Xianyu Wang

Organophosphate and brominated flame retardants in Australian indoor environments: Levels, sources, and preliminary assessment of human exposure

Concentrations of nine organophosphate flame retardants (OPFRs) and eight polybrominated diphenyl ethers (PBDEs) were measured in samples of indoor dust (n = 85) and air (n = 45) from Australian houses, offices, hotels, and transportation (buses, trains, and aircraft). All target compounds were detected in indoor dust and air samples. Median ∑9OPFRs concentrations were 40 μg/g in dust and 44 ng/m3 in indoor air, while median ∑8PBDEs concentrations were 2.1 μg/g and 0.049 ng/m3. Concentrations of FRs were higher in rooms that contained carpet, air conditioners, and various electronic items. Estimated daily intakes in adults are 14000 pg/kg body weight/day and 330 pg/kg body weight/day for ∑9OPFRs and ∑8PBDEs, respectively. Our results suggest that for the volatile FRs such as tris(2-chloroethyl) phosphate (TCEP) and TCIPP, inhalation is expected to be the more important intake pathway compared to dust ingestion and dermal contact.

Development and validation of a multi-residue method for the analysis of brominated and organophosphate flame retardants in indoor dust

Flame retardants are associated to numerous adverse health effects, can accumulate in humans and have been used intensively worldwide. Recently, dust has been identified as a major human exposure route for flame retardants. The aim of this study was to develop a multi-residue method using a two-step SPE purification. It enabled us to effectively limit co-extracted matrix/interferets and therefore a simultaneous analysis of brominated and organophosphate flame retardants for indoor dust was achieved. The optimized method was validated according to standard protocol and achieved good accuracy and reproducibility (percent error ranged from -29% to 28%). Standard Reference Material (SRM) for dust was also analysed, and good agreement was found with reported brominated and organophosphate flame retardants (OPFRs) concentrations. The applicability of the validated method was demonstrated by the analysis of ten indoor dust samples from ten Australian homes. Overall 89% of the analytes were detected in these samples. The average concentrations of ∑OPFRs and ∑PBDEs in those samples were 41 and 3.6μg/g, respectively. Tris(2-butoxyethyl) phosphate and tris(2-chloroisopropyl) phosphate were the most abundant OPFRs, accounting for 57-92% ∑OPFRs, while decabromodiphenyl ether dominated the Polybrominated diphenyl ethers (PBDE) congeners contributing between 71-94% to the ∑PBDEs.

Urinary metabolites of organophosphate esters: Concentrations and age trends in Australian children

There is growing concern around the use of organophosphate esters (OPEs) due to their suspected reproductive toxicity, carcinogenicity, and neurotoxicity. OPEs are used as flame retardants and plasticizers, and due to their extensive application in consumer products, are found globally in the indoor environment. Early life exposure to OPEs is an important risk factor for childrens health, but poorly understood. To study age and sex trends of OPE exposures in infants and young children, we collected, pooled, and analysed urine samples from children aged 0-5years from Queensland, Australia for 9 parent OPEs and 11 metabolites. Individual urine samples (n=400) were stratified by age and sex, and combined into 20 pools. Three individual breast milk samples were also analysed to provide a preliminary estimate on the contribution of breast milk to the intake of OPEs. Bis(1-chloroisopropyl) phosphate (BCIPP), 1-hydroxy-2-propyl bis(1-chloro-2-propyl) phosphate (BCIPHIPP), bis(1,3-dichloroisopropyl) phosphate (BDCIPP), dibutyl phosphate (DBP), diphenyl phosphate (DPHP), bis(2-butoxyethyl) phosphate (BBOEP), bis(2-butoxyethyl) 3-hydroxyl-2-butoxyethyl phosphate (3OH-TBOEP), and bis(2-butoxyethyl) hydroxyethyl phosphate (BBOEHEP) were detected in all urine samples, followed by bis(methylphenyl) phosphate (80%), and bis(2-ethylhexyl) phosphate (BEHP, 20%), and bis(2-chloroethyl) phosphate (BCEP, 15%). Concentrations of tris(2-chloroethyl) phosphate (TCEP), BCEP, tris(2-ethylhexyl) phosphate (TEHP), and DBP decreased with age, while bis(methylphenyl) phosphate (BMPP) increased with age. Significantly higher concentrations of DPHP (p=0.039), and significantly lower concentrations of TEHP (p=0.006) were found in female samples compared to males. The estimated daily intakes (EDIs) via breastfeeding, were 4.6, 26 and 76ng/kg/day for TCEP, TBP and TEHP, respectively, and were higher than that via air and dust, suggesting higher exposure through consumption of breast milk.

Concentrations of organophosphate flame retardants and plasticizers in urine from young children in Queensland, Australia and associations with environmental and behavioural factors

&NA; In recent years, the production and usage volumes of organophosphate flame retardants (OPFRs) has increased substantially. Certain OPFRs are suspected reproductive toxins, carcinogenic, and neurotoxic. Insufficient information is available on human exposure pathways to these chemicals, particularly in Australia. We aim to assess the association between OPFR concentrations in the urine of children to environmental and behavioural risk factors. Concentrations of eight OPFRs and eleven metabolites were measured in the urine of 51 children, aged 3–29 months, in Southeast Queensland, Australia and compared to their behavioural and environmental risk factor data obtained by an online questionnaire. Of the 11 OPFR metabolites analysed, 55% were frequently detected in the majority (> 80%) of samples. The most frequently detected metabolite was bis(1,3‐dichloroisopropyl) phosphate (BDCIPP) (detected in 100% of samples), followed by 1‐hydroxy‐2‐propyl bis(1‐chloro‐2‐propyl) phosphate (BCIPHIPP) (96%), diphenyl phosphate (DPHP) (94%) and bis(1‐chloroisopropyl) phosphate (BCIPP) (86%). In multivariable modelling, age was positively associated with concentrations of bis(2‐butoxyethyl) phosphate (BBOEP) and negatively associated with concentrations of BCIPP and BCIPHIPP. Other non‐age related factors, including vacuuming frequency, hand‐washing frequency and presence and number of some electrical appliances in the home were also associated with concentrations of OPFR metabolites. HighlightsEight OPFRs and eleven metabolites were measured in the urine of Australian kids.Age was positively associated with BBOEP and negatively associated with BCIPP.Mouthing activities were associated with higher concentrations of TBOEP, and TPHP.Children living with window AC units had higher concentrations of BCIPHIPP and DBP.

Emissions of Selected Semivolatile Organic Chemicals from Forest and Savannah Fires

The emission factors (EFs) for a broad range of semivolatile organic chemicals (SVOCs) from subtropical eucalypt forest and tropical savannah fires were determined for the first time from in situ investigations. Significantly higher (t test, P < 0.01) EFs (μg kg-1 dry fuel, gas + particle-associated) for polycyclic aromatic hydrocarbons (∑13 PAHs) were determined from the subtropical forest fire (7,000 ± 170) compared to the tropical savannah fires (1,600 ± 110), due to the approximately 60-fold higher EFs for 3-ring PAHs from the former. EF data for many PAHs from the eucalypt forest fire were comparable with those previously reported from pine and fir forest combustion events. EFs for other SVOCs including polychlorinated biphenyl (PCB), polychlorinated naphthalene (PCN), and polybrominated diphenyl ether (PBDE) congeners as well as some pesticides (e.g., permethrin) were determined from the subtropical eucalypt forest fire. The highest concentrations of total suspended particles, PAHs, PCBs, PCNs, and PBDEs, were typically observed in the flaming phase of combustion. However, concentrations of levoglucosan and some pesticides such as permethrin peaked during the smoldering phase. Along a transect (10-150-350 m) from the forest fire, concentration decrease for PCBs during flaming was faster compared to PAHs, while levoglucosan concentrations increased.

Concentrations of Organophosphate Esters and Their Specific Metabolites in Food in Southeast Queensland, Australia: Is Dietary Exposure an Important Pathway of Organophosphate Esters and Their Metabolites?

There were several studies that measured organophosphate esters (OPEs) in foods to assess the dietary intake of OPEs but none has measured OPE metabolites (mOPEs) in the same samples. In this study, we measured the concentrations of OPEs and mOPEs in 87 food samples and in five tap water samples collected in Queensland, Australia belonging to eight food groups. Tris(2-chloroisopropyl) phosphate (TCIPP) (detection frequency (DF), 77%) and tributyl phosphate (TBP) (DF, 71%), were the most frequently detected OPEs, while dibutyl phosphate (DBP) (DF, 84%) and diphenyl phosphate (DPhP) (DF, 86%) were the most frequently detected mOPEs. Vegetables had the highest concentrations of both ∑9OPEs and ∑11mOPEs, with the mean concentrations of 2.6 and 17 ng/g wet weight. Compared with dust ingestion and inhalation, dietary intake was the most important exposure pathway for tris(2-chloroethyl) phosphate (TCEP) (4.1 ng/kg bw/day), TCIPP (25 ng/kg bw/day), and TBP (6.7 ng/kg bw/day), accounting for >75% of total intake. Furthermore, we found that the intakes of some mOPEs, that is, bis(1,3-dichloroisopropyl) phosphate (BDCIPP) and DPhP from diet were typically higher than that of their parent OPEs. Such high levels of mOPE intakes could interfere with the utilization of mOPEs as biomarkers for assessing OPE exposure and warrant further investigation.

Emission Factors for Selected Semivolatile Organic Chemicals from Burning of Tropical Biomass Fuels and Estimation of Annual Australian Emissions

This study reveals that open-field biomass burning can be an important source of various semivolatile organic chemicals (SVOCs) to the atmosphere including polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), and a range of pesticides. Emission factors (EFs) for 39 individual SVOCs are determined from burning of various fuel types that are common in tropical Australia. Emissions of PAHs are found to be sensitive to differences in combustion efficiencies rather than fuel types, reflecting a de novo formation mechanism. In contrast, revolatilization may be important for other SVOCs such as PCBs. On the basis of the EFs determined in this work, estimates of the annual emissions of these SVOCs from Australian bushfires/wildfires are achieved, including, for example, ∑PAHs (160 (min)-1100 (max) Mg), ∑PCBs (14-300 kg), ∑PBDEs (8.8-590 kg), α-endosulfan (6.5-200 kg), and chlorpyrifos (up to 1400 kg), as well as dioxin toxic equivalents (TEQs) of ∑dioxin-like-PCBs (0.018-1.4 g). Emissions of SVOCs that are predominantly revolatilized appear to be related to their use history, with higher emissions estimated for chemicals that had a greater historical usage and were banned only recently or are still in use.