Contenus dans les textiles, lessives, médicaments, crèmes solaires, boîtes de conserve et sprays insecticides, les produits chimiques peuplent notre quotidien. Vivre sans eux? Souvent inimaginable. Et pourtant, l’utilisation généralisée de ces substances nécessite une évaluation préalable extrêmement soignée.

Diverses techniques sont actuellement envisagées pour compléter les chaînes de traitement afin d’améliorer l’élimination des micropolluants dans les stations d’épuration. De quels indicateurs chimiques et biologiques disposons-nous pour évaluer l’efficacité de ces traitements complémentaires?

Une fois rejetés dans le milieu naturel, les produits chimiques peuvent être transformés en substances plus stables, plus solubles et parfois même plus toxiques que leur composé d’origine. L’Eawag travaille au développement de méthodes permettant une meilleure évaluation de ces produits de transformation.

Les nanoparticules sont déjà employées dans un grand nombre de domaines. Il semble donc hautement probable qu’elles se retrouvent tôt ou tard dans l’environnement. Des études de l’Eawag ont démontré pour la première fois la réalité de ce phénomène et ­montrent d’autre part de quelle manière les nanoparticules synthétiques peuvent perturber les organismes aquatiques.

Seule la dose fait le poison. En est-il vraiment ainsi ? Et combien de temps faut-il aux organismes exposés pour se régénérer ? Qu’advient-il si plusieurs vagues de pollution viennent à se succéder ? C’est à ce type de questions que nous avons cherché à répondre par le biais d’expérimentations et de modélisations toxicocinétiques et toxicodynamiques.

Les micropolluants ne sont souvent que partiellement retenus dans les stations d’épuration. La partie restante et les éventuels sous-produits de dégradation sont alors rejetés dans le milieu naturel avec les effluents d’épuration. Quelles sont les options actuellement disponibles pour améliorer le rendement d’élimination de ces composés?

Biocides and pesticides are used to control harmful organisms in agriculture and in urban areas. But how do these substances ultimately find their way into natural waters? And is agriculture in fact the main source of water pollution? These questions are being investigated by Eawag researchers in various projects.

In natural waters, organisms are exposed to a mixture of chemicals and are also affected by other stressors such as temperature, ultraviolet radiation, parasites and pathogens. At Eawag, the risks associated with multiple stressors are being assessed using various methods, including analysis of altered protein expression patterns.

Chemicals – in textiles, detergents, medicines, sunscreens, canned products and insect sprays – are an integral, often indispensable, part of our daily lives. Even so, the widespread use of these substances calls for constant, critical evaluation.

Various ways of upgrading wastewater treatment plants so as to enhance the elimination of micropollutants are currently being considered. But what chemical and biological indicators can be used to evaluate the effectiveness of additional treatment steps?

Chemical substances can be transformed in the environment into products that are more stable, more readily water-soluble and even, in certain cases, more toxic than the parent compound. Eawag is developing methods that will allow the risk of these transformation products to be better assessed.

As nanoparticles are already widely used, it was only too likely that they would ultimately find their way into the environment. This has now been demonstrated for the first time by Eawag studies – which also show how engineered nanoparticles can exert toxic effects on aquatic organisms.

Is it true that “the dose makes the poison”? How long does it take for exposed organisms to recover? What are the effects of sequential exposure to contaminants? These are some of the questions we are trying to answer with the aid of toxicokinetic/toxicodynamic models and experiments.

In many cases, micropollutants are only partly eliminated at wastewater treatment plants. The remaining fraction, together with any transformation products, enters receiving waters with the treated effluents. What options can modern process engineering offer to improve elimination performance?

Biozide und Pestizide werden in der Landwirtschaft und im Siedlungsraum eingesetzt, um Schädlinge zu bekämpfen. Doch welche Wege nehmen diese Stoffe vom Einsatzort bis ins Gewässer? Und ist die Landwirtschaft tatsächlich die Hauptverursacherin der Gewässerbelastung? Fragen, die die Eawag in verschiedenen Projekten erforscht.

In den Gewässern sind die Organismen einem Mix von Chemikalien ausgesetzt und werden zudem durch weitere Stressoren wie Temperatur, UV-Einstrahlung, Parasiten und Pathogene beeinflusst. An der Eawag wird das Risiko multipler Stressoren unter anderem anhand veränderter Proteinmuster abgeschätzt.

Sie sind unsere täglichen Begleiter – Chemikalien in Textilien, Waschmitteln, Medikamenten, Sonnencremes, Konservendosen, Insektensprays. Ein Leben ohne sie? Oft nicht mehr denkbar. Und doch bedarf der breite Einsatz dieser Substanzen einer stetigen, kritischen Prüfung.

Pathogenic enteric bacteria are a major cause of drinking water related morbidity and mortality in developing countries. Solar disinfection (SODIS) is an effective means to fight this problem. In the present study, SODIS of two important enteric pathogens, <em>Shigella flexneri</em> and <em>Salmonella typhimurium,</em> was investigated with a variety of viability indicators including cellular ATP levels, efflux pump activity, glucose uptake ability, and polarization and integrity of the cytoplasmic membrane. The respiratory chain of enteric bacteria was identified to be a likely target of sunlight and UVA irradiation. Furthermore, during dark storage after irradiation, the physiological state of the bacterial cells continued to deteriorate even in the absence of irradiation: apparently the cells were unable to repair damage. This strongly suggests that for <em>S. typhimurium</em> and <em>Sh. flexneri</em>, a relatively small light dose is enough to irreversibly damage the cells and that storage of bottles after irradiation does not allow regrowth of inactivated bacterial cells. In addition, we show that light dose reciprocity is an important issue when using simulated sunlight. At high irradiation intensities (&gt;700 W m^–2) light dose reciprocity failed and resulted in an overestimation of the effect, whereas reciprocity applied well around natural sunlight intensity (&lt;400 W m^–2).

The regulation of benzene degradation by <I>Ralstonia pickettii</I> PKO1 in the presence of the alternative substrate succinate was investigated in batch and continuous culture. In batch culture, <I>R. pickettii</I> PKO1 achieved a maximum specific growth rate with benzene of 0.18 h<SUP>−1</SUP>, while succinate allowed much faster growth (μ<SUB>max</SUB> = 0.5 h<SUP>−1</SUP>). Under carbon excess conditions succinate repressed benzene consumption resulting in diauxic growth whereas under carbon-limited conditions in the chemostat both substrates were used simultaneously. Moreover, the effect of succinate on the adaptation towards growth with benzene was investigated in carbon-limited continuous culture at a dilution rate of 0.1 h<SUP>−1</SUP> by changing the inflowing carbon substrate from succinate to different mixtures of benzene and succinate. The adaptation process towards utilisation of benzene was rather complex. Three to seven hours after the medium shift biomass production from benzene started. Higher proportions of succinate in the mixture had a positive effect on both the onset of biomass production and on the time required for induction of benzene utilisation. Strikingly, after the initial increase in biomass and benzene-catabolising activities, the culture collapsed regularly and wash-out of biomass was observed. After a transient phase of low biomass concentrations growth on benzene resumed so that finally rather stable and high biomass concentrations were reached. The decrease in biomass and degradative activities cannot be explained so far, but the possibilities of either intoxication of the cells by benzene itself, or of inhibition by degradation intermediates were ruled out.

When exposed to strong sunlight, photosynthetic organisms encounter photooxidative stress by the increased production of reactive oxygen species causing harmful damages to proteins and membranes. Consequently, a fast and specific induction of defense mechanisms is required to protect the organism from cell death. In <I>Chlamydomonas reinhardtii</I>, the glutathione peroxidase homologous gene <I>GPXH</I>/<I>GPX5</I> was shown to be specifically upregulated by singlet oxygen formed during high light conditions presumably to prevent the accumulation of lipid hydroperoxides and membrane damage. We now showed that the GPXH protein is a thioredoxin-dependent peroxidase catalyzing the reduction of hydrogen peroxide and organic hydroperoxides. Furthermore, the <I>GPXH</I> gene seems to encode a dual-targeted protein, predicted to be localized both in the chloroplast and the cytoplasm, which is active with either plastidic TRXy or cytosolic TRXh1. Putative dual-targeting is achieved by alternative transcription and translation start sites expressed independently from either a TATA-box or an Initiator core promoter. Expression of both transcripts was upregulated by photooxidative stress even though with different strengths. The induction required the presence of the core promoter sequences and multiple upstream regulatory elements including a Sp1-like element and an earlier identified CRE/AP-1 homologous sequence. This element was further characterized by mutation analysis but could not be confirmed to be a consensus CRE or AP1 element. Instead, it rather seems to be another member of the large group of TGAC-transcription factor binding sites found to be involved in the response of different genes to oxidative stress.

In 25 lochs in the Grampians and Northwest Highlands of Scotland, miniature thermistors with integrated data loggers were employed in 2000 and 2001 to measure lake surface water temperatures (LSWTs). Results indicate that LSWTs fluctuate coherently in response to climatic forcing, and that additionally, they differ lttle in an absolute sense, implying that daily mean LSWTs can be upscaled easily. Regional coherence in LSWT is substantially higher in summer and autumn than in winter and spring. LSWT decreases approximately linearly with increasing altitude above sea level during winter and spring, but not otherwise; this contrasts strongly with the results of studies in other mountain regions, which show the most pronounced linear decrease in LSWT with altitude to occur in summer. LSWT showed no dependence on latitude at any time of the year, but showed a significant dependence on longitude - which can be interpreted as distance from the maritime influence of the Atlantic - especially during autumn and spring. In Summer, no consistent dependence of LSWT on either altitude, latitude or longitude was found, implying that any differences in LSWT that may exist among the lochs in summer are predominantly the result of lake-specific local effects. The duration of the period during which LSWT ≤4°C depends on altitude and longitude, but not on latitude. The timing of the onset of this period in autumn occurs essentially simultaneously throughout northern Scotland, whereas the timing of the end of the period in spring becomes later with increasing altitude and increasing distance towards the east. This suggests that the duration of inverse stratification or circulation at temperatures less than the temperature or maximum density will tend to be less in low-lying lochs and/or lochs close to the Atlantic coastline than in high-altitude lochs and/or lochs located further from the Atlantic coast, and that this difference is entirely due to differences in climatic forcing that occur in spring.

We have reconstructed the interplanetary magnetic field (IMF), its radial component, and the open solar magnetic flux using the solar modulation potential derived from cosmogenic <SUP>10</SUP>Be radionuclide data for a period covering the past 9300 years. Reconstructions using the assumption of both constant and variable solar wind speeds yielded closely similar results. During the Maunder Minimum, the strength of the IMF was approximately 2 nT compared to a mean value of 6.6 nT for the past 40 years, corresponding to an increase of the open solar magnetic flux of about 350%. We examine four cycles of the Hallstatt periodicity in the IMF with a mean period of ~2250 years and an amplitude of ~0.75 nT. Grand solar minima have largely occurred in clusters during the Hallstatt cycle minima around the years −5300, −3400, −1100, and +1500 A.D. The last cluster includes the Dalton, Maunder, and Spörer minima. We predict that the next such cluster will occur in about 1500 years. The long-term IMF has varied between ~2 nT and ~8 nT and does not confirm a proposed floor (lower limit). There is a slowly changing long-term trend of amplitude 1.5 nT, with a minimum around the year −4600 and a maximum around 0 A.D. that may be of solar origin but which also may be due to unknown long-term changes in the atmospheric effects or geomagnetic field intensity.

Ganzheitliches oder integrales Einzugsgebietsmanagement (IEM) ist eine der aktuellen Forderungen an die moderne Wasserwirtschaft. Wie das IEM in der Schweiz konkret aussehen könnte, wurde im VSA-Expertenworkshop vom 1. bis 3. Oktober 2008 in Emmetten diskutiert. Vielversprechende Ansätze für IEM sind in der Schweiz bereits vorhanden, die aber alle im Moment auch noch substantielle Schwächen zeigen. Deutlich wurde, dass das ganzheitliche Einzugsgebietsmanagement für die schweizerische Siedlungswasserwirtschaft ein zentrales Thema wird. Als Konsequenz dieser Veranstaltung hat der VSA-Vorstand das IEM als Kernthema in seine Arbeiten und Bestrebungen aufgenommen.

Effluents from wastewater treatment plants (WWTPs) are responsible for the input of estrogenic contaminants into aquatic ecosystems, leading to widespread effects in wildlife. In the present work, levels of estrone (E1), 17α- and 17β-estradiol (E2), 17α-ethinylestradiol (EE2), bisphenol A (BPA), and nonylphenol (NP) were quantified in effluents from WWTPs located in Ria de Aveiro (NW Portugal), as well as in the final effluent discharged into the Atlantic Ocean through the S. Jacinto submarine outfall. Reference sites, located at the entrance of the estuarine system and at the seaside, were also included. Samples were collected under summer (June 2005) and winter (February 2006) conditions. For the summer survey samples, estrogenicity and androgenicity were evaluated using the yeast estrogen screen (YES) and the yeast androgen screen (YAS) assay. Estrone levels varied from 0.5 to 85 ng/L in the summer survey and between <LOD (limits of detection) and 43 ng/L in winter; estradiol levels ranged from <LOD to 9.2 ng/L in summer and were always <LOD in the winter survey; EE2 levels were always <LOD for both surveys. NP concentrations ranged from 75 ng/L up to 2,350 ng/L in summer and from 10 to 2,410 ng/L in winter; BPA levels varied from 2.8 to 897 ng/L in summer and from 2.6 up to 316 ng/L in winter. Biological assays disclosed estrogenic levels at reference sites lower than the ones reported to pose risk for wildlife. However, the S. Jacinto outfall effluent released high concentrations of NP and BPA into the marine environment.

The article addresses new, horizontal and dialogue-oriented forms of political governance in transnational spaces. A normative-analytical model of deliberative governance will be developed to appraise the democratic potential of transnational structures and actions. The research is guided by the observation that th North American Great Lakes Regime reveals a high democratic-deliberative quality whereas international governance rather tends to de-democratization. This raises a challenging research question: To what extent does the deliberative governance of the Great Lakes Regime provide a model case, which allows drawing conclusions on institutional prerequisites and means how to "democratize" governance in similar issue areas.

Larvae of the black soldier fly, <I>Hermetia illucens</I> (Diptera: Stratiomyidae), are voracious feeders of organic material and may thus be used in simple engineered systems to reduce organic waste in low- and middle-income countries. Controlled feeding experiments with standard fodder were conducted to assess the optimum amount of organic waste to be added to a CORS system (Conversion of Organic Refuse by Saprophages). A daily feeding rate of 100 mg chicken feed (60% moisture content) per larva resulted in an optimum trade-off between material reduction efficiency (41.8%, SE 0.61) and biomass production (prepupal dry weight: 48.0 mg, SE 2.0). Applied to market waste and human faeces, this corresponds to a potential daily feeding capacity of 3—5 kg/m<SUP>2</SUP> and 6.5 kg/m<SUP>2</SUP>, respectively. In addition, <I>H. illucens</I> prepupae quality was assessed to determine their suitability to substitute fishmeal in animal feed production. The chitin-corrected crude protein content ranged from 28.2 to 42.5%, depending on the amount of food provided to the larvae. Based on our study, a waste processing unit could yield a daily prepupal biomass of 145 g (dry mass) per m<SUP>2</SUP>. We conclude that larvae of the black soldier fly are potentially capable of converting large amounts of organic waste into protein-rich biomass to substitute fishmeal, thereby contributing to sustainable aquaculture.

The present study addresses the key issue of linking the chemical speciation to the uptake of priority pollutants Cd(II) and Pb(II) in the wastewater treatment plant effluents, with emphasis on the role of the colloidal organic matter (EfOM). Binding of Cd(II) and Pb(II) by EfOM was examined by an ion exchange technique and flow field-flow fractionation coupled to inductively coupled plasma mass spectrometry in parallel to bioassays with green microalga <I>Chlorella kesslerii</I> in ultrafiltrate (<1 kDa) and colloidal isolates (1 kDa to 0.45 μm). The uptake of Cd by <I>C. kesslerii</I> was consistent with the speciation analysis and measured free metal ion concentrations, while Pb uptake was much greater than that expected from the speciation measurement. Better understanding of the differences in the effects of the EfOM on Cd(II) and Pb(II) uptake required to take into account the size dependence of metal binding by EfOM.

Colloidal organic matter from wastewater treatment plants was characterized and examined with respect to its role in metal distribution by using tangential flow ultrafiltration, liquid chromatography coupled with organic carbon and UV detectors, and an asymmetrical flow field-flow fractionation (AFlFFF) multidetection platform. Results revealed that a humic-like fraction of low aromaticity with an average molar mass ranging from 1600 to 2600 Da was the main colloidal component. High molar mass fractions (HMM), with molar mass ranges between 20 and 200 kDa, were present in lower proportions. Ag, Cd, Cu, Cr, Mn and Zn were found mainly in the dissolved phase (<0.45 μm) and their distribution between colloidal and truly dissolved fractions was strongly influenced by the distribution of dissolved organic carbon. AFlFFF coupled to ICP-MS showed that Ag, Cd, Cu, Cr, Mn and Zn associate to the low molar mass fraction of the colloidal pool, whereas Al, Fe and Pb were equally bound to low and high molar mass fractions.

The relationship between cadmium speciation and accumulation in periphyton was examined at environmentally relevant Cd concentrations under natural freshwater conditions. Periphyton was exposed in artificial recirculating channels containing natural freshwater to two Cd concentrations (20 and 40 nM), for which speciation was modified by the addition of a synthetic organic ligand (nitrilotriacetate, NTA). Labile metal concentrations were measured with the technique of diffusion gradient in thin-films (DGT) and major Cd species were estimated by modeling. Total and intracellular Cd content in periphyton increased within both Cd exposure concentrations with NTA additions and were related to an increase in DGT-labile Cd, which was caused by the competition of NTA with probably colloidal species. Bioaccumulation was thus not controlled by the free Cd concentrations, as predicted by the free ion activity model, but by the diffusion of labile Cd−NTA complexes, which constituted a large fraction of DGT-labile Cd. These findings confirm the importance of labile species for Cd accumulation in periphyton under freshwater conditions, as predicted by models considering diffusion and uptake kinetics.

For sustainable water resource management in semi-arid regions, sound information is required about interactions between the different components of the water system: rain/snow precipitation, surface/subsurface run-off, groundwater recharge. Exemplarily, the Huasco and Limarí river basins as water stressed river catchments have been studied by isotope and hydrochemical methods for (i) the origin of water, (ii) water quality, (iii) relations of surface and groundwater.<BR/>Applying the complex multi-isotopic and hydrochemical methodology to the water components of the Huasco and Limarí basins, a differentiation of water components concerning subsurface flow and river water along the catchment area and by anthropogenic impacts are detected. Sulphate and nitrate concentrations indicate remarkable input from mining and agricultural activities along the river catchment.<BR/>The <SUP>2</SUP>H-<SUP>18</SUP>O relations of river water and groundwater of both catchments point to the behaviour of river waters originated in an arid to semi-arid environment.<BR/>Consequently, the groundwater from several production wells in the lower parts of the catchments is related to the rivers where the wells located, however, it can be distinguished from the river water. Using the hydrological water balance and the isotope mixing model, the interaction between surface and subsurface flows and river flow is estimated.

Leaky sewers affect urban groundwater by the exfiltration of untreated wastewater. However, the impact of sewer exfiltration on the groundwater is poorly understood. Most studies on sewer exfiltration focus on water exfiltration, but not on the impact on groundwater quality. In this paper we present a new monitoring approach to estimate mass flow rates <I>M</I><I><SUB>ex</SUB></I> of different wastewater indicators (WWIs) from leaky sewers by applying integral pumping tests (IPTs). The problem of detecting and assessing heterogeneous concentrations in the vicinity of leaky sewers can be overcome with the IPT approach by the investigation of large groundwater volumes up- and downstream of leaky sewers. The increase in concentrations downstream of a leaky sewer section can be used to calculate <I>M</I><I><SUB>ex</SUB></I> with a numerical groundwater model. The new monitoring approach was first applied using four IPT wells in Leipzig (Germany). Over a pumping period of five days we sampled five inorganic WWIs: B , Cl<SUP>−</SUP>, K<SUP>+</SUP>, NO<SUB>3</SUB><SUP>−</SUP>, NH<SUB>4</SUB><SUP>+</SUP> and three xenobiotics: bisphenol-a, caffeine and tonalide. The resulting concentration–time series indicated an influence of wastewater at one IPT well downstream of the leaky sewer. We defined ranges of <I>M</I><I><SUB>ex</SUB></I> by implementing the uncertainty of chemical analyses. The results showed a <I>M</I><I><SUB>ex</SUB></I> of 0–10.9 g m<SUP>−1</SUP> d<SUP>−1</SUP>. The combination of <I>M</I><I><SUB>ex</SUB></I> with wastewater concentrations from the target sewer yielded an exfiltration rate <I>Q</I><I><SUB>ex</SUB></I> of 28.0–63.9 L m<SUP>−1</SUP> d<SUP>−1</SUP> for the conservative ion Cl<SUP>−</SUP>. Most non-conservative WWIs showed reduced mass flow rates in the groundwater downstream of the leaky sewer that indicate a mass depletion during their passage from the sewer to the pumping well. Application of the IPT methodology at other field sites is possible. The IPT monitoring approach provides reliable <I>M</I><I><SUB>ex</SUB></I> values that can help to assess the impact of leaky sewers on groundwater.

Based on a monitoring program over the course of a year, we characterize the temporal and spatial distribution of selected micropollutants in an urban watershed within the city of Leipzig, Germany. Micropollutants revealed a ubiquitous presence in untreated and treated wastewater, surface water and groundwater. The loads of 4-nonylphenol in the effluents of the municipal wastewater treatment plant followed a seasonal trend, whereas the loads of all other micropollutants were highly variable and not correlated to seasons. In the surface water, load seasonality of caffeine, galaxolide and tonalide resulted from a rapid removal with increased water temperature. The loads of 4-nonylphenol and of caffeine in the colder months increased when rainfall occurred. In the groundwater, complex spatial and temporal patterns were apparent and were related to varying input, retardation and removal processes. As a consequence, an assessment of micropollutants in urban waters should consider different micropollutants' temporal and spatial variability.

Arsenic (As) in soils and sediments is commonly mobilized when anoxic conditions promote microbial iron (Fe) and As reduction. Recent laboratory studies and field observations have suggested a decoupling between Fe and As reduction and release, but the links between these processes are still not well understood. In microcosm experiments, we monitored the formation of Fe(II) and As(III) in the porewater and in the soil solid-phase during flooding of a contaminated floodplain soil at temperatures of 23, 14, and 5 °C. At all temperatures, flooding induced the development of anoxic conditions and caused increasing concentrations of dissolved Fe(II) and As(III). Decreasing the temperature from 23 to 14 and 5 °C strongly slowed down soil reduction and Fe and As release. Speciation of As in the soil solid-phase by X-ray absorption spectroscopy (XAS) and extraction of the Fe(II) that has formed by reductive Fe(III) (hydr)oxide dissolution revealed that less than 3.9% of all As(III) and less than 3.2% of all Fe(II) formed during 52 days of flooding at 23 °C were released into the porewater, although 91% of the initially ascorbate-extractable Fe and 66% of the total As were reduced. The amount of total As(III) formed during soil reduction was linearly correlated to the amount of total Fe(II) formed, indicating that the rate of As(V) reduction was controlled by the rate of microbial Fe(III) (hydr)oxide reduction.

Die Wasserqualität der meisten Voralpenseen ist heute überwiegend in einem guten Zustand. Dagegen sind die Belastungen in den Uferzonen der Seen sehr hoch. Vermauerte Ufer und intensive Nutzungen der Uferzonen engen den Lebensraum zahlreicher Pflanzen- und Tierarten ein. Um den Zustand der Seeufer einschätzen zu können, wurde vom Schweizer Wasserforschungsinstitut (Eawag) ein Bewertungsmodul entwickelt. Es basiert auf verschiedenen Einzelkriterien, für die geprüft wird, in welchem Umfang ein Uferabschnitt dem Naturzustand (Referenz) entspricht oder von ihm abweicht. Das Modul wurde erfolgreich an mehreren Seen angewandt.

Darf ein Jagdschützenstand die Umwelt weiter mit Blei, Antimon und PAK belasten, bloss weil er schon da war, bevor diverse Schutzerlasse ergangen sind? Aus raumplanerischer Sicht vielleicht aus altlastenrechtlicher Sicht sicher nein.

Water productivity in smallholder rain-fed agriculture is of key interest for improved food and livelihood security. A frequently advocated approach to enhance water productivity is to adopt water harvesting and conservation technologies (WH). This study estimates water availability for potential in situ WH, and supplemental water demand (SWD) in smallholder agriculture in South Africa's Thukela River Basin (29 000 km<SUP>2</SUP>, mean annual precipitation 550–2000 mm yr<SUP>−1</SUP>). The study includes process dynamics governing runoff generation and crop water demands, quantification of prediction uncertainty, and an analysis of the reliability of in situ WH.<BR/>The agro-hydrological model SWAT (Soil and Water Assessment Tool) was calibrated and evaluated with the Sequential Uncertainty Fitting algorithm against observed discharge (at ten stations) and maize yield (the dominant crop type) for the period 1997–2006. The water availability was based on the generated surface runoff in smallholder areas. The SWD was derived from a scenario where crop water deficits were met from an unlimited external water source. The reliability was calculated as the percentage of years in which water availability ≥SWD. This reflects the risks of failure induced by the temporal variability in the water availability and the SWD.<BR/>The calibration reduced the predictive uncertainty and resulted in a satisfactory model performance. For smallholder maize yield, the Root Mean Squared Error was 0.02 t ha<SUP>−1</SUP> during both the calibration and the evaluation periods. The width of the uncertainty band was reduced by 23% due to the calibration. For discharge during the calibration (evaluation) period, the ten-station range in the weighted coefficient of determination (Φ) was 0.16–0.85 (0.18–0.73), and in the coefficient of determination (<I>R</I><SUP>2</SUP>) 0.42–0.83 (0.28–0.72). The calibration reduced the width of the uncertainty band by 25% on average.<BR/>The results show that the smallholder crop water productivity is currently low in the basin (spatiotemporal median: 0.08–0.22 kg m<SUP>−3</SUP>, 95% prediction uncertainty band (95PPU)). Water is available for in situ WH (spatiotemporal median: 0–17 mm year<SUP>−1</SUP>, 95PPU) which may aid in enhancing the crop water productivity by meeting some of the SWD (spatiotemporal median: 0–113 mm year<SUP>−1</SUP>, 95PPU). However, the reliability of in situ WH is highly location specific and overall rather low. Of the 1850 km<SUP>2</SUP> of smallholder lands, 20–28% display a reliability ≥25%, 13–16% a reliability ≥50%, and 4–5% a reliability ≥75% (95PPU). This suggests that the risk of failure of in situ WH is relatively high in many areas of the basin.

Differential habitat selection is a central component in the evolution of species, but it has been quantified rarely for sympatric species in relation to the multiple impacts of resources at the spatial scales at which animals operate. Our main goal was to quantify the selection of terrestrial summer habitats in a natural floodplain in Italy by two sympatric amphibians (<I>Bufo bufo spinosus</I> and <I>B. viridis</I>) as a function of habitat type, prey density, and temperature. We applied a Bayesian resource selection model at three spatial scales: (1) home range placement within the floodplain, (2) space use within 95% home ranges, and (3) space use within 50% core areas. Using these data we explored whether processes acting at large scales lead to space use patterns at small scales and whether the two species use the same habitat types in a way that would facilitate coexistence.<BR/>Habitat selection was determined by habitat type, prey density, and temperature at all spatial scales, resulting in slightly higher prey density and significantly lower temperature within than outside home ranges. We conclude that amphibians perceive the distribution of habitat types as well as gradients in prey density and temperature at all spatial scales. The effects of habitat type dominated home range placement while prey density and temperature most strongly affected space use within home ranges. Our results suggest that home range placement relies on broad habitat features that indicate resource availability at small spatial scales. At the smallest spatial scale, the selection of prey and refugia is most probably facilitated due to the accumulation of environmental information as animals may sample the entire area.<BR/>Both species largely preferred the same habitat types, but used them differently in relation to resources across the three spatial scales. For example, while one species used the same habitat type for foraging, the other used it for resting or both resting and foraging. Niche differentiation through differential resource selection within shared habitat types at all spatial scales may therefore facilitate the coexistence of the two species in terrestrial summer habitats.

Understanding individual space use remains a major issue in ecology, and it is complicated by definitions of spatial scale and the interplay of multiple factors. We quantified the effect of habitat and biotic and individual factors on space use by amphibians (<I>Bufo bufo spinosus</I> [BB] and <I>Bufo viridis</I> [BV]) that were radio-tracked in their terrestrial summer habitat. We analyzed two spatial scales, 50% core areas and 95% home ranges (excluding 50% core areas), thought to represent resting and foraging areas, respectively. The 50% core area of BB was best explained by habitat structure and prey density, whereas the 50% core area of BV was determined solely by habitat structure. This suggests that the resting and foraging areas of BB are not spatially separated. The 95% home range of BB was determined by prey density, while for BV both habitat structure and prey density determined home range size. We conclude that the terrestrial area requirements of amphibians depend on the productivity and spatiotemporal complexity of landscapes and that differential space use may facilitate their co-occurrence. Behavior-based a priori hypotheses, in combination with an information-theoretic approach and path analyses, provide a promising framework to disentangle factors that govern individual space use, thereby advancing home range studies.

The European Biocidal Products Directive 98/8/EC requires a risk assessment concerning possible effects of active ingredients on the environment. Biocides can be leached from treated materials exposed to outdoor use. These emissions have to be estimated and evaluated during the authorization procedure. Different immersion and irrigation tests were performed to investigate leaching of biocides from façade coatings. Several marketed formulations of textured coatings and paints spiked with a mixture of commonly used active ingredients (OIT, DCOIT, IPBC, carbendazim, isoproturon, diuron, terbutryn, and Irgarol 1051) were investigated. The emission process can be described by time-dependent functions that depend on the test conditions. The results of all test procedures confirm that leachability is related to water solubility and <I>n</I>-octanol−water partition coefficient of the active ingredients and that leaching of biocides from façade coatings is mainly a diffusion controlled process. Other factors like the composition of the product, availability and transport of water, concentration of active ingredients in the coatings, as well as UV-exposure of the coatings influence biocide emissions.

Abfließendes Regenwasser aus Siedlungsgebieten wird zunehmend dezentral abgeleitet und behandelt. Dazu gehört die Versickerung am Gebäude mit Bodenpassage (Abbildung 1). Die ungenügende Versickerungsfähigkeit des Bodens oder ein zu geringer Grundwasserflurabstand sind Gründe, warum Regenwasser alternativ auch über die Trennkanalisation abgeleitet werden kann (Abbildung 1). Dabei wird der Regenwasserabfluss entweder direkt in ein oberirdisches Gewässer eingeleitet oder in einem Retentionsbassin zwischengespeichert und verzögert ins Grund- oder Oberflächenwasser abgegeben. Mit dieser Entsorgungsstrategie sollen Kläranlagen hydraulisch entlastet und damit kritische Lastfälle bei Starkregen reduziert werden.

Zum Schutz vor Algen- und Pilzbefall werden kunststoff gebundene Farben und Putze für Aussenwärmedämmungen mit Bioziden ausgerüstet. Neue Untersuchungen zeigen, dass diese Problemstoffe ausgewaschen werden und über das abfliessende Regenwasser in die Gewässer gelangen können. Damit wird die bisher praktizierte Regenwasserentsorgung infrage gestellt. Bei der Lösung des Problems sind nicht nur die Produkthersteller gefordert, sondern auch Architekten und Bauherren.

Les peintures de façades, de même que les enduits, contiennent des biocides pour les protéger contre le développement d’algues et de champignons. Nos études ont montré que ces substances pouvaient être lessivées par les pluies et ainsi polluer les eaux de ruissellement ainsi que les eaux de surface. Le lessivage des façades est influencé par différents paramètres comme l’architecture, l’exposition, le temps, les substances actives ou les produits utilisés. Pour le législateur se pose ainsi la question de la gestion durable des eaux de ruissellement. Or, c’est seulement en réunissant tous les acteurs touchés par cette problématique que des solutions durables pour le sol et les eaux pourront être trouvées.

<I>Background, aim and scope </I> Sources of organic micropollutants occuring in surface waters are often unknown. Regarding environmental risk assessments for surface waters, construction materials have as till now, not been given much consideration, although biocides used as preservatives are known to reach urban storm water runoff. The study focused on biocides for facades coatings and aimed (1) to determine ecotoxicological effect values, (2) to quantify the leaching behaviour and (3) to assess the environmental risk for surface waters using a dynamic transport model.<BR/><I>Materials and methods</I> Eight biocides used in resin based facade coatings were investigated. Some biocides are substances known as pesticides for agricultural purposes like diuron, carbendazim and terbutryn. Ecotoxicological effect values for aquatic organisms were determined for every biocide. Leaching of four biocides from a render under UV-irradiation has been investigated in the laboratory including the influence of varying temperatures. Using 80 irrigation intervals over 28 days, facade runoff was sampled and followed by biocide chemical analysis. The total losses were calculated based on the concentration patterns. These data were used for modelling the transport of cybutryn from facades to surface waters. Biocide specific effect values and leaching characteristics have been taken into consideration.<BR/><I>Results</I> Acute and chronic effect values as well as predicted no effect concentrations for the investigated biocides indicate their high potential to affect aquatic organisms. The leaching of four biocides (diuron, terbutryn, cybutryn, carbendazim) from the facade render under the experimental conditions delivers high concentrations in the beginning followed by an exponential decrease. Rising temperature increased the concentration of biocides in the runoff. The total losses were between 7 % and 29 % depending on the substances. More than half of the losses occur in the runoff within the first 15 min of runoff from a 60 min irrigation cycle. The modelling result for cybutryn underlines its high environmental risk for small surface waters.<BR/><I>Discussion </I> The leaching of the biocides, their potential ecotoxic effects and persistence show clearly that the environmental risk for surface waters and soils seems to be high for certain biocides; whereas for others the risk seems to be significantly lower. With respect water quality criteria, polluted facades runoff has to be diluted before runoff can enter the discharge. Diuron and carbendazim are however also used as pesticides and preservatives for other materials and cybutryn is also used as an antifouling agent. All pathways have to be evaluated in order to identify relevant sources and to act more efficiently with respect to water and soil protection.<BR/><I>Conclusions</I> Concentrations with high environmental risk are expected at new facades, especially at facades with thermal insulation. With the given low predicted no effect concentrations in a range of a few ng/L and large amounts of biocides applied in paints and renders, the environmental risk for common biocides used in facade coatings has to be investigated in laboratory and field scale. It seems plausible that source control measures as the most efficient and sustainable precautionary principle need to be evaluated.<BR/><I>Recommendations and perspectives</I> Biocides and additives applied in construction materials have to be taken into consideration as relevant sources when evaluating the quality of storm water runoff, discharge into urban areas and the impact to soil and surface waters. A sustainable construction material management and storm water management are required. It is expected that ongoing laboratory and field studies with exterior paints, renders and flat sheets for waterproofing containing biocides and additives will give further insight into their environmental impact.

Solar water disinfection (SODIS) is a simple method designed to treat microbiologically contaminated drinking water at the household level. This study focused on the effective promotion of the SODIS method using various strategies. In a longitudinal field study, we compared 2 interpersonal strategies (promoters and opinion leaders) and a centralized strategy (health fair) with a control group. Indicators of effectiveness were SODIS knowledge, SODIS adoption rate, and potential reach. The results suggest that use of promoters is the most successful strategy in terms of reaching people and changing their behavior toward SODIS use. The opinion leaders - although less effective - show some potential to stimulate communication among people about SODIS. Only the health fair did not have a big impact on behavior. Further discussion includes the costs of the various promotional activities, limitations, and recommendations for future projects.

Biofilms are heterogeneous and dynamic systems. Evaluation of biofilm structure and function at the microscale has been greatly advanced through the application of multidimensional imaging, in-situ identification of the microbial community composition, function, and genetic regulation. Biofilm reactors are being applied for advanced biological treatment processes and their overall (macroscale) operation is well understood and controlled. What is missing is the link between micro and macroscale. In this horizon paper we suggest how understanding the overall biofilm ecosystem will require an integrated evaluation of the different length and time scales.

Shear is used to control fouling in membrane bioreactor (MBR) systems. However, shear also influences the physicochemical and biological properties of MBR biomass. The current study examines the relationship between the level of shear and extracellular polymeric substance (EPS) production in MBRs. Two identical MBRs were operated in parallel where the biomass in one reactor was exposed to seven times greater shear forces. The concentrations of floc-associated and soluble EPS were monitored for the duration of the experiment. The stickiness of extracted floc-associated EPS from each reactor was also characterized using atomic force microscopy. A mathematical model of floc-associated and soluble EPS production was applied to quantitatively describe changes in EPS production with shear. Biomass grown in a high shear environment has lower floc-associated EPS production compared to biomass grown in a lower shear environment. This decrease in floc-associated EPS production also corresponds to a decrease in soluble EPS production, which can be explained by both the lower concentration of floc-associated EPS and the production of stickier floc-associated EPS that is more erosion resistant in the high shear reactor. This research suggests that mechanical stresses can have a significant impact on the production rates of floc-associated and soluble EPS—key parameters governing membrane fouling in MBRs.

Paleoenvironmental records extending well into the last glacial period are scarce in the steppe regions of southern South America. Here, we present a continuous record for the past 55 ka from the maar lake Laguna Potrok Aike (51°58' S, 70°23' W, southern Patagonia, Argentina). Previous studies on a sedimentary core from a lake level terrace near the northern margin of the lake covered parts of Oxygen Isotope Stage (OIS) 3 (59–29 ka) whereas a second core from the centre of the basin comprised the last 16 ka. Tephrostratigraphical constraints and OSL ages from a third core located below the lake level terrace provide the crucial piece to close the gap between the previous coring sites. High-resolution XRF and magnetic susceptibility as well as grain size data indicate a positive hydrological balance alongside with relatively high aeolian activity during the glacial which is contemporaneous with increased dust fluxes in Antarctica. This is therefore the first evidence for contemporaneity of aeolian deposition in both the target area (Antarctica) and in the major source area of Patagonia. During the Holocene climatic conditions driving sediment deposition seem to have been more variable and less dominated by wind compared to glacial times. The identification of a minor lake level lowering at approximately 4 cal ka BP allows to refine earlier paleoenvironmental reconstructions for the Holocene. Within error margins the OSL ages are consistent with published radiocarbon-dated records offering hence a valuable tool for further studies of the sediments from Laguna Potrok Aike. The new chronology confirms the age of three tephra layers up to now only found in Laguna Potrok Aike sediments and ascribed to OIS 3.