Short- and medium-chain chlorinated paraffins in urban road dust of Shanghai, China: concentrations, source apportionment and human exposure assessment.

Chlorinated paraffins (CPs) are ubiquitous anthropogenic contaminants that have been found in various environmental media. The objective of this study was to determine concentrations, spatial distribution, possible sources and potential health risk of SCCPs and MCCPs in urban road dust collected from Shanghai, China. The concentrations ranged from 9.74 to 11,400 ng g-1 for ΣSCCPs, 44.1 to 49,900 ng g-1 for ΣMCCPs and 53.9 to 61,400 ng g-1 for total CPs, respectively. MCCPs were the dominant component in all road dust, averagely accounting for 82.8% of total CPs. The concentrations of CPs in dust collected from traffic and commercial areas were significantly higher than those from campus, industrial, park and residential areas (p < 0.01), which could be attributed to tire wear in heavy traffic. All dust samples were divided into two groups by hierarchical cluster analysis for both SCCPs and MCCPs, and the most abundant homologue groups in most samples were C10Cl7-10 and C13Cl7-9 for SCCPs, and C14Cl7-9 and C15Cl8-9 for MCCPs. Correlation analysis showed that all carbon homologues in road dusts were highly correlated each other, suggesting SCCPs and MCCPs in dust maybe came from similar sources. Three sources for CPs in dust samples were apportioned by the PMF model; their relative contributions to the total CPs burden in dust were 25.6% for factor 1 (commercial CP mixture), 13.7% for factor 2 (long-distance transport) and 60.7% for factor 3 (commercial CP mixture). The median estimated daily intakes of total CPs via road dust were 1.78 × 10-5 for children and 3.0 × 10-6 mg kg-1 day-1 for adults, respectively. Quantitative risk assessment using non-cancer hazard index and total margin of exposure of total CPs indicated that total CPs at the present level in road dust pose no significant risk for both children and adults in Shanghai.

Occurrence, source apportionment, and carcinogenic risk assessment of polycyclic aromatic hydrocarbons in urban road dusts in Shanghai.

Polycyclic aromatic hydrocarbons (PAHs), as a class of important environmental pollutants, have received considerable concern due to their widespread existence and biological toxicity. The main purpose of this study was to determine concentrations, spatial distribution, possible sources, and potential health risk of PAHs in urban road dust in Shanghai, China. The concentration of Σ26PAHs ranged from 53.0 to 28,700 ng g-1 in road dust samples from Shanghai, which is at the low to medium level compared with other areas around the world. PAHs with 4-5 rings were predominant components in road dust. The level of PAHs in road dust was significantly higher than those in soil and river sediment in Shanghai. Six possible sources of PAHs were apportioned by PMF model. The contribution of pyrogenic PAHs accounted for 91.3% of the total PAHs in road dusts. The motor vehicular emission, natural gas, and coal combustion were main sources for urban road dust PAHs from Shanghai. Four dibenzopyrene (DBP) isomers were contributed averagely 75% of total TEQBaP concentration. DBalP, BaP, DBaiP, BbF, and DBA were main contributors to total carcinogenic potency, which totally contributed from 69.6 to 91.8% (median 89.1%) to total TEQBaP in urban road dusts of Shanghai. The results of incremental lifetime carcinogenic risk (ILCR) assessment showed that the total risk values exposed to 24 PAHs in road dust were lower than 10-4 at all sampling sites, indicating that exposure to dust-bound PAHs at present level was unlikely to result in high carcinogenic risk for both children and adults in Shanghai.

Assessment of exposure to polybrominated diphenyl ethers associated with consumption of market hens in Guangzhou.

To evaluate contamination by polybrominated diphenyl ethers (PBDEs) in market hens and human PBDE exposure via hen consumption in Guangzhou, hens were collected and their muscle, liver, fat, blood, yolk, and ingluvies tissues were analyzed for 13 PBDE congeners. The median highest concentration of ∑PBDEs was found in the ingluvies (5.30 ng/g lw), followed by the muscle (2.53 ng/g lw), with the lowest located in the yolk (0.09 ng/g lw). The concentrations of PBDEs in the muscle tissue of market hens in Guangzhou were at medium levels compared to others reported around the world. BDE-47, -153, -99, and -183 were the predominant congeners. The daily intake concentrations of PBDEs from hen muscle were estimated to range from 0.08 to 0.31 ng/kg/day in this study, with a Hazard Quotient (HQ) below 1.0. These results suggest that the health risk of PBDEs for the general population, through the consumption of market hens in Guangzhou, was generally low. However, the intake of PBDEs via food consumption may be one major exposure pathway for the general population of Guangzhou.