Polycyclic aromatic hydrocarbons in soil-turfgrass systems in urban Shanghai: Contamination profiles, in situ bioconcentration and potential health risks

Previous studies on the distribution patterns and health risks of polycyclic aromatic hydrocarbons (PAHs) from cities were focused on soils, leaving the soil-plant system less investigated. In this study, PAHs in the soil-turfgrass system in the urban area of the megacity Shanghai were investigated. The results indicated that total PAH concentrations in soils and turfgrasses ranged from 163.02 to 14,289.30 ng g(-1) and 45.15 to 1076.98 ng g(-1), respectively. On average, four- and three-ring PAHs such as fluoranthene (14.4%) and pyrene (12.4%) were dominant in soils and naphthalene (37.1%) was especially enriched in turfgrasses. The significant differences in compositional profiles of PAHs between soils and turfgrasses implied selective uptake and translocation of PAHs by turfgrasses from soils. The in situ bioconcentration factors (BCFs) of Sigma PAHs(16) in turfgrasses ranged 0.004-1.3, with ryegrass the highest. BCFs decreased significantly with increasing PAH concentrations in soils, suggesting that turfgrass-assisted PAH removal vial root uptake may be more efficient in slightly contaminated soils. Source appointment results indicated that PAHs in Shanghai were majorly derived from fossil fuel/biomass combustion, vehicular emissions and coking. The incremental lifetime cancer risk (ILCR) analysis generally showed a potential cancer risk for adults (total ILCRs > 1 x 10(-6) for all sites) and children (total ILCRs > 1 x 10(-6) for most sites) especially through dermal contact with soil. Some sites showed total ILCR values above 1 x 10(-4), indicating high health risks for both. The results are informative for contamination prevention and control in urban soils from Shanghai and will provide guidance for further exploration of the phytoremediation potential of turfgrasses. (C) 2021 Elsevier Ltd. All rights reserved.