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  • Chemistry
  • SwePub (National Library of Sweden)  (10)
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  • 1
    Language: English
    In: Chemosphere, July 2013, Vol.92(5), pp.483-489
    Description: ► The invasive aquatic amphipod is more tolerant to lambda-cyhalothrin than the native one. ► Predation success on Baetis nymphs is substantially higher for than ► may contribute substantially to leaf litter decomposition. Invasive species are considered as one of the major threats for biodiversity worldwide. The Ponto-Caspian species , for instance, spread throughout continental Europe and was recorded for the first time also within Lake Constance in 2003. Although is a highly competitive species it was not capable of replacing the native completely in this ecosystem, especially in the riparian zones of the highly agriculturally used island “Reichenau”. As differences in pesticide sensitivity between both amphipod species may explain their distribution, the present study assessed the implication of the highly toxic pyrethroid lambda-cyhalothrin, which is authorized for application in the Lake Constance region, assuming the invasive species being more sensitive than the native one. However, both the feeding activity bioassays, which measured the leaf consumption over 7 d ( = 20), as well as the predation bioassay, which measured the predation rate upon nymphs in concert with the feeding activity on leaf material over 96 h ( = 13), revealed an up to 5-fold higher tolerance of towards lambda-cyhalothrin. These results suggest the investigated insecticide not being the trigger for the observed distribution pattern of both amphipod species. Hence, other factors like the diversity of habitat structures or the levels of ammonia may have facilitated the coexistence. Nevertheless, the present study uncovered a high leaf-shredding efficacy of the invasive species suggesting that its role in the leaf decomposition process may have been underestimated in the past.
    Keywords: Functional Feeding Group ; Insecticide ; Leaf Litter Decomposition ; Ecosystem Function ; Predator–Prey Interaction ; Freshwater Biodiversity ; Chemistry ; Ecology
    ISSN: 0045-6535
    E-ISSN: 1879-1298
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  • 2
    Language: English
    In: Chemosphere, 2011, Vol.82(3), pp.355-361
    Description: Advanced oxidation technologies such as ozonation have been proposed to improve removal efficiency of micropollutants during wastewater treatment. In a meta-analysis of peer-reviewed literature, we found no ecotoxicological effects of wastewater ozonation on invertebrates ( = 82), but significant adverse effects on bacteria ( = 24) and fish ( = 5). As information on functional endpoints or trophic interactions is lacking, we applied a bioassay relating to leaf litter decomposition to fill this gap. Leaf discs exposed to ozone-treated wastewater with a high (1.04 mg O (mg DOC) , = 49) ozone concentration were significantly preferred by an aquatic detritivore, , over discs conditioned in wastewater not treated with ozone. This effect might have been mediated by reduced bacterial and elevated fungal biomass, and appears to be the first demonstration of wastewater ozonation impacts on invertebrates and an associated ecosystem process. In accordance with the food-choice trials, chemical analyses revealed significantly decreased concentrations of organic micropollutants in wastewater treated with ozone at high concentrations. Thus, food-choice trials as applied here hold promise to assess environmental effects of advanced oxidation technologies in wastewater treatment and appear to be a valuable complement to the ecotoxicological toolbox in general.
    Keywords: Food Choice ; Indirect Effects ; Gammaridae ; Litter Decomposition ; Biocides ; Psychoactive Drugs ; Chemistry ; Ecology
    ISSN: 0045-6535
    E-ISSN: 1879-1298
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  • 3
    Language: English
    In: Chemosphere, 2011, Vol.85(10), pp.1563-1567
    Description: ► Effects of nTiO and ambient UV-irradiation affect representatives of detrital food webs. ► Accumulation of nTiO at the bottom of the test vessel seems to affect ecotoxicity. ► nTiO and ambient UV-irradiation increases ecotoxicity due to the formation of ROS. Production and use of engineered nanoparticles, such as titanium dioxide nanoparticles (nTiO ), is increasing worldwide, enhancing their probability to enter aquatic environments. However, direct effects of nTiO as well as ecotoxicological consequences due to the interactions of nTiO with environmental factors like ultraviolet (UV) irradiation on representatives of detrital food webs have not been assessed so far. Hence, the present study displayed for the first time adverse sublethal effects of nTiO at concentrations as low as 0.2 mg L on the leaf shredding amphipod both in presence and absence of ambient UV-irradiation following a 7-d exposure. In absence of UV-irradiation, however, the effects seemed to be driven by accumulation of nTiO at the bottom of the test vessels to which the gammarids were potentially exposed. The adverse sublethal and lethal effects on gammarids caused by the combined application of nTiO and ambient UV-irradiation are suggested to be driven by the formation of reactive oxygen species. In conclusion, both the accumulation of nTiO at the bottom of the test vessel and the UV induced formation of reactive oxygen species clearly affected its ecotoxicity, which is recommended for consideration in the environmental risk assessment of nanoparticles.
    Keywords: Nanoparticle ; Titanium Dioxide ; Ultraviolet Irradiation ; Gammarus Fossarum ; Accumulation ; Reactive Oxygen Species ; Chemistry ; Ecology
    ISSN: 0045-6535
    E-ISSN: 1879-1298
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  • 4
    Language: English
    In: Aquatic Toxicology, 15 January 2013, Vol.126, pp.163-168
    Description: ► nTiO concentrations one order of magnitude above the PEC caused adverse chronic effects. ► Particle size and product composition, i.e. crystalline structure, trigger differences in nTiO toxicity. ► nTiO accumulation at the bottom of the test vessel is an important effect pathway. ► Dissolved organic carbon influences fate and finally nTiO toxicity. The increasing use of titanium dioxide nanoparticles (nTiO ) inevitably results in their release into the environment, raising concerns about potential adverse effects in wildlife. By following standard test protocols, several studies investigated the ecotoxicity of nTiO among others to . These studies indicated a large variability – several orders of magnitude – in the response variables. However, other factors, like nanoparticle characteristics and test design, potentially triggering these differences, were largely ignored. Therefore, the present study assessed the chronic ecotoxicity of two nTiO products with varying crystalline structure (A-100; P25) to . A semi-static and a flow-through exposure scenario were compared, ensuring that both contained environmentally relevant concentrations of dissolved organic carbon. Utilizing the semi-static test design, a concentration as low as 0.06 mg/L A-100 (∼330 nm) significantly reduced the reproduction of daphnia indicating environmental risk. In contrast, no implication in the number of released offspring was observed during the flow-through experiment with A-100 (∼140 nm). Likewise, P25 (∼130 nm) did not adversely affect reproduction irrespective of the test design utilized. Given the present study's results, the particle size, the product composition, i.e. the crystalline structure, and the accumulation of nTiO at the bottom of the test vessel – the latter is relevant for a semi-static test design – may be suggested as factors potentially triggering differences in nTiO toxicity to . Hence, these factors should be considered to improve environmental risk assessment of nanoparticles.
    Keywords: Inorganic Nanoparticles ; Reproduction ; Growth ; Flow-through ; Crustacea ; Chemistry ; Ecology
    ISSN: 0166-445X
    E-ISSN: 1879-1514
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  • 5
    Language: English
    In: Aquatic Toxicology, 2011, Vol.104(1), pp.32-37
    Description: The energy stored in coarse particulate organic matter, e.g. leaf litter, is released to aquatic ecosystems by breakdown processes involving microorganisms and leaf shredding invertebrates. The palatability of leaves and thus the feeding of shredders on leaf material are highly influenced by microorganisms. However, implications in the colonization of leaves by microorganisms (=conditioning) caused by chemical stressors are rarely studied. Our laboratory experiments, therefore, investigated for the first time effects of a fungicide on the conditioning process of leaf material by means of food-choice experiments using (Crustacea: Amphipoda). Additionally, microbial analyses were conducted to facilitate the mechanistic understanding of the observed behavior. Gammarids significantly preferred control leaf discs over those conditioned in presence of the fungicide tebuconazole at concentrations of 50 and 500 μg/L. Besides the decrease of fungal biomass with increasing fungicide concentration, also the leaf associated fungal community composition showed that species preferred by gammarids, such as , , or , were more frequent in the control. , however, which is rejected by gammarids, was abundant in all treatments suggesting an increasing importance of this species for the lower leaf palatability – as other more palatable fungal species were almost absent – in the fungicide treatments. Hence, the food-choice behavior of seems to be a suitable indicator for alterations in leaf associated microbial communities, especially fungal species composition, caused by chemical stressors. Finally, this or similar test systems may be a reasonable supplement to the environmental risk assessment of chemicals in order to achieve its protection goals, as on the one hand, indirect effects may occur far below concentrations known to affect gammarids directly, and on the other hand, the observed shifts in leaf associated microbial communities may have perpetuating implications in leaf shredding invertebrates.
    Keywords: Fungal Community ; Leaf Litter Decomposition ; Confidence Interval Testing ; Aquatic Hyphomycetes ; Azole Fungicide ; Bacteria ; Chemistry ; Ecology
    ISSN: 0166-445X
    E-ISSN: 1879-1514
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  • 6
    Language: English
    In: Aquatic Toxicology, December 2016, Vol.181, pp.94-103
    Description: For in situ remediation of groundwater contaminated by halogenated hydrocarbons Carbo-Iron , a composite of microscale activated carbon and nano Fe , was developed. Against the background of intended release of Carbo-Iron into the environment in concentrations in the g/L-range, potential ecotoxicological consequences were evaluated in the present study. The nano Fei in Carbo-Iron acts as reducing agent and is oxidized in aqueous systems by chlorinated solvents, groundwater constituents (e.g. dissolved oxygen) and anaerobic corrosion. As Carbo-Iron is generally oxidized rapidly after application into the environment, the oxidized state is environmentally most relevant, and Carbo-Iron was used in its oxidized form in the ecotoxicological tests. The amphipod was selected as a surrogate test species for functionally important groundwater crustaceans. Effects of Carbo-Iron on were determined in a 10-d acute test, a 7-d feeding activity test and a 42-d chronic test. Additionally, a 56-d life cycle test was performed with a modified design to further evaluate effects of Carbo-Iron on adult and their offspring. The size of Carbo-Iron particles in stock and test suspensions was determined via dynamic light scattering. Potential uptake of particles into test organisms was investigated using transmission and scanning electron microscopy. At the termination of the feeding and acute toxicity test (i.e. after 7 and 10 d of exposure, respectively), Carbo-Iron had a significant effect on the weight, length and feeding rate of at the highest test concentration of 100 mg/L. While an uptake of Carbo-Iron into the gut was observed, no passage into the surrounding tissue was detected. In both chronic tests, the number of offspring was the most sensitive endpoint and significant effects were recorded at concentrations ≥50 mg/L (42-d experiment) and ≥12.5 mg/L (56-d experiment). Parental exposure to oxidized Carbo-Iron significantly exacerbated the acute effects of the nanocomposite on the subsequent generation of by a factor 〉10. The present study indicates risks for groundwater species at concentrations in the mg/L range. Carbo-Iron may exceed these effect concentrations in treated aquifers, but the presence of the pollutant has most likely impaired the quality of this habitat already. The benefit of remediation has to be regarded against the risk of ecological consequences with special consideration of the observed increasing sensitivity of juvenile .
    Keywords: Iron-Based Nanomaterial ; Nanocomposite ; Groundwater Remediation ; Environmental Risk ; Chemistry ; Ecology
    ISSN: 0166-445X
    E-ISSN: 1879-1514
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  • 7
    Language: English
    In: Aquatic Toxicology, August 2015, Vol.165, pp.154-159
    Description: In aquatic ecosystems, titanium dioxide nanoparticles (nano-TiO ) may adsorb co-occurring chemical stressors, such as copper (Cu). This interaction has the potential to reduce the concentration of dissolved Cu due to surface binding to the nanoparticles. The subsequent sedimentation of nano-TiO agglomerates may increase the exposure of benthic species towards the associated Cu. This scenario was assessed by employing the amphipod as model species and taking advantage of a 2 × 2-factorial design investigating absence and presence of 2 mg nano-TiO /L and 40 μg Cu/L ( = 45; = 24 d) in darkness, respectively. Nano-TiO alone did not affect mortality and leaf consumption, whereas Cu alone caused high mortality (〉70%), reduced leaf consumption (25%) and feces production (30%) relative to the control. In presence of nano-TiO , Cu-induced toxicity was largely eliminated. However, independent of Cu, nano-TiO decreased the gammarids’ assimilation and weight. Hence, nano-TiO may be applicable as Cu-remediation agent, while its potential long-term effects need further attention.
    Keywords: Heavy Metal ; Benthic Invertebrates ; Energy Processing ; Remediation ; Combined Toxicity ; Chemistry ; Ecology
    ISSN: 0166-445X
    E-ISSN: 1879-1514
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  • 8
    Language: English
    In: Aquatic Toxicology, 2015, Vol.169, pp.105-112
    Description: Animals involved in leaf litter breakdown (i.e., shredders) play a central role in detritus-based stream food webs, while their fitness and functioning can be impaired by anthropogenic stressors. Particularly fungicides can affect shredders via both waterborne exposure and their diet, namely due to co-ingestion...
    Keywords: Other Biological Topics ; Annan Biologi
    ISSN: 0166-445X
    E-ISSN: 18791514
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  • 9
    Language: English
    In: Environmental Toxicology and Chemistry, August 2004, Vol.23(8), pp.1984-1990
    Description: We investigated the acute (5 d) effects of particle‐associated azinphosmethyl (AZP) in multispecies microcosms and assessed the results in the context to data obtained from a parallel field study undertaken in the Lourens River, South Africa. A runoff simulation was carried out in stream microcosms containing the macroinvertebrate fauna of an uncontaminated Lourens River site exposed to particle‐associated AZP (control and 200, 1,000, 5,000, 20,000 μg/kg; three replicates each) for 1 h. Measured AZP concentrations in filtered microcosm water resulted in the following values: Not detectable (control) and 0.03, 0.2, 1.1, and 6.9 μg/L, respectively. The two highest treatments resulted in significantly (analysis of variance [ANOVA]) reduced total numbers of individuals, while the number of taxa was affected in the 20,000 μg/kg treatment only. A comparison with previous data suggests that observed effects partly resulted from particle‐associated AZP. Particularly affected were six out of 14 macroinvertebrate taxa such as mayfly and stonefly taxa. In parallel, the distribution of macroinvertebrates at a pesticide‐free and a contaminated stretch of the Lourens River was monitored five times during the spraying season in 2001 and 2002. Out of the 14 core taxa found in the microcosm study as well as in the field approach, 10 showed comparable reactions in the microcosm experiment and in their field distribution; they were either classified as affected or unaffected in both studies. Thus, we conclude that particle‐associated AZP has the potential to affect the invertebrate community structure of the Lourens River and that microcosm studies employing fieldrelevant exposure scenarios may be valuable for a local risk assessment of pesticide‐related community disruptions in the Lourens River.
    Keywords: Aquatic Macroinvertebrates ; Community Structure ; Microcosms ; Particle‐Associated Azinphosmethyl ; Runoff
    ISSN: 0730-7268
    E-ISSN: 1552-8618
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  • 10
    Language: English
    In: Physical Review B - Condensed Matter and Materials Physics, 2009, Vol.80(7), pp.075103 [5 pages
    Description: We use resonance Raman scattering (incident photon energies between 1.8 and 4.13 eV), LDA+U calculations, spectroscopic ellipsometry, and oblique IR reflectivity to characterize the strong electron-phonon interactions in the disordered perovskite LaFe0.5Cr0.5O3....
    Keywords: Kemi ; Chemical Sciences
    ISSN: 1098-0121
    E-ISSN: 1550235X
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