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  • Water Pollutants, Chemical  (24)
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  • 1
    Language: English
    In: Journal of Hazardous Materials, 2011, Vol.192(2), pp.772-778
    Description: ► Meta-analysis displays reduced toxicity of wastewater due to activated carbon or ozone. ► Groups of species (invertebrates) react different than others (e.g. bacteria). ► Purification via SPE may overestimate the detoxification potential. ► bioassays showed reduced ecotoxicity due to activated carbon, ozone and TiO and UV. ► Activated carbon adsorbs nutrients, which may jeopardize any positive effect of this technique. Advanced treatment techniques, like ozone, activated carbon and TiO in combination with UV, are proposed to improve removal efficiency of micropollutants during wastewater treatment. In a meta-analysis of peer-reviewed literature, we found significantly reduced overall ecotoxicity of municipal wastewaters treated with either ozone ( = 667) or activated carbon (=113), while TiO and UV was not yet assessed. As comparative investigations regarding the detoxification potential of these advanced treatment techniques in municipal wastewater are scarce, we assessed them in four separate -feeding trials with 20 replicates per treatment. These bioassays indicate that ozone concentrations of approximately 0.8 mg ozone/mg DOC may produce toxic transformation products. However, referred effects are removed if higher ozone concentrations are used (1.3 mg ozone/mg DOC). Moreover, the application of 1 g TiO /l and ambient UV consistently reduced ecotoxicity. Although activated carbon may remove besides micropollutants also nutrients, which seemed to mask its detoxification potential, this treatment technique reduced the ecotoxicity of the wastewater following its amendment with nutrients. Hence, all three advanced treatment techniques are suitable to reduce the ecotoxicity of municipal wastewater mediated by micropollutants and may hence help to meet the requirements of the European Water Framework Directive.
    Keywords: Meta-Analysis ; Feeding Rate ; Wastewater ; Advanced Oxidation ; Activated Carbon ; Engineering ; Law
    ISSN: 0304-3894
    E-ISSN: 1873-3336
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  • 2
    Language: English
    In: Environmental Pollution, January 2011, Vol.159(1), pp.244-249
    Description: Climate change scenarios predict lower flow rates during summer that may lead to higher proportions of wastewater in small and medium sized streams. Moreover, micropollutants (e.g. pharmaceuticals and other contaminants) continuously enter aquatic environments via treated wastewater. However, there is a paucity of knowledge, whether extended exposure to secondary treated wastewater disrupts important ecosystem functions, e.g. leaf breakdown. Therefore, the amphipod shredder was exposed to natural stream water (  = 34) and secondary treated wastewater (  = 32) for four weeks in a semi-static test system under laboratory conditions. exposed to wastewater showed significant reductions in feeding rate (25%), absolute consumption (35%), food assimilation (50%), dry weight (18%) and lipid content (22%). Thus, high proportions of wastewater in the stream flow may affect both the breakdown rates of leaf material and thus the availability of energy for the aquatic food web as well as the energy budget of . Micropollutants in wastewater cause functional and physiological alteration in a leaf-shredding amphipod.
    Keywords: Advanced Treatment Technology ; Ecological Functioning ; Gammarus Fossarum ; Leaf Litter Breakdown ; Wastewater ; Engineering ; Environmental Sciences ; Anatomy & Physiology
    ISSN: 0269-7491
    E-ISSN: 1873-6424
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  • 3
    Language: English
    In: Science of the Total Environment, 15 November 2016, Vol.571, pp.992-1000
    Description: Shredders play a central role in the breakdown of leaf material in aquatic systems. These organisms and the ecological function they provide may, however, be affected by chemical stressors either as a consequence of direct waterborne exposure or through alterations in food-quality (indirect pathway). To unravel the biological relevance of these effect pathways, we applied a 2 × 2-factorial test design. Leaf material was microbially colonized for 10 days in absence or presence of the fungicide epoxiconazole (15 μg/L) and subsequently fed to the shredder under exposure to epoxiconazole (15 μg/L) or in fungicide-free medium over a 28-day period ( = 40). Both effect pathways caused alterations in asselids' food processing, physiological fitness, and growth, although not always statistically significantly: assimilation either increased or remained at a similar level relative to the control suggesting compensatory behavior of to cope with the enhanced energy demand for detoxification processes and decreased nutritional quality of the food. The latter was driven by lowered microbial biomasses and the altered composition of fatty acids associated with the leaf material. Even with increased assimilation, direct and indirect effects caused decreases in the growth and lipid (fatty acid) content of with relative effect sizes between 10 and 40%. Moreover, the concentrations of two essential polyunsaturated fatty acids (i.e., arachidonic acid and eicosapentaenoic acid) were non-significantly reduced (up to ~ 15%) in asselids. This effect was, however, independent of the exposure pathway. Although waterborne effects were generally stronger than the diet-related effects, results suggest impaired functioning of via both effect pathways.
    Keywords: Asellus Aquaticus ; Biofilm ; Fatty Acid Composition ; Food Quality ; Leaf Litter Breakdown ; Shredder ; Environmental Sciences ; Biology ; Public Health
    ISSN: 0048-9697
    E-ISSN: 1879-1026
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  • 4
    Language: English
    In: Science of the Total Environment, 15 November 2015, Vol.533, pp.40-48
    Description: Large amounts of fungicides are applied globally and partly enter freshwater ecosystems. A few laboratory studies examined their effects on decomposer communities and the ecosystem process of litter decomposition (LD), whereas the field situation remains largely unknown. We conducted a field study with 17 stream sites in a German vineyard area where fungicides represent the dominant pest control agent. Passive samplers were used to monitor 15 fungicides and 4 insecticides in streams and their toxicity was described using the toxic unit approach, whereas sediment samples were taken to characterise total copper concentrations. Microbial and leaf-shredding invertebrate community composition and related LD rates were assessed at each site. The structure of microbial and shredder communities as well as fungal biomass changed along the fungicide toxicity gradient. The changes in microbial endpoints were associated with a reduction of microbial LD rate of up to 40% in polluted streams. By contrast, neither the invertebrate LD rate nor in-situ measured gammarid feeding rates correlated with fungicide toxicity, but both were negatively associated with sediment copper concentrations. A subsequent laboratory experiment employing field fungicide concentrations suggested that the microbial community changes are causal. Overall, our results suggest that fungicides can affect LD under field conditions.
    Keywords: Pesticide ; Leaf Breakdown ; Shredder ; Microorganism ; Aquatic Toxicity ; Environmental Sciences ; Biology ; Public Health
    ISSN: 0048-9697
    E-ISSN: 1879-1026
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  • 5
    Language: English
    In: Environmental Pollution, May 2018, Vol.236, pp.119-125
    Description: Systemic neonicotinoid insecticides such as imidacloprid are increasingly applied against insect pest infestations on forest trees. However, leaves falling from treated trees may reach nearby surface waters and potentially represent a neonicotinoid exposure source for aquatic invertebrates. Given imidacloprid's susceptibility towards photolysis and high water solubility, it was hypothesized that the leaves' toxicity might be modulated by UV-irradiation during decay on the forest floor, or by leaching and re-mobilization of the insecticide from leaves within the aquatic ecosystem. To test these hypotheses, the amphipod shredder was fed (over 7 d;  = 30) with imidacloprid-contaminated black alder ( ) leaves that had either been pre-treated (i.e., leached) in water for up to 7 d or UV-irradiated for 1 d (at intensities relevant during autumn in Central Europe) followed by a leaching duration of 1 d. Gammarids' feeding rate, serving as sublethal response variable, was reduced by up to 80% when consuming non-pretreated imidacloprid-contaminated leaves compared to imidacloprid-free leaves. Moreover, both leaching of imidacloprid from leaves (for 7 d) as well as UV-irradiation reduced the leaves' imidacloprid load (by 46 and 90%) thereby mitigating the effects on gammarids' feeding rate to levels comparable to the respective imidacloprid-free controls. Therefore, natural processes, such as UV-irradiation and re-mobilization of foliar insecticide residues in water, might be considered when evaluating the risks systemic insecticide applications in forests might pose for aquatic organisms in nearby streams. UV-irradiation and leaching in water reduce imidacloprid residues in contaminated leaves consequently mitigating toxicity for a leaf-shredding amphipod.
    Keywords: Neonicotinoids ; Imidacloprid ; Gammarus ; Leaf Fall ; Engineering ; Environmental Sciences ; Anatomy & Physiology
    ISSN: 0269-7491
    E-ISSN: 1873-6424
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  • 6
    Language: English
    In: Environmental Pollution, March 2017, Vol.222, pp.458-464
    Description: Leaf-shredding amphipods play a critical role in the ecosystem function of leaf litter breakdown, a key process in many low order streams. Fungicides, however, may adversely influence shredders' behavior and the functions they provide, while there is only limited knowledge concerning effects on their reproductive performance. To assess the latter, a semi-static 56-day partial life-cycle bioassay using the model shredder (  = 30) was performed applying two environmentally relevant concentrations of a model fungicide mixture (i.e., 5 and 25 μg/L) composed of five fungicides with different modes of toxic action. Variables related to the food processing (leaf consumption and feces production), growth (body length and dry weight), energy reserves (lipid content), and reproduction (amplexus pairs, number and length of offspring) were determined to understand potential implications in the organisms' energy budget. While the fungicides did not affect leaf consumption, both fungicide treatments significantly reduced amphipods' feces production (∼20%) compared to the control. This observation suggests an increased food utilization to counteract the elevated and stress-related energy demand: although growth as well as energy reserves were unaffected, amplexus pairs were less frequently observed in both fungicide treatments (∼50–100%) suggesting a tradeoff regarding energy allocation favoring the maintenance of fundamental functions at the organism level over reproduction. As a result, the time to release of first offspring was delayed in both fungicide treatments (7 and 14 days) and the median number of offspring was significantly lower in the 25-μg/L treatment (100%), whereas offspring length remained unaffected. The results of this study thus indicate that chronic fungicide exposures can negatively impact shredders' reproductive performance. This may translate into lower abundances and thus a reduced contribution to leaf litter breakdown in fungicide-impacted streams with potentially far-reaching consequences for detritus-based food webs. Chronic exposure to environmentally relevant fungicide concentrations can negatively impact leaf-shredders' reproductive performance.
    Keywords: Shredder ; Fungicide ; Mixture ; Energy Allocation ; Reproduction ; Engineering ; Environmental Sciences ; Anatomy & Physiology
    ISSN: 0269-7491
    E-ISSN: 1873-6424
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  • 7
    Language: English
    In: Environmental Pollution, December 2017, Vol.231, pp.1393-1397
    Description: Invertebrate-mediated leaf litter decomposition is frequently used to assess stress-related implications in stream ecosystem integrity. measures such as the mass loss from leaf bags or the feeding of caged invertebrates deployed for days or weeks may, however, fail to detect transient effects due to recovery or compensatory mechanisms. We assessed the relevance of transient effects using the peak exposure towards an insecticide (i.e., etofenprox) as a model scenario at three levels of complexity. These were 1) the assessment of the decomposition realised by invertebrate communities in stream mesocosms over 21 days via leaf bags, 2) 7-days lasting bioassays quantifying the leaf consumption of , and 3) a laboratory experiment determining the daily feeding rate of the same species over 7 days. Etofenprox did not trigger a significantly altered decomposition by invertebrate communities during the leaf bag assay, while bioassays detected a significant reduction in gammarids’ feeding rate at the highest tested concentration. The laboratory bioassay suggests that observed mismatches might be explained by recovery and post-exposure compensation. As leaf-shredding invertebrates are likely in a vulnerable state following transient effects, biomonitoring for implications of peak exposures and other pulsed stress events must happen at an adequate temporal resolution.
    Keywords: Compensatory Feeding ; Ecosystem Integrity ; Functional Response ; Insecticide Peak Exposure ; Engineering ; Environmental Sciences ; Anatomy & Physiology
    ISSN: 0269-7491
    E-ISSN: 1873-6424
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  • 8
    In: Global Change Biology, February 2018, Vol.24(2), pp.e402-e415
    Description: Ecosystem functions in streams (e.g., microbially mediated leaf litter breakdown) are threatened globally by the predicted agricultural intensification and its expansion into pristine areas, which is associated with increasing use of fertilizers and pesticides. However, the ecological consequences may depend on the disturbance history of microbial communities. To test this, we assessed the effects of fungicides and nutrients (four levels each) on the structural and functional resilience of leaf‐associated microbial communities with differing disturbance histories (pristine vs. previously disturbed) in a 2 × 4 × 4‐factorial design (=6) over 21 days. Microbial leaf breakdown was assessed as a functional variable, whereas structural changes were characterized by the fungal community composition, species richness, biomass, and other factors. Leaf breakdown by the pristine microbial community was reduced by up to 30% upon fungicide exposure compared with controls, whereas the previously disturbed microbial community increased leaf breakdown by up to 85%. This significant difference in the functional response increased in magnitude with increasing nutrient concentrations. A pollution‐induced community tolerance in the previously disturbed microbial community, which was dominated by a few species with high breakdown efficacies, may explain the maintained function under stress. Hence, the global pressure on pristine ecosystems by agricultural expansion is expected to cause a modification in the structure and function of heterotrophic microbial communities, with microbially mediated leaf litter breakdown likely becoming more stable over time as a consequence of fungal community adaptions. Agricultural land use is projected to expand and intensify globally, with elevated chemical stress release to adjacent streams. We assessed if leaf‐associated microbial communities adapt to a combination of two agricultural stressors, namely fungicides and nutrients. Under fungicide stress, previously disturbed communities showed an even stimulated rate of leaf litter breakdown, while microbial communities from a pristine site were negatively affected. Nutrients induced positive effects on leaf litter breakdown, which was stronger for the previously disturbed community. These observations are likely explained by a dominance of tolerant and effective fungal decomposers that were able to maintain their biomass and sporulation.
    Keywords: Agricultural Intensification ; Aquatic Hyphomycetes ; Bacteria ; Biofilm ; Ecosystem Function ; Fungicides ; Land Use ; Nutrients
    ISSN: 1354-1013
    E-ISSN: 1365-2486
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  • 9
    Language: English
    In: Environmental Pollution, 2015, Vol.205, pp.16-22
    Description: Copper (Cu) exposure can increase leaf-associated fungal biomass, an important food component for leaf-shredding macroinvertebrates. To test if this positive nutritional effect supports the physiological fitness of these animals and to assess its importance...
    Keywords: Other Biological Topics ; Annan Biologi
    ISSN: 0269-7491
    E-ISSN: 18736424
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  • 10
    Language: English
    In: Ecotoxicology and Environmental Safety, 2010, Vol.73(7), pp.1674-1680
    Description: Current aquatic environmental risk assessment of plant protection products or biocides does not consider effects on organisms involved in leaf litter breakdown, a fundamental ecosystem process in streams. Therefore, direct ecotoxicological implications of tebuconazole, a frequently used triazole fungicide, on the leaf-shredding amphipod , were assessed. While acute toxicity was low (96h-LC =1347 μg/L), feeding rate, a sublethal endpoint, was significantly reduced after seven days of exposure to 600 μg/L. At the same concentration, but during a three week exposure under semi-static conditions, gammarids showed significant reductions in feeding, but also in assimilation and growth. At 200 μg/L, however, only assimilation was significantly affected. As these endpoints can be used to evaluate the ecotoxicity of a broad range of chemicals and to deduce possible implications in the functioning of ecosystems, the inclusion of similar experimental set-ups might further improve aquatic environmental risk assessment.
    Keywords: Gammarus ; Shredder ; Triazole Fungicide ; Sublethal Endpoints ; Environmental Risk Assessment ; Confidence Interval Testing ; Ecology ; Public Health
    ISSN: 0147-6513
    E-ISSN: 1090-2414
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