Exposure to Mixed Phthalates in Czech Preschool and School Children.

Knowledge of population exposure to phthalates based on the urinary metabolite levels is of the highest importance for health risk assessment. Such data are scarce in the Czech population. In the study conducted in 2016, six urinary phthalate metabolites were analysed in a total of 370 first morning urine samples of healthy children aged 5 and 9 years, namely mono(2-ethylhexyl) phthalate (MEHP), mono(2-ethyl-5-hydroxyhexyl) phthalate (5OH-MEHP), mono(2-ethyl-5-oxohexyl) phthalate (5oxo-MEHP), mono-benzyl phthalate (MBzP), mono-iso-butyl phthalate (MiBP), and mono-n-butyl phthalate (MnBP). The two latter mono-butyl phthalate isoforms dominated among all samples with geometric means of 63.0 µg/L (MnBP) and 44.1 µg/L (MiBP), followed by 5OH-MEHP (20.6 µg/L), 5oxo-MEHP (12.9 µg/L), MBzP (3.65 µg/L), and MEHP (2.31 µg/L). Daily intake (DI) of the parent phthalates was estimated using the creatinine-based model. The highest DI values were found for di-n-butyl phthalate (DnBP) (median 2.5 µg/kg bw/day; 95th percentile 7.8 µg/kg bw/day) and di-2-ethylhexyl phthalate (DEHP) (median 2.3 µg/kg bw/day; 95th percentile 8.9 µg/kg bw/day) in 5-year-old children. The tolerable daily intake (TDI) set by the European Food Safety Authority (EFSA) was exceeded in case of DnBP (in 1% of 9-year-olds and in 3% of 5-year-olds). Exposure risk was assessed based on hazard quotients calculation and cumulative approach for similar health effect. The combined exposure to four phthalates expressed by hazard index (HI) for reprotoxicity revealed exceeding of HI threshold in 14% of 5-year-olds and in 9% of 9-year-olds. These findings strongly support the need to reduce the burden of children by phthalates.

Assessment of vitamin D status in Czech children.

OBJECTIVE: Vitamin D deficiency is a global health problem. The aim of this study was to determine the proportion of Czech children with vitamin D deficiency and examine related factors. METHODS: The study subjects were 419 healthy children aged 5 and 9 years. Severe vitamin D deficiency was defined as a serum 25(OH)D level of < 25 nmol/L (3% of children), deficiency as that of 25-50 nmol/L (24% of children), insufficiency as that of 50-75 nmol/L (40% of children) and sufficiency as that of > 75 nmol/L (34% of children). RESULTS: Serum 25(OH)D levels varied mainly with season. The highest levels of 25(OH)D were reached in autumn (median: 79.0 nmol/L), followed by summer (median: 67.8 nmol/L) and winter (median: 56.0 nmol/L). The lowest median value (49.8 nmol/L) was detected in spring. CONCLUSION: Children with sufficiency 25(OH)D levels were more frequently exposed to the sun and exposed a larger part of their body to the sun while spending time outdoors. Levels of 25(OH)D were also associated with using vitamin D supplements within six weeks before sampling.

Perfluorinated alkylated substances and brominated flame retardants in serum of the Czech adult population.

Persistent organic pollutants, such as perfluorinated alkylated substances (PFASs) and brominated flame retardants (BFRs) are widespread in the environment and most of them are bioaccumulated in wildlife and humans. The present study is the first investigation to reveal the PFAS and BFR levels of serum samples in the adult population of the Czech Republic. Altogether, 300 serum samples from blood donors in four cities were examined. In all samples 19 PFASs and 33 BFRs, including some of their metabolites, were targeted. The analyses were performed using ultra high performance liquid chromatography coupled with tandem mass spectrometry or gas chromatography with mass spectrometry (according to the type of analyte). PFASs, with the carbon chain length C6 and higher, dominated in all samples. Perfluorooctanesulfonate (PFOS; median: 2.43ng/mL), perfluorooctanoic acid (PFOA; median: 0.756ng/mL), perfluorodecanoic acid (PFDA; median: 0.145ng/mL) and perfluorohexanesulfonate (PFHxS; median: 0.184ng/mL) were detected in 100% of samples. Perfluorononanoic acid (PFNA; median: 0.325ng/mL) and perfluoroundecanoic acid (PFUdA; median: 0.058ng/mL) in 99.7% and 96.0% of samples, respectively. We observed statistically significant associations (p<0.05) between selected PFAS concentrations and the locality, gender, age of donors and education level. None of the BFRs was detected above the LOQ in more than 9% of the samples. The most frequently detected representatives of this group were congeners of polybrominated diphenyl ethers, namely BDE-47 (in 8.7%; range: 0.496-5.44ng/g lipid weight (l.w.)), BDE-99 (in 6.0%; range: 0.706-9.46ng/g l.w.), BDE-153 (in 7.3%; range: 0.736-6.44ng/g l.w.) and BDE-209 (in 7.0%; range: 13.7-2693ng/g l.w.).

25 years of HBM in the Czech Republic.

Since 1991 a human biomonitoring network has been established in the Czech Republic as part of the Environmental Health Monitoring System, which was set out by the Government Resolution. During the last quarter-century, important data was obtained to characterize exposure to both children and adult populations to significant toxic substances from the environment, to development trends over time, to establish reference values and compare them with existing health-related values. Moreover, the saturation of population with several essential substances as selenium, zinc, copper or iodine has also been monitored. Development of analytical and statistical methods led to increase the capacity building, improvement of QA/QC in analytical laboratories and interpretation of results. The obtained results are translated to policy actions and are used in health risk assessment processes at local and national levels.