Plastic Additives in Ambient Fine Particulate Matter in the Pearl River Delta, China: High-Throughput Characterization and Health Implications.

Elucidation of the chemical components of airborne fine particulate matter (PM2.5) facilitates the characterization of atmospheric contamination sources and associated human exposure risks. In the present study, we employed a high-throughput analytical approach to investigate the abundance and distribution of 163 plastic additives in ambient PM2.5 collected from 94 different sites across the Pearl River Delta region, China. These chemicals are from six categories, including organophosphate esters (OPEs), phthalate esters (PAEs), PAE replacements, bisphenol analogues, UV stabilizers, and antioxidants. Ninety-three of them exhibited a detection frequency greater than 50% in PM2.5, while the combined concentrations of target plastic additives ranged from 610 to 49,400 µg/g (median: 3500 µg/g) across sites. By category, concentrations of PAEs (median: 2710 µg/g) were one to three orders of magnitude greater than those of other groups, followed by PAE replacements (540 µg/g) and OPEs (76.2 µg/g). Chemical-dependent exposure risks to PM2.5-bound plastic additives were characterized via the estimated daily intake and hazard quotient (HQ) approaches, which resulted in two different risk prioritization systems. Although the HQ approach suggested no or very low health concerns when considering individual chemicals, the complexity of co-concurrent chemicals in PM2.5 raises the concern on potential health risks from exposure to airborne particles and a cocktail of chemical components.

Novel and Traditional Organophosphate Esters in House Dust from South China: Association with Hand Wipes and Exposure Estimation.

The present study investigated the occurrence of 20 organophosphate esters (OPEs) in house dust from 51 South China homes and the risks of human exposure to OPEs via two pathways: dust ingestion and hand-to-mouth contact. In addition to several traditional OPEs, five out of six novel OPEs, including bisphenol A bis(deiphenyl phosphate) (BPA-BDPP), t-butylphenyl diphenyl phosphate (BPDPP), cresyl diphenyl phosphate (CDP), isodecyl diphenyl phosphate (IDDPP), and resorcinol-bis(diphenyl)phosphate (RDP), were frequently detected in house dust (median concentration: 59.7-531 ng/g). Eight of the 20 target OPEs were frequently detected in hand wipes collected from adults and children ( n = 51 and 31, respectively), which in combination (referred to as Σ8OPEs) had a median mass of 76.9 and 58.9 ng, respectively. Increasing dust concentrations of Σ8OPEs or three individual substances among these eight OPEs, including tris(1-chloro-2-propyl) phosphate (TCIPP), tris(1,3-dichloro-2-propyl) phosphate (TDCIPP), and triphenyl phosphate (TPHP), were strongly associated with their levels in children's hand wipes ( p < 0.05 in all cases). By contrast, in adults' hand wipes only TPHP exhibited a marginally significant association with dust concentrations ( p = 0.04). Levels of Σ8OPEs in hand wipes from children, but not adults, were inversely influenced by hand washing frequency ( p = 0.002), while indoor temperature was inversely associated with hand wipe levels of Σ8OPEs from both children and adults ( p = 0.01 and 0.002, respectively). Exposure estimation suggests that hand-to-mouth contact represents another important pathway in addition to dust ingestion and that children are subjected to higher OPE exposure than adults.

Plastic additives and personal care products in south China house dust and exposure in child-mother pairs.

Indoor environment constitutes an important source of industrial additive chemicals to human exposure. We hypothesized that the influence of residential environment on human exposure varies among different types of additive chemicals and differs between children and mothers. This study determined a suite of additive chemicals in house dust from South China dwellings (n = 47) and urine from child-mother pairs. Concentrations of phthalates (PAEs; median 601 µg/g) were 2-3 orders of magnitude greater than those of parabens (0.82 µg/g), bisphenols (3.31 µg/g), and benzophenone-related chemicals (2.69 µg/g). Urinary concentrations differed between children and mothers, but the pattern of differences varied between chemical groups. Children exhibited greater urinary levels of mono-PAEs than mothers (510 versus 395 ng/mL, p = 0.152), while the latter population exhibited greater levels of parabens and benzophenones. Regression analyses indicate a lack of association between dust and urinary levels for most chemicals, suggesting that other exposure pathways can complicate human exposure scenarios. Indeed, we estimated that the daily intake via dust ingestion only constituted 0.002-0.81% of total daily intake estimated based on urine data for mothers and 0.04-5.61% for children. Future efforts are needed to better characterize source-specific exposure for different populations.

Exposure of children and mothers to organophosphate esters: Prediction by house dust and silicone wristbands.

Ubiquitous human exposure to organophosphorus tri-esters (tri-OPEs) has been reported worldwide. Previous studies investigated the feasibility of using house dust and wristbands to assess human OPE exposure. We hypothesized that these two approaches could differ in relative effectiveness in the characterization of children and adult exposure. In the participants recruited from Guangzhou, South China, urinary levels of major OPE metabolites, including diphenyl phosphate (DPHP) and bis(butoxyethyl) phosphate (BBOEP), were significantly higher in children than their mothers (median 6.6 versus 3.7 ng/mL and 0.11 versus 0.06 ng/mL, respectively). The associations of dust or wristband-associated OPEs with urinary metabolites exhibited chemical-specific patterns, which also differed between children and mothers. Significant and marginally significant associations were determined between dust concentrations of triphenyl phosphate (TPHP), tris(2-butoxyethyl) phosphate (TBOEP), trimethylphenyl phosphate (TMPP), or tris(1-chloro-2-propyl) phosphate (TCIPP) and their metabolites in children urine and between dust tris(1,3-dichloroisopropyl) phosphate (TDCIPP), TPHP or TMPP and urinary metabolites in mothers. By contrast, wristbands exhibited better efficiency of predicting internal exposure to TDCIPP. While both house dust and wristbands exhibited the potential as a convenient approach for assessing long-term OPE exposure, their feasibility requires better investigations via larger-scale studies and standardized sampling protocols.

Legacy and alternative flame retardants in house dust and hand wipes from South China.

The present study investigated the occurrence of legacy and alternative halogenated flame retardants (FRs) in house dust (n = 51) from Guangzhou, South China and hand wipes collected from adults (n = 51) and children (n = 31). In addition to polybrominated diphenyl ether (PBDE) congeners (particularly BDE-209), several alternative FRs were also detected in >60% of dust samples, including decabromodiphenylethane (DBDPE; median: 4600 ng/g), bis(2-ethylhexyl)-3,4,5,6-tetrabromo-phthalate (BEH-TEBP; 43.9 ng/g), 1,2-bis(2,4,6-tribormophenoxy)ethane (BTBPE; 9.2 ng/g), pentabromotoluene (PBT; 10.1 ng/g), and syn- and anti-dechlorane plus (DPs, 24.5 ng/g). BDE-47, BDE-209, DBDPE, BEH-TEBP, and DPs were also frequently detected on hand wipes from children (median mass: 0.1-1.1 ng) and adults (0.1-1.2 ng). Linear regression models suggest that dust concentrations of BDE-47 and DPs had significant or marginally significant associations with their masses on children's (10ß = 2.82; 95% CI: 1.20, 6.64 and 10ß = 5.57, 95% CI: 1.85, 16.75, respectively) and adults' hands (10ß = 4.46; 95% CI: 0.92, 21.58 and 10ß = 5.11; 95% CI: 1.74, 14.96, respectively), whereas no association was observed for any other FRs. Most of the investigated demographic, environmental, or behavioral factors did not significantly influence the levels of halogenated FRs on human hands. Estimation of human exposure risks via hand-to-mouth contact and dust ingestion indicates that children are subjected to elevated exposure than adults, and the relative importance of the two pathways is chemical-specific.