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Sardo A.M.,University of Aveiro | Pereira L.,University of Aveiro | Gerhardt A.,LimCo International | Gerhardt A.,University of Coimbra | Soares A.M.V.M.,University of Aveiro
Environmental Toxicology and Pharmacology | Year: 2011

Lumbriculus variegatus is a recommended species for use in sediment toxicity tests and is known to have a remarkable power of segmental regeneration. Here, we tested the effects of a chemical stressor on the regenerative ability of L. variegatus and investigated the potential of regenerative ability as an additional new parameter in standard toxicity tests. The worms were cut into two equal segments, and exposed to various concentrations of lead. Two assays were performed: one with sediment spiked with lead and the other with water spiked with lead. The endpoints were segmental regeneration, survival and behaviour. Regenerative ability was clearly affected by exposure to lead-contaminated sediment and lead-contaminated water. Organisms exposed to lead grew more slowly than those not exposed; worms exposed to contaminated water showed higher mortalities than those exposed to contaminated sediment. Results showed that L. variegatus' regenerative ability, as a developmental test parameter, is more sensitive than mortality. © 2010 Elsevier B.V.

Langer-Jaesrich M.,University of Tübingen | Kohler H.,University of Tübingen | Gerhardt A.,LimCo International
Journal of Soils and Sediments | Year: 2010

Purpose: The significance of chironomids mouthpart deformities as suitable indicators for pollutant contamination of natural waters and sediments has been investigated and discussed for several decades. Uncertainties still exist as further laboratory studies, with different pollutants and with the same experimental design are required. Materials and methods: In this study, the effects of four substances (i. e., nickel chloride, chlorpyrifos, imidacloprid and thiacloprid) were tested on the mouthpart deformity rates and patterns in Chironomus riparius. These compounds were investigated either individually or in mixtures. Results and discussion: No significant increase in the frequency of mouthpart deformities was found using different single substance treatments when compared to the controls. Consequently no concentration-effect relationships between substance concentration and deformity frequency were detected. In mixture experiments an increase in mouthpart deformities of C. riparius exposed to imidacloprid-thiacloprid mixtures was detected. This indicated that the effects of single substances and mixtures on mouthpart deformity frequency may differ considerably. Conclusions: The findings in this study from different laboratory approaches in combination with the published literature questions the reliability of chironomids mouthpart deformities as indicators of freshwater and sediment contamination by toxic substances. © Springer-Verlag 2010.

Stewart S.C.,Queen's University of Belfast | Dick J.T.A.,Queen's University of Belfast | Laming P.R.,Queen's University of Belfast | Gerhardt A.,LimCo International
Journal of Environmental Monitoring | Year: 2010

The Multispecies Freshwater Biomonitor™ is an online continuous biomonitor which utilises impedance conversion to quantitatively record behavioural responses of vertebrates and invertebrates to environmental change. Here, we extend the use of the MFB into the marine aquaculture environment using the Green crab (Carcinus maenas) as a biological monitor. As a ubiquitous and abundant species, C. maenas can be used in applications such as aquaculture and monitoring of diffuse and point source marine pollution. Four experiments were undertaken to establish: (1) if the electrical field generated by the apparatus had any effect on C. maenas; (2) if the behaviour of C. maenas was altered by the presence of ammonia; (3) if the behaviour of C. maenas was affected by the electrical field when ammonia was present and (4) if defined behaviours could be detected by the MFB. There was no significant effect of the current on C. maenas in the MFB. There was a significant difference in overall expression of behaviour in response to an increasing gradient of ammonia and activity of the chamber. Five behaviours, 'walking', 'climbing', 'leg stretch', 'cleaning' and 'inactivity' were detected by the MFB. C. maenas appears to be a suitable candidate for use in the MFB in a marine context. Further testing of the biomonitor and C. maenas is required using other toxicants to establish alarm thresholds that could be used in situ for water quality monitoring. © 2010 The Royal Society of Chemistry.

Langer-Jaesrich M.,University of Tübingen | Kienle C.,University of Tübingen | Kienle C.,Ecole Polytechnique Federale de Lausanne | Kohler H.-R.,University of Tübingen | Gerhardt A.,LimCo International
Ecotoxicology | Year: 2010

The effects of chemicals on biotic interactions, such as competition and predation, have rarely been investigated in aquatic ecotoxicology. This study presents a new approach for the investigation of predator-prey interactions between zebrafish (Danio rerio) and midge larvae (Chironomus riparius) impaired by chlorpyrifos (CHP), a neurotoxic insecticide. With a simple experimental design including four different treatments: (1) control, (2) predator exposed, (3) prey exposed and (4) both, predator and prey, exposed, we were able to detect by visual observation an increase in the feeding rate of zebrafish preying on exposed chironomids after acute (2 h) exposure to 6 μg/l CHP. Previously, a decrease in the burrowing behaviour of exposed chironomid larvae was observed. However, when pre-exposing simultaneously both predators and prey, no significant differences in the feeding rate of zebrafish were observed. This suggests an impairment in prey recognition of the exposed zebrafish. At a lower CHP concentration (1 μg/l), no differences in feeding rate of zebrafish were observed. We therefore propose the use of trophic interactions as parameters in higher tier studies for chemical testing and evaluation of ecotoxicological risk assessment. © 2010 Springer Science+Business Media, LLC.

The aim of the work was to study effects of suboptimal temperature on nickel toxicity under chronic exposure and to apply the Multispecies Freshwater Biomonitor® (MFB®) for the first time to soil organisms in order to link behavioral to physiological endpoints. Ground beetles Pterostichus oblongopunctatus were reared at 10 or 20°C on control or Ni-contaminated (2500 mg Ni kg-1) food. After 64 days half of the Ni-exposed beetles were transferred to uncontaminated food (elimination phase). The remaining Ni-exposed beetles were left on the contaminated food to the end of the experiment (96 days). After completing the experiment, respiration rate and locomotor activity were measured in Ni-contaminated beetles (Ni), Ni-contaminated ones after elimination (E), and controls (C). Then, the beetles were analyzed for Ni body loads. The respiration rate, which was always measured at 20°C for all experimental groups, was highest in Ni beetles reared at 10°C and did not differ between groups C and E. Similarly, locomotor activity was highest in Ni beetles, and marginally significant temperature effect was found. The study indicated thus that exposure to elevated Ni concentrations increased the maintenance costs in P. oblongopunctatus and that rearing the beetles at suboptimal temperature increased the respiration rate even further. However, the effects observed in both respiration rate and locomotor activity were reversible after decontamination. The study demonstrated also the potential of MFB® for assessing the behavior of soil-dwelling organism in environmental toxicology. © 2010 Springer Science+Business Media, LLC.

Holmstrup M.,University of Aarhus | Bindesbol A.-M.,University of Aarhus | Oostingh G.J.,University of Salzburg | Duschl A.,University of Salzburg | And 12 more authors.
Science of the Total Environment | Year: 2010

Ecotoxicological effect studies often expose test organisms under optimal environmental conditions. However, organisms in their natural settings rarely experience optimal conditions. On the contrary, during most of their lifetime they are forced to cope with sub-optimal conditions and occasionally with severe environmental stress. Interactions between the effects of a natural stressor and a toxicant can sometimes result in greater effects than expected from either of the stress types alone. The aim of the present review is to provide a synthesis of existing knowledge on the interactions between effects of "natural" and chemical (anthropogenic) stressors. More than 150 studies were evaluated covering stressors including heat, cold, desiccation, oxygen depletion, pathogens and immunomodulatory factors combined with a variety of environmental pollutants. This evaluation revealed that synergistic interactions between the effects of various natural stressors and toxicants are not uncommon phenomena. Thus, synergistic interactions were reported in more than 50% of the available studies on these interactions. Antagonistic interactions were also detected, but in fewer cases. Interestingly, about 70% of the tested chemicals were found to compromise the immune system of humans as judged from studies on human cell lines. The challenge for future studies will therefore be to include aspects of combined stressors in effect and risk assessment of chemicals in the environment. © 2009 Elsevier B.V.

Langer-Jaesrich M.,University of Tübingen | Kohler H.-R.,University of Tübingen | Gerhardt A.,LimCo International
Archives of Environmental Contamination and Toxicology | Year: 2010

Since data documentation on neonicotinic toxicity to nontarget organisms should be enhanced, we investigate the effects of thiacloprid, a novel neonicotinoid insecticide, on the sediment-dwelling nontarget insect Chironomus riparius. Further, we wanted to validate the sensitivity of end points on different biological levels and obtain the greatest amount of information regarding the effects of this compound by using a battery of several end points such as larval mortality, behavior, body weight gain, emergence rate, time of development, gender ratio, Hsp70 stress protein level, and larval mouthpart deformities after exposure at a concentration range of 0.1 to 1000 μg/L thiacloprid. C. riparius was impacted starting at concentrations of 0.5 μg/L, a concentration that can be considered environmentally relevant. Larval mortality, behavior, emergence, and Hsp70 protein level were sensitive indicators for the toxic effect of thiacloprid, whereas gender ratio and mouthpart morphology were not affected. In our case life-cycle end points like survival rate (LC 50: 1.57 μg/L) and emergence rate (EC 50: 0.54 μg/L) proved to be more sensitive than tested physiological end points for the neurotoxic insecticide. © 2009 Springer Science+Business Media, LLC.

Gerhardt A.,LimCo International | Gerhardt A.,Ecole Polytechnique Federale de Lausanne | Ud-Daula A.,Helmholtz Center for Environmental Research | Schramm K.-W.,Helmholtz Center for Environmental Research | Schramm K.-W.,TU Munich
Acta Protozoologica | Year: 2010

This review summarizes the application of Tetrahymena spp. in ecotoxicology, in order to promote a more integrated, multi-level ecotoxicological assessment approach regarding the effects of chemical stressors on several biological levels (from molecule to ecosystem). Such a multi-level testing approach in one species facilitates the establishment of missing causal relationships between biochemical responses and ecological effects. The review illustrates that Tetrahymena spp. represent excellent ecotoxicological test species due to their important role in the microbial foodweb, wide distribution and abundance, sequenced genome in T. thermophila, large background knowledge and scientific publications in cellular biology, ecology and ecotoxicology. Several bioassays have already been developed on different biological organisation levels, such as enzyme assays (biochemical level), behavioral tests (individual level), population growth tests (population level) and microcosms (community level). Moreover, specific mode-of-action based assays are available (e.g. genotoxicity), or are in development (e.g. endocrine disruption and neurotoxicity). Tetrahymena spp. combine traits of (1) a single cell, thus might replace or complement specific cell-line testing approaches, with traits of (2) a whole organism and population, thus allowing to study complete metabolic pathways and its consequences on population growth and genetic adaptation. Assays involving Tetrahymena spp. might easily be adapted for a rapid multi-level in situ or ex situ toxicity biosensor test system for ecologically relevant risk assessment.

PubMed | University of Jyväskylä, Finnish Environment Institute and LimCo International
Type: Journal Article | Journal: Environmental toxicology and chemistry | Year: 2016

Mining of sulfide-rich pyritic ores produces acid mine drainage waters and has induced major ecological problems in aquatic ecosystems worldwide. Biomining utilizes microbes to extract metals from the ore, and it has been suggested as a new sustainable way to produce metals. However, little is known of the potential ecotoxicological effects of biomining. In the present study, biomining impacts were assessed using survival and behavioral responses of aquatic macroinvertebrates at in situ exposures in streams. The authors used an impedance conversion technique to measure quantitatively in situ behavioral responses of larvae of the regionally common mayfly, Heptagenia dalecarlica, to discharges from the Talvivaara mine (Sotkamo, Northern Finland), which uses a biomining technique. Behavioral responses measured in 3 mine-impacted streams were compared with those measured in 3 reference streams. In addition, 3-d survival of the mayfly larvae and the oligochaete Lumbriculus variegatus was measured in the study sites. Biomining impacts on stream water quality included increased concentrations of sulfur, sulfate, and metals, especially manganese, cadmium, zinc, sodium, and calcium. Survival of the invertebrates in the short term was not affected by the mine effluents. In contrast, apparent behavioral changes in mayfly larvae were detected, but these responses were not consistent among sites, which may reflect differing natural water chemistry of the study sites. Environ Toxicol Chem 2017;36:147-155. 2016 SETAC.

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