Bioaccessibility of PBDEs present in indoor dust: A novel dialysis membrane method with a Tenax TA® absorption sink

Abstract

Human uptake of flame retardants (FRs) such as polybrominated diphenyl ethers (PBDEs) via indoor dust ingestion is commonly considered as 100% bioaccessible, leading to potential risk overestimation. Here, we present a novel in vitro colon-extended physiologically-based extraction test (CE-PBET) with Tenax TA® as an absorptive "sink" capable to enhance PBDE gut bioaccessibility. A cellulose-based dialysis membrane (MW cut-off 3.5kDa) with high pH and temperature tolerance was used to encapsulate Tenax TA®, facilitating efficient physical separation between the absorbent and the dust, while minimizing re-absorption of the ingested PBDEs to the dust particles. As a proof of concept, PBDE-spiked indoor dust samples (n=3) were tested under four different conditions; without any Tenax TA® addition (control) and with three different Tenax TA® loadings (i.e. 0.25, 0.5 or 0.75g). Our results show that in order to maintain a constant sorptive gradient for the low MW PBDEs, 0.5g of Tenax TA® are required in CE-PBET. Tenax TA® inclusion (0.5g) resulted in 40% gut bioaccessibility for BDE153 and BDE183, whereas greater bioaccessibility values were seen for less hydrophobic PBDEs such as BDE28 and BDE47 (~60%). When tested using SRM 2585 (n=3), our new Tenax TA® method did not present any statistically significant effect (p>0.05) between non-spiked and PBDE-spiked SRM 2585 treatments. Our study describes an efficient method where due to the sophisticated design, Tenax TA® recovery and subsequent bioaccessibility determination can be simply and reliably achieved.

In Vitro Inhalation Bioaccessibility of Phthalate Esters and Alternative Plasticizers Present in Indoor Dust Using Artificial Lung Fluids

“…Similarly to gut bioaccessibility which is partly governed by a pollutant's physico-chemical properties including MW and log Kow 56,57 , inhalation bioaccessibility of PEs decreased against the increasing trend in MW and log Kow (> 4). DiBP pulmonary uptake was 15.5 % and 12 %, in Gamble's solution and ALF, respectively, whereas DnBP and HMW PEs were 10 % and < 5 % bioaccessible in both media, including DEHP and its alternatives, DEHT and DINCH (Fig 1).…”

Membrane Enhanced Bioaccessibility Extraction (MEBE) of hydrophobic soil pollutants – Using a semipermeable membrane for separating desorption medium and acceptor solvent

“…K EtOH,w denotes the partition coefficient between dry 100% ethanol and water. 415 For different sorptive sink approaches 9,11,16,17,38,39 , A/V ratios between sink surface area and desorption medium volume (A sink /V solution ) are plotted against their capacity ratio (m sink /m soil ). High A/V ratios provide fast mass transfer of analytes from the desorption solution to the sink, and high capacity ratios are crucial for samples with high K D values.…”

“…Figure 2.For different sorptive sink approaches9,11,16,17,38,39 , A/V ratios between sink surface area and…”

Oral bioavailability reveals an overestimation of the toxicity of polycyclic aromatic hydrocarbons in atmospheric particulate matter

“…Furthermore, several in vitro bioaccessibility approaches for dibenz(a,h)anthracene, DBahA; benzo(g,h,i)perylene, BghiP; and indeno(1,2,3-cd)pyrene, IP)(acenaphthene, Ace; fluorene, Fl; phenanthrene, Phe; anthracene, Ant; fluoranthene, Ft; pyrene, Pyr; benzo(a) anthracene, BaA; chrysene, Chry; benzo(e)pyrene, BeP; benzo(b) fluoranthene + benzo(j)fluoranthene, BbF + BjF; benzo(k)fluoranthene, BkF; benzo(a)pyrene, BaP; dibenz(a,h)anthracene, DBahA; benzo(g,h,i)perylene, BghiP; and indeno(1,2,3-cd)pyrene, IP organic compounds involved the use of sorption sinks (i.e. silicone sheet (Gao et al 2019b), Tenax TA® absorption sink (Li et al 2015;Kademoglou et al 2018b) and activated carbon sink (Collins et al 2013)) to capture pollutants as the same time they are released from matrix. The addition of a silicone sheet as sorption skin was observed to increase PAH bioaccessibility ratios up 44 − 67% (Gao et al 2019b).…”

“…However, in vitro oral bioaccessibility studies of organic pollutants in particulate matter were not found in the literature, while there were some studies applied to indoor/outdoor dust and soils for organic compounds, i.e. PAHs (Tang et al 2006;Kang et al 2011;Collins et al 2013;Li et al 2015;Kademoglou et al 2018a), organophosphate flame retardants (Quintana et al 2017), semi-volatile organic compounds (Raffy et al 2018), polychlorinated biphenyls (Wang et al 2013) and polybrominated diphenyl ethers (Yu et al 2011;Kademoglou et al 2018b;Gao et al 2019b). The stringent analytical requirements (target pollutants enrichment, due to the low levels; and pollutant isolation from the synthetic fluids matrix) for organic pollutant quantification in bioaccessible/bioavailable fractions might explain the scare information.…”