Application of 96-well plate SPE method for analysis of persistent organic pollutants in low volume blood serum samples

Novel biomonitoring method for determining five classes of legacy and alternative flame retardants in human serum samples

Flame retardants (FRs) are ubiquitous in environment and biota and may pose harm to human health. In recent years, concern regarding legacy and alternative FRs has been intensified due to their widespread production and increasing contamination in environmental and human matrices. In this study, we developed and validated a novel analytical method for simultaneous determination of legacy and alternative FRs, including polychlorinated naphthalenes (PCNs), short- and middle-chain chlorinated paraffins (SCCPs and MCCPs), novel brominated flame retardants (NBFRs), and organophosphate esters (OPEs) in human serum. Serum samples were prepared by liquid-liquid extraction using ethyl acetate, and purified with Oasis® HLB cartridge and Florisil-silica gel columns. Instrumental analyses were carried out using gas chromatography-triple quadrupole mass spectrometry, high-resolution gas chromatography coupled with high-resolution mass spectrometry, and gas chromatography coupled with quadrupole time-of-flight mass spectrometry, respectively. The proposed method was validated for linearity, sensitivity, precision, accuracy, and matrix effects. Method detection limits for NBFRs, OPEs, PCNs, SCCPs, and MCCPs were 4.6 × 10^-4-8.6 × 10^-2, 4.3 × 10^-3-1.3, 1.1 × 10^-5-1.0 × 10^-4, 1.5, and 9.0 × 10^-1 ng/mL, respectively. Matrix spike recoveries ranged from 73%-122%, 71%-124%, 75%-129%, 92%-126%, and 94%-126% for NBFRs, OPEs, PCNs, SCCPs, and MCCPs, respectively. The analytical method was applied for detection of real human serum. CPs were the dominant FRs in serum, indicating CPs were widely presented in human serum and should be pay more attention for their health risk.

Validation of a Method Scope Extension for Simple Biomonitoring of 353 Pollutants in Serum Samples

Animals and humans are exposed to various residues that can have a detrimental impact on health, including carcinogenic potential, endocrine disruption, or fatal toxicity. The toxic burden can be evaluated in several biological samples, with serum being one of the preferred and most convenient options. In this study, we have applied and validated a method for detecting several hundred toxins in serum samples. This technique involved a single-step QuEChERS (quick, easy, cheap, effective, rugged, and safe) extraction followed by analysis using gas and liquid chromatography coupled with mass spectrometry. With this methodology, we could detect and quantify up to 353 compounds, including persistent organic pollutants (POPs), pesticides, pharmaceuticals, and rodenticides, using just 250 µL of serum. Among them, 92% could be measured at concentrations below 1.25 ng/mL, making it ideal for biomonitoring. We applied this method to samples collected from camels (n = 40) and humans (n = 25). We detected naproxen, ketoprofen, paracetamol, levamisole, and some POPs in these samples. This study validated the ability to simultaneously detect a broad range of compounds in small volumes of serum.

Accessibility investigation of semi-volatile organic compounds in indoor dust estimated by multi-ratio equilibrium passive sampling

Many semi-volatile organic compounds (SVOCs) accumulate in indoor dust, which serves as a repository for those compounds. The presence of SVOCs in indoor environments is of concern because many of them are suspected to have toxic effects. Total SVOC concentrations in the dust are generally used for exposure assessment to indoor contaminants, assuming that 100% of the SVOCs is accessible for human uptake. However, such an assumption may potentially lead to an overestimated risk related to dust exposure. We applied a multi-ratio equilibrium passive sampling (MR-EPS) for estimation of SVOC accessibility in indoor settled dust using silicone passive samplers and three particle size dust fractions, <0.25 mm, 0.25-0.5 mm, and 1-2 mm in dry and wet conditions. Equilibrations were performed at various sampler-dust mass ratios to achieve different degrees of SVOC depletion, allowing the construction of a desorption isotherm. The desorption isotherms provided accessible fractions (F_AS), equivalent air concentrations (C_AIR), dust-air partition coefficients (K_DUST-AIR) and organic carbon-air partition coefficients (K_OC-AIR). The highest F_AS were observed in the <0.25 mm dust fraction in wet conditions which is relevant for exposure assessment via oral ingestion. The highest C_AIR were estimated for several organophosphorus flame retardants (OPFRs), polycyclic aromatic hydrocarbons (PAHs) and synthetic musks. The logK_OC-AIR did not differ between dust particle sizes in dry and wet conditions but within compound groups, different relationships with hydrophobicity were observed. Equivalent lipid-based concentrations (C_L⇌DUST) calculated using available lipid-silicone partition coefficients (K_LIP-SIL) were compared with lipid-based concentrations (C_L) measured in human-related samples collected from Europeans. For hexachlorobenzene (HCB), C_L⇌DUST, and C_L were similar, indicating equilibrium attainment between environment and human samples. Lipid-based concentrations for persistent legacy contaminants were also similar but lower for PBDEs in human samples. Overall, accessibility estimation using MR-EPS in dust further contributes to human risk assessment.

Exposure to Novel Brominated Flame Retardants and Organophosphate Esters and Associations with Thyroid Cancer Risk: A Case-Control Study in Eastern China

Novel brominated flame retardant (NBFR) and organophosphate ester (OPE) exposure may engender adverse effects on human health. However, present epidemiological information regarding the effects of such exposure is limited and controversial. In this case-control study, 481 serum samples were collected from patients with thyroid cancer (n = 242) and healthy controls (n = 239) in Shandong Province, eastern China. The levels of NBFRs and OPEs, thyroid hormones, and serum lipid parameters were measured in all the participants. Pentabromotoluene, 2,3-dibromopropyl 2,4,6 tribromophenyl ether, decabromodiphenylethane (DBDPE), tris (2-chloroethyl) phosphate (TCEP), and triphenyl phosphate (TPP) were widely detected (detection frequency > 60%) in all the participants. A significantly high risk association was found between exposure of NBFRs and OPEs (namely 1,2,3,4,5-pentabromobenzene, DBDPE, tri-n-propyl phosphate, tri[(2R)-1-chloro-2-propyl] phosphate, tris (1,3-dichloro-2-propyl) phosphate, and tris (2-butoxyethyl) phosphate) and thyroid cancer in both males and females. In the females of the control group, TCEP levels exhibited a significantly positive association with thyroid-stimulating hormone and a negative association with triiodothyronine (T3), free triiodothyronine (FT3), and free thyroxine (FT4) levels. Weighted quantile sum regression evaluated the mixed effects of the compounds on thyroid hormones levels and thyroid cancer. As a result, TPP accounted for the majority of the T3, thyroxine, and FT3 amounts. Our results suggest that NBFR and OPE exposure contributes to alterations in thyroid function, thereby increasing thyroid cancer risk.

Addressing Exposome: An Innovative Approach to Environmental Determinants in Pediatric Respiratory Health

Developmental age is particularly vulnerable to impacts of environmental exposures. Until recent years, the field of environment and child health has predominantly relied on the study of single exposure-health effect relationships. The exposome is an emerging concept in epidemiology, encompassing the totality of the exposures experienced by an individual throughout life and their changes over time. This innovative approach provides a risk profile instead of individual predictors. Exposome research may contribute to better understand the complex relationships between environmental exposures and childhood respiratory health, in order to implement prevention strategies and mitigate adverse health outcomes across the life span. Indeed, an accurate assessment of the exposome needs several measurements as well as different technologies. High-throughput "omics" technologies may be promising tools to integrate a wide range of exposures. However, analyzing large and complex datasets requires the development of advanced statistical tools. This narrative review summarizes the current knowledge on exposome-based approaches in pediatric respiratory health. Further, it explores practical implementation, associated evidence gaps, research limitations and future research perspectives.