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von der Ohe P.C.,Helmholtz Center for Environmental Research | Dulio V.,INERIS | Slobodnik J.,Environmental Institute | De Deckere E.,University of Antwerp | And 7 more authors.
Science of the Total Environment | Year: 2011

Given the huge number of chemicals released into the environment and existing time and budget constraints, there is a need to prioritize chemicals for risk assessment and monitoring in the context of the European Union Water Framework Directive (EU WFD). This study is the first to assess the risk of 500 organic substances based on observations in the four European river basins of the Elbe, Scheldt, Danube and Llobregat. A decision tree is introduced that first classifies chemicals into six categories depending on the information available, which allows water managers to focus on the next steps (e.g. derivation of Environmental Quality Standards (EQS), improvement of analytical methods, etc.). The priority within each category is then evaluated based on two indicators, the Frequency of Exceedance and the Extent of Exceedance of Predicted No-Effect Concentrations (PNECs). These two indictors are based on maximum environmental concentrations (MEC), rather than the commonly used statistically based averages (Predicted Effect Concentration, PEC), and compared to the lowest acute-based (PNECacute) or chronic-based thresholds (PNECchronic). For 56% of the compounds, PNECs were available from existing risk assessments, and the majority of these PNECs were derived from chronic toxicity data or simulated ecosystem studies (mesocosm) with rather low assessment factors. The limitations of this concept for risk assessment purposes are discussed. For the remainder, provisional PNECs (P-PNECs) were established from read-across models for acute toxicity to the standard test organisms Daphnia magna, Pimephales promelas and Selenastrum capricornutum. On the one hand, the prioritization revealed that about three-quarter of the 44 substances with MEC/PNEC ratios above ten were pesticides. On the other hand, based on the monitoring data used in this study, no risk with regard to the water phase could be found for eight of the 41 priority substances, indicating a first success of the implementation of the WFD in the investigated river basins. © 2011 Elsevier B.V. Source

Pedescoll A.,University of Leon | Pedescoll A.,Environmental Institute | Rodriguez L.,University of Leon | Saranana A.A.,University of Leon | And 2 more authors.
Ecological Engineering | Year: 2016

In comparison with conventional activated sludge treatment systems, for which a large body of research has been carried out on their microfauna and their role in bacteria and pollutant removal, only a few studies have focused on microfaunal communities inhabiting constructed wetlands (CWs). The aim of this study was to evaluate the microfaunal communities of horizontal CWs with differing design configurations in order to determine those design factors affecting their abundance and community structure and to discover their role in bacteria removal. Total bacteria, ciliates, amoebae and metazoa were counted in the effluents of an experimental plant combining the most common design configurations of CWs. Three different hydraulic designs (hydroponic, free water surface-FWS and subsurface flow-SSF), presence vs. absence of vegetation, two plant species (Typha angustifolia vs. Phragmites australis) and two organic loading rates were compared. SSF and vegetation favoured bacteria removal whereas abundance of protozoa and diversity of metazoa was greater in FWS-planted wetlands. Microfauna community structure and bacterial removal were clearly affected by vegetation and flow type, although no significant relationships were observed between microfauna and bacteria abundance at the outflow. Therefore, other mechanisms such as filtration, sedimentation or adsorption, seem to be more important than predation in removing bacteria from constructed wetlands. © 2016 Elsevier B.V. Source

von der Ohe P.C.,Helmholtz Center for Environmental Research | Schmitt-Jansen M.,Helmholtz Center for Environmental Research | Slobodnik J.,Environmental Institute | Brack W.,Helmholtz Center for Environmental Research
Environmental Science and Pollution Research | Year: 2012

Introduction: Triclosan (TCS) is a multi-purpose biocide. Its wide use in personal care products (PCPs) fosters its dispersal in the aquatic environment. Despite enhanced awareness of both scientists and the public in the last decade with regard to fate and effects, TCS received little attention regarding its prioritisation as a candidate river basin-specific pollutant or even priority substance, due to scarce monitoring data. Methods: Applying a new prioritisation methodology, the potential risk of TCS was assessed based on a refined hazard assessment and occurrences at 802 monitoring sites in the Elbe River basin. Results: The suggested acute-based predicted no-effect concentration (PNEC) of 4. 7 ng/l for the standard test species Selenastrum capricornutum was in good agreement with effect concentrations in algal communities and was exceeded in the Elbe River basin at 75% of the sites (limit of quantification of 5 ng/l). The 95th percentile of the maximum environmental concentrations at each site exceeded the PNEC by a factor of 12, indicating potential hazards for algal communities. Among 500 potential river basin-specific pollutants which were recently prioritised, triclosan ranks on position 6 of the most problematic substances, based on the Elbe River data alone. Conclusion: Considering the worldwide application of PCPs containing triclosan, we expect that the TCS problem is not restricted to the Elbe River basin, even if monitoring data from other river basins are scarce. Thus, we suggest to include TCS into routine monitoring programmes and to consider it as an important candidate for prioritisation at the European scale. © 2011 Springer-Verlag. Source

Andersen R.,James Hutton Institute | Andersen R.,Environmental Institute | Chapman S.J.,James Hutton Institute | Artz R.R.E.,James Hutton Institute
Soil Biology and Biochemistry | Year: 2013

Even though large extents of boreal peatlands are still in a pristine condition, especially in North America, extensive areas have been affected by natural or anthropogenic disturbances that change some of the systems from being sinks to sources of carbon dioxide and shift the methane production/consumption patterns through alterations of both above- and below-ground communities and functions. In order to fully assess the role of peatlands on global C balance, now and in the future, it is imperative that we deepen our understanding of the relative contributions of various groups of microorganisms to organic matter transformations. Here, we review the drivers structuring fungal, bacterial and archaeal communities in natural peatlands and the response of these microbial communities to natural and anthropogenic disturbances, including fire, drainage, nutrient deposition, peat mining and climate change. The microbial diversity in peatlands is characterized by organisms that have developed physiological and metabolic adaptations to cope with the constraining conditions found in these ecosystems, such as low oxygen availability, cold temperature, acidity and oligotrophy. Furthermore, these unique organisms sometimes appear to be organized as repeat mosaics responding to vegetation, physico-chemical and hydrological characteristics more than to geographical distance, in other words, similar to the much valued biodiversity aspects of the peatland vegetation itself and associated higher organisms. The response of microbial communities to disturbances is far from fully understood. In particular, whilst many studies have identified changes in microbial community composition or on microbially driven processes following a given disturbance, it remains unclear how the two components, diversity and function, relate with each other. Future challenges involve designing studies that will test whether ecological theories like species sorting, stress physiology, temporal niche or functional redundancy can be used to understand what regulates microbial populations and activity in peatlands, and studies that will allow us to predict more accurately how peatlands respond to global change or anthropogenic disturbances. © 2012 Elsevier Ltd. Source

Slobodnik J.,Environmental Institute | Von Der Ohe P.C.,Amalex
Handbook of Environmental Chemistry | Year: 2015

Following the requirements of the European Water Framework Directive (WFD), a process of selecting pollutants relevant at the river basin scale started in 2001. In the Danube river basin, the process was aided by two Joint Danube Surveys (JDS1 and JDS2) organised by the International Commission for the Protection of the Danube River (ICPDR) in 2001 and 2007, respectively. This study was retrospectively analysing all data on organic substances identified in the water samples collected within the two surveys and comparing them to the latest Environmental Quality Standards (EQSs) as well as ecotoxicological threshold values (Predicted No Effect Concentrations; PNECs) that were not available at the time of writing the JDS1/2 Final Scientific Reports. The results showed that 26 out of 89 substances detected in the samples exceeded the EQS/PNEC values in at least one sampling site and 53 substances were found above their limit of quantification (LOQ) at more than five sampling sites within the basin. The above-mentioned 26 substances deserve closer attention as candidates for the list of Danube River Basin Specific Pollutants (DRBSPs). A novel approach of ranking gas chromatography-mass spectrometry (GC-MS) nontarget screening data, based on the assessment of (1) available literature PNEC values (19 substances), (2) derived provisional PNEC (P-PNEC) values (160 substances) and (3) estimated concentrations of tentatively identified substances, has been applied too. Sixty-five out of a total of 179 compounds identified in the JDS samples exceeded the ecotoxicological threshold value in at least one sampling site, which makes them potential candidates for inclusion into future investigative monitoring schemes. © 2015 Springer-Verlag Berlin Heidelberg. Source

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