Brominated Flame Retardants in Children's Room: Concentration, Composition, and Health Risk Assessment

Toxic trespassers: Uncovering phthalates and organophosphate flame retardants in children's rooms and their health implications

Organophosphate flame retardants (OPEs) and phthalates have garnered significant attention due to their widespread presence in indoor environments. Many recent investigations have reported extensive contamination of indoor dust, air, children's toys, and other environmental compartments with these chemicals. This research aimed to analyze OPEs and phthalates in air (PM10) and dust samples collected from the bedrooms of children (N = 30) residing in various households in Jeddah, Saudi Arabia. High mean levels (ng/g) of phthalates namely DEHP (1438600) and DnBP (159200) were found in indoor dust while TPhP (5620) was the major OPEs in indoor dust. Similarly, DEHP and DnBP were the predominant phthalates in PM10 samples, exhibiting mean levels of 560 and 680 ng/m3, respectively. However, TCPP was the main OPEs with average levels of 72 ng/m3 in PM10 samples. The majority of individual phthalates and OPEs were detected in 90-100 % of the dust samples, whereas in PM10 samples, their presence ranged from 25 % to 100 %. The concentrations of OPEs were notably greater than those of PBDEs and other BFRs previously reported in these samples, suggesting their broader use than alternative BFRs. The estimated long-term non-carcinogenic risk, hazardous index (HI) and daily exposure via dust for children was above threshold levels for DEHP. On the other hand, the cumulative risk of cancer was below the concerning levels. Further research is required to explore diverse groups of chemicals in indoor microenvironments particularly significant for children, such as kindergartens, primary schools, and their rooms at home.

Current status of indoor dust PBDE pollution and its physical burden and health effects on children

Polybrominated diphenyl ethers (PBDEs) are widely detected in indoor dust, which has been identified as a more important route of PBDE exposure for children than food intake. The physical burden and health hazards to children of PBDE exposure in house dust have not been adequately summarized; therefore, this article reviews the current status of PBDE pollution in indoor dust associated with children, highlighting the epidemiological evidence for physical burden and health risks in children. We find that PBDEs remain at high levels in indoor dust, including in homes, schools, and cars, especially in cars showing a significant upward trend. There is a trend towards an increase in the proportion of BDE-209 in household dust, which is indicative of recent PBDE contamination. Conversely, PBDE congeners in car and school indoor dust tended to shift from highly brominated to low brominated, suggesting a shift in current pollution patterns. Indoor dust exposure causes significantly higher PBDE burdens in children, especially infants in early life, than in adults. Exposure to dust also affects breast milk, putting infants at high risk of exposure. Although evidence is limited, available epidemiological studies suggest that exposure to indoor dust PBDEs promotes neurobehavioral problems and cancer development in children.

Profiling of phthalates, brominated, and organophosphate flame retardants in COVID-19 lockdown house dust; implication on the human health

In this study, brominated flame retardants (BFRs), phthalates, and organophosphate flame retardants (PFRs) were analyzed in indoor household dust collected during the COVID-19 related strict lockdown (April-July 2020) period. Floor dust samples were collected from 40 households in Jeddah, Saudi Arabia. The levels of most of the analyzed chemicals were visibly high and for certain chemicals multifold high in analyzed samples compared to earlier studies on indoor dust from Jeddah. Bis (2-ethylhexyl) phthalate (DEHP) was the primary chemical in these dust samples, with a median concentration of 769,500 ng/g of dust. Tris (2-butoxy ethyl) phosphate (TBEP) and Decabromodiphenyl ether (BDE 209) contributed the highest among PFRs and BFRs with median levels of 5990 and 940 ng/g of dust, respectively. The estimated daily exposure in the worst case scenario (23,700 ng/kg bw/day) for Saudi children was above the reference dose (20,000 ng/kg bw/day) for DEHP, and the hazardous index (HI) was also >1. The long-term carcinogenic risk was above the 1 × 10^-5, indicating a risk to the health of Saudi young children from getting exposed to DEHP from indoor dust. This study draws attention to the increased indoor pollution during the lockdown period when all of the daily activities by adults and children were performed indoors, which negatively impacted human health, as suggested by the calculated risk. However, the current study has limitations and warrants more monitoring studies from different parts of the world to understand the phenomenon. At the same time, this study also highlights another side of COVID-19 related to our lives.

Aerobic Degradation Characteristics and Mechanism of Decabromodiphenyl Ether (BDE-209) Using Complex Bacteria Communities

Complex bacteria communities that comprised Brevibacillus sp. (M1) and Achromobacter sp. (M2) with effective abilities of degrading decabromodiphenyl ether (BDE-209) were investigated for their degradation characteristics and mechanisms under aerobic conditions. The experimental results indicated that 88.4% of 10 mg L^-1 BDE-209 could be degraded after incubation for 120 h under the optimum conditions of pH 7.0, 30 °C and 15% of the inoculation volume, and the addition ratio of two bacterial suspensions was 1:1. Based on the identification of BDE-209 degradation products via liquid chromatography-mass spectrometry (LC-MS) analysis, the biodegradation pathway of BDE-209 was proposed. The debromination, hydroxylation, deprotonation, breakage of ether bonds and ring-opening processes were included in the degradation process. Furthermore, intracellular enzymes had the greatest contribution to BDE-209 biodegradation, and the inhibition of piperyl butoxide (PB) for BDE-209 degradation revealed that the cytochrome P450 (CYP) enzyme was likely the key enzyme during BDE-209 degradation by bacteria M (1+2). Our study provided alternative ideas for the microbial degradation of BDE-209 by aerobic complex bacteria communities in a water system.

In-situ generation of fluorescent silica nano-aggregates of silatranyl appended furfural Schiff base and its application to the spectrofluorimetric analysis of phenolic brominated flame retardants in aqueous medium

A silatranyl appended furfural Schiff base (Silt-FUR) has been synthesized and characterized by spectroscopic techniques, elemental analysis and mass spectrometry. The dissolution of Silt-FUR in methanol-water (90:10 v/v) results in the formation of fluorescent nano-aggregates due to the hydrolysis of the silatranyl ring. The formation of nano-aggregates has been confirmed by dynamic light scattering, scanning electron microscopy and transmission electron microscopy. The nano-aggregates exhibit quenching of fluorescence in the presence of phenolic brominated flame retardants such as 3,3',5,5'-tetrabromobisphenol A, 2,4-dibromophenol, 2,4,6-tribromophenol, and pentabromophenol. Density-Functional Theory and NMR titration suggest that acid-base pair formation between azomethinic functionality and flame retardants is the main cause of quenching of fluorescent signal as it causes photoinduced electron transfer. Due to the excellent spectrofluorimetric response of Silt-FUR nano-aggregates to detect brominated phenols, a spectrofluorimetric method has been standardized for the quantification of brominated flame retardants. The detection limit for pentabromophenol obtained is 0.432 µM under optimal experimental conditions, and the linear range of the determination is 0.0495-1.35 µM. Thus, the in-situ generation of nano-aggregates offers a user-friendly method for the detection, quantification and extraction of the brominated phenols with exceptionally high sensitivity and selectivity for pentabromophenol.