Distribution,bioaccessability and toxicity equivalence of polycyclic aromatic hydrocarbons in different particle-size fractions of road dust in Fuzhou
The content and composition of polycyclic aromatic hydrocarbons(PAHs)in different particle-size fractions(＞250 μm,250-53 μm and＜53 μm)of the road dust from Fuzhou city were studied.Moreover,the bioaccessability of PAHs and the toxic equivalent concentration based on the toxicity of benzo(a)pyrene(BaP)(TEQBaP)of the bioavailable PAHs in different particle-size fractions of the dust were evaluated by an in vitro digestion model combined with solid phase extraction technique.The results showed that:(1)the total contents of PAHs in different particle-size fractions of the dust increased with the decrease of particle size(＞250 μm,0.597 mg·kg-1;250-53 μm,1.235 mg·kg-1;＜53 μm,3.931 mg·kg-1).The compositions of PAHs in different particle-size fractions of the dust were basically the same,all of which were in the sequence of 4-ring(58.5％±0.8％)＞5-ring(21.5％±0.4％)＞3-ring(13.3％±0.9％)＞6-ring(4.8％±0.2％)＞2-ring(2.0％±0.3％);(2)The total contents of the bioavailable PAHs in different particle-size fractions of the dust increased with the decrease of particle size,but the bioaccessability of PAHs was significantly higher in the＞250 μm dust than in the 250-53 μm and＜53 μm dust(P＜0.05).Overall,the bioaccessability of low-ring(2-,3-,and 4-ring)PAHs was greater than that of high-ring(5-,6-ring)PAHs;(3)The total TEQBaP value of the bioavailable PAHs in different particle-size fractions of the dust increased with the decrease of particle size,and the TEQBaP values of 4-ring and 5-ring PAHs in different particle-size fractions of the dust were significantly higher than those of other ring number PAHs(P＜0.05).The 4-ring PAH content was the highest in different particle-size fractions of the dust and they also had high bioaccessability and TEQBaP values,thus their potentially toxic risk in human was the highest.
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