关键词: 城市硬质地表, 暴雨径流, PAHs质量负荷, 沥青路面, 环境影响

Abstract:

In order to reveal the difference of rainstorm-hard surface runoff and PAHs load between on urban and between on suburban, the PAHs load characteristics in rainstorm, rainstorm-runoff on hard surface was carried out to study by the means of location-contrast observation in Maofeng mountain forest area (suburb experimental forest area) and Huolushan forest park side (urban experimental area) of Guangzhou for 3 years. The results show that the periodic parameter of the number of the rainstorm days in 59 years of Guangzhou are extremely beneficial for predicting the copious year or shortage year of rainstorm. Compared with the urban experimental area, the rainstorm intensity of experimental forest area in suburb was significantly affected by the topographic factors. The average mass concentration of ∑16PAHs in the rainstorm in the urban experimental area achieved (134.4±48.7) ng∙L^-1 that was higher than in the experimental forest area by 6.9 ng∙L^-1. Among them, the average mass concentration of 2—3 ring PAHs and FLA, BbF were all greater than the corresponding concentration in the experimental forest area, while the average mass concentration of IcdP, BghiP, BkF and 4 ring BaA, CHR were all relatively smaller than in the corresponding concentration in the experimental forest area. It indicates differences in the affected sources. The average mass concentration of ∑16PAHs in rainstorm-runoff on the asphalt pavement in the urban experimental area reached a higher value of (317.4±34.5) ng∙L^-1. And that was 2.1 times that of the corresponding the experimental forest area. Among them, there were six components that the net increase over 1.1 times in concentration relative to that in the experimental forest area. They were in that order CHR by 3.41 times, PYR by 2.67 times, ANT by 1.52 times and BaP by 1.29 times, BghiP by 1.19 times, FLA by 1.11 times. It was shown that the influence of traffic exhaust emission and dust on the mass concentration of PAHs in the rainstorm runoff on urban asphalt pavement was very significantly greater than in the corresponding experimental forest area. According to the difference between every kind PAHs concentration in runoff and rainstorms divided by corresponding concentrations in rainstorms to count. In the two experimental areas, the high-fold net increase constituents in rainstorm-runoff on the asphalt pavement were all of 4 ring PAHs and 3 kinds of high ring PAHs, meanwhile the relative net decrease components had 4—5 kinds of 2—3 ring PAHs. Such as CHR and other 7 kinds of PAHs component mass concentration was relatively very significant net increase range from 11.02 to 1.12 times in urban asphalt pavement runoff respectively. Which was 2.1 to 24.4 times that of the corresponding the experimental forest area. Explain that traffic exhaust emissions, coal products and wood burning materials were the main sources of PAHs concentration increase in the rainstorm runoff of asphalt pavement. While asphalt pavement could reduce the mass concentration of low-ring PAHs derived from oil volatiles in rainstorm runoff. There was no significant difference between the average concentration of ∑16PAHs in the rainstorm runoff on the cement surface of the two experimental areas. Concentration of that in urban experimental area was 1.14 times that of the experimental forest area. Moreover, the cement surface could reduce the total concentration of PAHs in corresponding rainstorm in two experimental areas.

Key words: urban hard surface, rainstorm-runoff, PAHs mass load, asphalt pavement, environmental impact