Effects of source materials on desorption kinetics of carcinogenic PAHs from contaminated soils

Linbo Yu; Luchun Duan; Ravi Naidu; Fanbo Meng; Kirk T Semple

doi:10.1016/j.chemosphere.2023.139095

Effects of source materials on desorption kinetics of carcinogenic PAHs from contaminated soils

Chemosphere. 2023 Sep:335:139095. doi: 10.1016/j.chemosphere.2023.139095. Epub 2023 May 31.

Authors

Linbo Yu¹, Luchun Duan², Ravi Naidu³, Fanbo Meng⁴, Kirk T Semple⁵

Affiliations

¹ Global Centre for Environmental Remediation (GCER), College of Engineering, Science and Environment, The University of Newcastle, Callaghan, 2308, Australia; Cooperative Research Centre for Contamination Assessment and Remediation of the Environment (CRC CARE), The University of Newcastle, Callaghan, 2308, Australia. Electronic address: longbowylb@hotmail.com.
² Global Centre for Environmental Remediation (GCER), College of Engineering, Science and Environment, The University of Newcastle, Callaghan, 2308, Australia; Cooperative Research Centre for Contamination Assessment and Remediation of the Environment (CRC CARE), The University of Newcastle, Callaghan, 2308, Australia.
³ Global Centre for Environmental Remediation (GCER), College of Engineering, Science and Environment, The University of Newcastle, Callaghan, 2308, Australia; Cooperative Research Centre for Contamination Assessment and Remediation of the Environment (CRC CARE), The University of Newcastle, Callaghan, 2308, Australia. Electronic address: Ravi.Naidu@newcastle.edu.au.
⁴ Jinan Environmental Research Academy, Jinan, Shandong Province, 250102, China.
⁵ Lancaster Environment Centre, Lancaster University, Lancaster, LA1 4YQ, UK.

PMID: 37268225
DOI: 10.1016/j.chemosphere.2023.139095

Abstract

Research investigating the desorptive behaviour of PAHs from contaminated soils often overlooked the effects of source materials, especially coal tar and coal tar pitch and materials alike. In this study, a refined experimental approach was adopted to establish a simple-to-complex continuum of systems that allow the investigation of desorption kinetics of benzo(a)pyrene (BaP) and 3 other carcinogenic PAHs (cPAHs) over an incubation period of 48 d. By comparing the modelled desorption parameters, elucidation of the effects of PAH source materials on their desorptive behaviour was achieved. Desorption of cPAHs from coal tar and pitch was enhanced when they were added to soils, with rapidly desorbing fraction (F_rap) of BaP increased from 0.68% for pitch to 1.10% and 2.66% for pitch treated soils, and from 2.57% for coal tar to 6.24% for coal tar treated soil G and 8.76% for coal tar treated sand (1 d). At 1 d, desorption of target cPAHs from solvent and source material spiked soils generally followed the order of solvent > coal tar > pitch. Increases in F_rap of cPAHs were observed in coal tar-treated soils after 48 d soil incubation (0.33%-1.16% for soil M, p ≥ 0.05, 6.24%-9.21% for soil G, p < 0.05) and was attributed to the continuous migration of coal tar as a non-aqueous phase liquid (NAPL) into soil pore structures. Slow desorption was dominated by source materials, whereas the extents and rates of rapid desorption (F_rap and k_rap) were more controlled by the quantity of soil organic matter (SOM), rather than quality of SOM (as in solvent-spiked soils). The results of this study challenged the role of PAH source materials as 'sinks' and led to the proposed roles of coal tar and pitch and source materials alike as 'reservoirs' with a risk-driven perspective.

Keywords: Desorption kinetics; PAHs; Soil; Source materials.

MeSH terms

Carcinogens
Coal Tar* / chemistry
Kinetics
Polycyclic Aromatic Hydrocarbons* / analysis
Soil / chemistry
Soil Pollutants* / analysis
Solvents

Substances

Carcinogens
Coal Tar
Polycyclic Aromatic Hydrocarbons
Solvents
Soil
Soil Pollutants