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  • Veröffentlichung
    Development of a multi-compartment pharmacokinetic model to characterize the exposure to Hexamoll® DINCH®
    (2015) Schütze, Andre; Apel, Petra; Lorber, Matthew; Gawrych, Katarzyna; Kolossa-Gehring, Marike; Brüning, Thomas; Koch, Holger Martin
    We developed and calibrated a multi compartment pharmacokinetic (PK) model to predict urinary concentrations after oral exposure of four specific DINCH metabolites: MINCH, OH-MINCH, cx-MINCH, and oxo-MINCH. This descriptive model has 4 compartments: a "stomachŁ (SC) compartment, a "holdingŁ (HC) compartment, a "bloodŁ (BC) compartment and a "bladderŁ (BLC) compartment. DINCH is assumed to first deposit into the SC, with transfer split between the HC and the BC. Unmetabolized DINCH from the HC then transfers to the BC. The DINCH metabolism is assumed to occur in the BC before excretion via the BLC. At each urination event, all the metabolite mass in the BLC is excreted. The model was calibrated using published urine metabolite data from 3 different male volunteers, each orally dosed with 50 mg DINCH. Full urine voids were taken for 48 h after dosage. The predicted values showed a good agreement with the observed urinary DINCH metabolite concentrations, with a Spearman correlation coefficient exceeding 0.7 for all oxidized metabolites. We showed the importance of a holding reservoir. Without it, a good agreement could not be found. We applied the model to a set of 24-h general population samples measured for DINCH metabolites. The model was unable to duplicate the ratio of metabolites seen in the 24-h samples. Two possibilities were offered to explain the difference: the exposure pattern in the general population did not match the oral exposure in the dosing experiments, or the long-term toxicokinetics of DINCH was not captured in the 48-h controlled dosing experiments.Quelle: http://www.sciencedirect.com
  • Veröffentlichung
    Phthalate metabolites in 24-h urine samples of the German Environmental Specimen Bank (ESB) from 1988 to 2015 and a comparison with US NHANES data from 1999 to 2012
    (2017) Koch, Holger M.; Apel, Petra; Schütze, Andre; Conrad, André; Pälmke, Claudia; Kolossa-Gehring, Marike; Brüning, Thomas; Rüther, Maria
    The German Environmental Specimen Bank (ESB) continuously collects 24-h urine samples since theearly 1980s in Germany. In this study we analyzed 300 urine samples from the years 2007 to 2015 for 21phthalate metabolites (representing exposure to 11 parent phthalates) and combined the data with twoprevious retrospective measurement campaigns (1988 to 2003 and 2002 to 2008). The combined datasetcomprised 1162 24-h urine samples spanning the years 1988 to 2015. With this detailed set of humanbiomonitoring data we describe the time course of phthalate exposure in Germany over a time frame of27 years. For the metabolites of the endocrine disrupting phthalates di(2-ethylhexyl) phthalate (DEHP),di-n-butyl phthalate (DnBP) and butylbenzyl phthalate (BBzP) we observed a roughly ten-fold decline inmedian metabolite levels from their peak levels in the late 1980s/early 1990s compared to most recentlevels from 2015. Probably, bans (first enacted in 1999) and classifications/labelings (enacted in 2001 and2004) in the European Union lead to this drop. A decline in di-isobutyl phthalate (DiBP) metabolite levelsset in only quite recently, possibly due to its later classification as a reproductive toxicant in the EU in 2009.In a considerable number of samples collected before 2002 health based guidance values (BE, HBM I) havebeen exceeded for DnBP (27.2%) and DEHP (2.3%) but also in recent samples some individual exceedancescan still be observed (DEHP 1.0%). A decrease in concentration for all low molecular weight phthalates,labelled or not, was seen in the most recent years of sampling. For the high molecular weight phthalates,DEHP seems to have been substituted in part by di-isononyl phthalate (DiNP), but DiNP metabolite levelshave also been declining in the last years. Probably, non-phthalate alternatives increasingly take overfor the phthalates in Germany. A comparison with NHANES (National Health and Nutrition ExaminationSurvey) data from the United States covering the years 1999 to 2012 revealed both similarities anddifferences in phthalate exposure between Germany and the US. Exposure to critical phthalates hasdecreased in both countries with metabolite levels more and more aligning with each other, but highmolecular weight phthalates substituting DEHP (such as DiNP) seem to become more important in theUS than in Germany.
    © 2016 Elsevier GmbH. All rights reserved
  • Veröffentlichung
    Daily intake and hazard index of parabens based upon 24 h urine samples of the German Environmental Specimen Bank from 1995 to 2012
    (2016) Moos, Rebecca K.; Apel, Petra; Schröter-Kermani, Christa; Kolossa-Gehring, Marike; Brüning, Thomas; Koch, Holger M.
    In recent years, exposure to parabens has become more of a concern because of evidence of ubiquitous exposure in the general population, combined with evidence of their potency as endocrine disruptors. New human metabolism data from oral exposure experiments enable us to back calculate daily paraben intakes from urinary paraben levels. We report daily intakes (DIs) for six parabens based on 660 24h urine samples from the German Environmental Specimen Bank collected between 1995 and 2012. Median DI values ranged between 1.1Ţg/kg bw/day for iso-butyl paraben and 47.5Ţg/kg bw/day for methyl paraben. The calculated DIs were compared with acceptable levels of exposure to evaluate the hazard quotients (HQs) that indicate that acceptable exposure is exceeded for values of >1. Approximately 5% of our study population exceeded this threshold for individual paraben exposure. The hazard index (HI) that takes into account the cumulative risk of adverse estrogenic effects was 1.3 at the 95th percentile and 4.4 at maximum intakes, mainly driven by n-propyl paraben exposure. HI values of >1 indicate some level of concern. However, we have to point out that we applied most conservative assumptions in the HQ/HI calculations. Also, major exposure reduction measures were enacted in the European Union after 2012. Quelle: www.nature.com
  • Veröffentlichung
    Human biomonitoring reference values: Differences and similarities between approaches for identifying unusually high exposure of pollutants in humans
    (2019) Apel, Petra; Conrad, André; Kolossa-Gehring, Marike; Rucic, Enrico; Vogel, Nina
    In exposure and risk assessment, the indication of unusually high exposure levels in humans to chemicals has been considered as an important objective for decades. To realize this objective, reference values (RV) need to be derived. However, while there is a tendency towards using the 95th percentile as a basis for deriving these reference values there is still no consensus. Moreover, side approaches have evolved including deriving RVs based on other percentiles, reporting multiple RVs or only reporting percentiles. The purpose of this article is to give an overview of the current literature, to point out differences and similarities between existing approaches, and to highlight important criteria for the derivation of RVs. We observe the majority of studies to base RVs on the 95th percentile and its 95% confidence interval which can been justified by statistical paradigms, present arguments for a single defined reference value, and discuss characteristics which call for more consistency. To conclude, our overview provides a first step towards a more homogenous and standardized derivation procedure to identify unusually high exposures in exposure science. © 2018 The Authors. Published by Elsevier GmbH.
  • Veröffentlichung
    Time trend of exposure to the phthalate plasticizer substitute DINCH in Germany from 1999 to 2017: Biomonitoring data on young adults from the Environmental Specimen Bank (ESB)
    (2019) Kasper-Sonnenberg, Monika; Apel, Petra; Koch, Holger M.; Kolossa-Gehring, Marike; Rüther, Maria
    DINCH (cyclohexane-1,2-dicarboxylic acid-diisononyl ester) is a phthalate plasticizer substitute introduced into the market in 2002. It is increasingly used especially in the production of toys, food contact materials and medical devices. In this measurement campaign on 24-h urine samples of young adults (20-29 years) from the German Environmental Specimen Bank (ESB) collected in 2010, 2011, 2013, 2015 and 2017 (in total 300 samples, 60 samples/year) we analyzed three specific, oxidized DINCH metabolites (OH-MINCH: cyclohexane-1,2-dicarboxylic acid-mono(hydroxy-isononyl) ester; cx-MINCH: cyclohexane-1,2-dicarboxylic acid-mono(carboxy-isooctyl) ester, oxo-MINCH: cyclohexane-1,2-dicarboxylic acid-mono(oxo-isononyl) ester). We merged these data with earlier data of the ESB from the years 1999-2012 and are now able to report levels and time trends of internal DINCH exposure from 1999 to 2017. After first detections of the major oxidized DINCH metabolite OH-MINCH in 2006 (6.7%) detection rates rapidly increased to 43.3% in 2009, 80% in 2010 and 98.3% in 2011 and 2012. From the year 2013 on we could detect OH-MINCH in every urine sample analyzed. The median concentrations of OH-MINCH rapidly increased from 0.15 (Mü)g/L in 2010 to twice the concentration in 2011 (0.31 (Mü)g/L) with further increases in 2013 (0.37 (Mü)g/L), 2015 (0.59 (Mü)g/L) and 2017 (0.70 (Mü)g/L). Similar increases, albeit at lower detection rates and concentration levels, could be observed for cx-MINCH and oxo-MINCH. All metabolites strongly correlate with each other. For the ESB study population, DINCH exposures are still far below health based guidance values such as the German Human Biomonitoring Value (HBM-I; 4,500 (Mü)g/L for the sum of OH-MINCH and cx-MINCH) or the tolerable daily intake (TDI) of EFSA (1mg/kg/bw/d). The median daily DINCH intake (DI) calculated for 2017 was 0.23 (Mü)g/kg bw/d, thus 4,310-times lower than the TDI. The maximum DI calculated for one individual in 2012 (42.60 (Mü)g/kg bw/d) was a factor of more than 20 below the TDI. The ongoing increase in DINCH exposure needs to be closely monitored in the future, including populations with potentially higher exposures such as children. This close monitoring will enable timely exposure and risk reduction measures if exposures reached critical levels, or if new toxicological data lead to lower health based guidance values. DINCH belongs to the European Human Biomonitoring Initiative (HBM4EU) priority substances for which policy relevant questions still have to be answered. © 2019 Elsevier GmbH. All rights reserved.
  • Veröffentlichung
    German Environmental Specimen Bank: 24-hour urine samples from 1999 to 2017 reveal rapid increase in exposure to the para-phthalate plasticizer di(2-ethylhexyl) terephthalate (DEHTP)
    (2019) Lessmann, F.; Apel, Petra; Kolossa-Gehring, Marike; Rüther, Maria
    The worldwide plasticizer markets are facing constant substitution processes. Many classic ortho-phthalate plasticizers like di(2-ethylhexyl) phthalate (DEHP) are phased out, due to their proven toxicity to reproduction. Assumedly less critical, less regulated plasticizers such as di(2-ethylhexyl) terephthalate (DEHTP) are increasingly applied in consumer near products like toys, food contact materials, and medical devices. With the increasing use of DEHTP, increasing exposures of the general population have to be expected likewise. Human biomonitoring is a well-established tool to determine population exposures. In the present study we investigate the time trend of exposure to DEHTP using 24-hour urine samples of the German Environmental Specimen Bank (ESB) collected from 1999 to 2017. In these samples (60 per odd-numbered year, 600 samples in total) collected from young German adults (20-29 years, equal gender distribution) we determined four specific urinary metabolites as biomarkers of DEHTP exposure. From 1999 to 2009, the main specific urinary metabolite 5cx-MEPTP was quantifiable in <10% of the samples. Thereafter, detection rates and levels constantly increased, in line with rapidly increasing DEHTP consumption volumes. In 2017, all samples had 5cx-MEPTP levels above the limit of quantification (LOQ) with a median concentration of 3.35 ng/L (95th percentile: 12.8 ng/L). The other metabolites were detected less frequently and at lower levels but correlated well with 5cx-MEPTP robustly confirming the increasing DEHTP exposure. All 5cx-MEPTP concentrations were well below the German health based guidance value (HBM-I) of 2800 ng/L for adults. Likewise, the median calculated daily intake, based on 5cx-MEPTP measured in 2017, was 0.74 ng/kg bw*d (95th percentile: 3.86 ng/kg bw*d), still well below the tolerable daily intake (TDI) of 1000 ng/kg bw*d. Based on current toxicological knowledge we can hence conclude that for the population investigated, DEHTP exposure gives no reason for immediate concern. However, the steep ongoing increase of DEHTP exposure warrants further close monitoring in the future, preferably also in sub-populations with known higher exposures to plasticizers, especially children. © 2019 The Authors. Published by Elsevier Ltd.
  • Veröffentlichung
    Time course of phthalate cumulative risks to male developmental health over a 27-year period: Biomonitoring samples of the German Environmental Specimen Bank
    (2020) Apel, Petra; Kortenkamp, Andreas; Conrad, André; Koch, Holger Martin; Kolossa-Gehring, Marike; Rüther, Maria
    In several human biomonitoring surveys, changes in the usage patterns of phthalates have come to light, but their influence on the risks associated with combined exposures is insufficiently understood. Based on the largest study to date, the 27-year survey of urinary phthalate metabolite levels in 24-hour urine samples from the German Environmental Specimen Bank, we present a deep analysis of changing phthalate exposures on mixture risks. This analysis adopts the Hazard Index (HI) approach based on the five phthalates DBP, DIBP, BBP, DEHP and DINP. Calculations of the hazard index for each study participant included updated phthalate reference doses for anti-androgenicity (RfDAAs) that take account of new evidence of phthalates' developmental toxicity. The Maximum Cumulative Ratio (MCR) approach was used to establish whether a subjectâ€Ìs combined exposure was dominated by one phthalate or was influenced by several phthalates simultaneously. Generally, over the years there was a shift towards lower HIs and higher MCRs, reflecting an increased complexity of the combined exposures. The decade from 1988 to about 1999 was characterised by rather high HIs of between 3 and 7 (95th percentile) which were driven by exposure to DBP and DEHP, often exceeding their single acceptable exposures. Traditional single phthalate risk assessments would have underestimated these risks by up to 50%. From 2006 onwards, no study participant experienced exposures above acceptable levels for a single phthalate, but combined exposures were still in excess of HI = 1. From 2011 onwards most individuals stayed below HI = 1. In interpreting these results, we caution against the use of HI = 1 as an acceptable limit and develop proposals for improved and more realistic mixture risk assessments that take account of co-exposures to other anti-androgenic substances also capable of disrupting the male reproductive system. From this perspective, we regard HIs between 0.1 and 0.2 as more appropriate for evaluating combined phthalate exposures. Assessed against lowered HIs of 0.1 - 0.2, the combined phthalate exposures of most study participants exceeded acceptable levels in all study years, including 2015. Continued monitoring efforts for phthalate combinations are required to provide the basis for appropriate risk management measures. © 2020 The Authors.
  • Veröffentlichung
    Human biomonitoring initiative (HBM4EU) - Strategy to derive human biomonitoring guidance values (HBM-GVs) for health risk assessment
    (2020) Apel, Petra; Rouselle, Christophe; Kolossa-Gehring, Marike; Lange, Rosa
    The European Joint Program "HBM4EU" is a joint effort of 30 countries and the European Environment Agency, co-funded under the European Commission's Horizon 2020 program, for advancing and implementing human biomonitoring (HBM) on a European scale and for providing scientific evidence for chemical policy making. One important outcome will be a Europe-wide improvement and harmonization of health risk assessment following the coordinated derivation or update of health-related guidance values referring to the internal body burden. These guidance values - named HBM guidance values or HBM-GVs - can directly be compared with HBM data. They are derived within HBM4EU for priority substances identified by the HBM4EU chemicals prioritization strategy based on existing needs to answer policy relevant questions as raised by national and EU policy makers. HBM-GVs refer to both the general population and occupationally exposed adults. Reports including the detailed reasoning for the values' proposals are subjected to a consultation process within all partner countries of the consortium to reach a broad scientific consensus on the derivation approach and on the derived values. The final HBM-GVs should be applied first within the HBM4EU project, but may also be useful for regulators and risk assessors outside this project. The subsequent adoption of derived HBM-GVs at EU-level needs to be discussed and decided within the responsible EU bodies. Nevertheless, the establishment of HBM-GVs as part of HBM4EU is already a step forward in strengthening HBM-based policy efforts for public and occupational health. The strategy for deriving HBM-GVs which is based on already existing approaches from the German HBM Commission, the French Agency for Food, Environmental and Occupational Health & Safety (ANSES) as well as from the US-based scientific consultant Summit Toxicology, the allocation of a level of confidence to the derived values, and the consultation process within the project are comprehensively described to enlighten the work accomplished under the HBM4EU initiative. © 2020 The Author(s).
  • Veröffentlichung
    Human biomonitoring initiative (HBM4EU): Human biomonitoring guidance values (HBM-GVs) derived for cadmium and its compounds
    (2021) Lamkarkach, Farida; Apel, Petra; Ougier, Eva; Garnier, Robert; Kolossa-Gehring, Marike; Lange, Rosa
    Aims The methodology agreed within the framework of the HBM4EU project is used in this work to derive HBM-GVs for the general population (HBM-GVGenPop) and for workers (HBM-GVWorker) exposed to cadmium (Cd) and its compounds. Methods For Cd, a significant number of epidemiological studies with doseââą Ìresponse relationships are available, in particular for kidney effects. These effects are described in terms of a relation between urinary Cd (U-Cd) or blood Cd (B-Cd) levels and low molecular weight proteinuria (LMWP) markers like beta-2-microglobulin (Î22M) and retinol-binding protein (RBP). In order to derive HBM-GVs for the general population and workers, an assessment of data from evaluations conducted by national or international organisations was undertaken. In this work, it appeared relevant to select renal effects as the critical effect for the both groups, however, differences between general population (including sensitive people) and workers (considered as an homogenous population of adults who should not be exposed to Cd if they suffer from renal diseases) required the selection of different key studies (i.e. conducted in general population for HBM-GVGenPop and at workplace for HBM-GVWorker). Results and conclusions For U-Cd, a HBM-GVGenPop of 1 (my)g/g creatinine (creat) is recommended for adults older than 50 years, based on a robust meta-analysis performed by EFSA (EFSA, 2009a). To take into account the accumulation of Cd in the human body throughout life, threshold or 'alert' values according to age were estimated for U-Cd. At workplace, a HBM-GVWorker of 2 (my)g/g creat is derived from the study of Chaumont et al., (2011) for U-Cd, and in addition to this recommendation a HBM-GVworker for B-Cd of 5 Ìg/L is also proposed. The HBM-GVWorker for U-Cd is similar to the biological limit value (BLV) set by the new amendment of the European Carcinogens and Mutagens Directive in June 2019 (2 (my)g/g creat for U-Cd). © 2021 The Authors