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Based on the balneotherapeutic applications of mineral spring water and particularly sulphurous water, the aim of our research was to study the physicochemical and microbiological parameters of some drainage waters of Siriu dam that showed a strong hydrogen sulphide odour. In addition, due to the corrosive effect of some groups of microorganisms, such as iron-oxidizing bacteria and sulphatereducing bacteria, the present paper also aimed to detect their presence in order to signal the need for some disinfection measures. According to physicochemical analysis, there has been found an external drain that is suitable for use in balneotherapy, presenting a balanced content of mineral elements such as sulphur, calcium, silicon, chlorine and potassium. However, due to the presence of potentially toxic phytoplankton microorganisms such as Microcystis sp. and Phormidium sp. it is necessary to disinfect this water source before using it for any purpose. On the other hand, the identification of both sulphate-reducing bacteria and iron-oxidizing bacteria in the drainage waters of Siriu dam should be considered as an alarm signal as they may lead to bio-corrosion and deterioration of metallic or concrete structures, affecting the integrity of the dam and hydropower constructions.

Despite the growing list of elements assessed and recognised as environmental and human health hazards, pollution monitoring and mitigation strategies are mandatory only for a limited number of metals, for which ambient air quality limits are defined by national and international policies. In order to overcome this deficiency, and promote cost-effective strategies and methods to assess airborne pollution, biomonitoring has been employed on several occasions using various protocols and organisms. Here we present a complex national monitoring study based on a combined approach that integrates air pollution data obtained through passive biomonitoring using the foliar content of various tree species and active biomonitoring with Hylocomium splendens moss bags. Concentrations of seven air pollutant metals, Al, Cr, Co, Cu, Fe, Mn and Zn, not regularly monitored and lacking established legal limit values, were measured in 410 passive and 142 active biomonitoring sampling sites across Romania, in two seasons, representing the largest study reported up-to-date applying complementary passive and active biomonitoring. Literature data reporting concentrations from uncontaminated areas was used to establish the concentration limits for four pollution levels (no, low, medium and high pollution), in order to develop a colour-coded warning system. High pollution levels were measured for 4.7% of passive and 9.8% of active monitoring samples. The largest proportions of samples showing high pollution levels were obtained for zinc (38.4%, for active monitoring) and chromium (18.9%, for passive monitoring). A significantly higher element content was found in moss bag samples than in leaves/needles. Though we emphasize the potential of both passive and active biomonitoring in assessing airborne pollution, our experiences and findings show that the more standardized methodology of moss-bag biomonitoring is sounder and better suited for such large-scale studies than a study conducted on multiple tree species. Some of the difficulties encountered during the two biomonitoring studies are also reported, including the range limit of species and the lack of established reference values for pollution limits.

Eutrophication of shallow lakes often triggers a series of cascading ecological effects. Among these are shifts in the zooplankton community structure due to phytoplankton changes, or shifts in the fish community reducing size-selective feeding of planktivorous fish. In such conditions, larger zooplankton (e.g. Daphnia) can have a selective advantage. Re-oligotrophication can reverse such food-web interactions. Europe’s largest wetland system (the Danube Delta) went through a period of eutrophication and is now slowly recovering again. However, changes in the Daphnia populations triggered by eutrophication in this system have remained unstudied. We used different sampling strategies to screen 24 lakes (which differ in their ecological state) for the presence of Daphnia as well as for biotic and abiotic parameters potentially explaining Daphnia abundance. Daphnia densities were surprisingly low. We found D. magna ephippia in the sediment, but no D. magna in the water column. Microsatellite analyses on pelagic Daphnia populations confirmed the presence of the D. longispina complex and provided evidence for significant hybridisation events. FluoroProbe data showed that Daphnia was mainly present in lakes with a higher phytoplankton production. Our study provides insights into the spatial and temporal distribution of Daphnia in a very dynamic wetland system.

Biomonitoring, i.e. using plant species for measuring pollution levels, has been previously explored in several locations using various protocols and organisms in the search for effective strategies and practices for monitoring and reducing the levels of pollution. Here we present a tested and functional cost-effective method of using the foliar accumulation of tree species to develop a system for the long-term monitoring of airborne heavy metal bioaccumulation at a large, national scale. A total number of 1230 leaf samples have been collected during a vegetation season in 410 sampling locations scattered across Romania. Concentration levels were determined using an inductively coupled plasma mass spectrometer. Data from literature were used as reference values for the natural concentration of heavy metals in plants. Values exceeding these levels were considered as indicators of pollution, and used to define pollution thresholds. The maximum amounts measured in the collected samples were 152 mg kg−1 dry weight for lead, 25.65 mg kg−1 dry weight for cadmium, 65.51 mg kg−1 dry weight for nickel and 4.81 mg kg−1 dry weight for arsenic. For analysing and communicating the findings, the BioMonRo software has been developed as a novel tool for warning-informing and decision-making. The software, now implemented by the Ministry of Environment for monitoring environmental quality, uses concentration data to build up national heavy metal pollution maps and can generate reports, which are automatically sent to various stakeholders. Based on our findings, we consider that tree species are efficient biomonitors, and similar methods could be successfully used in extensive biomonitoring programmes (national, regional or European), and for informing authorities.

This study analyzed the metabolic potential of some functional groups of bacteria in aquatic urban systems and evaluated the abundance of communities of total heterotrophic bacteria in the water in relation to the monitored physico-chemical factors. The results obtained showed seasonal differences, especially in spring. The high values of the abundance of heterotrophs in winter are related to human activity at the sampling stations. Screening for four types of extracellular hydrolytic enzyme with potential for degradation of organic matter (amylases, lipases, proteases and cellulases) led to the conclusion that lipolytic bacteria were dominant in the studied ecosystems, while proteolytic bacteria were observed in low numbers, but were present in urbanized areas. The presence of cellulolytic bacteria is correlated with the development of macrophytic vegetation. The aim of the present study was oriented towards the evaluation of the anthropogenic input in several lakes surrounding Bucharest in the Nord-Eastern region. These urban ecosystems are generated as a requirement of city development. The microbiological and general enzymatic approaches generated some novel results concerning the pollution degree of aquatic urban ecosystems and could be considered as a platform for further investigation.

Rotifers are known as cosmopolitan organisms, found in high density in most waters, often representing the dominant group in terms of species diversity and abundance in the zooplankton community. Since the functionality of an ecosystem is closely related to the diversity of communities, analysis of rotifers assemblage may be a useful tool in understanding the mechanisms of the spatial and temporal changes on this level. Data were collected from 2008 until 2010, in distinct areas of Danube, Sf ntu Gheorghe branch with different degrees of human impact. Sf ntu Gheorghe river branch has distinct features conferred by the construction of new canals and cutting off the meanders. Due to these regularization changes, a complex of ecosystems with different features resulted. The impact of engineering may determine a reduction in species diversity and abundance in the new ecosystems. The canals of Sf ntu Gheorghe branch presented the lowest value of the species richness and diversity indices in comparison with the other two areas. The constant species belong to Brachionus, Keratella, Asplanchna, Synchaeta genus. The branch environmental conditions allow the development loricate species and soft-bodied type, the dominant species belonging to Brachionidae family. This study reveals a close resemblance between natural sectors and meanders in terms of diversity and abundance of the rotifer assemblage. Opposites, in the newly created canals, the species richness and abundance registered a decreasing reflecting the impact of human interventions on the ecological system.

As airborne pollution is recognised as the single largest environmental health hazard in Europe, the necessity to develop effective systems for monitoring and reducing the level of air pollutants, becomes imperative. The paper describes a tested and implemented long-term biomonitoring system for airborne heavy metals at a national scale. Moss bags (Hylocomium splendens) were exposed in 142 monitoring stations designated in Romania, and the content of Pb, Cd, Ni and As was quantified using inductively coupled plasma mass spectrometry. The results revealed that the accumulation of heavy metals exceeded the established thresholds, marking high pollution levels in 8.8% of samples for As, in 5.63% samples for Cd, in 3.17% samples for Pb, and in 0.35% samples for Ni. The maximum heavy metal concentration was 113.77 mg kg−1 dry weight for Pb, 44.93 mg kg−1 dry weight for Ni, 14.68 mg kg−1 dry weight for As, and 3.88 mg kg−1 dry weight for Cd, with several overlaps for at least two metals, thus marking pollution hotspots. In order to process, summarise and communicate the obtained data, a software named BioMonRo has been developed as the core part of a complex monitoring and warning-informative system. The software is able to generate heavy metal pollution maps and specific reports, depicting the levels and patterns of distribution, which can be automatically sent to a number of interested recipients. The results show that the developed national system is functional, cost-effective, and could be successfully used for long-term monitoring of airborne heavy metals.

This paper reports the invasive subspecies Podonevadne trigona ovum (Zernov, 1901), as dominant in the Danube-Black Sea Canal. In the first two years of the existence of the anthropogenic ecosystem (1985-1986) the zooplankton summarizes only 72 species. Over two decades it recorded the presence of 127 species. As a result of nutrient accumulation, in 2005, the zooplankton abundance has significantly increased, reaching 330 ind L-1, followed by an evident growth of biomass (2285 μg wet weight L-1). In 2005, the productivity registered 731.8 μg wet weight L-1/24h. Resume. Le present papier rapport l’existence de la sous-espece envahissante Podonevadne trigona ovum (Zernov, 1901), dominante dans le canal Danube – Mer Noire. La sous-espece appartient a l’ordre Onychopoda, et elle a une origine Caspienne. Dans les premieres deux annees qui suit l’apparition de cet ecosysteme anthropogenique (1985-1986), le zooplancton a ete represente par 72 especes; apres deux decennies, le nombre d’especes a augmente a 127. A la suite d’accumulation de nutriments, en 2005 l’abondance du zooplancton a augmentee de maniere significative, atteignant 330 ind L-1, suivie d’une augmentation marquee de la biomasse (2285 mg s.um. L-1). En 2005, la productivite du zooplancton a enregistre 731,8 mg mat.hum. L-1/24h.

Sfântu Gheorghe fluvial branch belongs to the macroregional hydrological system of the Danube Delta. In order to improve the navigation on the river branches, between 1983 and 1989 various technical works have been initiated, which later proved to be one of the most aggressive factors leading to changes over time in the Danube Delta. The influence of anthropogenic impact on the zooplankton biomass distribution patterns in Sfântu Gheorghe was investigated in 2008 - 2010 interval. From this perspective, the aim of this paper was to emphasize the structure and distribution of zooplankton in the new conditions of the river system. Seasonal sampling shows that Copepoda and Cladocera were the dominant groups while the protozoans (Ciliata and Testacea) presented the smallest values of biomass and also emphasized distinct differences among the three sampling periods: summer, spring and autumn.

Long-term dynamics of zooplankton in the Matiţa and Merhei shallow lakes (the Danube Delta, Romania). 1. Diversity and abundance The present paper presents significant changes occurred in the multi-annual dynamics of zooplankton diversity and abundance (1980-2007), under the pressure of human-induced eutrophication in two shallow lakes specific for the Danube Delta. Zooplankton community from lakes Matiţa and Merhei was characterized by high species richness but low abundance values until 1981, in ecological conditions unaffected by eutrophication. For the next ten years, due to obvious increases of human pressures, zooplankton species richness decreased with 52% and 63%, respectively, while abundance values increased with 39% and 16%, respectively. After 1991, the social and economic changes in the Danube countries from the Central Europe led to nutrient input decreases. As a result, lake ecosystems from the Danube Delta showed lower trophicity values and their ecological parameters tended to recover. Analyses on the dynamics of the Shannon-Wiener's informational entropy index, Pielou's evenness and Simpson's index of dominance offered additional information and reduced the heterogeneity of the data regarding the species richness and the numerical abundance dynamics. Moreover, correlation analyses suggested the influences of human-induced changes of nutrient inputs on the multi-annual zooplankton dynamics.