Now showing 1 - 10 of 215
  • Publication
    Detection and determination limits of priority organic pollutants in soil
    ( 1995)
    Terytze, K.
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    Kördel, Werner
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    Aldag, R.
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    Hanel, J.
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    Hein, D.
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    Keller, E.
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    Kuhnt, G.
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    Müller-Wegener, U.
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    Scheunert, I.
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    Schmidt, M.
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    Spiteller, M.
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    Trenck, K.T. von der
    At present, the situation regarding data on concentration patterns in soils of areas with background contaminations are insufficient. For soil protection these data are essential for deriving reference values. Therefore the article presents and interprets detection and determination limits for a selection of priority organic pollutants in soils. Based on these results determination limits for the determination of background values for larger areas are proposed. Background values for organic contaminants is not specifically polluted soils and groundwaters may be very low with extreme demands on chemical analysis. In case of sampling from larger areas therefore a compromise has to be found between what is possible with great technical effort and what is requested and desirable for soil and groundwater protection.
  • Publication
    Nanomaterials to microplastics: Swings and roundabouts
    ( 2017)
    Scott-Fordsmand, Janeck J.
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    Navas, Jose Maria
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    Nowack, Bernd
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    Amorim, Monica J.B.
    In recent years, the testing of nanomaterials during their use in products has been increasingly emphasized, as this will provide a more realistic risk assessment (RA) compared with RA based on pristine nanomaterials. We show that (i) using such an approach for a "realistic" RA is increasing the complexity of the RA, (ii) several testing-aspects render this approach more challenging than the conventional methods, (iii) interpretation of the results becomes difficult, and (iv) the resulting RA may need to be evaluated carefully as it yields improved understanding of the short-term fate of the individual product, but long-term consequences may be neglected.
  • Publication
    Guidance on the use of probabilistic methodology for modelling dietary exposure to pesticide residues
    ( 2012)
    Boesten, Jos
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    Bolognesi, Claudia
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    Brock, Theo
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    Capri, Ettore
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    Hardy, Anthony
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    Hart, Andrew
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    Hirsch-Ernst, Karen
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    Hougaard Bennekou, Susanne
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    et. al.
    The European Food Safety Authority (EFSA) asked the Panel on Plant Protection Products and their Residues to provide guidance on methodology for performing probabilistic dietary exposure assessment of single or multiple active substances, as a potential additional tool to supplement or complement the standard deterministic methodologies which are currently used in the EU for conducting dietary exposure assessments for pesticides. Specific guidance is provided for basic assessments but not for refined assessments, where specialized expertise is required to select methods appropriate to the assessment in hand. The guidance includes probabilistic methods for quantifying some of the major sources of variability and uncertainty affecting dietary exposure to pesticides. Other important sources of variability and uncertainty might be quantified probabilistically in refined assessments but are addressed more simply in basic assessments by conducting alternative model runs with optimistic and pessimistic assumptions. Guidance is provided on problem formulation, including definition of appropriate scenarios for acute and chronic exposure assessment in the differing contexts of approval of new substances, MRL setting, authorisation of products, evaluation of residues found above the MRL, and annual reviews of residue monitoring data. Detailed guidance is provided on methodology for probabilistic modelling of acute and chronic exposures and for quantifying variability and uncertainty in food consumption and residues. For basic probabilistic assessments, optimistic and pessimistic assumptions are used for the effects of processing and for residues below the level of reporting. A separate section is devoted to additional approaches required for modelling exposure to multiple substances (cumulative assessment): the use of relative potency factors to cumulate exposures to different substances, and a basic methodology for addressing gaps in data on the co-occurrence of residues of different substances. Specific guidance is provided on the types and formats of outputs that should be produced from a probabilistic assessment. Particular emphasis is placed on characterising the upper tail of the exposure distribution and on 'drill down' techniques to evaluate the reliability of the estimates. A general approach is recommended for evaluating uncertainties affecting the model outputs. An appendix to the guidance describes uncertainties associated with the methodology recommended in this guidance, and provides a general evaluation of their potential impacts on estimated exposures. The guidance also includes a checklist of key issues to be considered when writing or peer-reviewing reports on probabilistic exposure assessments, a discussion of approaches to validating probabilistic assessment approaches, and a list of desirable characteristics of software for probabilistic exposure modelling. Some comments are provided on the interpretation of results, while recognising that risk management is outside the remit of EFSA. Case studies are included in an appendix, illustrating some but not all of the recommended approaches. Further work will be required to make the methods in this guidance available to end-users in more practical form, including software and more specific user instructions. Some recommendations on this are provided.
  • Publication
    Single versus repeated applications of CuO and Ag nanomaterials and their effect on soil microflora
    Nanomaterials enter the terrestrial environment via the repeated application of sludge to soils over many years. The goal of this investigation was to compare the effects of CuO and Ag nanomaterials on soil microorganisms after a single application and after repeated applications ultimately resulting in the same test concentrations. The effect on soil microorganisms was determined using the ammonium oxidation (ISO 15685), enzymatic activity patterns (ISO 22939) and MicroResp tests on days 28, 56 and 84. The comparability of single and repeated applications of ion-releasing nanomaterials depended on the test endpoint and duration. No significant differences between single and repeated applications were observed when testing nitrifying microorganisms and exoenzymes, but differences were observed in the substrate-induced respiration test. The three test systems used together provide more comprehensive information about the impact of different nanomaterials on the soil microflora and its diversity.
  • Publication
    Environmental quality standards for mixtures
    ( 2013)
    Knauer, Katja
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    Traces of pesticides are frequently detected in surface waters. As a consequence, specific environmental quality criteria (EQS) for a set of single pesticides in surface waters were defined by the environmental authorities in several countries. In this context, the aim of this study was to investigate if the sum of the five percentile hazard concentration (SigmaHC 5-95percent, meaning that 5 percent of the aquatic assemblage remains affected considering a 95 percent confidence interval) of three herbicides with the same mode of action derived from a species sensitivity distribution based on acute toxicity data (EC50 values) of the most sensitive taxonomic group is a suitable EQS for surface water addressing the occurrence of herbicide mixtures as common exposure scenario. Therefore, an outdoor mesocosm study was performed with three replicates per treatment for a period of 173 days. Results demonstrated that a constant long-term exposure over 35 days to the HC 5-95 percent of a mixture of three PSII inhibitors did not lead to adverse effects on the aquatic community in this field mesocosm study. Neither adverse effects on very sensitive functional endpoints such as photosynthesis measurements of algae and macrophytes nor adverse effects on structural endpoints such as abundance data and species composition were determined. In contrast and as a positive control, the HC30 treatment affected statistically significant all investigated endpoints and it was demonstrated that the PSII inhibitors acted additive on various level of organization (Knauert et al., 2008). This study is filling the gap that no empirical evidence is published indicating that the chronic exposure at the HC5-95 percent estimate is leading to no adverse effects for the aquatic community and is therefore a suitable EQS for surface waters in the agriculture landscape.
  • Publication
    Spatial and temporal trends of metals and arsenic in German freshwater compartments
    ( 2014) ; ; ; ;
    Paulus, Martin
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    Ricking, Mathias
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    Koschorreck, Jan
    Cadmium, lead, mercury, copper, nickel, zinc, and arsenic were analyzed in suspended particulate matter (SPM), zebra mussels, and bream sampled yearly under the program of the German Environmental Specimen Bank (ESB) in the rivers Rhine, Elbe, Danube, Saar, Mulde, and Saale and in Lake Belau. Temporal and spatial trends were analyzed, correlations between metal levels in different specimen types assessed, and sampling sites ranked according to their metal levels by calculating a Multi-Metal Index (MMI) for every specimen type and site. SPM: Highest metal loads were detected in Mulde, Saale, and Elbe right downstream of the Saale confluence. In the Elbe, metal loads in SPM were mostly highest in the upper and middle section of the river while in Rhine and Saar concentrations increased downstream. Temporal trends since 2005 were detected only at three sites. Zebra mussel: MMIs were highest in the tidal section of the Elbe and the lower Rhine and lowest in Lake Belau and the upper Danube. Different temporal trends were detected since the early 1990s depending on site and metal. Bream: As, Pb, Cu, and Hg were analyzed in muscle tissue and Pb, Cd, Cu, and Zn in liver. For both tissues, MMIs were highest in Mulde and Saale and the lower and middle Elbe. Since the early 1990s, Hg, Pb, and Cu decreased in bream muscle at many sites while As increased at 6 of the 17 sites. The findings indicate that Hg, Pb, and Cu have obviously decreased in many freshwater ecosystems in recent years, whereas As and Ni levels have increased at several sites. Metal levels and temporal trends mostly differed between the specimen types under investigation and only few correlations between specimen types were detected. This underlines the importance of including different components of an ecosystem when assessing its environmental quality.
  • Publication
    A microcosm study to support aquatic risk assessment of nickel: Community-level effects and comparison with bioavailability-normalized species sensitivity distributions
    ( 2016) ; ; ; ;
    Schamphelaere, Karel de
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    Schlekat, Chris
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    Rogevich Garman, Emily
    The aquatic risk assessment for nickel in the European Union is based on chronic Species Sensitivity Distributions (SSD) and the use of bioavailability models. To test if a bioavailability-based safe threshold of nickel (the Hazardous Concentration for 5% of the species, HC5) is protective for aquatic communities, microcosms were exposed to 5 stable nickel treatments (6-96 mikrog/L) and a control for 4 mo to assess bioaccumulation and effects on phytoplankton, periphyton, zooplankton and snails. Ni concentrations in the periphyton, macrophytes and snails measured at the end of the exposure period increased in a dose-dependent manner, but did not indicate biomagnification. Abundance of phytoplankton and snails decreased in 48 and 96 mikrog Ni/L treatments, which may have indirectly affected the abundance of zooplankton and periphyton. Exposure up to 24 mikrog Ni/L had no adverse effects on algae and zooplankton while the rate of population decline of the snails at 24 mikrog Ni/L was significantly higher than in the controls. Therefore, the study-specific overall no observed adverse effect concentration (NOAEC) is 12 mikrog Ni/L. This NOAEC is approximately twice the HC5 derived from a chronic SSD considering the specific water chemistry of the microcosm by means of bioavailability models. Thus, the study provides support to the protectiveness of the bioavailability-normalized HC5 for freshwater communities.
  • Publication
    Bewertung der Grundwasserbelastung durch Wirkstoffe - was wollen wir schützen?
    Das Schutzgut Trinkwasser ist bei der Bewertung einer Grundwasserbelastung immer noch dominant, wird aber künftig besonders für Wirkstoffe ergänzt durch ökotoxikologische Risikoabschätzungen für die vielfältige Lebensgemeinschaft von Grundwasserorganismen. In einem Projekt des Umweltbundesamtes wurde bereits 2001 untersucht, ob die vorhandenen Testverfahren mit Arten aus Oberflächengewässern auch für Grundwasserarten protektiv sind. Typische Vertreter der Grundwasser-Lebensgemeinschaft wurden nach systematischer Repräsentativität ausgewählt und in ihre Empfindlichkeit gegen unterschiedliche Wirktypen von Stoffen bei 10°C getestet: das den Aufbaustoffwechsel hemmende Fungizid Cyprodinil, das neurotoxischen Insektizid lambda-Cyhalothrin, sowie das Herbizid Bromoxynil-Octanoat, welches auf Tiere narkotisch wirkt. Cyprodinil wirkt im Grundwasser 5-10fach verlangsamt. Die akute Wirkung von lambda-Cyhalothrin ist abhängig von der Nervenstruktur und Aktivität und betrifft die Niederen Krebse in Grund- und Oberflächenwasser ähnlich. Höhere Krebse sind durch ihre Neurophysiologie und die in Oberflächengewässern besonders hohe Aktivität stärker betroffen. Brunnenkrebse sind ebenso empfindlich, reagieren aber 5-10fach verlangsamt. Die narkotische Wirkung von Bromoxynil-Octanoat ist unabhängig vom Habitat nach vergleichbaren Zeiträumen gleich stark. Die Lebensgemeinschaft des Grundwassers ist durch das Empfindlichkeitsspektrum der Organismen aus Oberflächengewässern ausreichend repräsentiert; bestehende Standard-Testverfahren bieten nach gegenwärtigem Kenntnisstand genügend Sicherheit auch für die Grundwasser-Lebensgemeinschaft, wenn bei Hinweisen auf Auswirkungen auf Höhere Krebse neben Daphnia magna ein Höherer Krebs getestet wird.
  • Publication
    Selection of scenarios for exposure of soil organisms to plant protection products
    ( 2010)
    Tiktak, Aaldrik
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    Vanderborght, Jan
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    et. al.
    European scenarios for exposure of soil organisms to plant protection products are currently not available. As part of the revision of the Guidance Document on Persistence in Soil (9188/VI/97 rev 8 published in 2000), the PPR-panel was therefore asked to start the development of tiered exposure-assessment approaches for soil organisms in which European exposure scenarios play an important role. This report contributes to this revision by developing a systematic approach to the selection of realistic worst-case scenarios for exposure of soil organisms. Realistic worst-case conditions are defined as the 90th spatial percentile of the exposure concentration (the maximum over time) in the intended area of use in each of three regulatory zones defined in Council regulation (EC) 1107/2009. Separate scenarios were developed for the concentration in total soil (mg kg-1) and for the concentration in the liquid phase (mg l-1), giving six scenarios to be developed. The scenario selection began with the compilation of a coherent database. Then, a simplified model was selected to generate maps of the concentration in total soil and the concentration in the liquid phase over the entire area of annual crops in the three zones. In the subsequent two steps, procedures were applied to account for parameter uncertainty and scenario uncertainty (i.e. the likelihood that a scenario that is derived for one substance is not conservative enough for another). In the final step, the six scenarios were selected by defining their air temperature, soil organic matter content and their soil textural class. The concentration in total soil was shown to decrease in the order North>Central>South, whereas the concentration in the liquid phase showed an opposing trend with the highest concentration in the Southern European scenario. The scenario development was based on the total area of annual crops in the EU-27, but the endpoint of the exposure assessment is the 90th percentile of the intended use area. The scenarios may therefore not be conservative enough. To ensure that the selected scenarios are sufficiently conservative, safety factors were derived.
  • Publication
    Analysis and Optimization of Ecotoxicological Models under Uncertainty
    The problem of assessing the environmental risk of pesticides can be formulated as a robust feasibility problem: A pesticide is only approved by regulatory agencies of Germany and the entire European Union, if it causes no damage to the environment and man in any possible scenarios. Typically, experimental toxicity studies are used to construct a scenario based approximation of an uncertainty set. In doing so, the considered scenarios are possibly unrealistic, but they aim to represent the worst case. Thus, an overestimation of the effects is accepted to be certain that all possible risks are covered. We consider mechanistic models that do not only describe the effect of pesticides but also aim to explain the underlying processes. Such models may build a more realistic approximation of uncertainty set and thus be instrumental in assessing the risk. This allows the consideration of more complex scenarios. Currently, the use of the models is discussed but at most used in addition to conventional standard tests in European risk assessment. One reason is that they are not well documented. There exists a large family of models differing in complexity as well as precision. Furthermore, there are no standardized model test scenarios, yet. Especially, it is not clear how trustworthy the predictions of the models as well as the models themselves are. Mathematically, we consider parametrized systems of nonlinear differential equations and the complex interdependency of two associated problems. On the one hand, we have the inverse problem of identifying the model parameters. On the other hand, we have the direct problem of predicting effects under varying environmental conditions. This step requires an in depth analysis of the discretization error (ordinary differential equations), extrapolation error (situations not covered by calibration), conceptual model error (situation not covered by model) and consequences of changes in parameter values (sensitivity and uncertainty analysis). Furthermore, the characterization of the physically sound parameters is in special interest in view of the construction of model test scenarios. Besides a realistic modeling, the solution of the model system (exact, approximate) and the choice of the initial values of the inverse problem play a prominent role. We study three different models in the main chapters that are connected by the aim of describing mechanistically the effect of active substances in the environment. The first part deals with the unified framework of the model guts (General Unified Threshold model of Survival). This model is based on two different mortality hypotheses: stochastic death (sd) and individual tolerance (it). The second and third part concentrate on models describing the sublethal effects of active substances on growth of the water plant Lemna. Although both models treat the same species and have the same objective, the models differ in concept and complexity. The first model is a logistic growth model with an effective growth rate that is influenced by environmental conditions and dosage of a pesticide. The second model involves Dynamic Energy Budget theory (deb) describing growth in terms of changing the energy budget in time. We analyze and quantify uncertainties and errors in the considered ecotoxicological models. Furthermore, we develop methodologies to reduce the uncertainties such that the prediction of the models is enhanced. Thus, this thesis provides a foundation for the use of sophisticated mathematical models in environmental risk assessment of pesticides.