BACKGROUND: Temporal trends of chemicals in the population are key to identifying changing sources of chemicals and determining the effectiveness of various legislative measures. OBJECTIVE: The present study focused on time comparisons to explore a possible decrease in PAH metabolite levels in the Czech population. Legislative measures occurred between sampling periods, including restricting smoking and the Air Protection Act. METHODS: Ten metabolites of PAHs were measured in urine samples collected in 2011-2012 from mothers and children from DEMOCOPHES-CZ study (N = 235) and in 2019-2020 from children, teenagers, and young adults from CELSPAC studies (N = 809). Multivariate linear regression, Kruskal-Wallis ANOVA, and Mann-Whitney test (MW) were used to investigate differences in OH-PAHs between periods, age categories, and exposure determinants. RESULTS: Median concentrations significantly decreased between 2011-2020 by 30-35% for 1-OH-NAP, 2-and 3-OH-FLUO, 85% for 1-OH-PHE, and 44% for 2/3-OH-PHE, while 2-OH-NAP increased by 29% in non-smoking adults. In children, median concentrations of all metabolites decreased by 10-51%, with 2-OH-NAP rising by 49%. Smokers showed the largest differences, with significant decreases of 46-59% in the median concentrations of 2-OH-NAP, 2/3-OH-PHE, 9-OH-PHE, and 1-OH-PYR, and 76-91% in OH-FLUOs, 1-OH-NAP, and 1-OH-PHE. Fish and offal consumption, season, locality, and type of cooking were significant factors associated with levels of OH-PAHs, explaining 4-9% of the variability. Smoking was the main contributor in 2011, explaining up to 45% variability; no difference was found between smokers and non-smokers in 2019. New reference values of OH-PAHs in urine were calculated for the Czech population. IMPACT: This study analyses the temporal trends of OH-PAHs in the population in the context of introduced legislative measures. In addition, it examines OH-PAH exposure in children, adolescents, and young adults in relation to lifestyle factors and establishes new reference values for polycyclic aromatic hydrocarbons that are important for public health decision-making. Biomonitoring over time is an essential tool for establishing new measures to protect public health. Created in BioRender. Komprdova, K. (2025) https://BioRender.com/u10q831 .

• Keywords
• Biomonitoring, Chemical exposure, Legislation, Polycyclic aromatic hydrocarbons,
• Publication type
• Journal Article MeSH

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.

• Keywords
• HBM4EU, exposure, human biomonitoring, phthalates, pollutants,
• Publication type
• Journal Article MeSH