Multi-species toxicity tests were conducted using a broad range of freshwater nematode species to assess interspecific differences in sensitivity to chemical stress and to compare the toxicity to that on the standard test organism Caenorhabditis elegans. The lethal effects of nine different chemical treatments, including metals and polycyclic aromatic hydrocarbons (PAHs) in single and mixture application, were determined for nematodes exposed for 48 h to spiked aqueous solutions. The investigated freshwater nematodes exhibited distinct differences in their sensitivity. Ranking of the susceptibility of 27 species to chemical stress showed that the effects were largely independent of the tested chemical compounds. Overall, the responses of C. elegans were well within the range of those of freshwater nematode species, being slightly less tolerant to metals, but more tolerant to PAHs than the average freshwater species response. Therefore, this study justified the use of C. elegans as representative model for freshwater nematode species in toxicity testing.

The production of hexachlorocyclohexanes (HCHs) at Bitterfeld, Germany, caused heavy contamination of sediments in the receiving waters and soils of riverbanks and floodplains of the Spittelwasser creek with adverse effects on the rivers Mulde and Elbe. This study was launched to investigate the isomer specific behaviour of aged and non-aged hexachlorocyclohexanes focusing on their transformation, sorption and bioaccumulation. Spiked residues of - and -HCH were transformed in aerobic water/sediment systems, while no elimination was observed for -, - and epsilon-HCH. In contrast, aged residues of all HCH isomers were entirely stable under these aerobic conditions, while under anaerobic conditions a significant transformation was found for all spiked HCH isomers. Desorption hysteresis was identified for all isomers. Ageing led to an increase in the binding strength of HCH isomers to sediment, indicated by elevated logK(OC)-values and increased the persistence of HCH isomers in aerobic water/sediment systems. HCH bioaccumulated in benthic organisms of Spittelwasser creek and Schachtgraben canal. After their confluence the lipid normalised HCH concentrations in benthic organisms of Spittelwasser creek increased by a factor of 10, indicating the central role of HCH residues from the Schachtgraben canal for the HCH exposure of benthic biota in the aquatic system of the Spittelwasser creek.

Because soft sediments are often hotspots of chemical contamination, their assessment can aid in identifying the causes of environmental stress and the implementation of measures to improve the health of the respective ecosystems. Achieving a “good ecological status” of surface waters, as required by the European Water Framework Directive, strongly depends on recognition of the chemical status of sediments. Meiobenthic organisms are important, but widely neglected components of the ecologically relevant fauna of a wide variety of ecosystems. In the present study, microcosms containing freshwater sediments were used to investigate the effects of eight different metals and polycyclic aromatic hydrocarbons (PAHs), in single and mixed applications, on natural meiofaunal assemblages. Structural (abundance and biomass) and functional (secondary production) parameters of the investigated assemblages were measured as ecologically relevant endpoints. Their sensitivity in revealing both the differential effects and the responses of meiofaunal taxa was evaluated to assess the general suitability of meiofauna and, in particular, of individual tested taxa, as bioindicators of soft sediment contamination. Structural parameters were found to be more valuable indicators than functional measurements, with more pronounced effects observed on the taxon level than on total meiofauna. Among the meiofaunal taxa considered in this study, nematodes were of particular utility as early indicators of chemical stress in freshwater soft sediments. Overall, this study provides new insights into the impact of toxicants on soft freshwater sediments and demonstrates the suitability of meiofaunal communities, especially nematodes, in assessing contamination of this ecosystem.

A novel approach was investigated for the assessment of leaching from a one-component polyurethane (1C-PU) coating used for hydraulic structures using nontarget analysis via LC-QTOF-MS. Leaching behavior of the 1C-PU coating was studied using experiments in which the coating was exposed to water for defined periods (6 h, 24 h, 3 d, 14 d). Three hardening durations for the 1C-PU coating were tested (0 h, 24 h, 14 d) as well as two water matrices (ultrapure water and river water), including a successive water renewal. Dissolved organic carbon, total nitrogen bound and nontarget measurements via LC-QTOF-MS showed that under all tested conditions organic substances were leached out of the 1C-PU coating. The shorter the hardening duration and the longer the leaching duration, the higher were the number and quantities of the eluted substances, while the influence of the water matrix was minor with respect to substance elution. Based on the MS2 spectra from the LC-QTOF-MS measurements, 30 substances released from the 1C-PU coating were tentatively identified. These substances belong to five chemical groups: derivatives of (i) N-(tosyl)carbamate, (ii) p-toluenesulfonamide (PTSA), (iii) 4,4'-methylenediphenyl diisocyanate (4,4'-MDI), (iv) toluenediisocyanate (TDI), and (v) oligo(ethylene) ([C2H4O]n) as well as p-toluenesulfonic acid. The identity of seven substances was confirmed by authentic reference standards, all of which exhibited an elevated bacterial toxicity to Aliivibrio fischeri. p-Toluenesulfonic acid was present in a German canal (Teltowkanal) with concentrations of up to 11 μg L-1.

Freshwater microcosms were used to investigate the effects of various metals and polycyclic aromatic hydro-carbons (PAHs), applied as single substances and in mixtures, on sediment-inhabiting nematode assemblages. Several community measures, including nematode abundance, biomass, species richness, species composition and the NemaSPEAR[%]-index, were assessed and their changes in response to the chemical treatments were compared with the results of single-species toxicity testing using the nematode Caenorhabditis elegans. The diagnostic power of endpoints revealing toxic effects was then evaluated to assess the general suitability of nematodes as bioindicators of sediment contamination by a set of relevant chemicals. Overall, community measures based on species-level (detected with principle response curves) responded most sensitively to chemical stress in the microcosms, especially in terms of biomass, with the C. elegans toxicity test was for the most part as sensitive to the chemicals as the nematode species composition. Generally, this study justified the suitability of nematodes in assessments of the risk of chemicals frequently associated with freshwater sediments and underlined the value of C. elegans in the prospective risk assessment of chemicals, as this species was able to indicate the negative effects of comparatively low sediment concentrations of the contaminants.

Today, basic requirements for construction works include the protection of human health and of the environment. In the tension area between economic demands, circular flow economy and environmental safety, a link between the results from standardized leaching tests and the respective environmental quality standards must be created. To derive maximum release limits of metals and metalloids for armourstones in hydraulic engineering, this link is accomplished via a simple model approach. By treating natural materials and industrial by-products the same way, the article delivers an overview on the recent regulative situation in Europe as well as describes and discusses an innovative approach to derive maximum release limits for monolithic construction products in hydraulic engineering on a conceptual level. On a practical level, a list of test parameters is derived by connecting an extensive dataset (seven armourstone materials with five repetitions and 31 elements tested with the worldwide applied dynamic surface leaching test) with surface water quality standards and predicted no effect concentrations. Finally, the leaching tests results are compared with the envisaged maximum release limits, offering a direct comparison between natural materials and industrial by-products.

Benzotriazole UV stabilizers (BUVSs) are widely applied in plastics to prevent discoloration and to enhance product stability. This study describes for the first time the occurrence of nine different lipophilic BUVSs (UV-326, UV-320, UV-329, UV-350, UV-328, UV-327, UV-928, UV-234 and UV-360) in sediment, suspended particulate matter (SPM) and bream liver samples of German rivers. All investigated BUVSs were detected in sediments and SPM at concentrations in the low ng/g dry weight (dw) range. The so far rarely analyzed compound UV-360 as well as UV-326 were the predominant BUVSs in sediments and SPM from the river Rhine reaching maximum concentrations of 62 and 44 ng/g dw, respectively. Five BUVSs were also confirmed to bioaccumulate in bream liver, but neither UV-360 nor UV-326 was detected above the limit of quantification (LOQ). In contrast, highest concentrations in bream liver were determined for UV-327 (65 ng/g dw) and UV-328 (40 ng/g dw). A retrospective time trend analysis of BUVSs in SPM from two sites (river Rhine, 2005 to 2013; river Saar, 2006 to 2013) revealed increasing contamination levels of UV-329 and decreasing levels of UV-320 and UV-350. At one site (river Rhine) time trends of BUVS concentrations were also investigated in bream liver (1995-2013) and supported a considerably reduced exposure to UV-350. A first assessment of the environmental fate of BUVSs by sediment-water batch systems revealed a rapid partitioning into the sediment and no considerable degradation within 100 d.

Für eine gewinnbringende Forschung zur Förderung nachhaltiger Entwicklung des Verkehrs werden im Expertennetzwerk die Schutzziele verkehrsträgerund projektübergreifend definiert, die multifaktoriellen Probleme gemeinsam erkannt und mit harmonisierten und projektübergreifend abgestimmten Methoden erfasst und bewertet. Dieses Vorgehen ermöglicht es, UrsacheWirkungszusammenhänge zuverlässig zu beschreiben, zu analysieren und Maßnahmen vorzuschlagen, die in einer KostenNutzen-Abwägung priorisiert werden. Gemäß dem Leitmotiv des Expertennetzwerks „Wissen-Können-Handeln“ wird die Chance ergriffen, Lösungen für eine nachhaltige Mobilität unter Entkopplung von Verkehrsentwicklung und Umweltwirkungen zu finden. Forschungsergebnisse für eine nachhaltige Entwicklung bereitgestellt. Zunächst konkret fünf Projekte werden im Zeitraum 2016– 2019 in einem engvernetzten Forschungsverbund in Angriff genommen:

Soft sediments are often hotspots of chemical contamination, and a thorough ecotoxicological assessment of this habitat can help to identify the causes of stress and to improve the health of the respective ecosystems. As an important component of the ecologically relevant meiobenthic fauna, nematodes can be used for sediment assessments, with various assay tools ranging from single-species toxicity tests to field studies. In the present study, microcosms containing sediment were used to investigate direct and indirect effects of zinc on natural nematode assemblages, and acute community toxicity tests considering only direct toxicity were conducted. The responses of the various freshwater nematode species in both approaches were compared with those of Caenorhabditis elegans, determined in standardized tests (ISO 10872). At a median lethal concentration (LC50) of 20 mg Zn/L, C. elegans represented the median susceptibility of 15 examined nematode species examined in the acute community toxicity tests. In the microcosms, Zn affected the nematodes dose-dependently, with changes in species composition first detected at 13 mg Zn/kg to 19 mg Zn/kg sediment dry weight. The observed species sensitivities in the microcosms corresponded better to field observations than to the results of the acute community toxicity tests. (C) 2016 SETAC

Bioaccumulation, the accumulation of a chemical in an organism relative to its level in the ambient medium, is of major environmental concern. Thus, monitoring chemical concentrations in biota are widely and increasingly used for assessing the chemical status of aquatic ecosystems. In this paper, various scientific and regulatory aspects of bioaccumulation in aquatic systems and the relevant critical issues are discussed. Monitoring chemical concentrations in biota can be used for compliance checking with regulatory directives, for identification of chemical sources or event-related environmental risk assessment. Assessing bioaccumulation in the field is challenging since many factors have to be considered that can affect the accumulation of a chemical in an organism. Passive sampling can complement biota monitoring since samplers with standardised partition properties can be used over a wide temporal and geographical range. Bioaccumulation is also assessed for regulation of chemicals of environmental concern whereby mainly data from laboratory studies on fish bioaccumulation are used. Field data can, however, provide additional important information for regulators. Strategies for bioaccumulation assessment still need to be harmonised for different regulations and groups of chemicals. To create awareness for critical issues and to mutually benefit from technical expertise and scientific findings, communication between risk assessment and monitoring communities needs to be improved. Scientists can support the establishment of new monitoring programs for bioaccumulation, e.g. in the frame of the amended European Environmental Quality Standard Directive.

Equilibrium sampling can be applied to measure freely dissolved concentrations (C-free) of hydrophobic organic chemicals (HOCs) that are considered effective concentrations for diffusive uptake and partitioning. It can also yield concentrations in lipids at thermodynamic equilibrium with the sediment (C-lip reversible arrow sed) by multiplying concentrations in the equilibrium sampling polymer with lipid to polymer partition coefficients. We have applied silicone coated glass jars for equilibrium sampling of seven 'indicator' polychlorinated biphenyls (PCBs) in sediment samples from ten locations along the River Elbe to measure c(free) of PCBs and their C-lip reversible arrow sed. For three sites, we then related c(lip reversible arrow sed) to lipid-normalized PCB concentrations (cbio,lip) that were determined independently by the German Environmental Specimen Bank in common bream, a fish species living in close contact with the sediment: (1) In all cases, c(bio,lip) were below c(lip reversible arrow sed), (2) there was proportionality between the two parameters with high R-2 values (0.92-1.00) and (3) the slopes of the linear regressions were very similar between the three stations (0.297; 0.327; 0.390). These results confirm the close link between PCB bioaccumulation and the thermodynamic potential of sediment-associated HOCs for partitioning into lipids. This novel approach gives clearer and more consistent results compared to conventional approaches that are based on total concentrations in sediment and biota-sediment accumulation factors. We propose to apply equilibrium sampling for determining bioavailability and bioaccumulation potential of HOCs, since this technique can provide a thermodynamic basis for the risk assessment and management of contaminated sediments. (C) 2015 The Authors. Published by Elsevier Ltd.

With respect to their high abundances, their role as intermediaries between microorganisms and higher trophic levels, and their ubiquitous occurrence in all habitats, nematodes are of strong potential interest as environmental indicators. Ecotoxicological methods to evaluate the risk of anthropogenic pollutants on ecosystems require both in vitro and in vivo toxicity tests to investigate either mechanisms or pathways of toxicity and to set accurate toxicity thresholds. For this, the interest in nematodes as model organisms in ecotoxicology increased over the past few decades and existing appropriate experimental methods are reviewed in this manuscript. An overview of the various existing ecotoxicological tools for nematodes, ranging from molecular laboratory methods to experimental model ecosystem approaches, and their role as indicator organisms is given. The reviewed studies, approaches that range from species-based to community-based methods, reveal exciting possibilities for the future use of nematodes in ecotoxicological studies. Suitable ecotoxicological tools and ecological indices for nematodes should be integrated in weight-of-evidence approaches for assessing the ecological risk of contamination.

Background studies of the Federal Institute of Hydrology (BfG) and the State Office for flood control and water management (LHW) of SaxonyAnhalt in the navigable part of the Saale between Bad Durrenberg and the inflow in the Elbe are presented. The results refer both to the barrages of the federal waterway and to the relevant tributaries and side structures in the responsibility of the State Saxony-Anhalt. Conclusions are drawn for the sediment quality in the river Saale and for the potentially mobile amounts of contaminated fine sediments as well as for the impact of these sediments on the overall situation in the whole Elbe basin. Thus, the results substantially contribute to the sediment management concepts of the ICPER (IKSE 2014) and of the EGG ELBE (2013). According to the classification scheme used in the sediment management concept of the ICPER (IKSE 2014), the river Saale is an almost continuously contaminated water body in terms of 29 relevant contaminants. The creek Schlusselstollen is the most important point source in the Saale catchment. The average annual load of suspended particulate matter of the river Saale into the Elbe (2003-2008) amounted to approximately 128,000 t (min. 83,000 t, max. 228,000 t). This corresponds to an averaged suspended matter portion of 20 % at the monitoring station Schnackenburg (Elbe). The main transport of suspended matter and sediments into the Elbe takes place via the weirs (85-90 %). Nevertheless, in 2013 approx. 108,000 m(3) of fine grained, potentially mobile sediment (thereof approx. 54,000 m3 in Calbe, Rothenburg and Rischnnible) were deposited in the federal waterway Saale, with approx. 61,000 m3 in the surveyed tributaries and approx. 150,000 m(3) in the branches. Between 1994 and 2012, approx. 194,000 m3(252,000 t) of fine sediment were removed by dredging. The growth of deposits in the barrages amounted to approx. 14,400 m3 in a one-year period from May 2012 to April 2013. The studies for estimating the sediment quality and the amount of potentially mobile fine sediments took place in selected, characteristic water stretches. Results for the overall potential load were obtained by extrapolation of these data to the whole study area. Studies for erosion stability were conducted in branches and tributaries, not in the barrages. Entries and output of sediments from the river banks and surrounding areas were not included in the balance sum of sediment amounts/volumes.

Introduction: Sediment management needs costefficient tools for sediment quality assessment that help to prioritize management or further assessment options. Sediment quality guidelines (SQGs) are chemical (threshold) concentrations that can be used as predictors of the toxic potential of sediments or the probability of the incidence of toxicity. Moreover, their advantage is that they were effect-based derived and thus, the SQGs are directly related to biological effects. Once derived, they can be cost-efficiently applied as a screening tool or, if required, taken for a chemical line of evidence in a comprehensive weight-of-evidence framework. Here, SQGs are presented that were derived based on chemical and nematode community analysis of freshwater sediment samples from several river basins across Germany (e.g., Elbe, Rhine, Danube). Nematodes were chosen because they are frequently the most abundant and diverse taxonomic group in sediments and they fulfill key positions in benthic food webs due to their various feeding types. In addition, as endobenthic organisms, they are subjected via various pathways to any noxious substances in sediments throughout their whole lifecycle. Moreover, nematodes are often more dominant than macroinvertebrates in fine sediments, which are of particular interest in terms of water quality due to their high potential to accumulate pollutants. The aim of this study was to develop SQGs that also protect meiobenthic organisms, such as nematodes, which have been rather neglected so far despite their high ecological relevance. Moreover, this study wants to gather more information about how meiobenthic organisms, as exclusively endobenthic organisms, may complement existing sediment quality assessments with special respect to fine sediments.

The pharmaceutical ivermectin is used to treat parasitic infections, such as those caused by nematodes. While several studies have demonstrated the severe effects of ivermectin on non-target organisms, little is known about the drug's impact on free-living nematodes. In the present work, a full life-cycle experiment was conducted to estimate how an ivermectin lowest observed effect concentration derived from a Caenorhabditis elegans bioassay (endpoint reproduction) might translate into effects at the population level of this free-living nematode. The results showed that fecundity decreased to levels similar to those determined in the bioassay after a time of corresponding duration (18.6 % inhibition compared to the control), but the impact then rather weakened until the end of the experiment, at which point the net reproductive rate (R(0)) was still, but not significantly, reduced by 12.4 %. Moreover, the average lifespan, length of the reproductive period, maximum daily reproduction rate, and intrinsic rate of increase (r(m)) were significantly reduced by 30.0, 25.9, 11.2, and 3.5 %, respectively. The experiment revealed that a 4-day bioassay is protective enough for C. elegans with respect to ivermectin's effects on fecundity. However, the pronounced effects of a low drug concentration on survival, a highly elastic trait, may better account for the observed population-level response, i.e., a decrease of r(m), than the effects on fecundity. These results emphasize that full life-cycle experiments are valuable for assessment of pollutants, because the effects on several life-cycle traits can be simultaneously measured and integrated into an ecologically relevant parameter, the population growth rate, that reflects a population's response to a specific pollutant.

Introduction: Since the early 1990s, sediments from the German part of the River Elbe have regularly been monitored for total concentrations of contaminants by the German Federal Institute of Hydrology. In contrast, freely dissolved concentrations (Cfree) of hydrophobic contaminants in these sediments are largely unknown though they are considered the effective concentrations. They are more indicative of potential exposure of aquatic organisms than total concentrations. Recently, the applicability of equilibrium sampling using polydimethylsiloxane (PDMS) coated glass jars has been shown in marine sediments with background contamination of polychlorinated biphenyls (PCBs) [1]. The aims of the present study were to 1.) test the applicability of equilibrium sampling using coated glass jars to sediments from the River Elbe, 2.) assess freely dissolved sediment porewater concentrations of PCBs (PCB 28, 52, 101, 118, 138, 153, 180) as well as Dichlordiphenyltrichlorethane (DDT) and its metabolites and 3.) determine site-specific sediment/water distribution ratios (KD).

Sediments along the river Saale, one of the main tributaries of the river Elbe, were characterized with the yeast estrogen screen to elucidate possible sources of endocrine-disrupting compounds that might contribute to the downstream contamination of the river Elbe. At two sampling sites, elevated levels of estrogenic activity up to 55,000ng ethinylestradiol equivalents per kilogram sediment dry weight were detected in the respective sediment extracts. Aliquots of the sediment extracts were analyzed for 4-nonylphenols and natural steroidal estrogens as possible candidates with an estrogenic potential. The maximal concentrations of 4-iso-nonylphenol and estrone were 115mg/kg dry weight and 20 mu g/kg dry weight at the sampling site Luppe, which showed in accordance the highest biological activity. Under consideration of compound concentration and compound specific estrogenic activity the 4-iso-nonylphenols contributed most to the observed estrogenic effect. A strong correlation between the measured estrogenic activity and the concentration of the sediment-associated 4-iso-nonylphenol underlines the relevance of this compound class as a xenoestrogen in the catchment area of the river Saale. Environ. Toxicol. Chem. 2013;32:526534. (c) 2012 SETAC