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Rüther, Maria

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  • 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
    Glyphosate in German adults - Time trend (2001 to 2015) of human exposure to a widely used herbicide
    (2017) Conrad, André; Schröter-Kermani, Christa; Hoppe, Hans-Wolfgang; Kolossa-Gehring, Marike; Pieper, Silvia; Rüther, Maria
  • Veröffentlichung
    Metabolites of the alkyl pyrrolidone solvents NMP and NEP in 24-h urine samples of the German Environmental Specimen Bank from 1991 to 2014
    (2018) Ulrich, Nadin; Bury, Daniel; Koch, Holger Martin; Kolossa-Gehring, Marike; Rüther, Maria; Weber, Till
    Purpose The aim of this study was to get a first overview of the exposure to the solvents and reproductive toxicants N-methyl-2-pyrrolidone (NMP) and N-ethyl-2-pyrrolidone (NEP) in Germany. NMP and NEP metabolite concentrations were determined in 540 24-h urine samples of the German Environmental Specimen Bank collected from 1991 to 2014. With these data we were able to investigate NMP/NEP exposures over time and to evaluate associated risks. Methods NMP metabolites 5-hydroxy-N-methyl-2-pyrrolidone (5-HNMP) and 2-hydroxy-N-methylsuccinimide (2-HMSI) and NEP metabolites 5-hydroxy-N-ethyl-2-pyrrolidone (5-HNEP) and 2-hydroxy-N-ethylsuccinimide (2-HESI) were determined by stable isotope dilution analysis using solid phase extraction followed by derivatization (silylation) and GCâ€ÌEIâ€ÌMS/MS. Results We were able to quantify 5-HNMP and 2-HMSI in 98.0 and 99.6% and 5-HNEP and 2-HESI in 34.8 and 75.7% of the samples. Metabolite concentrations were rather steady over the timeframe investigated, even for NEP which has been introduced as an NMP substitute only in the last decade. Calculated median daily intakes in 2014 were 2.7 Ìg/kg bw/day for NMP and 1.1 Ìg/kg bw/day for NEP. For the combined risk assessment of NMP and NEP exposure, the hazard index based on the human biomonitoring assessment I values (HBM I values) was less than 0.1. Conclusions Based on the investigated subpopulation of the German population, individual and combined NMP and NEP exposures were within acceptable ranges in the investigated timeframe. Sources of NEP exposure in the 90s and 00s remain elusive. © Springer-Verlag GmbH Germany, part of Springer Nature 2018
  • 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.