Improved method for the determination of endocrine-disrupting chemicals in urine of school-age children using microliquid-liquid extraction and UHPLC-MS/MS

Risk assessment of food contact materials

Bisphenol A (BPA) is authorised for use as a chemical compound for the production of plastic food contact materials (FCMs) under Regulation (EU) No 10/2011. But according to requirements of the Regulation (EU) No 2018/213, BPA has been banned in the manufacture of polycarbonate drinking cups or feeding bottles intended for infants and young children. Food has been identified as the main source of human exposure to BPA, followed by dermal absorption, air and dust inhalation, revealing ubiquitous and continuous contact with BPA. Considering that BPA is able to enter the food chain through the migration from food packaging into foodstuffs, assessment of dietary exposure is necessary for accurate estimations and identification of potential exposure from food sources. In 2015, EFSA set a temporary tolerable daily intake (TDI) for BPA of 4 μg/kg body weight (bw) per day and concluded that no health concern from BPA exposure for any age group was to be expected. In 2023, EFSA has re-evaluated BPA safety and the new TDI was reduced by a factor of 20,000 resulting in a TDI of 0.2 ng/kg bw per day. In this case, the CEP Panel concluded that there is a health concern from dietary exposure to BPA. Amongst others, the BfR identified several points of criticism which, in the opinion of the BfR, call into question the risk assessment carried out by EFSA. The BfR derived a TDI of 200 ng/kg bw per day and suggests taking this into account for risk assessment. In the proposed EU-FORA programme, the fellow had the opportunity to gain experience in the exposure assessment and then integrate the data together with the BfR hazard assessment to perform a comprehensive risk assessment. As second objective of the work programme, the fellow was in charge of performing a toxicokinetic analysis in an attempt to correlate external exposure with urinary BPA levels.

Levels of Bisphenol A and its analogs in nails, saliva, and urine of children: a case control study

Introduction

A growing number of studies link the increase in overweight/obesity worldwide to exposure to certain environmental chemical pollutants that display obesogenic activity (obesogens). Since exposure to obesogens during the first stages of life has been shown to have a more intense and pronounced effect at lower doses, it is imperative to study their possible effects in childhood. The objective here was to study the association of Bisphenol A (BPA) and 11 BPA analogs in children, using three biological matrices (nails, saliva and urine), and overweight and obesity (n = 160).

Methods

In this case-control study, 59 overweight/obese children and 101 controls were included. The measuring of Bisphenols in the matrices was carried out by ultra-high performance liquid chromatography coupled with triple quadrupole tandem mass spectrometry (UHPLC-MS/MS). Logistic regression was used to study the association between overweight/obesity and Bisphenol exposure.

Results

The results suggested that BPF in nails is associated with overweight/ obesity in children (OR:4.87; p = 0.020). In saliva, however, the highest detected concentrations of BPAF presented an inverse association (OR: 0.06; p = 0.010) with overweight/obesity. No associations of statistical significance were detected between exposure to BPA or its other analogs and overweight/obesity in any of the biological matrices.

Human nails as a valuable noninvasive alternative for estimating exposure to parabens

Exposure of human to parabens (commonly used preservatives) is inevitable due to their extensively applied in numerous consumer products. Thus, a reliable noninvasive matrix reflecting long-term exposure to parabens is essential for human biomonitoring study. Human nails are potentially a valuable alternative for measuring intergrated exposure to parabens. In this work, we collected 100 paired nail and urine samples from university students in Nanjing, China, and measured simultaneously for six parent parabens and four metabolites. Methylparaben (MeP), ethylparaben (EtP), and propylparaben (PrP) were three predominant paraben analogue in both matrices, with the median concentrations being 12.9, 0.753, and 3.42 ng/mL in urine, and 1540, 154, and 961 ng/g in nail, respectively, while 4-hydroxybenzoic acid (4-HB) and 3,4-dihydroxybenzoic acid (3,4-DHB) were the most abundant metabolites (median values of 143 and 35.9 ng/mL, respectively) in urine. Gender-related analysis suggested that females exposed to more higher parabens than males. Significantly positive correlations were found between levels of MeP, PrP, EtP, and OH-MeP (r = 0.54-0.62, p < 0.01) in paired urine and nail samples. Our result here suggests that human nails, as an emerging biospecimen, are a potentially valuable biological matrix to evaluate human long-term exposure to parabens.

Presence of Parabens in Different Children Biological Matrices and Its Relationship with Body Mass Index

Parabens have been accepted almost worldwide as preservatives by the cosmetic, food, and pharmaceutical industries. Since epidemiological evidence of the obesogenic activity of parabens is weak, the aim of this study was to investigate the association between parabens exposure and childhood obesity. Four parabens (methylparaben/MetPB, ethylparaben/EthPB, propylparaben/PropPB, and butylparaben/ButPB) were measured in 160 children's bodies between 6 and 12 years of age. Parabens measurements were performed with ultrahigh-performance liquid chromatography coupled with tandem mass spectrometry (UHPLC-MS/MS). Logistic regression was used to evaluate risk factors for elevated body weight associated with paraben exposure. No significant relation was detected between children's body weight and the presence of parabens in the samples. This study confirmed the omnipresence of parabens in children's bodies. Our results could be a basis for future research about the effect of parabens on childhood body weight using nails as a biomarker due to the ease of its collection and its non-invasive character.