Occurrence and Release Behavior of PAHs Accumulated in Road Sediment in Urban-Rural Fringe in Beijing, China

ABSTRACT

Due to the rapid expansion of cities, the impermeable area has increased. This exacerbated the accumulation of pollutants in road particles and made the road sediment one of the most widely distributed pollution carriers in the urban area. Urban-rural fringe is the frontier of urban expansion and the most dynamic area in the urban region, but less knowledge was available on the pollution status of the region. In this study, the occurrence, release behavior, and environmental risk of polycyclic aromatic hydrocarbons (PAHs) accumulated in road sediment in urban-rural fringe were systematically studied and compared with five other urban functional areas (i.e., commercial area, industrial park, residential area, traffic area, and leisure area) in Beijing, china. The concentration of ∑16PAHs in the road sediment followed in the order of petrol station (2.223 mg/kg)>crossroad (1.506 mg/kg)>main road (0.949 mg/kg)>university gate (0.841 mg/kg)>bus station (0.839 mg/kg). The PAHs concentration in the road sediment with different land use followed in the order of traffic area (3.030 mg/kg)>urban-rural fringe (1.338 mg/kg)>commercial area (0.946 mg/kg)>residential area (0.866 mg/kg)>industrial park (0.673 mg/kg)>leisure area (0.316 mg/kg). The cancer risk in the urban-rural fringe was second only to the traffic area. PAHs with low ring numbers were easier to release into the water, as indicated by that 20–95% nap could be released from the road sediment to runoff. In contrast, high-ring PAHs were more likely to accumulate in the particulate matter as <18.3% of PHE, FLA, and PYR (corresponding to 0.002–0.010 mg/kg) could be released into the water phase, which means that the removal of road sediment plays an important role in reducing pollution. Overall, this study reveals that pollution in the urban-rural fringe cannot be ignored and provides scientific data to support pollution control and risk assessment, especially for urban-rural areas.

Graphical abstract

KEYWORDS:

• Urban-rural fringe
• road sediment
• PAHs
• human health risk
• pollution characteristics

Acknowledgments

This research was supported by the National Key R&D Program of China (Grant No. 2020YFC1808804); Construction of High Level Teaching Teams in Universities of Beijing–the Youth Top–Notch Talent Cultivation Program (CIT&TCD201804051); National Natural Science Foundation of China (51978032, 51508017); The Youth Beijing Scholars program (NO.024).

Disclosure statement

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Additional information

Funding

This work was supported by the National Natural Science Foundation of China [51508017]; the Construction of High Level Teaching Teams in Universities of Beijing–the Youth Top–Notch Talent Cultivation Program [CIT&TCD201804051]; The Youth Beijing Scholars program [NO.024].