Determinants of exposure to acrylamide in European children and adults based on urinary biomarkers: results from the "European Human Biomonitoring Initiative" HBM4EU participating studies

Little is known about exposure determinants of acrylamide (AA), a genotoxic food-processing contaminant, in Europe. We assessed determinants of AA exposure, measured by urinary mercapturic acids of AA (AAMA) and glycidamide (GAMA), its main metabolite, in 3157 children/adolescents and 1297 adults in the European Human Biomonitoring Initiative. Harmonized individual-level questionnaires data and quality assured measurements of AAMA and GAMA (urine collection: 2014-2021), the short-term validated biomarkers of AA exposure, were obtained from four studies (Italy, France, Germany, and Norway) in children/adolescents (age range: 3-18 years) and six studies (Portugal, Spain, France, Germany, Luxembourg, and Iceland) in adults (age range: 20-45 years). Multivariable-adjusted pooled quantile regressions were employed to assess median differences (β coefficients) with 95% confidence intervals (95% CI) in AAMA and GAMA (µg/g creatinine) in relation to exposure determinants. Southern European studies had higher AAMA than Northern studies. In children/adolescents, we observed significant lower AA associated with high socioeconomic status (AAMA:β =  - 9.1 µg/g creatinine, 95% CI - 15.8, - 2.4; GAMA: β =  - 3.4 µg/g creatinine, 95% CI - 4.7, - 2.2), living in rural areas (AAMA:β =  - 4.7 µg/g creatinine, 95% CI - 8.6, - 0.8; GAMA:β =  - 1.1 µg/g creatinine, 95% CI - 1.9, - 0.4) and increasing age (AAMA:β =  - 1.9 µg/g creatinine, 95% CI - 2.4, - 1.4; GAMA:β =  - 0.7 µg/g creatinine, 95% CI - 0.8, - 0.6). In adults, higher AAMA was also associated with high consumption of fried potatoes whereas lower AAMA was associated with higher body-mass-index. Based on this large-scale study, several potential determinants of AA exposure were identified in children/adolescents and adults in European countries.

Exposure to Phthalates in European Children, Adolescents and Adults since 2005: A Harmonized Approach Based on Existing HBM Data in the HBM4EU Initiative

Phthalates are mainly used as plasticizers and are associated inter alia with adverse effects on reproductive functions. While more and more national programs in Europe have started monitoring internal exposure to phthalates and its substitute 1,2-Cyclohexanedicarboxylic acid (DINCH), the comparability of results from such existing human biomonitoring (HBM) studies across Europe is challenging. They differ widely in time periods, study samples, degree of geographical coverage, design, analytical methodology, biomarker selection, and analytical quality assurance level. The HBM4EU initiative has gathered existing HBM data of 29 studies from participating countries, covering all European regions and Israel. The data were prepared and aggregated by a harmonized procedure with the aim to describe-as comparably as possible-the EU-wide general population's internal exposure to phthalates from the years 2005 to 2019. Most data were available from Northern (up to 6 studies and up to 13 time points), Western (11; 19), and Eastern Europe (9; 12), e.g., allowing for the investigation of time patterns. While the bandwidth of exposure was generally similar, we still observed regional differences for Butyl benzyl phthalate (BBzP), Di(2-ethylhexyl) phthalate (DEHP), Di-isononyl phthalate (DiNP), and Di-isobutyl phthalate (DiBP) with pronounced decreases over time in Northern and Western Europe, and to a lesser degree in Eastern Europe. Differences between age groups were visible for Di-n-butyl phthalate (DnBP), where children (3 to 5-year olds and 6 to 11-year olds) had lower urinary concentrations than adolescents (12 to 19-year-olds), who in turn had lower urinary concentrations than adults (20 to 39-year-olds). This study is a step towards making internal exposures to phthalates comparable across countries, although standardized data were not available, targeting European data sets harmonized with respect to data formatting and calculation of aggregated data (such as developed within HBM4EU), and highlights further suggestions for improved harmonization in future studies.

Long-term time trend of lead exposure in young German adults - Evaluation of more than 35 Years of data of the German Environmental Specimen Bank

Lead is a ubiquitous pollutant with well-known effects on human health. As there is no lower toxicological threshold for lead in blood and since data gaps on lead exposure still exist in many European countries, HBM data on lead is of high importance. To address this, the European Human Biomonitoring Initiative HBM4EU classified lead as a priority substance. The German Environmental Specimen Bank (German ESB) has monitored lead exposure since more than 35 years. Using data from the early 1980s to 2019 we reveal and discuss long-term trends in blood lead levels (BLLs) and current internal exposure of young adults in Germany. BLLs in young adults decreased substantially in the investigated period. As results from the ESB sampling site Muenster demonstrate, the geometric mean of BLLs of young adults decreased from 1981 (78,7 μg/L) to 2019 (10.4 μg/L) by about 87%. Trends in human exposure closely correlate with air lead levels (ALLs) provided by the European Monitoring and Evaluation Programme (EMEP). Hence, the decrease of BLLs largely reflects the drop in air lead pollution. Known associations of sex, smoking, alcohol consumption, and housing situation with BLLs are confirmed with data of the German ESB. Although internal lead exposure in Germany decreased substantially, the situation might be different in other European countries. Since 2010, BLLs of young adults in Germany levelled out at approximately 10 μg/L. The toxicity of lead even at low levels is known to cause adverse health effects especially in children following exposure of the child or the mother during pregnancy. To identify current exposure sources and to minimize future lead exposure, continuous monitoring of lead intake and exposure levels is needed.

N-methylmalonamic acid (NMMA) as metabolite of methylisothiazolinone and methylchloroisothiazolinone in 24-h urine samples of the German Environmental Specimen Bank from 2000 to 2017 - exposure and time trends

Methylisothiazolinone (MI) and the mixture of methylchloroisothiazo¬linone/methylisothiazolinone (MCI/MI, 3:1) are widespread biocides used in cosmetics, household products, paints or as disinfectant in air-conditioning systems. Exposure to these compounds has raised concerns due to their sensitizing potential, as rates of skin sensitization were reported to increase in the last decade. We have analyzed N-methylmalonamic acid (NMMA), a common metabolite of MI and MCI in 24-h urine samples of the German Environmental Specimen Bank collected from 480 participants (240 male/240 female) between the years 2000 and 2017. Using these data, we were able to calculate the overall daily intake of MI and/or MCI/MI (3:1) of the study participants and point out time trends. NMMA was determined in all urine samples investigated above the LOQ of 0.5 μg/L urine. Median and 95th percentile level of NMMA in all 24-h urine samples was 4.1 μg/g creatinine and 8.5 μg/g creatinine, respectively. This would correspond to a median and 95th percentile daily intake of 0.35 μg/kg bw and 0.71 μg/kg bw for exclusive uptake of MI and 0.64 μg/kg bw and 1.28 μg/kg bw for exclusive uptake of MCI/MI (3:1). We noted only slight variations over time for median exposures, but an increasing time trend in the 95th percentile exposure between 2006 and 2011 with a decrease in recent years, probably reflecting regulatory measures on MI and MCI/MI (3:1) in cosmetic products. Increasing knowledge on determinants of exposure to MI and/or MCI/MI (3:1) would be necessary to further lower exposure to these sensitizing compounds.

Time course of phthalate cumulative risks to male developmental health over a 27-year period: Biomonitoring samples of the German Environmental Specimen Bank

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 (RfD_AAs) that take account of new evidence of phthalates' developmental toxicity. The Maximum Cumulative Ratio (MCR) approach was used to establish whether a subject's 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.

Correction to: Metabolites of the alkyl pyrrolidone solvents NMP and NEP in 24-h urine samples of the German Environmental Specimen Bank from 1991 to 2014

The article Metabolites of the alkyl pyrrolidone solvents NMP and NEP in 24-h urine samples of the German Environmental Specimen Bank from 1991 to 2014.

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)

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 μg/L (95th percentile: 12.8 μg/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 μg/L for adults. Likewise, the median calculated daily intake, based on 5cx-MEPTP measured in 2017, was 0.74 μg/kg bw∗d (95th percentile: 3.86 μg/kg bw∗d), still well below the tolerable daily intake (TDI) of 1000 μg/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.

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)

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 μg/L in 2010 to twice the concentration in 2011 (0.31 μg/L) with further increases in 2013 (0.37 μg/L), 2015 (0.59 μg/L) and 2017 (0.70 μg/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 μg/L for the sum of OH-MINCH and cx-MINCH) or the tolerable daily intake (TDI) of EFSA (1 mg/kg bw/d). The median daily DINCH intake (DI) calculated for 2017 was 0.23 μg/kg bw/d, thus 4,310-times lower than the TDI. The maximum DI calculated for one individual in 2012 (42.60 μg/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.

Glyphosate in German adults - Time trend (2001 to 2015) of human exposure to a widely used herbicide

The broadband herbicide glyphosate (N-[phosphonomethyl]-glycine) and its main metabolite aminomethylphosphonic acid (AMPA) were analyzed by GC-MS-MS in 24h-urine samples cryo-archived by the German Environmental Specimen Bank (ESB). Samples collected in 2001, 2003, 2005, 2007, 2009, 2011, 2012, 2013, 2014, and 2015 were chosen for this retrospective analysis. All urine samples had been provided by 20 to 29 years old individuals living in Greifswald, a city in north-eastern Germany. Out of the 399 analyzed urine samples, 127 (=31.8%) contained glyphosate concentrations at or above the limit of quantification (LOQ) of 0.1μg/L. For AMPA this was the case for 160 (=40.1%) samples. The fraction of glyphosate levels at or above LOQ peaked in 2012 (57.5%) and 2013 (56.4%) after having discontinuously increased from 10.0% in 2001. Quantification rates were lower again in 2014 and 2015 with 32.5% and 40.0%, respectively. The overall trend for quantifiable AMPA levels was similar. Glyphosate and AMPA concentrations in urine were statistically significantly correlated (spearman rank correlation coefficient=0.506, p≤0.001). Urinary glyphosate and AMPA levels tended to be higher in males. The possible reduction in exposure since 2013 indicated by ESB data may be due to changes in glyphosate application in agricultural practice. The ESB will continue monitoring internal exposures to glyphosate and AMPA for following up the time trend, elucidating inter-individual differences, and contributing to the ongoing debate on the further regulation of glyphosate-based pesticides.

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

The German Environmental Specimen Bank (ESB) continuously collects 24-h urine samples since the early 1980s in Germany. In this study we analyzed 300 urine samples from the years 2007 to 2015 for 21 phthalate metabolites (representing exposure to 11 parent phthalates) and combined the data with two previous retrospective measurement campaigns (1988 to 2003 and 2002 to 2008). The combined dataset comprised 1162 24-h urine samples spanning the years 1988 to 2015. With this detailed set of human biomonitoring data we describe the time course of phthalate exposure in Germany over a time frame of 27 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 in median metabolite levels from their peak levels in the late 1980s/early 1990s compared to most recent levels from 2015. Probably, bans (first enacted in 1999) and classifications/labelings (enacted in 2001 and 2004) in the European Union lead to this drop. A decline in di-isobutyl phthalate (DiBP) metabolite levels set 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) have been exceeded for DnBP (27.2%) and DEHP (2.3%) but also in recent samples some individual exceedances can 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 levels have also been declining in the last years. Probably, non-phthalate alternatives increasingly take over for the phthalates in Germany. A comparison with NHANES (National Health and Nutrition Examination Survey) data from the United States covering the years 1999 to 2012 revealed both similarities and differences in phthalate exposure between Germany and the US. Exposure to critical phthalates has decreased in both countries with metabolite levels more and more aligning with each other, but high molecular weight phthalates substituting DEHP (such as DiNP) seem to become more important in the US than in Germany.

Studies on the Process of Formation, Nature and Stability of Binding Sites in Molecularly Imprinted Polymers

In Molecular Imprinting the nature of the templated binding sites and the mechanism of their formation are still poorly understood. For this reason our groups are carrying out fundamental studies concerning known imprinting protocols, with the primary aim of shedding light on the role of the template in the different steps of the polymerisation, from the formation of primary chains to the build-up of the porous structure. In this paper we report our initial results concerning copolymers of methacrylic acid (MAA) and ethyleneglycol dimethacrylate (EDMA) and their formation in presence or absence of the templates 9-ethyladenine, ametryn or terbutylazine. Monitoring the monomer disappearance by 1H-NMR showed that the presence of templates such as 9-ethyladenine significantly retarded the polymerisation but otherwise had minor influence on the relative reactivity of the monomers. The latter appeared in most cases to be stoichiometrically incorporated into the polymer. The signals arising from the template experienced little or no shift in the early stage of the polymerisation, although pronounced broadening was observed. By delaying the addition of the template, it was observed that binding sites with high selectivity could be induced more than one hour after the gel point of the system had been passed. Finally, the results of post-polymerisation curing on the dry and swollen state porosities and the recognition properties of terbutylazine imprinted polymers are reported. This treatment when performed at temperatures between 100-120°C, slightly enhanced the selectivity of the polymers, whereas at higher temperatures the polymers lost their molecular recognition properties. Swollen state porosity derived from inverse size exclusion chromatography (ISEC) revealed an interesting sharpening of the pore size distribution for the imprinted compared to the non-imprinted polymers.

[Comparison of 99m Tc-HMPAO-labeled leukocytes and 99m Tc-nanocolloid in osteomyelitis]

Six patients with proven or suspected osteomyelitis were studied with both 99mTc-HMPAO-labelled leukocytes and 99mTc-nanocolloid. In all cases the findings of both procedures were in good agreement. In 3 patients there was markedly increased accumulation of labelled cells and colloid, respectively. Two patients showed slightly increased accumulation of both agents and in one patient the finding was (correctly) negative. Further studies are necessary to determine whether or not colloid scintigraphy might replace the time-consuming leukocyte scintigraphy.