Thomas Göen

GerES IV: phthalate metabolites and bisphenol A in urine of German children.

Urine samples from GerES IV were analysed for concentrations of the metabolites of DEHP (MEHP, 5OH-MEHP, 5oxo-MEHP, 5cx-MEPP, and 2cx-MMHP), DnBP and DiBP (MnBP and MiBP), BBzP (MBzP), DiNP (7OH-MMeOP, 7oxo-MMeOP and 7cx-MMeHP), and bisphenol A (BPA) to assess the exposure of German children on a representative basis. 600 morning urine samples had been randomly chosen from stored 1800 GerES IV samples originating from 3 to 14 year old children living in Germany. All metabolites could be detected in nearly all urine samples (N=599). Descriptive data analysis leads to mean concentrations of 5-OH-MEHP and 5-oxo-MEHP of 48microg/l and 37microg/l, respectively. The mean concentration of 7OH-MMeOP was 11microg/l. MnBP, MiNP, MBzP showed mean levels of 96microg/l, 94microg/l, and 18microg/l, respectively. The concentrations of the phthalate metabolites decreased with increasing age. Compared to German adults all children showed three to five fold higher urine concentrations than adults analysed in the same decade. For some children the levels of the sum of 5OH-MEHP and 5oxo-MEHP in urine were higher than the German human biomonitoring value (HBM I) of 500mcirog/l, which indicates that adverse health effects cannot be excluded for these subjects with sufficient certainty. The mean concentration of BPA in urine was 2.7microg/l. A rough calculation of the daily intakes on the basis of the measured concentrations in urine resulted in daily intakes two orders of magnitude lower than the current EFSA reference dose of 50microg/kgbw/d.

Efficient drug-delivery using magnetic nanoparticles — biodistribution and therapeutic effects in tumour bearing rabbits

UNLABELLED To treat tumours efficiently and spare normal tissues, targeted drug delivery is a promising alternative to conventional, systemic administered chemotherapy. Drug-carrying magnetic nanoparticles can be concentrated in tumours by external magnetic fields, preventing the nanomaterial from being cleared by metabolic burden before reaching the tumour. Therefore in Magnetic Drug Targeting (MDT) the favoured mode of application is believed to be intra-arterial. Here, we show that a simple yet versatile magnetic carrier-system (hydrodynamic particles diameter <200nm) accumulates the chemotherapeutic drug mitoxantrone efficiently in tumours. With MDT we observed the following drug accumulations relative to the recovery from all investigated tissues: tumour region: 57.2%, liver: 14.4%, kidneys: 15.2%. Systemic intra-venous application revealed different results: tumour region: 0.7%, liver: 14.4 % and kidneys: 77.8%. The therapeutic outcome was demonstrated by complete tumour remissions and a survival probability of 26.7% (P=0.0075). These results are confirming former pilot experiments and implying a milestone towards clinical studies. FROM THE CLINICAL EDITOR This team of investigators studied drug carrying nanoparticles for magnetic drug targeting (MDT), demonstrating the importance of intra-arterial administration resulting in improved clinical outcomes in the studied animal model compared with intra-venous.

Two-year follow-up biomonitoring pilot study of residents’ and controls’ PFC plasma levels after PFOA reduction in public water system in Arnsberg, Germany

Residents in Arnsberg, Germany, had been supplied by drinking water contaminated with perfluorooctanoate (PFOA). Biomonitoring data from 2006 evidenced that plasma PFOA concentrations of residents from Arnsberg were 4.5-8.3 times higher than those in reference groups. The introduction of charcoal filtration in July 2006 distinctly reduced PFOA concentrations in drinking water. Our one-year follow-up study showed a 10-20% reduction of PFOA plasma levels in residents from Arnsberg. Here we report the first results of the two-year follow-up study Arnsberg 2008. Additionally, the results of the two-year follow-up examination of the reference group are included. Paired plasma samples of 138 study participants (45 children, 46 mothers and 47 men) collected in 2006 and 2008 were considered in the statistical analyses. Within the two years plasma concentrations of PFOA, perfluorooctanesulfonate (PFOS) and perfluorohexanesulfonate (PFHxS) decreased in residents from Arnsberg and in control groups. The geometric means of PFOA plasma levels declined by 39% (children and mothers) and 26% (men) in Arnsberg and by 13-15% in the corresponding subgroups from the reference areas. For the population from Arnsberg a geometric mean plasma PFOA half-life of 3.26 years (range 1.03-14.67 years) was calculated. Our results confirm an ongoing reduction of the PFOA load in residents from Arnsberg. The decline of PFC levels in plasma of participants from the reference areas reflects the general decrease of human PFC exposure during the very recent years.

Organophosphate flame retardants and plasticizers in the air and dust in German daycare centers and human biomonitoring in visiting children (LUPE 3)

Organophosphate (OP) flame retardants and plasticizers are chemicals that have been used in large quantities in diverse consumer and building-related products for decades. In the present study, OPs were measured in paired indoor air and dust samples from 63 daycare centers in Germany. Moreover, the urine of 312 children between 22 and 80 months old who attend these facilities was analyzed for the presence of eight OP metabolites. Tri-(2-butoxyethyl)-phosphate (TBEP), tris-(2-chloroisopropyl) phosphate (TCPP), and tri-n-butyl-phosphate (TnBP) were present in low concentrations in indoor air, with median values of 49 ng/m(3), 2.7 ng/m(3), and 2.2 ng/m(3), respectively. In dust, median values of 225 mg/kg for TBEP, 2.7 mg/kg for TCPP, 1.1mg/kg for diphenyl(2-ethylhexyl) phosphate, and 0.5mg/kg for tri-phenyl-phosphate (TPhP) were found. In the urine samples, the metabolites di-phenyl-phosphate, di-n-butyl-phosphate, and di-(2-butoxyethyl)-phosphate had median values (95th percentiles) of 0.8 μg/l (4.0 μg/l), 0.2 μg/l (0.9 μg/l), and 2.0 μg/l (10.7 μg/l), respectively. A significant correlation was found between the dust and air samples in the levels of TnBP, tris(2-chloroethyl) phosphate (TCEP), and TBEP. For TCEP and TBEP, significant correlations were also observed between the levels in dust and the respective metabolite levels in urine. For TCEP, there was also a significant correlation between the concentration in indoor air and metabolite levels in urine. Based on the 95th percentile in dust and air in our study and data from residences in a previously published study, the daily intake of the most abundant OP (TBEP) is high (i.e., 3.2 μg/kg b.w.). This level is approximately 6.4% of the reference dose (RfD) established by the NSF, U.S.A. Overall, our study shows that daycare centers are indoor environments that contribute to OP exposure.

Trends of the internal phthalate exposure of young adults in Germany—Follow-up of a retrospective human biomonitoring study

The exposure of the general population to phthalates is of increasing public health concern. Variations in the internal exposure of the population are likely, because the amounts, distribution and application characters of the phthalate use change over time. Estimating the chronological sequences of the phthalate exposure, we performed a retrospective human biomonitoring study by investigating the metabolites of the five most prominent phthalates in urine. Therefore, 24h-urine samples from the German Environmental Specimen Bank (ESB) collected from 240 subjects (predominantly students, age range 19-29 years, 120 females, 120 males) in the years 2002, 2004, 2006 and 2008 (60 individuals each), were analysed for the concentrations of mono-n-butyl phthalate (MnBP) as metabolite of di-n-butyl phthalate (DnBP), mono-iso-butyl phthalate (MiBP) as metabolite of di-iso-butyl phthalate (DiBP), mono-benzyl phthalate (MBzP) as metabolite of butylbenzyl phthalate (BBzP), mono-(2-ethylhexyl) phthalate (MEHP), mono-(2-ethyl-5-hydroxyhexyl) phthalate (5OH-MEHP), mono-(2-ethyl-5-oxohexyl) phthalate (5oxo-MEHP), mono-(2-ethyl-5-carboxypentyl) phthalate (5cx-MEPP) and mono-(2-carboxymethyl hexyl) phthalate (2cx-MMHxP) as metabolites of di(2-ethylhexyl) phthalate (DEHP), monohydroxylated (OH-MiNP), monooxidated (oxo-MiNP) and monocarboxylated (cx-MiNP) mono-iso-nonylphthalates as metabolites of di-iso-nonyl phthalates (DiNP). Based on the urinary metabolite excretion, together with results of a previous study, which covered the years 1988-2003, we investigated the chronological sequences of the phthalate exposure over two decades. In more than 98% of the urine samples metabolites of all five phthalates were detectable indicating a ubiquitous exposure of people living in Germany to all five phthalates throughout the period investigated. The medians in samples from the different years investigated are 65.4 (2002), 38.5 (2004), 29.3 (2006) and 19.6 μg/l (2008) for MnBP, 31.4 (2002), 25.4 (2004), 31.8 (2006) and 25.5 μg/l (2008) for MiBP, 7.8 (2002), 6.3 (2004), 3.6 (2006) and 3.8 μg/l (2008) for MBzP, 7.0 (2002), 5.6 (2004), 4.1 (2006) and 3.3 μg/l (2008) for MEHP, 19.6 (2002), 16.2 (2004), 13.2 (2006) and 9.6 μg/l (2008) for 5OH-MEHP, 13.9 (2002), 11.8 (2004), 8.3 (2006) and 6.4 μg/l (2008) for 5oxo-MEHP, 18.7 (2002), 16.5 (2004), 13.8 (2006) and 10.2 μg/l (2008) for 5cx-MEPP, 7.2 (2002), 6.5 (2004), 5.1 (2006) and 4.6 μg/l (2008) for 2cx-MMHxP, 3.3 (2002), 2.8 (2004), 3.5 (2006) and 3.6 μg/l (2008) for OH-MiNP, 2.1 (2002), 2.1 (2004), 2.2 (2006) and 2.3 μg/l (2008) for oxo-MiNP and 4.1 (2002), 3.2 (2004), 4.1 (2006) and 3.6 μg/l (2008) for cx-MiNP. The investigation of the time series 1988-2008 indicates a decrease of the internal exposure to DnBP by the factor of 7-8 and to DEHP and BzBP by the factor of 2-3. In contrast, an increase of the internal exposure by the factor of 4 was observed for DiNP over the study period. The exposure to DiBP was found to be stable. In summary, we found decreases of the internal human exposure for legally restricted phthalates whereas the exposure to their substitutes increased. Future investigations should verify these trends. This is of increasing importance since the European Commission decided to require ban or authorization from 1.1.2015 for DEHP, DnBP, DiBP and BzBP according to REACh Annex XIV.

Perfluorinated Compounds in Fish and Blood of Anglers at Lake Möhne, Sauerland Area, Germany

Perfluorinated compounds (PFCs) were measured in fish samples and blood plasma of anglers in a cross-sectional study at Lake Möhne, Sauerland area, Germany. Human plasma and drinking water samples were analyzed by solid phase extraction, high-performance liquid chromatography (HPLC), and tandem mass spectrometry (MS/MS). PFCs in fish fillet were measured by ion pair extraction followed by HPLC and MS/MS. PFOS concentrations in 44 fish samples of Lake Möhne ranged between 4.5 and 150 ng/g. The highest median PFOS concentrations have been observed in perches (median: 96 ng/g) and eels (77 ng/g), followed by pikes (37 ng/g), whitefish (34 ng/g), and roaches (6.1 ng/g). In contrast, in a food surveillance program only 11% of fishes at retail sale contained PFOS at detectable concentrations. One hundred five anglers (99 men, 6 women; 14-88 years old; median 50.6 years) participated in the human biomonitoring study. PFOS concentrations in blood plasma ranged from 1.1 to 650 μg/L (PFOA: 2.1-170 μg/L; PFHxS: 0.4-17 μg/L; LOD: 0.1 μg/L). A distinct dose-dependent relationship between fish consumption and internal exposure to PFOS was observed. PFOS concentrations in blood plasma of anglers consuming fish 2-3 times per month were 7 times higher compared to those without any fish consumption from Lake Möhne. The study results strongly suggest that human internal exposure to PFC is distinctly increased by consumption of fish from PFC-contaminated sites.

Determination of six hydroxyalkyl mercapturic acids in human urine using hydrophilic interaction liquid chromatography with tandem mass spectrometry (HILIC–ESI-MS/MS) ☆

Mercapturic acids are increasingly used as biomarkers for exposure to certain carcinogenic substances. Glycidol, ethylene oxide, propylene oxide, acrolein and 1,3-butadiene are important intermediates of toxicological concern used in the industrial production of various chemicals. The main urinary metabolites of these alkylating substances are hydroxyalkyl mercapturic acids. Therefore, we developed and validated an analytical method for the simultaneous determination of six hydroxyalkyl mercapturic acids in human urine after solid phase extraction. The mercapturic acids were separated using hydrophilic interaction liquid chromatography (HILIC) and quantified by tandem mass spectrometry using isotopically labelled internal standards. The developed method enables for the first time the determination of 2,3-dihydroxypropyl mercapturic acid (DHPMA), a metabolite of glycidol, in human urine. Additionally, the mercapturic acids of ethylene oxide (hydroxyethyl mercapturic acid, HEMA), propylene oxide (2-hydroxypropyl mercapturic acid, 2-HPMA), acrolein (3-hydroxypropyl mercapturic acid, 3-HPMA) as well as of 1,3-butadiene(3,4-dihydroxybutyl mercapturic acid, DHBMA and monohydroxy-3-butenyl mercapturic acid, MHBMA) can be determined. The limits of detection range from 3.0 to 7.0 μg/L. Intra- and inter-day precision was determined to range from 1% to 9%. Due to the good accuracy and precision and the low limits of detection the developed method is well suited for the determination of occupational exposure to alkylating substances as well as for the determination of background concentrations of the respective mercapturic acids in the general population.

Analysis of nitroaromatic compounds in urine by gas chromatography-mass spectrometry for the biological monitoring of explosives

Organic nitrocompounds are the most frequently used constituents of explosives and some of them have been evaluated to be highly toxic or even carcinogenic. Human contact with explosives may originate from a variety of sources, including occupational exposure during the production of ammunition as well as environmental exposure due to the contamination of soil and ground water reservoirs on former military production sites and training areas. This paper describes two gas chromatography-mass spectrometry-selected ion monitoring methods for the determination of twelve nitroaromatic compounds in urine (nitrobenzene, 1,2-dinitrobenzene, 1,3-dinitrobenzene, 1,3,5-trinitrobenzene, 2-nitrotoluene, 3-nitrotoluene, 4-nitrotoluene, 2,4-dinitrotoluene, 2,6-dinitrotoluene, 2,4,6-trinitrotoluene, 2-amino-4,6-dinitrotoluene, 4-amino-2,6-dinitrotoluene). The analytes are detectable in the lowest microg/l range, with imprecisions of 3-22% within series and 5-29% between series, depending on the compound of interest. Both procedures are rapid and relatively easy to perform and, therefore, are advantageous for the screening of occupationally or environmentally exposed persons. We analysed urine samples obtained from nine workers from an ammunition dismantling workshop and from twelve control persons. 2,4,6-Trinitrotoluene was detected in six samples at concentrations between 4 and 43 microg/l. The main metabolites of 2,4,6-trinitrotoluene, 4-amino-2,6-dinitrotoluene and 2-amino-4,6-dinitrotoluene, were found in a concentration range from 143 to 16,832 microg/l and from 24 to 5787 microg/l, respectively. Nonconjugated aminodinitrotoluenes were present as varying percentages of the total amount. 2,4-Dinitrotoluene and 2,6-dinitrotoluene were found in two samples (2-9 microg/l). Nitroaromatics were not detectable in urine specimens from control persons.

External quality assessment of human biomonitoring in the range of environmental exposure levels.

The number of human biomonitoring (HBM) applications for identifying and assessing the chemical exposure of the general population from the environment has distinctly increased during the last decade. An appropriate external quality assessment of the applied methods is essential to assure the accuracy and the comparability of HBM results. The international programme of the German External Quality Assessment Scheme (G-EQUAS) provides proficiency testing for most of the HBM parameters, which are commonly used for the assessment of the human exposure to chemicals. Since 1992, G-EQUAS provides intercomparison runs for biological monitoring parameters in the environmental exposure range twice a year, with a successive increase of parameter numbers. In round no. 45 (2010) 18 metals in blood, plasma and urine und 36 organic parameters in urine and plasma were provided. Additionally analyses of 4 haemoglobin adducts were offered. For each parameter, two samples with different concentrations of the biomarker were sent to the participants. The target values as well as the tolerance ranges were estimated on the basis of the results from reference laboratories. The successful participation was certified, if the participants results were within the tolerance ranges for both samples. The number of participants ranged from 3 to 37 international laboratories according to the individual parameter. The highest interest was observed for the detection of metals in blood, serum and urine, whereas only a few of the participants took part in the analyses of organophosphate metabolites and haemoglobin adducts. The rate of a successful participation ranged from 38 to 100%. Poor success rates were found for organophosphate metabolites, 1-naphthol and cotinine in urine. A training effect was observed for a group of laboratories which participated regularly in the analysis of organochlorinated compounds in serum.

Perfluorinated compounds in the vicinity of a fire training area--human biomonitoring among 10 persons drinking water from contaminated private wells in Cologne, Germany.

In Cologne, Germany, increased concentrations of perfluorinated compounds (PFC) have been observed in two private wells used for drinking water purposes. Both wells are located in the vicinity of a fire training area. Use of well water as a source of drinking water was prohibited by the Public Health Department of the City of Cologne. A human biomonitoring (HBM) survey was performed among all persons, who consumed water from these private wells (N=10). PFC concentrations in water of the private wells and in blood samples were analysed by tandem mass spectrometry with electrospray ionization (LC-ESI-MS/MS). Repeated water analyses (seven measurements between December 2009 and November 2010) indicated a decrease of PFOS from 8.35 to 1.60 μg/l, (PFHxS: 2.36-0.15 μg/l; PFOA: 0.16-0.03 μg/l) in one private well. Although situated close together, PFC-concentrations in the other private well were significantly lower. PFOS-concentrations in blood samples of private well water consumers ranged from 4.8 to 295 μg/l (PFHxS: 12.1-205 μg/l; PFOA: 4.0-18 μg/l). Although no data on the formulation of the firefighting foams applied on the fire training area is available, firefighting foams are supposed to be the most likely source of contamination. These findings give reason to track systematically the application of PFC-containing firefighting foams in order to identify contaminations of surface, ground and drinking waters.