Global survey of dioxin- and thyroid hormone-like activities in consumer products and toys.

BACKGROUND: Children and consumers are exposed to increasingly complex mixtures of known and as-yet-unknown toxic chemicals from toys and products. However traditional chemical analysis methods only evaluate a small number of chemicals at a time thereby restricting consumer awareness of the full range of potentially harmful chemicals in products. METHODS: We used high-throughput effect-based non-animal methods to investigate exposures to complex chemical mixtures of several kinds of brominated flame retardants (BFRs) for their dioxin- and thyroid hormone-like activities in various kinds of consumer products and toys from 26 different countries, on four continents (Africa, America, Asia and Europe) in combination with chemical analysis of various polybrominated flame retardants (BFRs) and their impurities (such as polyhalogenated PCDD/Fs and PBDD/Fs). RESULTS: We found high levels of polybrominated dibenzo-p-dioxins and dibenzofurans (PBDD/Fs) in toys and now, for the first time, also in consumer products that are manufactured from black plastics containing certain brominated flame retardants (BFRs). The presence of PBDD/PBDFs as well as other BFRs in various black plastic materials from additional countries as well as additional kinds of consumer products as confirmed by effect-based in vitro reporter gene DR CALUX and TTR-TRß CALUX assays as well as congener-specific chemical analysis. We compared total Toxicity Equivalent (TEQ) levels of PBDD/F-TEQs analysed by chemical analysis to by CALUX bioassay measured Biological equivalence (BEQ) concentrations (for further info see at ISO 23196, ISO, 2022). In the case of TBBPA, both chemical and TTR-TRß CALUX analysis measure direct the amount of TBBPA. Finally, the daily ingestion of 2,3,7,8-TCDD equivalents from PBDD/Fs-contaminated plastic toys by child mouthing habits have been related to our earlier study (Budin et al., 2020). CONCLUSIONS: Interaction of children with such contaminated plastics may significantly contribute to the daily uptake of dioxin- and thyroid hormone transport disrupting-like compounds. Effect-based bioassays for dioxin- and thyroid hormone-like activities are relevant to pick-out such complex mixtures of known and yet unknown (and therefore not regulated) substances for safer and more sustainable plastics. Low POPs Content Levels and other mechanisms set under the Basel and Stockholm Conventions are set far too high to prevent a significant flow of BFRs and PBDD/Fs into consumer products.

Hormone receptor activities of complex mixtures of known and suspect chemicals in personal silicone wristband samplers worn in office buildings.

Humans are exposed to increasingly complex mixtures of hormone-disrupting chemicals from a variety of sources, yet, traditional research methods only evaluate a small number of chemicals at a time. We aimed to advance novel methods to investigate exposures to complex chemical mixtures. Silicone wristbands were worn by 243 office workers in the USA, UK, China, and India during four work shifts. We analyzed extracts of the wristbands for: 1) 99 known (targeted) chemicals; 2) 1000+ unknown chemical features, tentatively identified through suspect screening; and 3) total hormonal activities towards estrogen (ER), androgen (AR), and thyroid hormone (TR) receptors in human cell assays. We evaluated associations of chemicals with hormonal activities using Bayesian kernel machine regression models, separately for targeted versus suspect chemicals (with detection ≥50%). Every wristband exhibited hormonal activity towards at least one receptor: 99% antagonized TR, 96% antagonized AR, and 58% agonized ER. Compared to men, women were exposed to mixtures that were more estrogenic (180% higher, adjusted for country, age, and skin oil abundance in wristband), anti-androgenic (110% higher), and complex (median 836 detected chemical features versus 780). Adjusted models showed strong associations of jointly increasing chemical concentrations with higher hormonal activities. Several targeted and suspect chemicals were important co-drivers of overall mixture effects, including chemicals used as plasticizers, fragrance, sunscreen, pesticides, and from other or unknown sources. This study highlights the role of personal care products and building microenvironments in hormone-disrupting exposures, and the substantial contribution of chemicals not often identifiable or well-understood to those exposures.

Paleotoxicity of petrogenic and pyrogenic hydrocarbon mixtures in sediment cores from the Athabasca oil sands region, Alberta (Canada).

Despite the economic benefits of the oil and gas industry in Northern Alberta, significant concerns exist regarding the impacts of increased oil production on the environment and human health. Several studies have highlighted increases in the concentrations of polycyclic aromatic compounds (PACs) and other hydrocarbons in the atmosphere, water, soil and sediments, plants, wildlife and fish in the Athabasca Oil Sands Region (AOSR) as a result of oil sands industrial activity. Sediment cores can provide information on the temporal trends of contaminants to the environment and provide important baseline information when monitoring data are absent. Here we combined analytical chemistry and a mammalian cell-based bioassay in dated lake sediment cores to assess paleotoxicity in freshwater systems in the AOSR. Sediment intervals were radiometrically dated and subsequently analysed for PACs. PAC extracts from select dated intervals were used in cell-based bioassays to evaluate their endocrine disrupting properties. We demonstrated spatial and temporal variability in the PAC composition of sediment cores around the AOSR with some of the highest concentrations of PACs detected near oil sands industrial activity north of Fort McMurray (AB) in La Saline Natural Area. Recent sediment had positive enrichment factors across most PAC analytes at this site with heavier pyrogenic compounds such as benz(a)anthracene/chrysene and benzofluoranthene/benzopyrene dominating. Our study is the first to link chemical analysis of sediment cores with biological effect assessments of endocrine activity showing feasibility of extending the usefulness of sediment cores in monitoring programs interested in complex mixture assessments. While we observed no spatial or temporal differences in ERα mediated signaling, AhR CALUX results mirrored those of the chemical analysis, demonstrating the utility of coupling biological effects assessments to historical reconstructions of contaminant inputs to the natural environment.

GR CALUX assay detects synthetic glucocorticoids in calf urine: a validation study.

Member States of the EU are required to monitor the use of pharmacologically active substances in food-producing animals. There is evidence, however, that the target-based approach currently applied in official monitoring plans might under-estimate the real incidence of growth promoter abuse in livestock. As demonstrated for sex hormones, the association of effect-oriented biological screening with chemical confirmatory techniques could be the best strategy in revealing the abuse of veterinary drugs. Here we demonstrate the reliability of a cell-based assay to screen calf urine samples for synthetic glucocorticoids. The validation included the most widely used synthetic drugs (flumethasone, dexamethasone, betamethasone, methylprednisolone and prednisolone) and was developed according to the Commission Decision 2002/657/EC, thus including the verification of cut-off level, the ß error, the specificity, ruggedness and stability. The study was carried out using prednisolone as representative substance at 5 ng mL-1 concentration. All blank and spiked urine fulfilled the EU criteria, moreover the method resulted in being specific and sound, and the analytes in urine were stable for at least 30 days. The assay results indicated its suitability for a qualitative analysis of calf urine samples. This method enabled the detection of low doses of synthetic glucocorticoids (GCs) in matrix (<2 ng mL-1 for flumethasone, dexamethasone, betamethasone; < 4 ng mL-1 for methylprednisolone; 5 ng mL-1 for prednisolone), with the possibility of detecting new or unknown molecules and cumulative effects of low-level mixtures with glucocorticoid bioactivity.

Intra- and interlaboratory calibration of the DR CALUX bioassay for the analysis of dioxins and dioxin-like chemicals in sediments.

In the Fourth National Policy Document on Water Management in The Netherlands, it is defined that in 2003, in addition to the assessment of chemical substances, special guidelines for the assessment of dredged material should be recorded. The assessment of dredged material is based on integrated chemical and biological effect measurements. Among others, the DR CALUX (dioxin responsive-chemically activated luciferase expression) bioassay has tentatively been recommended for inclusion in the dredged material assessment. To ensure the reliability of this bioassay, an intra- and interlaboratory validation study, or ring test, was performed, organized by the Dutch National Institute for Coastal and Marine Management (RIKZ) in cooperation with BioDetection Systems BV (BDS). The intralaboratory repeatability and reproducibility and the limit of detection (LOD) and quantification (LOQ) of the DR CALUX bioassay were determined by analyzing sediment extracts and dimethyl sulfoxide (DMSO) blanks. The highest observed repeatability was found to be 24.1%, whereas the highest observed reproducibility was calculated to be 19.9%. Based on the obtained results, the LOD and LOQ to be applied for the bioassay are 0.3 and 1.0 pM, respectively. The interlaboratory calibration study was divided into three phases, starting with analyzing pure chemicals. During the second phase, sediment extracts were analyzed, whereas in the third phase, whole sediments had to be extracted, cleaned, and analyzed. The average interlaboratory repeatability increased from 14.6% for the analysis of pure compound to 26.1% for the analysis of whole matrix. A similar increase in reproducibility with increasing complexity of handlings was observed with the interlaboratory reproducibility of 6.5% for pure compound and 27.9% for whole matrix. The results of this study are intended as a starting point for implementing the integrated chemical-biological assessment strategy and for systematic monitoring of dredged materials and related materials in the coming years.