Phosphorus flame retardants and Bisphenol A in indoor dust and PM 2.5 in kindergartens and primary schools in Hong Kong.

Organophosphate flame retardants (PFRs) and bisphenol A (BPA) were measured in indoor dust and PM2.5 samples from nine kindergartens and two primary schools in Hong Kong. The average levels of PM2.5 ranged from 4.0E+03 ng/m3 to 1.5E+04 ng/m3 . Average levels of PFRs (from 1.5 ng/m3 to 20 ng/m3 in PM2.5 ; from 8.0E-02 μg/g dw to 2.4 μg/g dw in dust) and BPA (from 6.4E-01 ng/m3 to 1.0 ng/m3 in PM2.5 ; from 1.0E-02 μg/g dw to 2.0E-01 μg/g dw in dust) were detected in most of the sampling sites. Tri-(2-Chloroethyl) phosphate (TCEP), tris(1,3-Dichloro-2-propyl) phosphate (TDCP), tris-(chloroisopropyl) phosphate (TCPP), and triphenyl phosphate (TPHP) were present in low levels in PM2.5 with medians of 16, 14, 8.7, and 3.2 ng/m3 , respectively. In dust, the medians were 1.5E-01, 5.5E-02, 5.9E-01, 8.6E-01, and 8.5E-02 μg/g dw for TCEP, TCPP, TDCPP, TPHP, and 2-ethylhexyl diphenyl phosphate, respectively. The medians of BPA were 6.4E-01 ng/m3 and 7.4E-02 μg/g dw for PM2.5 and dust, respectively. A positive correlation was found between indoor PM2.5 and dust in the levels of TCEP (r = 0.85; p = .05). In the individual classroom in this survey, the predominant PFRs were similar, that is, TDCP and TCEP in indoor PM2.5 while TPHP and TDCP in dust. TPHP and TCEP in primary schools were obviously lower than those in kindergartens. The estimated daily intakes via PM2.5 and dust for all selected PFRs ranged from 1.3E-4 μg/kg/d to 2.0E-02 μg/kg/d, and the value of less than the detection limit at 3.5E-4 μg/kg/d was found for BPA. The EDI values of TPHP in dust non-dietary intake fraction were higher than those in the others. Calculated hazard indices (EDI/RfD) ranged from 4.8E-06 and 5.5E-03, showing that PFRs and BPA in PM2.5 and dust presented no health risks to children.