Organophosphate flame retardants in college dormitory dust of northern Chinese cities: Occurrence, human exposure and risk assessment.

Organophosphate flame retardants (OPFRs) are widely added to consumer products and building materials, which may pose potential health risk to humans. But information on their contamination and human exposure in the indoor environment especially dormitories in northern China is rare. In this study, twelve OPFRs were investigated in college dormitory dust that collected from Harbin, Shenyang, and Baoding, in northern China. Indoor dust samples were also collected from homes and public microenvironments (PMEs) in Harbin for comparison. The median ∑OPFR concentrations in dormitory dust in Shenyang samples (8690 ng/g) were higher than those in Baoding (6540 ng/g) and Harbin (6190 ng/g). The median ∑OPFR concentrations in home dust (7150 ng/g) were higher than in dormitory and PME dust (5340 ng/g) in Harbin. Tris(2‑chloroethyl) phosphate (TCEP) and tris (2-chloroisopropyl) phosphate (TCIPP) were the most abundant chlorinated OPFRs, while triphenyl phosphate (TPHP) and tris(2‑butoxyethyl) phosphate (TBOEP) were the dominant non-chlorinated OPFRs. The daily intakes of ∑OPFR were estimated, with the median values for female students (2.45 ng/kg-day) higher than those for male students (2.15 ng/kg-day) while were similar to adults (2.45 ng/kg-day) in homes. The estimated daily intakes (EDI) of these OPFRs from indoor dust in Harbin were all below the recommended values. The calculated non-carcinogenic hazard quotients (10-8-10-3) from OPFRs were much lower than the theoretical risk threshold. Meanwhile, carcinogenic risk (CR) of tri‑n‑butyl phosphate (TNBP), TCEP, tris(2‑ethylhexyl) phosphate (TEHP), and tris(1,3‑dichloroisopropyl) phosphate (TDCIPP) were also estimated. The highest carcinogenic risk of TCEP for gender-specific and age-specific category range from 1.75 × 10-7 to 2.46 × 10-7 from exposure to indoor dust indicated a low potential carcinogenic risk for human exposure.

Sun Y ，Liu LY ，Sverko E ，Li YF ，Li HL ，Huo CY ，Ma WL ，Song WW ，Zhang ZF ... -  《-》

Occurrence and seasonal variations of organophosphate flame retardants in air and dust from college microenvironments at Qingdao, China: Implications for student's exposure and risk assessment.

Organophosphate flame retardants (OPFRs) are widely used as alternatives to brominated flame retardants in a variety of consumer products and their consumption has continuously increased in recent years. However, their concentrations and human exposures in indoor microenvironments, particularly in a university environment, have received limited attention. In this study, the concentrations and seasonal variations of 15 OPFRs were assessed in typical microenvironments of two universities, including dormitories, offices, public microenvironments (PMEs: classroom, dining hall, gymnasium and library), and laboratories on the northern coast of China. Analysis of the OPFRs in both air and dust samples indicated widespread distribution in college campuses. The average concentration of ∑15OPFRs in the winter (12,774.4 ng/g and 5.3 ng/m3 for dust and air, respectively) was higher than in the summer (2460.4 ng/g and 4.6 ng/m3 for dust and air, respectively). The dust and air samples collected from PMEs and laboratories exhibited higher concentrations of OPFRs, followed by offices and dormitories. An equilibrium was reached between dust and air in all collected microenvironments. The daily intakes of OPFRs were significantly lower than the reference dose. Dust ingestion was the primary intake pathway in the winter, while inhalation and dust ingestion were the main intake pathways in the summer. The non-carcinogenic hazard quotients fell within the range of 10-7-10-3 in both the summer and winter, which are below the theoretical risk threshold. For the carcinogenic risk, the LCR values ranged from 10-10 to 10-8, indicating no elevated carcinogenic risk due to TnBP, TCEP, and TDCP in indoor dust and air.

Wang Z ，Qi A ，Lv J ，Zhang T ，Xu P ，Wang M ，Xiao Y ，Yang L ，Ji Y ，Wang W ... -  《-》

Temporal variations of PM(2.5)-bound organophosphate flame retardants in different microenvironments in Beijing, China, and implications for human exposure.

In the present study, the temporal distribution of PM2.5-bound organophosphate flame retardants (OPFRs) was comprehensively investigated in various indoor environments as well as outdoor air in Beijing, China over a one-year period. The mean concentrations of Σ9OPFRs were 22.7 ng m-3 and 1.40 ng m-3 in paired indoor and outdoor PM2.5, respectively. The concentrations of tri-n-butyl phosphate (TNBP), tris (2-chloroethyl) phosphate (TCEP) and tris (2-chloroisopropyl) phosphate (TCIPP) in indoor PM2.5 were significantly correlated with those in outdoor PM2.5. For different indoor microenvironments, mean concentrations of Σ9OPFRs were in the order of office (29.0 ± 11.7 ng m-3) > home (24.0 ± 9.4 ng m-3) > dormitory (19.4 ± 4.9 ng m-3) > activity room (14.4 ± 3.1 ng m-3). TCIPP was the most abundant compound in the indoor PM2.5, followed by TCEP. Significantly higher concentrations of OPFRs were observed in indoor environments with more furnishing, electronics or other materials (p < 0.05). Moreover, lower levels of OPFRs in indoor air were observed at well-ventilated (with higher air exchange rate) indoor sampling sites. Concentrations of Σ9OPFRs in the activity room, dormitory, homes and outdoor sites generally increased in summer and heating seasons (November 2016 to February 2017). Significant correlations (p < 0.05) were observed between temperatures and mass concentrations of OPFRs with higher vapor pressures, i.e. TNBP, TCEP and TCIPP in all indoor and outdoor samples. Seasonal differences in human exposure were observed and the highest daily exposure dose occurred in summer. Toddlers may suffer the highest exposure risk of PM2.5-bound OPFRs via inhalation among all age groups. This is one of the very few studies that have revealed the seasonal variation and human exposure of PM2.5-bound OPFRs in different microenvironments, which shed light on emission sources and fate of OPFRs and potential human exposure pathway.

Wang D ，Wang P ，Wang Y ，Zhang W ，Zhu C ，Sun H ，Matsiko J ，Zhu Y ，Li Y ，Meng W ，Zhang Q ，Jiang G ... -  《-》

Characterization and human exposure assessment of organophosphate flame retardants in indoor dust from several microenvironments of Beijing, China.

Ten target organophosphate flame retardants (PFRs) were measured from floor dust samples collected from homes (n = 21), offices (n = 23) and daycare centers (room n = 16) located in Beijing, China, and paired elevated surface dust and floor dust from the same daycare centers (room n = 9) were analyzed in this study. Most PFRs were detected in analyzed dust samples, and detection frequency up to 100% was observed on tris (2-chloroethyl) phosphate (TCEP), tris (2-chloroisopropyl) phosphate (TCIPP), triphenyl phosphate (TPHP) and tris (2-butoxyethyl) phosphate (TBOEP). Among studied microenvironments, office samples showed significantly (p < 0.05) higher PFRs contamination level (1687-200,489 ng/g), followed by homes (4571-67,450 ng/g), and daycare centers (1489-33,316 ng/g). TCEP was the predominant PFR in both home and daycare center samples, while TCIPP was dominant in floor dust from offices. TCEP, TCIPP and TBOEP showed positive correlations (p < 0.05) between their levels in elevated surface dust and corresponding floor dust, and the mean concentrations of TPHP (1116 ng/g) and tricresyl phosphate (TMPP) (336 ng/g) were significantly higher (p < 0.05) in floor dust than those in elevated surface dust (269 and 93 ng/g, respectively). Estimated exposures of toddlers, average adults and the elderly to PFRs via dust ingestion were 38, 6 and 5 ng/kg bw/day, respectively (assuming the average daily time spent are 62.5% home and 37.5% daycare center for toddlers, 62.5% home and 37.5% office for average adults, and 100% home for the elderly; assuming median concentrations and average dust ingestion rate).

Wu M ，Yu G ，Cao Z ，Wu D ，Liu K ，Deng S ，Huang J ，Wang B ，Wang Y ... -  《-》

Organophosphate esters in dust samples collected from Danish homes and daycare centers.

Organophosphates are used in a wide range of materials and consumer products and are ubiquitous in indoor environments. Certain organophosphates have been associated with various adverse health effects. The present paper reports mass fractions of organophosphates in dust samples collected from 500 bedrooms and 151 daycare centers of children living in Odense, Denmark. The identified compounds include: tris(isobutyl) phosphate (TIBP), tri-n-butyl phosphate (TNBP), tris(2-chloroethyl) phosphate (TCEP), tris(2-chloroisopropyl) phosphate (TCIPP), tris(1,3-dichloroisopropyl) phosphate (TDCIPP), tris(2-butoxyethyl) phosphate (TBOEP), triphenylphosphate (TPHP), 2-ethylhexyl-diphenyl phosphate (EHDPP), tris(2-ethylhexyl) phosphate (TEHP) and tris(methylphenyl) phosphate (TMPP). Both the number of organophosphates with median values above the limit of detection and the median values were higher for samples from daycare centers than for samples from homes. Organophosphates with median mass fractions above the limit of detection were: TCEP from homes (6.9 μg g(-1)), and TCEP (16 μg g(-1)), TCIPP (5.6 μg g(-1)), TDCIPP (7.1 μg g(-1)), TBOEP (26 μg g(-1)), TPHP (2.0 μg g(-1)) and EHDPP (2.1 μg g(-1)) from daycare centers. When present, TBOEP was typically the most abundant of the identified OPs. The sum of the organophosphate dust mass fractions measured in this study was roughly in the mid-range of summed mass fractions reported for dust samples collected in other countries. On a global scale, the geographical distribution of organophosphates in indoor dust is quite variable, with higher concentrations in industrialized countries. This trend differs from that for phthalate esters, whose geographic distribution is more homogeneous. Exposure to organophosphates via dust ingestion is relatively low, although there is considerable uncertainly in this assessment.

Langer S ，Fredricsson M ，Weschler CJ ，Bekö G ，Strandberg B ，Remberger M ，Toftum J ，Clausen G ... -  《-》