Polycyclic aromatic hydrocarbons (PAHs) in urban surface dust of Guangzhou, China: Status, sources and human health risk assessment.

Ninety-six urban surface dust samples collected from Guangzhou, a typical urban center in South China, were analyzed for 16 PAHs (2-6 rings). ∑PAHs concentrations in the urban surface dust ranged from 0.84 to 12.3μg/g with a mean of 4.80μg/g. High molecular weight compounds (4-6 rings) contributed to 62 to 94% of ∑PAHs mass in the surface dust samples. Four hotspots with highest ∑PAHs were identified via kriging prediction mapping, representing the highly-urbanized regions: central downtown, highway and industrial area. Two major origins of PAHs inputs to urban surface dust were identified as vehicle emissions (51.9%) and coal combustion (26.8%). The 95% UCL of Incremental Lifetime Cancer Risk (ILCR) due to human exposure to urban surface dust PAHs in central South China was 3.03×10(-6) for children and 2.92×10(-6) for adults.