Work

Hydroxypropyl-β-cyclodextrin (HPCD) extraction of urban soils: mass balance, bioaccessibility, and cancer risk assessment of 71 polycyclic aromatic hydrocarbons (PAH) from petrogenic and pyrogenic sources

Year: 2025

Type: article

Abstract: Bioaccessibility of polycyclic aromatic hydrocarbons (PAH) in soils is often determined by extraction with hydroxypropyl-β-cyclodextrin (HPCD), yet there is no standardized approach for determining bioaccessible concentrations ( c bio ), which are either calculated or directly measured. Additionally, most studies analyze solely the 16 EPA PAH, neglecting more carcinogenic PAH with higher relative potency factors (RPFs) and often disregarding PAH sources. This study examines optimal c bio determination by providing mass balances of HPCD extraction. Moreover, this study investigates the bioaccessibility of 71 PAH in five urban soils, considering their petrogenic to pyrogenic sources and their carcinogenic potential. Checking HPCD mass balances revealed that mechanical stress and residual HPCD can artificially increase the residual PAH content ( c non-bio ), making c bio calculation using c non-bio unfeasible. We therefore recommend re-extraction of HPCD extracts to measure c bio . The measured c bio of PAH depended on PAH sources, with lower c bio observed in petrogenic coal-containing soils. Within c bio , 7 H -benzo[ c ]fluorene contributes most to toxicity equivalents (TEQs), while the most carcinogenic EPA PAH, benzo[ a ]pyrene, contributes little. Dibenzopyrenes, considered highly carcinogenic, were not bioaccessible. TEQs could only be calculated for 24 PAH with available RPFs. However, additional PAH with evidence for carcinogenicity were also bioaccessible, with 2-methylfluoranthene and benzo[ c ]phenanthrene reaching c bio of >1 mg/kg. Notably, benzo[ c ]phenanthrene is classified by the IARC as a group 2B carcinogen. These findings suggest that particularly 7 H -benzo[ c ]fluorene and benzo[ c ]phenanthrene should be included in routine risk assessments due to their carcinogenic categorization and bioaccessibility. Future studies should focus on expanding carcinogenicity data and RPF values for additional PAH.

Source: The Science of The Total Environment

DOI: 10.1016/j.scitotenv.2025.179639

Authors: Viviane J. Bayer, Alicja Behrensmeier, Christine Achten

Institution: University of Münster

Language: English

Topic: Toxic Organic Pollutants Impact

Subfield: Health, Toxicology and Mutagenesis

Field: Environmental Science

Domain: Physical Sciences

SDG: Good health and well-being

Open Access status: hybrid

Estimated APC paid: $4,250