (e.g. catchment, landscape and climate variables). Then, we used a variance partitioning approach to evaluate the interaction between lake-scale and catchment-scale variables in explaining local species richness. Finally, we analysed the residuals of predictive models to identify potential vectors of improvement of phytoplankton species richness predictive models.Lake-scale and catchment-scale drivers provided similar predictive accuracy of local species richness (R2=0.458 and 0.424, respectively). Both models suggested that seasonal temperature variations and nutrient supply strongly modulate local species richness. Integrating lake- and catchment-scale predictors in a single predictive model did not provide increased predictive accuracy; therefore suggesting that the catchment-scale model probably explains observed species richness variations through the impact of catchment-scale variables on in-lake water quality characteristics.Models based on catchment characteristics, which include simple and easy to obtain variables, provide a meaningful way of predicting phytoplankton species richness in temperate lakes. This approach may prove useful and cost-effective for the management and conservation of aquatic ecosystems.

Testate amoebae as indicators of water quality and contamination in shallow lakes of the Middle and Lower Yangtze Plain

Testate amoebae are micro-organisms characterized by an agglutinated or autogenous shell enclosing the cytoplasm. Testate amoebae have been widely proposed as valuable bioindicators in a range of ecosystems (such as soils, peatlands and lakes). The use of testate amoebae as bioindicators of water quality in aquatic ecosystems is much less developed than for other microorganisms and previous research is geographically restricted. We investigated a large range of environmental variables and their relations to testate amoeba communities from 37 shallow lakes in the middle and lower Yangtze River Plain of China. Multiple factor analysis, redundancy analysis (RDA) and a forward-selection approach were used to explore the overall community structure and the links between the environmental variables and testate amoeba composition. Results showed that testate amoebae are widely distributed in most of the lakes despite often high levels of pollution. Our data highlight some links between water quality variables and testate amoeba communities. In particular, our results suggest that heavy metals have a role in shaping testate amoeba assemblage structure, although correlations are comparatively weak, perhaps due to lagged responses. Our results support previous suggestions that testate amoebae may be useful bioindicators in aquatic ecosystems but emphasize the need for an improved mechanistic understanding.

Protist metabarcoding and environmental biomonitoring: Time for change

High-throughput amplicon sequencing of environmental DNA and/or RNA proved to be a powerful tool to describe protist diversity. This new approach called also the metabarcoding has totally transformed our view of protist diversity, revealing a large number of novel lineages and expanding the range of protist phylogenetic diversity at almost every taxonomic level. However, until now the objectives of the vast majority of metabarcoding studies were purely academic. Practical applications of protist metabarcoding are surprisingly scarce, despite the fact that several groups of protists are commonly used as bioindicators of environmental impacts in freshwater or marine ecosystems. Here, we are reviewing studies that examine the ecological applications of metabarcoding for two groups of well-known protist bioindicators: diatoms and foraminifera. The results of these studies show that despite some biological and technical biases, molecular data quite faithfully reflect the morphology-based biotic indices and provide a similar assessment of ecosystem status. In view of these results, protist metabarcoding appears as a rapid and accurate tool for the evaluation of the quality of aquatic ecosystems. Hence, we plead for integration of protist metabarcoding in future biomonitoring projects as a complement of traditional methods and a source of new biosensors for environmental impact assessment.

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Aquaculture activities are often blamed for the degradation of water quality of aquatic ecosystem. Present study was conducted to determine the water quality of Taal Lake at two different study sites viz. one under intense fish cage farming activities and the other without aquaculture activities. The study aims to assess the effect of aquaculture activities on selected water quality parameters, which include transparency, temperature, pH, nitrates, phosphates, salinity, total dissolved solids (TDS) and dissolve oxygen (DO). The study was conducted over a ten-month period in 2013-2014. Results of the study revealed no significant differences in water temperature, pH, salinity, transparency and DO between the aquaculture and non-aquaculture sites of the lake, although DO and transparency were consistently lower in the aquaculture sampling stations throughout the 10-month sampling period. DO dipped to critical level (<4 ppm) for aquatic organisms in the months of January and February. Nitrates, phosphates and TDS were significantly higher in the area with fish cage farming activities as compared to the non aquaculture site. Further, the study also reports the efforts of stakeholders to sustain fish cage farming in the lake which include participative, multi-sectoral action planning, information and education, policy formulation, regulation and licensing.

Improving real-time forecasting of water quality indicators with combination of process-based models and data assimilation technique

Water quality indicators can be used to characterize the status and quantify and qualify the change of aquatic ecosystems under different disturbance regimes. Although many studies have been done to develop and assess indicators and discuss interactions among them, few studies have focused on how to improve the predicted indicators and explore their variations in receiving water bodies. Accurate and effective predictions of ecological indictors are critical to better understand changes of water quality in aquatic ecosystems, especially for the real-time forecasting. Process-based water quality models can predict the spatiotemporal variations of the water quality indicators and provide useful information for policy-makers on sound management of water resources. Given their inherent constraints, however, such process models alone cannot actually guarantee perfect results since water quality models generally have a large number of parameters and involve many processes which are too complex to be efficiently calibrated. To overcome these limitations and explore a fast and efficient forecasting method for the change of water quality indictors, we proposed a new framework which combines the process-based models and data assimilation technique. Unlike most traditional approaches in which only the model parameters or initial conditions are updated or corrected and the models are run online, this framework allows the information extracted from observations and outputs of process models to be directly used in a data-driven local/modified local model. The results from the data-driven model are then assimilated into the original process model to further improve its forecasting ability. This approach can be efficiently run offline to directly correct and update the output of water quality models. We applied this framework in a real case study in Singapore. Two of the water quality indicators, namely salinity and oxygen were selected and tested against the observations, suggesting that a good performance of improving the model results and reducing computation time can be obtained. This approach is simple and efficient, especially suitable for real-time forecasting systems. Thus, it can enhance forecasting of water quality indictors and thereby facilitate the effective management of water resources.

Influence of dams on sediment continuity: A study case of a natural metallic contamination

Sediments play an important role on the quality of aquatic ecosystems, notably in the reservoir areas where they can either be a sink or a source of contaminants, depending on the management and hydrological conditions. The physicochemical properties of 25 surface sediments samples of a reservoir catchment (Vaussaire, Cantal, France) were studied. Results show a strong influence of dam presence, notably on the grain size and organic matter (OM) contents. The concentrations of trace metals and metalloids (As, Cd, Cr, Cu, Ni, Pb and Zn) were also measured and compared with worldwide reservoir concentrations and international sediment quality guideline levels in order to assess the intensity of the metallic contamination. Cr and Ni are the trace elements presenting the significantly highest values at the catchment scale. Enrichment Factors (EF), calculated using both local and national backgrounds, show that metals have mainly a natural origin, explaining especially the Cr and Ni values, linked with the composition of parental rocks. Unexpectedly, all the observed metal concentrations are lower in the reservoir than upstream and downstream, which might be related to the high fresh OM inputs in the reservoir, diluting the global metallic contamination. Multivariate statistical analyses, carried out in order to identify the relationship between the studied metals and sediment characteristics, tend to support this hypothesis, confirming the unusually low influence of such poorly-degraded OM on trace element accumulation in the reservoir.

Differential regulation of pro- and antiapoptotic proteins in fish adipocytes during hypoxic conditions.

Worldwide, the frequencies and magnitudes of hypoxic events in estuarine waters have increased considerably over the past two decades. Fish populations are suitable indicators for the assessment of quality of aquatic ecosystems and often comprise a variety of adaptation systems by triggering oxidants, antioxidants and hypoxia-responsive signaling proteins. Signaling pathway may lead to cell survival or cell death which is fine-tuned by both positive and negative factors, which includes hypoxia-inducible factor-1α (HIF1α), heat-shock protein-70 (HSP70), phospho-c-Jun N-terminal kinase 1/2 (p-JNK1/2) and apoptosis signal-regulating kinase-1 (ASK1). In the present study, we attempt to determine stress-mediated signaling changes and molecular mechanism behind the cell survival by comparing adipocytes of fish from field hypoxic condition and laboratory-induced hypoxic condition (in vitro hypoxia). Comparison of field and laboratory studies in fish adipocytes showed differential expression of HIF1α, HSP70, p-JNK1/2 and ASK1 with altered oxidants and antioxidants. Further, the results also suggest that in vitro hypoxic conditions mimic field hypoxic conditions. Trends of hypoxia response were same in in vitro hypoxia of control adipocytes as in Ennore estuary, and hypoxia response was more pronounced in the test adipocytes under in vitro hypoxic condition. Results of the present work suggest that hypoxia is the major crusade of water pollutants affecting fish by differential regulation of pro- and antiapoptotic proteins probably through HSP70. This may play a vital role by providing cytoprotection in pollutant-induced stressed fish adipocytes substantiated by the in vitro hypoxic studies.

DEVELOPMENT ELECTRONIC MAPS OF ECOLOGICAL STATUS OF WATER OBJECTS OF THE VOLGA RIVER DELTA

Abstract. Aim. The aim of this work was the comprehensive study of the ecological state of water objects of the Volga River delta. Methods. The following methods were used: field (collection, observation, organoleptic), uniform chemical analysis techniques are based on colorimetric, settlement, photometric, spectrometric measurement methods. Results. On the basis of results of researches for 2010-2014 performed a comparative analysis of the dynamics of the content of hydro-chemical indicators of environmental quality in waters of the Volga River delta and the residential areas of the background. Applying an integrated approach to the study of biological indicators of water quality. Created digitized map of the quality of aquatic ecosystems of the Volga River delta. Displaying modern ecological condition of watercourses investigated, determined the degree of contamination, the overall trophic and saprobic. Main conclusions. The work has identified adverse environmental situation in water objects of the Astrakhan and the surrounding areas. Average annual concentrations of toxicological substances water objects in the background zone 10 times less than in the water objects of settlements. As a result of work on the basis of ArcGis 10.2.2 created information environment Eco-monitor, which is a systematic set of information, and quantitatively characterizing the ecological status of water objects. Created on the basis of ArcGis 10.2.2 information environment monitoring system of waterways allows for a temporary and spatial analysis, to assess the quality of different streams in the control sections.

A fish-based index for assessing the ecological status of Polish transitional and coastal waters

Fish assemblages are considered indicators of aquatic ecosystem quality. Based on how fish communities respond to anthropogenic pressures, we developed a multimetric fish index for evaluating the health of both coastal and transitional waters. Fish data were collected along the Polish coast in the years 2011, 2013 and 2014 using different types of gear. Redundancy analysis showed that the most important environmental factor affecting fish community was salinity. Responses to anthropogenic disturbances of 20 candidate metrics were tested by generalized linear models, taking into account salinity, sampling protocol and the proxy of human pressures described by the Baltic Sea Impact Index (BSII). Five selected metrics were combined in a Multimetric Index, which showed negative significant correlation with BSII. The index presented herein appeared to be a good tool for assessing the ecological state of highly impacted Polish transitional and coastal areas and complies with the Water Framework Directive requirements.

Key factors affecting urban runoff pollution under cold climatic conditions

Urban runoff contains various pollutants and has the potential of deteriorating the quality of aquatic ecosystems. In this study our objective is to shed light on the factors that control the runoff water quality in urbanized catchments. The effects of runoff event characteristics, land use type and catchment imperviousness on event mass loads (EML) and event mean concentrations (EMC) were studied during warm and cold periods in three study catchments (6.1, 6.5 and 12.6 ha in size) in the city of Lahti, Finland. Runoff and rainfall were measured continuously for two years at each catchment. Runoff samples were taken for total nutrients (tot-P and tot-N), total suspended solids (TSS), heavy metals (Zn, Cr, Al, Co, Ni, Cu, Pb, Mn) and total organic carbon (TOC). Stepwise multiple linear regression analysis (SMLR) was used to identify general relationships between the following variables: event water quality, runoff event characteristics and catchment characteristics. In general, the studied variables explained 50–90% of the EMLs but only 30–60% of the EMCs, with runoff duration having an important role in most of the SMLR models. Mean runoff intensity or peak flow was also often included in the runoff quality models. Yet, the importance (being the first, second or third best) and role (negative or positive impact) of the explanatory variables varied between the cold and warm period. Land use type often explained cold period concentrations, but imperviousness alone explained EMCs weakly. As for EMLs, the influence of imperviousness and/or land use was season and pollutant dependent. The study suggests that pollutant loads can be – throughout the year – adequately predicted by runoff characteristics given that seasonal differences are taken into account. Although pollutant concentrations were sensitive to variation in seasonal and catchment conditions as well, the accurate estimation of EMCs would require a more complete set of explanatory factors than used in this study.

Morpho-histological characterization of immature of the bioindicator midge Chironomus sancticaroli Strixino and Strixino (Diptera, Chironomidae)

Chironomidae immature are used as bioindicators of sediment quality in aquatic ecosystems and ecotoxicological assays. Histological descriptions for this family are outdated and limited and there are no studies with Neotropical species. The aim of this study was to describe the tissue architecture of several organs of the larva of Chironomus sancticaroli. For the description of the histological pattern, the larvae were fixed in Duboscq solution for insects at 56°C, followed by routine histologic processing, infiltration in paraffin, and the sections were stained with Hematoxylin–Eosin. After examining the slides, the tube digestive, salivary gland, excretory, nervous, endocrine, circulatory, and integumentary systems and fat body were histologically characterized. The histology allows evaluation of cell morphology, and for being not expensive and easily accessible can be routinely used in biomonitoring. In addition, is a useful tool in ecotoxicological assays and allow to evaluate biomarkers at tissue and cell levels.

Two-Year Monitoring of Water Samples from Dam of Iskar and the Black Sea, Bulgaria, by Molecular Analysis: Focus on Mycobacterium spp.

The coast of the Bulgarian Black Sea is a popular summer holiday destination. The Dam of Iskar is the largest artificial dam in Bulgaria, with a capacity of 675 million m3. It is the main source of tap water for the capital Sofia and for irrigating the surrounding valley. There is a close relationship between the quality of aquatic ecosystems and human health as many infections are waterborne. Rapid molecular methods for the analysis of highly pathogenic bacteria have been developed for monitoring quality. Mycobacterial species can be isolated from waste, surface, recreational, ground and tap waters and human pathogenicity of nontuberculose mycobacteria (NTM) is well recognized. The objective of our study was to perform molecular analysis for key-pathogens, with a focus on mycobacteria, in water samples collected from the Black Sea and the Dam of Iskar. In a two year period, 38 water samples were collected—24 from the Dam of Iskar and 14 from the Black Sea coastal zone. Fifty liter water samples were concentrated by ultrafiltration. Molecular analysis for 15 pathogens, including all species of genus Mycobacterium was performed. Our results showed presence of Vibrio spp. in the Black Sea. Rotavirus A was also identified in four samples from the Dam of Iskar. Toxigenic Escherichia coli was present in both locations, based on markers for stx1 and stx2 genes. No detectable amounts of Cryptosporidium were detected in either location using immunomagnetic separation and fluorescence microscopy. Furthermore, mass spectrometry analyses did not detect key cyanobacterial toxins. On the basis of the results obtained we can conclude that for the period 2012–2014 no Mycobacterium species were present in the water samples. During the study period no cases of waterborne infections were reported.