Compositions, Sources and Health Risks of Polycyclic Aromatic Hydrocarbons (PAHs) in Surface Dusts from Driving-schools in a City of Henan Province, China

Abstract

The contamination of polycyclic aromatic hydrocarbons (PAHs) in surface dusts attracts great attentions due to their properties of threatening human health. Twenty-nine surface dust samples were collected from driving-schools in a city of Henan. Concentrations of 16 priority PAHs were analyzed by gas chromatography-mass spectrometry (GC-MS). The health risks exposed to dust PAHs for three different scenarios (working for 5 a, 10 a and 20 a in driving-school) were estimated by the health risk assessment model (ILCRs). Source identification was analyzed by diagnostic ratio, composition analysis, and principal component analysis. The results showed that concentrations of the ∑PAHs in dusts ranged from 198.21 to 3400.89 μg·kg-1, with a mean of 908.72 μg·kg-1. Among individual PAHs, the contents of naphthalene (Nap), phenanthrene (Phe), anthracene (Ant) and fluoranthene (Flu) were higher, and the content of dibenzo[a, h]anthracene (DBA) was the lowest. The dominant compounds were 2-3 ring PAHs, which accounted for 55.79%, while the 4-6 ring PAHs accounted for 44.21%. The health risks exposed to PAHs in dust in three different scenarios were 9.27×10-8, 1.85×10-7, and 3.71×10-7 respectively; only sample J11 was with potential health risk in scenario 3, and the other samples were all without risks. Average daily doses by dermal contact of dust particles for the PAHs was the main exposure way. PAHs in dusts of driving-school were mainly originated from the combustion of fossil fuels and mixture combustion. The major sources of dust PAHs in farmland area driving-schools were natural gas and diesel combustion (56.44%), coal combustion (26.55%), gasoline combustion and the leakage (17.01%); dust PAHs in industrial area driving-schools were from mixture combustion (76.26%), gasoline combustion and the leakage (22.85%), coking and coal combustion (0.89%); and dust PAHs in mixed area driving-schools were from coal combustion (45.57%), natural gas and diesel combustion (45.41%), gasoline combustion and the leakage (9.02%). The concentrations and health risks of heavy metals in dusts were closely related to the surroundings around driving-schools and the previous land use status.