Biomonitoring of PFOA, PFOS and PFNA in human milk from Czech Republic, time trends and estimation of infant's daily intake.

BACKGROUND: Perfluoralkylated substances (PFASs) are persistent and bioaccumulative environmental contaminants. They are included on the list of emergent compounds monitored in the frame of HBM4EU project. OBJECTIVES: To analyze PFASs levels in human milk samples collected in the period 2006 through 2017, to follow their time trends, to assess the PFASs exposure in breastfed infants, to calculate the daily intake of PFASs and to compare it with the tolerable daily/weekly) intakes and to quantify risk from exposure using the hazard quotient and hazard index approach. MATERIAL AND METHODS: A broad spectrum of PFASs were analyzed by means of UHPLC-MS/MS in primipara human milk samples collected in four consecutive time periods 2006, 2010/11, 2014, and 2017; N = 46, 183, 164 and 232, respectively. Mothers living in urban and suburban residences were recruited after their delivery at maternity hospitals, and milk samples were taken within 2 and 8 weeks after delivery. The questionnaire was focused on possible sources of exposure, dietary habits and lifestyle. RESULTS: Only perfluorooctane sulfonate (PFOS) and perfluorooctanoid acid PFOA (in 2017, also perfluorononanoic acid (PFNA)) were quantified in more than 90% of analyzed human milk samples. In all sampling periods, the levels of PFOA were higher than those of PFOS (p < 0.05). A significant downward temporal trend (p < 0.001) was observed for both PFOA and PFOS levels. The median concentrations in sampling years 2006, 2010/11, 2014, and 2017 were 0.075, 0.059, 0.035, and 0.023 ng/mL for PFOA and 0.045, 0.031, 0.029, and 0.020 ng/mL for PFOS, respectively. In 2017, PFNA was also quantified in 99% of samples with the median concentration of 0.007 ng/mL. The levels of PFASs correlated with maternal sea fish consumption. No maternal age-related relationship was observed. Using the tolerably daily intake (TDI) values for PFOS and PFOA set by the European Food Safety Authority (EFSA) in 2008, the calculated daily intakes from breastfeeding were clearly below these limits. Using the new, more conservative EFSA Provisional Tolerably Weekly Intake (PTWI) values set in 2018, we demonstrated a considerable exceedance of PTWI, with a hazard index above 1. CONCLUSION: Significant time-related decreasing trends in the PFOS and PFOA levels in human milk were observed. Nevertheless, the body burden of infants from breastfeeding might pose an enhanced health risk to infants when the current PTWI values are applied. These findings strongly support the present EU efforts to phase out PFOA, its salts and PFOA related compounds. Since PFOS exposure there has still been widely detected despite PFOS usage reduction measures, the major exposure routes should be further monitored and, if possible, eliminated.

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.

Urinary Cadmium and Cotinine Levels and Hair Mercury Levels in Czech Children and Their Mothers Within the Framework of the COPHES/DEMOCOPHES Projects.

The COPHES/DEMOCOPHES twin project was performed in 2011-2012 in 17 European countries to harmonize all steps of the human biomonitoring survey. Urinary cadmium, cotinine, phthalate metabolites, and hair mercury were measured in children (N = 120, 6-11 years) and their mothers of reproductive age, living in urban or rural areas. Cadmium in mothers' and children's urine was detected at a geometric mean (GM) concentration 0.227 and 0.109 µg/L, respectively; 95th percentile (P95) was 0.655 and 0.280 µg/L in mothers and children, respectively. No age-related, education-related, or urban versus rural differences were observed within the frame of each population group. Cadmium urinary level in mothers was about twofold compared with children. Higher levels were obtained in all smoking mothers but not in occasionally smoking or mothers and children exposed to environmental tobacco smoke (ETS). Mercury values in mothers were significantly higher in urban than in rural populations but not in children. GM and P95 for mercury in children's hair were 0.098 and 0.439 µg/g and in mothers' hair were 0.155 and 0.570 µg/g. Concentrations for mercury in the Czech samples were lower than European average. Hair mercury increased significantly with consumption of fish or seafood and with number of amalgam tooth fillings (in children). A positive association was found with family educational level. No influence of age was observed. Urinary cadmium and hair mercury levels were lower than health-based guidelines with one exception. High levels of urinary cotinine were found in the 12 smoking mothers (GM approximately 500 µg/L); lower levels in occasionally smoking mothers, N = 11 (34.5 µg/L). The mean cotinine levels in nonsmoking mothers who reported daily exposure to ETS was 10.7 µg/L. A similar mean value (10.8 µg/L) was obtained in six children who had daily exposure to ETS. In children without exposure to ETS, the mean cotinine level was 1.39 µg/L urine. Cotinine in the urine of children demonstrates limited protection of the Czech children against exposure to ETS.

Case study: Possible differences in phthalates exposure among the Czech, Hungarian, and Slovak populations identified based on the DEMOCOPHES pilot study results.

OBJECTIVE: Phthalates and their metabolites are classified as endocrine modulators. They affect the hormonal balance in both children and adults. The aim of this publication was to compare the urinary levels of phthalate metabolites in selected populations of the Czech Republic (CZ), Slovakia (SK), and Hungary (HU) in relation to the sources of phthalate exposure identified by means of questionnaire (personal care products, floor and wall coverings, plastic toys, and some kinds of foods). METHODS: Data were obtained through the twin projects COPHES (COnsortium to Perform Human biomonitoring on a European Scale) and DEMOCOPHES (DEMOnstration of a study to COordinate and Perform Human biomonitoring on a European Scale) from 2009 to 2012. The target groups were children aged 6-11 years old and their mothers up to 45 years of age. The metabolites of phthalates (monomethyl phthalate (MMP), monoethyl phthalate (MEP), monobenzyl phthalate (MBzP), mono-cyclohexyl phthalate (MCHP), mono-(2-ethylhexyl) phthalate (MEHP), mono-(2-ethyl-5-hydroxyhexyl) phthalate (5OH-MEHP), and mono-(2-ethyl-5-oxohexyl) phthalate (5OXO-MEHP)) were analysed in first morning urine samples. After enzymatic glucuronide cleavage, the urine sample analyses were performed using ultra-high-performance liquid chromatography-electrospray ionization tandem mass spectrometry (UHPLC-ESI-MS/MS) in one laboratory that qualified in the External Quality Assessment exercises organised by COPHES. RESULTS: Significant differences in phthalate exposure between countries were revealed for children only but not for mothers. The concentrations of 5-OH-MEHP (P<0.001), 5OXO-MEHP (P<0.001), and their sum (P<0.001) were the highest in SK compared to CZ and HU. The health based guidance values for the sum of DEHP metabolites 5-OH MEHP and 5OXO-MEHP established by the German Commission for biomonitoring of 300 µg/L and 500 µg/L for women adults and children, respectively, were only exceeded in one mother and three boys. A significant difference was also found for MEP (P=0.0149), with the highest concentrations detected in HU. In all countries, the increasing frequency of using personal care products significantly elevated the concentrations of MEP. CONCLUSION: Some differences were observed between countries in the concentrations of individual urinary phthalate metabolites in children. However, the questionnaire results give no direct explanation for the differences between the countries except the variation in using personal care products.