| 1. |
- Li, Li, et al.
(författare)
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Characterization of residential household dust from Shanghai by particle size and analysis of organophosphorus flame retardants and metals
- 2019
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Ingår i: Environmental Sciences Europe. - : Springer. - 2190-4707 .- 2190-4715. ; 31:1
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Tidskriftsartikel (refereegranskat)abstract
- Background: Physical and biological properties of dust particles might affect the availability and distribution of chemicals associated to indoor dust; however it has not been adequately examined. In this study, household dust from Shanghai was fractionated into five particle sizes and size distribution, morphology, surface area, organic matter, microorganisms, elemental composition, metals and organophosphorus flame retardants (OPFRs) compositions were characterized. Also, household dust samples from Stockholm that has previously been characterized were included in the analysis of OPFRs for comparison.Results: The respirable fraction had a yield of 3.3% in mass percentage, with a particle size of 2.22 +/- 2.04 mu m. As expected, both metals and OPFRs concentrations increased with decreased particle size. Al and Fe dominated (66-87%) followed by the concentrations of Zn (5-14%) and Ga (1.8-5%) of the sum of 16 metals in the dust. The concentrations of OPFRs in Shanghai dust ranged from 5.34 to 13.7 mu g/g (median: 7.21 mu g/g), compared to household dust from Stockholm that ranged from 16.0 to 28.3 mu g/g (median: 26.6 mu g/g). Tris(2-chloroisopropyl) phosphate (TCIPP) and tris(2-chloroethyl) phosphate (TCEP) dominated in Shanghai dust samples while tris(2-butoxyethyl) phosphate (TBOEP) dominated in dust from Stockholm homes.Conclusion: The results showed that mass percentage for each particle size fraction was not evenly distributed. Furthermore, the particle-bound microorganisms and OPFRs increased with decreased particle size, whereas metals had the highest concentrations at specific dust sizes. Therefore, it is essential to select the proper particle size in order to assess any specific human exposure study to indoor pollutants.
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| 2. |
- Weiss, Jana M., et al.
(författare)
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Daily intake of phthalates, MEHP, and DINCH by ingestion and inhalation
- 2018
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Ingår i: Chemosphere. - : Elsevier. - 0045-6535 .- 1879-1298. ; 208, s. 40-49
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Tidskriftsartikel (refereegranskat)abstract
- Phthalate esters, suspected endocrine disrupting chemicals, are used in a wide range of applications. Because phthalate esters are not covalently bound, they can easily leach into the indoor environment and associate to dust particles. Thus, exposure may occur through inhalation, ingestion, or contact with the skin. However, it is unclear to what degree indoor dust contributes to the daily intake of phthalate esters.This study investigates household dust as an exposure pathway for seven phthalate esters, the monoester MEHP, and the plasticizer DINCH. Household dust collected from children's sleeping rooms and from living rooms were analysed using gas and liquid chromatography tandem mass spectrometry. To compare two exposure pathways, different dust particle sizes were generated: a respirable fraction (<5 mu m) and an ingested particle fraction in the anticipated size range of skin adherence (<75 mu m). Modelling of dust inhalation and ingestion showed that the daily intake of dust-bound phthalate esters was likely to be 2 times (inhalation) to 12 times (ingestion) higher for 21-month-old children than for adults. These children's daily uptake of phthalate esters was 40-140 times higher through ingestion than inhalation. Furthermore, dust may be an exposure pathway for phthalate esters as well as for MEHP. Therefore, phthalate monoesters could be environmental contaminants of their own and need to be considered in health risk assessments. (C) 2018 Elsevier Ltd. All rights reserved.
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| 3. |
- Brits, Martin, et al.
(författare)
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Brominated and organophosphorus flame retardants in South African indoor dust and cat hair
- 2019
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Ingår i: Environmental Pollution. - : Elsevier BV. - 0269-7491 .- 1873-6424. ; 253, s. 120-129
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Tidskriftsartikel (refereegranskat)abstract
- Flame retardants (FRs), such as brominated flame retardants (BFRs) and organophosphorus flame retardants (OPFRs), are diverse groups of compounds used in various products related to the indoor environment. In this study concentrations of eight polybrominated diphenyl ethers (PBDEs), two alternative BFR5 and ten OPFRs were determined in indoor dust (n = 20) and pet cat hair (n = 11) from South Africa. The OPFRs were the major FRs, contributing to more than 97% of the total FR concentration. The median Sigma(10)OPFRs concentrations were 44,800 ng/g in freshly collected dust (F-dust), 19,800 ng/g in the dust collected from vacuum cleaner bags (V-dust), and 865 ng/g in cat hair (C-hair). Tris(1-chloro-2-propyl) phosphate (TCIPP) was the dominant OPFR in the dust samples with median concentrations of 7,010 ng/g in F-dust and 3,590 ng/g in V-dust. Tris(2-butoxyethyl) phosphate (TBOEP) was the dominant OPFR in C-hair, with a median concentration of 387 ng/g. The concentrations of Sigma 8PBDEs were higher in F-dust than in V-dust. BDE209 was the dominant BFR in all three matrices. Bis(2-ethylhexyl)-3,4,5,6-tetrabromo-phthalate (BEH-TEBP) and 2-ethylhexyl-2,3,4,5- tetrabromobenzoate (EH-TBB) showed notable contributions to the BFR profile in cat hair. A worst-case dust exposure estimation was performed for all analytes. The estimated TCIPP daily intake through dust ingestion was up to 1,240 ng/kg bw for toddlers. The results indicate that OPFRs are ubiquitous in South African indoor environment. Indoor dust is a major source of human exposure to environmental contaminants. This can for example occur through hand-to-mouth contact of toddlers, and is an important route of exposure to currently used FRs accumulated on dust particles. The presence of FRs, in particular high concentrations of OPFRs, suggests that children and indoor pet cats may have greater exposure to FRs than adults.
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| 4. |
- Brits, Martin, et al.
(författare)
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Comprehensive two-dimensional gas chromatography coupled to high resolution time-of-flight mass spectrometry for screening of organohalogenated compounds in cat hair
- 2018
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Ingår i: Journal of Chromatography A. - : Elsevier BV. - 0021-9673 .- 1873-3778. ; 1536, s. 151-162
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Tidskriftsartikel (refereegranskat)abstract
- The coupling of comprehensive two-dimensional gas chromatography with high-resolution time of-flight mass spectrometry offers the best separation efficiency combined with accurate mass measurements over a wide mass range. The tremendous power of this screening tool is illustrated by trace qualitative screening analysis of organohalogenated compounds (OHCs) in pet cat hair. Tentative identification was supported by mass spectral database searches and elemental formula prediction from the experimentally determined accurate mass data. This screening approach resulted in the first tentative identification of pentabromoethylbenzene, decabromodiphenyl ethane, hexabromocyclododecane, trisbromoneopentyl alcohol, tris(2-chloroethyl) phosphate and tris(2-chloroisopropyl)phosphate in the South African indoor environment. A total of seventy-two OHCs were identified in the samples and include known flame retardants, such as polybrominated diphenyl ethers, and legacy contaminants such as polychlorinated biphenyls and organochlorine, organophosphorous and pyrethroid pesticides. The results obtained from cat hair indicate that these pets are exposed to complex mixtures of OHCs and the detection of these compounds suggests that non-invasive cat hair samples can be used to model indoor exposure with reference to external deposition of OHCs present in the air and dust surrounding people. Toddlers share the same environment as pet cats and therefore also the same health risks.
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| 5. |
- Brits, Martin, et al.
(författare)
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Critical review of the analysis of brominated flame retardants and their environmental levels in Africa
- 2016
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Ingår i: Chemosphere. - : Elsevier BV. - 0045-6535 .- 1879-1298. ; 164, s. 174-189
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Forskningsöversikt (refereegranskat)abstract
- World-wide, the prevalence of brominated flame retardants (BFRs) is well documented for routine analysis of environmental and biological matrices. There is, however, limited information on these compounds in the African environment and insufficient information on the analytical approaches used to obtain data. This paper presents a review on BFR levels in the African environment and the various analytical methodologies specifically applied in Africa for polybrominated diphenyl ethers (PBDEs), polybrominated biphenyls and alternative-BFRs. The analyses include liquid sample preparation using liquid-liquid and solid phase extraction and solid sample preparation involving Soxhlet extraction, with ultrasound-assisted extraction increasingly being applied. Instrumental detection techniques were limited to gas chromatography coupled with electron capture detector and electron impact ionisation with single quadrupole mass spectrometers. Information on congener profile prevalence in indoor dust, soil, aquatic environment (water, sediment, and aquatic organisms), eggs, wastewater treatment plant compartments, landfills (leachate and sediment) and breast milk are presented. Although PBDEs were inconsistently detected, contamination was reported for all investigated matrices in the African environment. The manifestation in remote regions indicates the ubiquitous prevalence and long-range transport of these compounds. Levels in sediment, and breast milk from some African countries were higher than reported for Asia and Europe. Due to limited data or non-detection of alternative-BFRs, it is unclear whether banned formulations were replaced in Africa. Most of the data reported for BFR levels in Africa were obtained in non-African laboratories or in South Africa and formed the basis for our discussion of reported contamination levels and related methodologies.
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| 6. |
- Brits, Martin, et al.
(författare)
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Short-, medium-, and long-chain chlorinated paraffins in South African indoor dust and cat hair
- 2020
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Ingår i: Chemosphere. - : Elsevier BV. - 0045-6535 .- 1879-1298. ; 238
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Tidskriftsartikel (refereegranskat)abstract
- Polychlorinated n-alkanes or chlorinated paraffins (CPs) contain a magnitude of structural isomers and are categorized as short-chain (SCCPs), medium-chain (MCCPs), and long-chain (LCCPs) CPs, according to the carbon chain lengths. In this study the Sigma SCCPs, Sigma MCCPs, and Sigma LCCP concentrations are reported for South African indoor dust and pet cat hair. The median concentrations of the Sigma CPs (C-9-C-37) ranged from 33 to 663 mu g/g for freshly collected dust (FD), 36-488 mu g/g for dust collected from household vacuum cleaner bags (VD), and 1.2-15 mu g/g for cat hair (CH) samples. MCCPs were the dominant CP group, followed by SCCPs and LCCPs. The Sigma MCCP concentration ranged from 13 to 498 mu g/g in dust and 0.6-6.5 mu g/g in cat hair. SCCPs with shorter carbon chains and lower chlorine substitution were observed in cat hair. LCCPs with carbon chains > C(20)were detected in dust and hair samples, possibly indicating the use of wax grade LCCP formulations. Non-traditional Kendrick mass defect plots were used to obtain information on the magnitude of CPs and provide evidence of possible interfering compounds. This is the first report on the occurrence of SCCPs, MCCPs, and LCCPs in the South African indoor environment.
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| 7. |
- Dracheva, Elena, et al.
(författare)
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In Silico Identification of Potential Thyroid Hormone System Disruptors among Chemicals in Human Serum and Chemicals with a High Exposure Index
- 2022
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Ingår i: Environmental Science and Technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 56:12, s. 8363-8372
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Tidskriftsartikel (refereegranskat)abstract
- Data on toxic effects are at large missing the prevailing understanding of the risks of industrial chemicals. Thyroid hormone (TH) system disruption includes interferences of the life cycle of the thyroid hormones and may occur in various organs. In the current study, high-throughput screening data available for 14 putative molecular initiating events of adverse outcome pathways, related to disruption of the TH system, were used to develop 19 in silico models for identification of potential thyroid hormone system-disrupting chemicals. The conformal prediction framework with the underlying Random Forest was used as a wrapper for the models allowing for setting the desired confidence level and controlling the error rate of predictions. The trained models were then applied to two different databases: (i) an in-house database comprising xenobiotics identified in human blood and ii) currently used chemicals registered in the Swedish Product Register, which have been predicted to have a high exposure index to consumers. The application of these models showed that among currently used chemicals, fewer were overall predicted as active compared to chemicals identified in human blood. Chemicals of specific concern for TH disruption were identified from both databases based on their predicted activity.
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| 8. |
- Engelhardt, A. Josefin, 1992-, et al.
(författare)
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Anthropogenic Organic Contaminants Analysed in Human Blood and Combined Risk
- 2023
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Ingår i: Exposure and Health. - : Springer Science and Business Media LLC. - 2451-9766 .- 2451-9685. ; 15:3, s. 551-565
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Forskningsöversikt (refereegranskat)abstract
- The number of chemicals in the anthroposphere is increasing and some of them end up in humans. A literature search was made to assess which anthropogenic organic contaminants (OCs) that have been analysed in blood from the general population. The reviewed articles were used to create a database of studies [human blood database (HBDB), containing 559 OCs] reporting blood analyses made worldwide. All studies analysing blood from the Swedish population were compiled into a second database [Swedish exposure database (SEDB), containing 166 OCs] listing blood concentrations of OCs. Data from the SEDB showed decreasing levels of regulated chemicals in blood over time, indicating that regulation had made an impact. The Hazard Index (HI) approach was used as a qualitative mixture risk assessment of the OCs with established human biomonitoring guidance values (HBM-GVs) and blood levels in the SEDB. Nine HBM-GVs were found and the HI of the corresponding OCs/groups of OCs showed that a risk of adverse effects in the general population could not be excluded, which is a cause for concern considering that only a fraction of the analysed OCs in the SEDB were included. This study presents the OCs identified in human blood and concentration time trends. The study highlights the lack of HBM-GVs needed for mixture risk assessments to assess the combined risk of chemical exposure to the general population.
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| 9. |
- Gustafsson, Åsa, 1975-, et al.
(författare)
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Estimated daily intake of per- and polyfluoroalkyl substances related to different particle size fractions of house dust
- 2022
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Ingår i: Chemosphere. - : Pergamon Press. - 0045-6535 .- 1879-1298. ; 303:Pt 2
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Tidskriftsartikel (refereegranskat)abstract
- Indoor environmental pollutants are a threat to human health. In the current study, we analysed 25 per- and polyfluoroalkyl substances (PFASs) in seven different size fraction of house dust including the two relevant for exposure via ingestion and inhalation. The highest PFAS concentration is found in the inhalable particulate fraction which is explained by the increased surface area as the particulate's sizes decrease. The estimated daily intake (EDI) of the individual PFAS and exposure pathways were calculated for children and adults. In addition, the total EDI for PFOA and its precursors was estimated. The polyfluoroalkyl phosphoric acid diesters (diPAP), followed by PFOA and PFHxA fluortelomer, showed the highest concentrations of PFAS analysed. The cumulative EDI of PFAS for children was 3.0 ng/kg bw per day, a worst-case scenario, which is 17 times higher than the calculated EDI for adults. For children, ingestion of dust was found to result in 800 times higher PFOA exposure than via inhalation. The contribution from PFOA precursors corresponded to only 1% of the EDI from dust indicating PFOA as the main source of exposure. The EDI's of PFOA and PFOS from dust were lower than the calculated EDI's from food ingestion reported by the Swedish Food Agency. Our data indicate that the EDI for the sum of four PFASs: PFOA, PFNA, PFHxS and PFOS from dust intake alone is close to the established tolerable weakly intake of 4.4 ng/kg bw in children, set by European Food Safety Authority (EFSA) in 2020. The combined EDI levels PFOA and PFOS from both dust and food exceeded the EFSA TWI for both children and adults. This study demonstrates that dust is a relevant exposure pathway for PFAS intake and that analysis of relevant particle size fractions is important for evaluation of dust as an exposure pathway.
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| 10. |
- Hamers, Timo, et al.
(författare)
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Transthyretin-Binding Activity of Complex Mixtures Representing the Composition of Thyroid-Hormone Disrupting Contaminants in House Dust and Human Serum
- 2020
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Ingår i: Journal of Environmental Health Perspectives. - 0091-6765 .- 1552-9924. ; 128:1
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: House dust contains many organic contaminants that can compete with the thyroid hormone (TH) thyroxine (T-4) for binding to transthyretin (TTR). How these contaminants work together at levels found in humans and how displacement from TTR in vitro relates to in vivo T-4-TTR binding is unknown. OBJECTIVES: Our aims were to determine the TTR-binding potency for contaminant mixtures as found in house dust, maternal serum, and infant serum; to study whether the TTR-binding potency of the mixtures follows the principle of concentration addition; and to extrapolate the in vitro TTR-binding potency to in vivo inhibition levels of T-4-TTR binding in maternal and infant serum. METHODS: Twenty-live contaminants were tested for their in vitro capacity to compete for TTR-binding with a fluorescent FITC-T-4 probe. Three mixtures were reconstituted proportionally to median concentrations for these chemicals in house dust, maternal serum, or infant serum from Nordic countries. Measured concentration-response curves were compared with concentration-response curves predicted by concentration addition. For each reconstituted serum mixture, its inhibitor-TTR dissociation constant (K-i) was used to estimate inhibition levels of T-4-TTR binding in human blood. RESULTS: The TTR-binding potency of the mixtures was well predicted by concentration addition. The similar to 20% inhibition in FITC-T-4 binding observed for the mixtures reflecting median concentrations in maternal and infant serum was extrapolated to 1.3% inhibition of T-4-TTR binding in maternal and 1.5% in infant blood. For nontested mixtures reflecting high-end serum concentrations, these estimates were 6.2% and 4.9%, respectively. DISCUSSION: The relatively low estimated inhibition levels at median exposure levels may explain why no relationship between exposure to TTR-binding compounds and circulating T-4 levels in humans has been reported, so far. We hypothesize, however, that 1.3% inhibition of T-4-TTR binding may ultimately be decisive for reaching a status of maternal hypothyroidism or hypothyroxinemia associated with impaired neurodevelopment in children.
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