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  • 2018  (56)
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  • 2018  (56)
  • 1
    Language: English
    In: Science of the Total Environment, 15 October 2018, Vol.639, pp.516-525
    Description: The decades-long agricultural use of insecticides resulted in frequent contamination of surface waters globally regularly posing high risks for the aquatic biodiversity. However, the concentration levels of individual insecticide compounds have by now not been compiled and reported using global scale data, hampering our knowledge on the insecticide exposure of aquatic ecosystems. Here, we specify measured insecticide concentrations (MICs, comprising in total 11,300 water and sediment concentrations taken from a previous publication) for 28 important insecticide compounds covering four major insecticide classes. Results show that organochlorine and organophosphate insecticides, which dominated the global insecticide market for decades, have been detected most often and at highest concentration levels in surface waters globally. In comparison, MICs of the more recent pyrethroids and neonicotinoids were less often reported and generally at lower concentrations as a result of their later market introduction and lower application rates. An online insecticide classification calculator (ICC; available at: ) is provided in order to enable the comparison and classification of prospective MICs with available global insecticide concentrations. Spatial analyses of existing data show that most MICs were reported for surface waters in North America, Asia and Europe, whereas highest concentration levels were detected in Africa, Asia and South America. An evaluation of water and sediment MICs showed that theoretical organic carbon-water partition coefficients (K ) determined in the laboratory overestimated K values based on actual field concentrations by up to a factor of more than 20, with highest deviations found for highly sorptive pyrethroids. Overall, the comprehensive compilation of insecticide field concentrations presented here is a valuable tool for the classification of future surface water monitoring results and serves as important input data for more field relevant toxicity testing approaches and pesticide exposure and risk assessment schemes.
    Keywords: Pesticides ; Surface Water Exposure ; Monitoring ; Global Survey ; Koc ; Environmental Sciences ; Biology ; Public Health
    ISSN: 0048-9697
    E-ISSN: 1879-1026
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  • 2
    Language: English
    In: Science of the Total Environment, 01 September 2018, Vol.635, pp.687-698
    Description: The aquatic environment is strongly connected to the surrounding agricultural landscapes, which regularly serve as sources of stressors such as agrochemicals. Genetically modified crops, which are cultivated on a large scale in many countries, may also act as stressors. Despite the commercial use of genetically modified organisms (GMOs) for over 20 years, their impact on the aquatic environment came into focus only 10 years ago. We present the status quo of the available scientific data in order to provide an input for informed aquatic risk assessment of GMOs. We could identify only 39 publications, including 84 studies, dealing with GMOs in the aquatic environment, and our analysis shows substantial knowledge gaps. The available information is restricted to a small number of crop plants, traits, events, and test organisms. The analysis of effect studies reveals that only a narrow range of organisms has been tested and that studies on combinatorial actions of stressors are virtually absent. The analysis of fate studies shows that many aspects, such as the fate of leached toxins, degradation of plant material, and distribution of crop residues in the aquatic habitat, are insufficiently investigated. Together with these research needs, we identify standardization of test methods as an issue of high priority, both for research and risk assessment needed for GMO regulation.
    Keywords: Genetically Modified Crops ; Aquatic Ecosystems ; Environmental Risk Assessment ; Non-Target Effects ; Bt Toxin ; Environmental Sciences ; Biology ; Public Health
    ISSN: 0048-9697
    E-ISSN: 1879-1026
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  • 3
    Language: English
    In: Science of the Total Environment, 01 April 2018, Vol.619-620, pp.391-400
    Description: The effects of sediment contamination on fish are of high significance for the protection of ecosystems, human health and economy. However, standardized sediment bioassays with benthic fish species, that mimic bioavailability of potentially toxic compounds and comply with the requirements of alternative test methods, are still scarce. In order to address this issue, embryos of the benthic European weatherfish ( ) were exposed to freeze-dried sediment (via sediment contact assays (SCA)) and sediment extracts (via acute fish embryo toxicity tests) varying in contamination level. The extracts were gained by accelerated solvent extraction with (i) acetone and (ii) pressurized hot water (PHWE) and subsequently analyzed for polycyclic aromatic hydrocarbons, polychlorinated biphenyls and polychlorinated dibenzodioxins and dibenzofurans. Furthermore, embryos of the predominately used zebrafish ( ) were exposed to extracts from the two most contaminated sediments. Results indicated sufficient robustness of weatherfish embryos towards varying test conditions and sensitivity towards relevant sediment-bound compounds. Furthermore, a compliance of effect concentrations derived from weatherfish embryos exposed to sediment extracts (96 h-LC ) with both measured gradient of sediment contamination and previously published results was observed. In comparison to zebrafish, weatherfish embryos showed higher sensitivity to the bioavailability-mimicking extracts from PHWE but lower sensitivity to extracts gained with acetone. SCAs conducted with weatherfish embryos revealed practical difficulties that prevented an implementation with three of four sediments tested. In summary, an application of weatherfish embryos, using bioassays with sediment extracts from PHWE might increase the ecological relevance of sediment toxicity testing: it allows investigations using benthic and temperate fish species considering both bioavailable contaminants and animal welfare concerns.
    Keywords: Acute Fish Embryo Toxicity Test ; Pressurized Hot Water Extraction ; Sediment Contact Assay ; Environmental Risk Assessment ; Alternative Test Method ; Early Life Stage ; Zebrafish ; Environmental Sciences ; Biology ; Public Health
    ISSN: 0048-9697
    E-ISSN: 1879-1026
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  • 4
    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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  • 5
    Language: English
    In: Science of the Total Environment, 10 December 2018, Vol.644, pp.342-349
    Description: The environmental risk assessment of pesticides is mainly performed on individual active ingredients. In surface waters within the agricultural landscape, however, contamination is usually characterized by complex pesticide mixtures. To estimate the joint effects caused by these complex mixtures, mathematical models have been proposed. Among these, the model of concentration addition (CA) is suggested as default model for the risk assessment of chemical mixtures as it is considered protective for mixtures composed of similar and dissimilar acting substances. Here we assessed the suitability of CA predictions for seven field relevant pesticide mixtures using acute (immobility) and chronic (reproduction) responses of the standard test species . Pesticide mixtures indicated largely additive or less than additive effects when using CA model predictions as a reference. Moreover, we revealed that deviations from CA predictions are lower for chronic (up to 3.2-fold) relative to acute (up to 7.2-fold) response variables. Additionally, CA predictions were in general more accurate for complex mixtures relative to those composed of only a few pesticides. Thus, this study suggests CA models as largely protective for the risk assessment of pesticide mixtures justifying its use as default model. At the same time, extrapolating conclusions about the joint effects of pesticides from acute to chronic responses is uncertain, due to partly large discrepancies with regards to the deviation of model prediction and observed effects between exposure scenarios.
    Keywords: Mixture Toxicity ; Pesticide ; Mode of Toxic Action ; Concentration Addition ; Daphnia ; Environmental Sciences ; Biology ; Public Health
    ISSN: 0048-9697
    E-ISSN: 1879-1026
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  • 6
    Language: English
    In: Science of the Total Environment, 01 January 2018, Vol.610-611, pp.810-819
    Description: Agricultural land-use frequently results in short pulse exposures of insecticides such as pyrethroids in river systems, adversely affecting local invertebrate communities. In order to assess insecticide-induced effects, stream mesocosms are used within higher tier aquatic risk assessment. Regulatory acceptable concentrations (RACs) derived from those studies are often higher compared with tier 1 RACs. Hence, the present mesocosm study evaluates this aspect using a pulse exposure scenario typical for streams and the pyrethroid insecticide etofenprox. A 6-h pulse exposure with measured concentrations of 0.04, 0.3 and 5.3 μg L etofenprox was used. We considered abundance, drift and emergence of invertebrates as structural endpoints and the in situ-measured feeding rates of the isopod as functional endpoint. Most prominent effects were visible at 5.3 μg L etofenprox which caused adverse effects of up to 100% at the individual and population level, as well as community structure alterations. Transient effects were observed for invertebrate drift (effect duration ≤ 24 h) and for the invertebrate community (9 days after exposure) at 0.3 μg L etofenprox. Furthermore, 0.04 μg L etofenprox affected the abundance of the mayfly (decrease by 66%) and the feeding rate of (decrease by 44%). Thus, implications for the functional endpoint leaf litter breakdown in heterotrophic ecosystems may be expected. A hypothetical RAC derived from the present mesocosm study (0.004 μg L ) is in line with the official tier 1 RAC (0.0044 μg L ) and thus shows that the present mesocosm study did not result in a higher RAC.
    Keywords: Functional Endpoint ; Aquatic Guidance Document ; Community ; Drift ; Emergence ; Environmental Sciences ; Biology ; Public Health
    ISSN: 0048-9697
    E-ISSN: 1879-1026
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  • 7
    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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  • 8
    Language: English
    In: Environmental Pollution, October 2018, Vol.241, pp.549-556
    Description: Waterborne exposure towards fungicides is known to trigger negative effects in aquatic leaf-associated microbial decomposers and leaf-shredding macroinvertebrates. We expected similar effects when these organisms use leaf material from terrestrial plants that were treated with systemic fungicides as a food source since the fungicides may remain within the leaves when entering aquatic systems. To test this hypothesis, we treated black alder ( ) trees with a tap water control or a systemic fungicide mixture (azoxystrobin, cyprodinil, quinoxyfen, and tebuconazole) at two worst-case application rates. Leaves of these trees were used in an experiment targeting alterations in two functions provided by leaf-associated microorganisms, namely the decomposition and conditioning of leaf material. The latter was addressed via the food-choice response of the amphipod shredder . During a second experiment, the potential impact of long-term consumption of leaves from trees treated with systemic fungicides on was assessed. Systemic fungicide treatment altered the resource quality of the leaf material resulting in trends of increased fungal spore production and an altered community composition of leaf-associated fungi. These changes in turn caused a significant preference of for microbially conditioned leaves that had received the highest fungicide treatment over control leaves. This higher food quality ultimately resulted in a higher gammarid growth (up to 300% increase) during the long-term feeding assay. Although the underlying mechanisms still need to be addressed, the present study demonstrates a positive indirect response in aquatic organisms due to systemic pesticide application in a terrestrial system. As the effects from the introduction of plant material treated with systemic fungicides strongly differ from those mediated via other pathways (e.g., waterborne exposure), our study provides a novel perspective of fungicide-triggered effects in aquatic detritus-based food webs. Leaves from trees treated with systemic fungicides cause positive effects in an aquatic decomposer-detritivore system.
    Keywords: Aquatic Hyphomycetes ; Gammarus Fossarum ; Resource Quality ; Systemic Pesticides ; Engineering ; Environmental Sciences ; Anatomy & Physiology
    ISSN: 0269-7491
    E-ISSN: 1873-6424
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  • 9
    Language: English
    In: Knowledge and Management of Aquatic Ecosystems, 01 January 2018, Issue 419, p.43
    Description: A stocking program for the endangered European weatherfish (Misgurnus fossilis L.) was conducted in the German federal states of Rhineland-Palatinate and Hesse, southwest Germany. An initial monitoring enabled to identify local broodstock and to assess habitats regarding their ecological suitability for reintroduction. In a second step, broodstock were caught for artificial propagation and cultured fry were released in previously selected river sectors. Furthermore, reintroduction sectors were biannually monitored to assess stocking success. Within the study period (2014–2016), a total number of approximately 83,500 juveniles were stocked in three river sectors for reintroduction and approximately 85,000 juveniles were stocked in four other river sectors to strengthen existing populations. During the post-release monitoring, 45 individuals were recaptured in two sectors. The documented short-term reintroduction success (i.e. survival of released individuals) indicates appropriateness of the selected stocking strategy. Furthermore, the provided course of action might be transferred to further states or countries and thereby contribute to weatherfish conservation at larger scales.
    Keywords: Conservation ; Artificial Propagation ; Endangered Species ; Stocking ; Rhine ; Agriculture
    E-ISSN: 1961-9502
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  • 10
    Language: English
    In: BMC Geriatrics, 01 April 2018, Vol.18(1), pp.1-9
    Description: Abstract Background Mobility is a key outcome in older patients with cognitive impairment. The de Morton Mobility Index (DEMMI) is an established measure of older people’s mobility that is promising for use in older patients with cognitive impairment. The aim of this study was to examine the DEMMI’s psychometric properties in older patients with dementia, delirium or other cognitive impairment. Methods This cross-sectional study was performed in a geriatric hospital and includes older acute medical patients with cognitive impairment indicated by a Mini Mental State Examination (MMSE) score ≤ 24 points. A Rasch analysis was performed to check the DEMMI’s unidimensionality. Construct validity was assessed by testing 13 hypotheses about expected correlations between the DEMMI and outcome measures of similar or related constructs, and about expected differences of DEMMI scores between groups differing in mobility related characteristics. Administration times were recorded. Results A sample of 153 patients with mild (MMSE 19–24 points; 63%) and moderate (MMSE: 10–18 points; 37%) cognitive impairment was included (age range: 65–99 years; mean MMSE: 19 ± 4, range: 8–24 points; diagnosis of dementia and delirium: 40% and 18%, respectively). Rasch analysis indicated unidimensionality with an overall fit to the model (P = 0.107). Internal consistency reliability was excellent (Cronbach’s alpha = 0.92). Eleven out of 13 (85%) hypotheses on construct validity were confirmed. The DEMMI showed good feasibility, and no adverse events occurred. The mean administration time of 5 min (range: 1–10) was not influenced by the level of cognitive impairment. In contrast to some other comparator instruments, no floor or ceiling effects were evident for the DEMMI. Conclusions Results indicate sufficient psychometric properties of the DEMMI in older patients with cognitive impairment. Trial registration German Clinical Trials Register (DRKS00005591). Registered February 2, 2015.
    Keywords: Mobility Limitation ; Outcome Assessment ; Geriatric Assessment ; Psychometrics ; Rehabilitation ; Physiotherapy ; Medicine
    E-ISSN: 1471-2318
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