Source, distribution, and health risk assessment of polycyclic aromatic hydrocarbons in urban street dust from Tianjin, China

To better assess and understand potential health risk of urban residents exposed to urban street dust, the total concentration, sources, and distribution of 16 polycyclic aromatic hydrocarbons (PAHs) in 87 urban street dust samples from Tianjin as a Chinese megacity that has undergone rapid urbanization were investigated. In the meantime, potential sources of PAHs were identified using the principal component analysis (PCA), and the risk of residents' exposure to PAHs via urban street dust was calculated using the Incremental Lifetime Cancer Risk (ILCR) model. The results showed that the total PAHs (Sigma PAHs) in urban street dust from Tianjin ranged from 538 mu g kg(-1) to 34.3 mg kg(-1), averaging 7.99 mg kg(-1). According to PCA, the two to three-and four to six-ring PAHs contributed 10.3 and 89.7 % of Sigma PAHs, respectively. The ratio of the sum of major combustion specific compounds (SCOMB)/Sigma PAHs varied from 0.57 to 0.79, averaging 0.64. The ratio of Ant/(Ant+Phe) varied from 0.05 to 0.41, averaging 0.10; Fla/(Fla+Pyr) from 0.40 to 0.68, averaging 0.60; BaA/(BaA+Chry) from 0.29 to 0.51, averaging 0.38; and IcdP/(IcdP+BghiP) from 0.07 to 0.37, averaging 0.22. The biomass combustion, coal combustion, and traffic emission were the main sources of PAHs in urban street dust with the similar proportion. According to the ILCR model, the total cancer risk for children and adults was up to 2.55x10(-5) and 9.33x10(-5), respectively.