Impact of digestate and its fractions on mineralization of 14C-phenanthrene in aged soil

Ibeto, C. and Omoni, V. and Fagbohungbe, M. and Semple, K. (2020) Impact of digestate and its fractions on mineralization of 14C-phenanthrene in aged soil. Ecotoxicology and Environmental Safety, 195. ISSN 0147-6513

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The impact of whole digestate (WD) and its fractions (solid [SD] and liquid [LD]) on 14C-phenanthrene mineralization in soil over 90 d contact time was investigated. The 14C-phenanthrene spiked soil was aged for 1, 30, 60 and 90 d. Analysis of water-soluble nitrogen, phosphorus, total (organic and inorganic) carbon, and quantitative bacterial count were conducted at each time point to assess their impact on mineralization of 14C-phenanthrene in soils. Indigenous catabolic activity (total extents, maximum rates and lag phases) of 14C-phenanthrene mineralization were measured using respirometric soil slurry assay. The soil amended with WD outperformed the SD and LD fractions as well as showed a shorter lag phase, higher rate and extent of mineralization throughout the study. The digestates improved (P < 0.05) the microbial population and nutritive content of the soil. However, findings showed that spiking soil with phenanthrene generally reduced the growth of microbial populations from 1 to 90 d and gave a lower nutritive content in comparison with the non-spiked soil. Also, soil fertility and bacteria count were major factors driving 14C-phenanthrene mineralization. Particularly, the non-phenanthrene degraders positively influenced the cumulative mineralization of 14C-phenanthrene after 60 d incubation. Therefore, the digestates (residue from anaerobic digestion) especially WD, which enhanced 14C-phenanthrene mineralization of the soil without minimal basal salts medium nor additional degraders should be further exploited for sustainable bioremediation of PAHs contaminated soil.

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Journal Article
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Ecotoxicology and Environmental Safety
Additional Information:
This is the author’s version of a work that was accepted for publication in Ecotoxicology and Environmental Safety. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Ecotoxicology and Environmental Safety, 195, 2020 DOI: 10.1016/j.ecoenv.2020.110482
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25 Nov 2020 10:05
Last Modified:
19 Sep 2023 02:24