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Emerging PAHs in urban soils: Concentrations, bioaccessibility, and spatial distribution

Gao, Peng, da Silva, Evandro B., Townsend, Timothy, Liu, Xue, Ma, Lena Q.
The Science of the total environment 2019 v.670 pp. 800-805
United States Environmental Protection Agency, bioavailability, butanol, carcinogenicity, cities, computer software, fluorenes, geographic information systems, polluted soils, urban soils
Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous organic contaminants, with soil being the most important sink. This study determined the concentrations, bioaccessibility and spatial distributions of 6 emerging PAHs in Orlando and Tampa urban soils. They included 3 carcinogenic (anthanthrene, 7H-benzo[c]fluorene, and dibenzo[a,l]pyrene: 3cPAHs) and 3 non-carcinogenic (dibenzo[a,e]pyrene, dibenzo[a,i]pyrene and dibenzo[a,h]pyrene) PAHs. Based on benzo[a]pyrene-equivalent, the 7 USEPA priority cPAHs (7cPAHs) and 3cPAHs in Orlando soils averaged 452 and 7387 μg kg−1, and Tampa soils 802 and 4943 μg kg−1, respectively, with ∑3cPAHs being 6–16 times greater than ∑7cPAHs. Based on ArcGIS maps, the concentrations of ∑3cPAHs in commercial sites, business district and heavy-traffic areas were higher. The concentrations of ∑3cPAHs have not been reported, but they had significant impacts on risk assessment of urban soils due to their high relative potency factor. However, their bioaccessibility based on n-butanol extraction in soils of both cities were low, averaging 3.4–7.4%. Therefore, to accurately assess the risk of soils contaminated with PAHs, emerging cPAHs together with USEPA 7cPAHs and their bioaccessibility need to be considered.