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Taupp T.,University of Koblenz-Landau | Wetzel M.A.,University of Koblenz-Landau | Wetzel M.A.,German Federal Institute of Hydrology BfG
Ecological Indicators | Year: 2013

In the context of the requirements of the European Water Framework Directive (WFD) numerous benthic indices have been proposed recently to assess the ecological quality of marine and transitional waters. In several studies these metrics were applied to coastal and estuarine environments under diverse anthropogenic pressures. Although currently the dumping of dredged material is one of the most prominent human impacts that modify estuaries, the performance of benthic indices to detect effects of dredged sediment relocation has not yet been tested explicitly. Hence we examined a selection of common metrics (species richness, Shannon diversity, AMBI, M-AMBI, W-value, BO2A) at 11 dumping and 11 nearby reference areas in the highly modified Elbe estuary (Germany), where permanent dredging is necessary to maintain the depth of the navigation channel. In order to cover the entire estuary, the study area spanned over the whole salinity gradient from limnic to euhaline. Additionally, we investigated changes in benthic communities due to dredged material placement. All indices, except the W-value, were suitable to differentiate between dumping and reference areas and showed significantly better index values exclusively at reference areas. The applicability of AMBI and M-AMBI was restricted in the limnic stretch due to the more frequent occurrence of freshwater species there. The W-value and BO2A were non-satisfactory in the case of azoic sediment, and in most cases these two indices indicated much better ecological status classifications than the other indices tested. Furthermore, the BO2A had restricted applicability with increasing salinity. At eight of eleven sites the benthic communities differed significantly between dumping and reference areas. Our findings show that the power of conventional benthic indices to detect physical disturbances like the dumping of dredged sediment varies greatly. Having this in mind, we suggest to choose carefully the benthic indices for ecological quality assessments according to the WFD in estuaries in order to avoid misclassifications. Such errors may lead to unnecessarily expensive remediation activities or, in the opposite case, to inactivity although actions were necessary. Furthermore, in order to better meet the WFD requirements we suggest that, regarding frequency and volume, dumping should be adapted as far as possible to the natural processes of sediment movement. © 2013 Elsevier Ltd. All rights reserved.


Brinke M.,Bielefeld University | Hoss S.,ECOSSA Ecological Sediment and Soil Assessment | Fink G.,German Federal Institute of Hydrology BfG | Ternes T.A.,German Federal Institute of Hydrology BfG | And 2 more authors.
Aquatic Toxicology | Year: 2010

Ivermectin is a widely applied veterinary pharmaceutical that is highly toxic to several non-target organisms. So far, little is known about its impact on benthic freshwater species, although its rapid sorption to sediment particles and high persistence in aquatic sediments have raised concerns about the risk for benthic organisms. In the present study, indoor microcosms were used to assess the impact of ivermectin on freshwater meiobenthic communities over a period of 224 days. Microcosm sediments were directly spiked with ivermectin to achieve nominal concentrations of 0.9, 9, and 45μgkg-1 dw. Initially measured ivermectin concentrations (day 0) were 0.6, 6.2, and 31μgkg-1 dw. In addition to abundance of major meiobenthic organism groups, the nematode community was assessed on the species level, assuming a high risk for free-living nematodes due to their close phylogenetic relationship to the main target organisms of ivermectin, parasitic nematodes. Benthic microcrustaceans (cladocerans, ostracods) and nematodes showed the most sensitive response to ivermectin, while tardigrades profited from the presence of the pharmaceutical. The most pronounced effects on the meiofauna community composition occurred at the highest treatment level (31μgkg-1 dw), leading to a no observed effect concentration (NOECCommunity) of 6.2μgkg-1 dw. However, the nematode community was already seriously affected at a concentration of 6.2μgkg-1 dw with two bacterivorous genera, Monhystera and Eumonhystera, being the most sensitive, whereas species of omnivorous genera (Tripyla, Tobrilus) increased in abundance after the application of ivermectin. Thus, a NOECCommunity of 0.6μgkg-1 dw was derived for nematodes. Direct and indirect effects of ivermectin on meiobenthic communities could be demonstrated. The pharmaceutical is likely to pose a high risk, because its NOECs are close to predicted environmental concentrations (PECs) in sediments (0.45-2.17μgkg-1 dw), resulting in worst case risk quotients (RQs) of 1.05-36.2. This observation lends support to efforts aimed at preventing the repeated entry of ivermectin in aquatic environments and thus its accumulation in sediments. Moreover, this study points out that model ecosystem studies should be part of environmental risk assessments (ERAs) of veterinary medicinal products (VMPs). © 2010 Elsevier B.V.


Taupp T.,University of Koblenz-Landau | Wetzel M.A.,University of Koblenz-Landau | Wetzel M.A.,German Federal Institute of Hydrology BfG
Estuarine, Coastal and Shelf Science | Year: 2014

The Venice System is one of the best-known and most applied systems to classify waters with respect to salinity. It has often been subject to criticism because the criteria used to derive zone boundaries were not made explicit. Consequently, an alternative multivariate PCA method that aimed at identifying salinity zones by means of the salinity ranges preferred by species was introduced by Bulger etal. (1993). We tested the applicability of both methods using salinity and benthic macroinvertebrate data for the poikilohaline Elbe Estuary (Germany) from 1997 to 2012. This was done by comparing the resultant salinity zone limits from the two approaches with boundaries where significant community changes were found by means of cluster analysis. Only the Venice System polyhaline and limnetic zone boundaries, and the PCA method outer estuary zone limit, showed good agreement with the benthic community pattern. None of the other Venice System or PCA method zone limits reflected the benthic community patterns. Our findings suggest that zone limits can only be well determined from mean salinity at the inner and outer end of the estuary, where the variation of salinity is relatively low. In contrast, in the middle of the estuary variation in salinity is the better predictor of zone boundaries. Thus, application of the Venice System or the PCA method in poikilohaline estuaries, such as the Elbe, is not meaningful and their use should be limited to homoiohaline systems. For poikilohaline systems, we found cluster analysis to be a better tool to identify salinity-zone boundaries. © 2014 Elsevier Ltd.


Wetzel M.A.,German Federal Institute of Hydrology BfG | Wetzel M.A.,University of Koblenz-Landau | Von Der Ohe P.C.,Helmholtz Center for Environmental Research | Manz W.,University of Koblenz-Landau | And 3 more authors.
Ecological Indicators | Year: 2012

Indices to assess the ecological status of water bodies according to the European Water Framework Directive (WFD) frequently produce widely differing results when applied to estuarine systems. Although several ecological indices have been employed to coastal environments and in estuaries in particular, there is still a lack of knowledge about their suitability for assessing the ecological status of heavily modified water bodies. Thus, we evaluated the performances of indices and fauna parameters (AMBI, M-AMBI, BOPA, BO2A, W-value, Shannon diversity, species richness, abundance) that have been discussed in the WFD context using data on invertebrates dwelling in two typical morphological units: the navigation channel and the river bank habitats of Elbe estuary (Germany). In addition, we tested their ability to identify several environmental factors (grain size distribution and chemical sediment contamination). All indices were able to detect major changes in macrofauna composition along the estuarine salinity gradient and were able to differentiate between navigation channel and shallow bank habitats. A strong significant correlation was found with most indices with the exceptions of the W-value and the BOPA with mean grain size. Almost all indices signaled poor ecological quality in the coarser fairway sediments against the finer sublitoral bank sediments. However, AMBI and BOPA showed the opposite: both indicators classified the invertebrate assemblages from the navigation channel better compare than the shallower habitats. The correlation of ecological indices and parameters with sediment contaminants and the toxicity of the sediment calculated as toxic units showed a diverse picture: all indices, except species richness and the BOPA, had a certain significant correlation with several individual sediment pollutants, however, only one index, the W-value, was correlated significant with the majority of chemical pollutants (Pb, Cd, Cu, Ni, Hg, Zn, β-HCH, pp′-DDD, and TBT) and the toxic units. Our results show clearly that ecological quality classification of heavily modified estuaries depends strongly on both the index and the habitat. Thus, we conclude that no index should be used on its own to estimate the ecological quality of estuaries. Further investigations and the improvement or development of such indices should place emphasis on their independence from the grain size spectrum of the sediments and on their good correlation with its pollution status. © 2011 Elsevier Ltd. All rights reserved.


Wetzel M.A.,German Federal Institute of Hydrology BfG | Wetzel M.A.,University of Koblenz-Landau | Scholle J.,Bioconsult Schuchardt and Scholle GbR | Teschke K.,Alfred Wegener Institute for Polar and Marine Research
Marine Environmental Research | Year: 2014

Artificial substrates are omnipresent today in most estuaries mostly in form of massive rip-rap used for groynes and jetties. In the Weser estuary, Germany, 60% of the shoreline is covered with such artificial substrates while, natural rocky substrate is lacking, as in all Wadden Sea estuaries. This large quantity of artificial substrates may be colonized by a benthic hard-substrate community which differs from the local natural soft-substrate assemblage. In this study we examined species compositions, abundances, biomass, and numbers of species of subtidal benthic communities on groynes and in the natural habitat, the sediment, along the salinity gradient of the Weser estuary. Species composition changed on both substrates significantly with salinity and was also significantly different between the substrates. In a comparison with the sediment, the groynes did not provide any benefit for non-indigenous nor for endangered species in terms of abundance, biomass, and number of species, but represent habitats with higher total abundances and biomass; though some non-indigenous species even occurred exclusively on groynes. In particular, groynes supported filter-feeding organisms which play an important role by linking benthic and pelagic food webs. The dominance of the suspension feeders affects crucial estuarine ecosystem services and may have important implications for the estuarine management by altering the estuarine ecological quality status. Hence, artificial substrates should be considered in future conservation planning and in ecological quality monitoring of the benthic fauna according to the European Water Framework Directive. © 2014 Elsevier Ltd.


Biran A.,Hebrew University of Jerusalem | Ben Yoav H.,Tel Aviv University | Yagur-Kroll S.,Hebrew University of Jerusalem | Pedahzur R.,Hebrew University of Jerusalem | And 4 more authors.
Analytical and Bioanalytical Chemistry | Year: 2011

A bacterial genotoxicity reporter strain was constructed in which the tightly controlled strong promoter of the Escherichia coli SOS response gene sulA was fused to the alkaline phosphatase-coding phoA reporter gene. The bioreporter responded in a dose-dependent manner to three model DNA-damaging agents-hydrogen peroxide, nalidixic acid (NA), and mitomycin C (MMC)-detected 30-60 min after exposure. Detection thresholds were 0.15 μM for MMC, 7.5 μM for nalidixic acid, and approximately 50 μM for hydrogen peroxide. A similar response to NA was observed when the bioreporter was integrated into a specially designed, portable electrochemical detection platform. Reporter sensitivity was further enhanced by single and double knockout mutations that enhanced cell membrane permeability (rfaE) and inhibited DNA damage repair mechanisms (umuD, uvrA). The rfaE mutants displayed a five- and tenfold increase in sensitivity to MMC and NA, respectively, while the uvrA mutation was advantageous in the detection of hydrogen peroxide. A similar sensitivity was displayed by the double rfaE/uvrA mutant when challenged with the pre-genotoxic agents 2-amino-3-methylimidazo[4,5-f]quinoline and 2-aminoanthracene following metabolic activation with an S9 mammalian liver fraction. © 2011 Springer-Verlag.


Wetzel M.A.,German Federal Institute of Hydrology BfG | Wetzel M.A.,University of Koblenz-Landau | Wahrendorf D.-S.,German Federal Institute of Hydrology BfG | von der Ohe P.C.,Helmholtz Center for Environmental Research
Science of the Total Environment | Year: 2013

Sediment contamination is one of the most pressing environmental problems in estuaries of industrialized countries and is of special interest to water managers involved in waterway maintenance dredging. In the present study, eight heavy metals (As, Pb, Cd, Cr, Cu, Ni, Hg, and Zn) and 41 organic compounds (pentachlorbenzol (PeCB), hexachlorbenzol (HCB), 7 polychlorinated biphenyls (PCBs), the hexachlorocyclohexanes α-HCH, β-HCH, γ-HCH, 6 dichlorodiphenyltrichloroethane isomers, organochlorine styrene (OCS), octachloronaphthalene (OCN), 15 polycyclic aromatic hydrocarbons (PAHs), and 6 organotin (OT) compounds) were analyzed in surface sediments at 36 sites in the Elbe estuary in 2006. Correlation analysis showed a general decrease in sediment contaminant concentrations from the stations near the port of Hamburg towards the open sea. This decrease was significant (Spearman's rank correlation, p. <. 0.05) with most pollutants. In addition, cluster analysis identified five groups of sites with different sediment contaminant patterns within the Elbe estuary. Worst case toxic risks stemming from sediment-bound organic pollutants were predicted using the Toxic Unit approach, based on estimated pore-water concentrations under equilibrium conditions and acute LC50 values for three standard test organisms of the trophic levels of fish, invertebrates, and algae. The estimated sediment toxicity was significantly higher in the inner part (river-km 630 to 660) compared with the estuarine mouth. Moreover, potential toxicity of organic pollutants estimated for invertebrates and for fish exceeded acute-based effect thresholds at 30 and 24 stations, respectively. Chronic effects for invertebrates are expected at all sites investigated. We conclude that sediment pollution and related potential toxicity in the Elbe estuary may have more influence on the benthos fauna than expected to date. © 2013 Elsevier B.V.


Reifferscheid G.,German Federal Institute of Hydrology BfG | Buchinger S.,German Federal Institute of Hydrology BfG | Cao Z.,Athlone Institute of Technology | Claus E.,German Federal Institute of Hydrology BfG
Environmental and Molecular Mutagenesis | Year: 2011

Extracts of sediments from an area of concern in the Elbe river basins (Spittelwasser creek) were analyzed with the Ames-fluctuation test and in parallel with gas chromatography/mass spectrometry for compound identification. The standard test strains TA 98 and TA 100 showed mutagenicity mainly in medium-polar fractions of the sediment extracts. PAHs contribute to the overall mutagenic potential of the sample. Especially, cyclopenta[c,d]pyrene that was previously not defined as a priority hazardous substance has to be considered as well. The addition of metabolically competent test strains, which overexpress nitroreductase and acetyltransferase (e.g., YG1041 and YG1042) to the test battery, increased significantly the sensitivity of the Ames test for medium polar to polar genotoxins. The increased mutagenicity that was found in these bacterial strains indicates the presence of nitroarenes and/or aromatic amines. In fact, a number of heterocyclic and nitrogen-substituted aromatic compounds were identified in the sediments of the Spittelwasser creek of which methyl parathion, 1-naphthylamine, and N-phenyl-2-naphthylamine are mutagenic. © 2010 Wiley-Liss, Inc.


PubMed | German Federal Institute of Hydrology BFG, Hamburg University of Applied Sciences, Helmholtz Center for Environmental Research and Technical University of Denmark
Type: Journal Article | Journal: Environmental science & technology | Year: 2016

Mixtures of organic contaminants are ubiquitous in the environment. Depending on their persistence and physicochemical properties, individual chemicals that make up the mixture partition and distribute within the environment and might then jointly elicit toxicological effects. For the assessment and monitoring of such mixtures, a variety of cell-based in vitro and low-complexity in vivo bioassays based on algae, daphnids or fish embryos are available. A very important and sometimes unrecognized challenge is how to combine sampling, extraction and dosing to transfer the mixtures from the environment into bioassays, while conserving (or re-establishing) their chemical composition at adjustable levels for concentration-effect assessment. This article outlines various strategies for quantifiable transfer from environmental samples including water, sediment, and biota into bioassays using total extraction or polymer-based passive sampling combined with either solvent spiking or passive dosing.


PubMed | German Federal Institute of Hydrology BfG, Hebrew University of Jerusalem and Hadassah College
Type: Journal Article | Journal: Applied microbiology and biotechnology | Year: 2016

We report the results of a study of the potential negative effects of the freeze-drying process, normally considered a benign means for long-term conservation of living cells and the golden standard in bacterial preservation. By monitoring gene induction using a whole-cell Escherichia coli bioreporter panel, in which diverse stress-responsive gene promoters are fused to luminescent or fluorescent reporting systems, we have demonstrated that DNA repair genes belonging to the SOS operon (recA, sulA, uvrA, umuD, and lexA) were induced upon resuscitation from the freeze-dried state, whereas other stress-responsive promoters such as grpE, katG, phoA, soxS, and sodA were not affected. This observation was confirmed by the UMU-chromotest (activation of the umuD gene promoter) in Salmonella typhimurium, as well as by real-time PCR analyses of selected E. coli SOS genes. We further show that a functional SOS operon is important in viability maintenance following resuscitation, but that at the same time, this repair system may introduce significantly higher mutation rates, comparable to those induced by high concentrations of a known mutagen. Our results also indicate that the entire freeze-drying process, rather than either freezing or drying separately, is instrumental in the induction of DNA damage.

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