Occurrence, distribution and human exposure of phthalic esters in road dust samples across China.

203 road dust samples were conducted across China covering 28 provinces from January to February，2016 to comprehensively investigates the occurrence, distribution and human exposure of 21 phthalic esters (PAEs). The concentration of Σ21PAEs in road dust ranged from 2.3 to 531 mg/kg, with a mean concentration of 64.1 ± 57.2 mg/kg. DEHP, DnBP and DiBP were the dominant components accounting for 63.3-97.9% (mean: 92.1%) of the Σ21PAEs. Significant Pearson correlation (r = 0.51, p < 0.0001) between Σ21PAEs concentrations and longitude demonstrated a distinguished geographical trend. Higher concentration of PAEs in sidewalk (SW) and trunk road (TR) may reflect influence of human activities such as shoe wear and traffic load. Significant differences were found among different human activities area (urban commercial, urban residential, and suburbs/rural). For total daily intake of Æ©21PAEs via street dust, children had the highest exposure risk followed by teenagers and adults with the median values of 160.8, 43.6, and 37.7 ng/kg-bw/day, respectively. The maximum exposure risk of PAEs calculated based on measurement and simulation were all far below reference values. The sensitivity analysis results demonstrated that concentrations, ingestion rate (IR) and fraction of PAEs absorbed in the skin (AF) were most important parameters on the assessment of exposure risk of PAEs via street dust. Specific parameters based on China and Chinses population is needed to obtain more reliable exposure risk via street dust.

Occurrence, composition profiles and risk assessment of polycyclic aromatic hydrocarbons in municipal sewage sludge in China.

A nationwide survey, including 75 sludge samples and 18 wastewater samples taken from different wastewater treatment plants (WWTPs) from 23 cities, was carried out to investigate the occurrence and composition profiles of polycyclic aromatic hydrocarbons (PAHs) in China. In total, the concentrations of ∑16PAHs in sludge ranged from 565 to 280,000 ng/g (mean: 9340 ng/g) which was at a moderate level in the world. The composition profiles of PAHs were characterized by 3- and 4-ring PAHs in textile dyeing sludge and 4- and 5-ring PAHs in domestic sludge. Significant variations in regional distribution of PAHs were observed. Both the principal components analysis and diagnostic ratios revealed that vehicle exhaust, coal and natural gas combustion were the main sources of PAHs in China. The estimated concentrations of PAHs were 3820 ng/L and 1120 ng/L in influents and effluents of the WWTPs, respectively. The high toxic equivalent quantity (TEQ) values of PAHs are ascribed to the high PAH levels. Risk quotient values (RQs) in sludge indicated that there was low potential risk to soil ecosystem after sludge had been applied one year except for indeno [1,2,3-cd]pyrene (IcdP) detected in Huaibei, Anhui province.