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Mechanisms regulating bioavailability of phenanthrene sorbed on a peat soil‐origin humic substance
Author(s) -
Yang Yu,
Shu Liang,
Wang Xilong,
Xing Baoshan,
Tao Shu
Publication year - 2012
Publication title -
environmental toxicology and chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.1
H-Index - 171
eISSN - 1552-8618
pISSN - 0730-7268
DOI - 10.1002/etc.1844
Subject(s) - chemistry , humin , bioavailability , environmental chemistry , phenanthrene , biodegradation , organic matter , humic acid , sorption , soil organic matter , soil water , organic chemistry , adsorption , soil science , environmental science , biology , fertilizer , bioinformatics
The organic matter–mineral complex plays an important role in regulating the fate of hydrophobic organic compounds (HOCs) in the environment. In the present study, the authors investigated the microbial bioavailability of phenanthrene (PHE) sorbed on the original and demineralized humic acids (HAs) and humin (HM) that were sequentially extracted from a peat soil. Demineralization treatment dramatically decreased the 720‐h mineralized percentage of HM‐sorbed PHE from 42.5 ± 2.6% to 3.4 ± 1.3%, whereas the influence of this treatment on the biodegradability of HA‐associated PHE was much lower. Degradation kinetics of HA‐ and HM‐sorbed PHE showed that its initial degradation rate was negatively correlated with the aromatic carbon content of humic substances ( p < 0.05). This was attributed to the strong interactions between PHE and the aromatic components of humic substances, which hampered its release and subsequent biodegradation. The 720‐h mineralized percentage of PHE was inversely correlated with the estimated thickness of the organic matter layer at the surfaces of HAs and HMs. Therefore, in a relatively long term, diffusion of PHE within the organic matter layer could be an important factor that may limit the bioavailability of PHE to bacteria. Results of the present study highlight the molecular‐scaled mechanisms governing bioavailability of PHE sorbed on humic substances. Environ. Toxicol. Chem. 2012; 31: 1431–1437. © 2012 SETAC