Association of exposure to perfluoroalkyl substances (PFAS) and phthalates with thyroid hormones in adolescents from HBM4EU aligned studies

Monocarboxyoctyl phthalate is associated with platelet count: evidence from a large cross-sectional study

Introduction

Phthalates are environmental pollutants that are harmful to human health. However, the impact of phthalate on platelet count remains unclear. This study aimed to examine the correlation between five phthalate metabolites in urine and platelet count, as well as the impact of phthalate metabolite exposure on platelet count in adults.

Methods

This cross-sectional study included 11,409 non-pregnant participants aged >20 years using data available from the National Health and Nutrition Examination Survey (NHANES) between 2005 and 2018. Weighted logistic regression, restricted cubic spline (RCS) modeling, and weighted quantile sum (WQS) were employed to investigate the effects of mono-(carboxyisononyl) phthalate (MCNP), mono-(carboxyoctyl) phthalate (MCOP), mono-(3-carboxypropyl) phthalate (MCPP), mono-isobutyl phthalate (MiBP) and mono-isononyl phthalate (MNP) on platelet count.

Results

Logistic regression analysis suggested that MCOP [odds ratio (OR) (95% confidence interval CI) = 0.009 (0.002-0.036)] was significantly associated with the platelet count. Subgroup analysis showed negative correlations between MCOP and platelet count across all age and sex groups, and MCNP [OR (95% CI) = 0.083(0.013-0.552)] displayed a negative association with platelet count in females. MCOP had a nonlinear relationship with the platelet count in the RCS model. WQS also revealed that MCOP was related to platelet count.

Conclusion

Higher urinary MCOP level was associated with lower platelet count. Further investigation is necessary to substantiate these findings, considering the shortcomings of the NHANES study.

Quality assurance and quality control for human biomonitoring data-focus on matrix reference materials

Human biomonitoring (HBM) is an essential tool for making evidence-based policy decisions upon assessment of human exposure to pollutants. In contrast, the heterogeneity of data reliability across studies has been identified as a weakness in current HBM research. The scientific community is currently encountering measurement challenges due to gaps in the availability of quality assurance/quality control (QA/QC) tools. This article provides a summarised view on the availability of reference materials in human matrices such as hair, serum, blood, plasma, urine, and breast milk for selected groups of organic contaminants (e.g., pesticides, flame retardants, perfluorinated compounds, perchlorate, phthalates, phenols) and elements (e.g., mercury, arsenic, cadmium, chromium, lead, nickel, tin) of relevance to human health. The QA/QC situation of HBM measurement data with regard to laboratories' performance in proficiency testing schemes is also addressed, highlighting areas for improvement. Finally, the article uses the example of per- and polyfluoroalkyl substance analysis to illustrate QA/QC challenges specifically related to the HBM field.

Comprehensive analysis of transplacental transfer of environmental pollutants detected in paired maternal and cord serums

Prenatal exposure to hazardous environmental pollutants is a critical global concern due to their confirmed presence in umbilical cord blood, indicating the ability of pollutants to cross the placental barrier and expose the fetus to harmful compounds. However, the transplacental transfer efficiencies (TTEs) of many pollutants remain underexplored. Herein, we developed a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method to quantitatively analyze 91 environmental pollutants, including 13 bisphenols (BPs), 18 organophosphorus flame retardants (OPFRs), 7 brominated and other flame retardants (BFRs), 34 phthalates (PAEs), and 19 per- and polyfluoroalkyl substances (PFASs), in paired maternal and cord serums. 38 pollutants were detected in serums, including 5 BPs, 13 OPFRs, 2 BFRs, 4 PAEs, and 14 PFASs. Among the detected pollutants, bisphenol A (BPA) exists in the highest concentration (GM: 10.92 ng/mL in maternal serums and 12.66 ng/mL in cord serums), followed by tris(1,3-dichloro-2-propyl) phosphate (TDCIPP), perfluorooctanoic acid (PFOA), and 4,4'-(1,3-phenylenediisopropylidene) bisphenol (BPM). The exposure concentrations of the same type of pollutants were highly correlated between maternal and cord serums. Perfluorohexanoic acid (PFHxA) had the highest TTE value (5.526), while perfluorooctane sulfonic acid (PFOS) had the lowest (0.206). TTEs of PFOS and perfluorononanoic acid (PFNA) were higher for female newborns, whereas TTEs of perfluorohexadecanoic acid (PFHxDA) and perfluorodecane sulfonic acid (PFDS) were higher for male newborns. Moreover, the expression levels of the transplacental transporters ABCA1, ABCC2, ABCC3, ABCC4, ABCG1, SLCO3A1, and SLC22A3 were associated with the transplacental transfer of triphenyl phosphate (TPHP), TDCIPP, di-n-propyl phthalate (DPRP), perfluoroundecanoic acid (PFUnDA), perfluorotridecanoic acid (PFTrDA), and PFOS. Further research is essential to unveil the mechanisms involved in the transplacental transfer of environmental pollutants, ultimately boosting our comprehension of their impact on fetal health and birth outcomes.

PFAS in landfill leachate: Practical considerations for treatment and characterization

Per- and polyfluoroalkyl substances (PFAS) are widely used in consumer products and are particularly high in landfill leachate. The practice of sending leachate to wastewater treatment plants (WWTPs) is an issue for utilities that have biosolids land application limits based on PFAS concentrations. Moreover, landfills may face their own effluent limit guidelines for PFAS. The purpose of this review is to understand the most appropriate treatment technology combinations for mitigating PFAS in landfill leachate. The first objective is to understand the unique chemical characteristics of landfill leachate. The second objective is to establish the role and importance of known and emerging analytical techniques for PFAS characterization in leachate, including quantification of precursor compounds. Next, an overview of technologies that concentrate PFAS and technologies that destroy PFAS is provided, including fundamental background content and key operating parameters. Finally, practical considerations for PFAS treatment technologies are reviewed, and recommendations for PFAS treatment trains are described. Both pros and cons of treatment trains are noted. In summary, the complex matrix of leachate requires a separation treatment step first, such as foam fractionation, for example, to concentrate the PFAS into a lower-volume stream. Then, a degradation treatment step can be applied to the concentrated PFAS stream.

The impact of exposure to phthalates in thyroid function of children and adolescents: a systematic review

Phthalic acid esters, or phthalates, are plasticizers commonly used in the plastics industry and they are known for their endocrine-disrupting effects. Numerous epidemiological studies have been conducted to evaluate the effects of phthalate exposure on thyroid function, both in adults and children. However, there is still considerable debate surrounding this issue. Therefore, a systematic review was conducted to clarify existing evidence and offer new insights into the magnitude of this disruption and its potential consequences for children and adolescents' health. A comprehensive literature search using MEDLINE, Scopus, and Web of Science databases was performed. The inclusion criteria for the studies were the determination of regression coefficients between phthalates concentrations and thyroid levels, in children and adolescents. The quality assessment of the included studies was performed using the Newcastle Ottawa Scale for longitudinal studies and the Critical Appraisal Checklist for Analytical Cross-Sectional Studies scale for cross-sectional studies. Seventeen studies were included in this review, involving a total of 5616 participants, with similar phthalate levels across the diverse studies. Significant positive correlations between T3 (total and free) levels and phthalate exposure were found, as well as persistent negative associations between total-T4 levels and phthalate exposure. On the contrary, associations found regarding TSH and free-T4 did not show a consistent pattern. Conclusion: This review gathered enough evidence to conclude that exposure to phthalates causes an increase in T3 (total and free) levels and a decrease in total-T4 levels, which is consistent with previous animal studies. These findings highlight the importance of minimizing contact with plasticizers and microplastics in the environment, guaranteeing the safety of food products for the health of children and adolescents.

Associations of per- and polyfluoroalkyl substances and heavy metals with blood lipid profiles in a representative sample of Korean adolescents

BACKGROUND

Previous studies on the associations of per- and polyfluoroalkyl substances (PFASs) and heavy metals with lipid profiles among adolescents have been scarce. We sought to investigate the associations of PFASs and heavy metals with blood lipid levels in a representative sample of Korean adolescents.

METHODS

Data from the Korean National Environmental Health Survey (2018-2020) were used. Concentrations of PFASs [perfluorooctanoic acid (PFOA), perfluorooctane sulfonic acid (PFOS), perfluorohexane sulfonic acid, perfluorononanoic acid (PFNA), and perfluorodecanoic acid (PFDeA)], lead, and mercury were measured in serum, whole blood, and urine samples, respectively. Linear regression, Bayesian kernel machine regression (BKMR), and k-means clustering analyses were employed to evaluate the associations between pollutants and lipid levels.

RESULTS

In the linear regression analyses, PFOA levels were associated with higher low-density lipoprotein cholesterol (LDL-C) levels; PFOS with higher total cholesterol (TC) levels; PFNA with higher TC, LDL-C, and non-high-density lipoprotein cholesterol (non-HDL-C) levels; PFDeA with higher TC, LDL-C, non-HDL-C, and high-density lipoprotein cholesterol levels; and mercury with higher TC and non-HDL-C levels. The BKMR analysis revealed that the PFAS and heavy metal mixture was associated with higher LDL-C levels (1.8% increase in LDL-C at the 75th percentile of all PFAS and heavy metal concentrations compared to their median values, 95% credible interval: 0.5, 3.1), primarily driven by the effect of PFDeA. Compared to individuals in the low pollutant exposure cluster (geometric mean levels of PFOA, PFOS, PFHxS, PFNA, PFDeA, lead, and mercury were 2.7 μg/L, 6.2 μg/L, 1.6 μg/L, 0.7 μg/L, 0.4 μg/L, 0.8 μg/dL, and 0.3 μg/L, respectively), those in the high pollutant exposure cluster (5.1 μg/L, 10.7 μg/L, 3.7 μg/L, 1.3 μg/L, 0.6 μg/L, 0.9 μg/dL, and 0.4 μg/L, respectively) demonstrated higher TC levels (2.5% increase in TC, 95% confidence interval: 0.1, 5.0) in the k-means clustering analysis.

CONCLUSION

Due to the limitations of this study, such as its cross-sectional design, these results should be interpreted cautiously and confirmed in future studies before drawing implications for public health strategies aimed at promoting health during adolescence and later in life.

Phthalates and substitute plasticizers: Main achievements from the European human biomonitoring initiative HBM4EU

Phthalates and the substitute plasticizer DINCH belong to the first group of priority substances investigated by the European Human Biomonitoring Initiative (HBM4EU) to answer policy-relevant questions and safeguard an efficient science-to-policy transfer of results. Human internal exposure levels were assessed using two data sets from all European regions and Israel. The first collated existing human biomonitoring (HBM) data (2005-2019). The second consisted of new data generated in the harmonized "HBM4EU Aligned Studies" (2014-2021) on children and teenagers for the ten most relevant phthalates and DINCH, accompanied by a quality assurance/quality control (QA/QC) program for 17 urinary exposure biomarkers. Exposures differed between countries, European regions, age groups and educational levels. Toxicologically derived Human biomonitoring guidance values (HBM-GVs) were exceeded in up to 5% of the participants of the HBM4EU Aligned Studies. A mixture risk assessment (MRA) including five reprotoxic phthalates (DEHP, DnBP, DiBP, BBzP, DiNP) revealed that for about 17% of the children and teenagers, health risks cannot be excluded. Concern about male reproductive health emphasized the need to include other anti-androgenic substances for MRA. Contaminated food and the use of personal care products were identified as relevant exposure determinants paving the way for new regulatory measures. Time trend analyses verified the efficacy of regulations: especially for the highly regulated phthalates exposure dropped significantly, while levels of the substitutes DINCH and DEHTP increased. The HBM4EU e-waste study, however, suggests that workers involved in e-waste management may be exposed to higher levels of restricted phthalates. Exposure-effect association studies indicated the relevance of a range of endpoints. A set of HBM indicators was derived to facilitate and accelerate science-to-policy transfer. Result indicators allow different groups and regions to be easily compared. Impact indicators allow health risks to be directly interpreted. The presented results enable successful science-to-policy transfer and support timely and targeted policy measures.