Effects of biochar and the earthworm Eisenia fetida on the bioavailability of polycyclic aromatic hydrocarbons and potentially toxic elements

Gomez-Eyles, J. L., Sizmur, T. ORCID: https://orcid.org/0000-0001-9835-7195, Collins, C. D. and Hodson, M. E. (2011) Effects of biochar and the earthworm Eisenia fetida on the bioavailability of polycyclic aromatic hydrocarbons and potentially toxic elements. Environmental Pollution, 159 (2). pp. 616-622. ISSN 0269-7491 doi: 10.1016/j.envpol.2010.09.037

Abstract/Summary

Polycyclic aromatic hydrocarbons (PAHs) and potentially toxic elements (PTEs) were monitored over 56 days in calcareous contaminated-soil amended with either or both biochar and Eisenia fetida. Biochar reduced total (449 to 306mgkg(-1)) and bioavailable (cyclodextrin extractable) (276 to 182mgkg(-1)) PAHs, PAH concentrations in E. fetida (up to 45%) but also earthworm weight. Earthworms increased PAH bioavailability by >40%. Combined treatment results were similar to the biochar-only treatment. Earthworms increased water soluble Co (3.4 to 29.2mgkg(-1)), Cu (60.0 to 120.1mgkg(-1)) and Ni (31.7 to 83.0mgkg(-1)) but not As, Cd, Pb or Zn; biochar reduced water soluble Cu (60 to 37mgkg(-1)). Combined treatment results were similar to the biochar-only treatment but gave a greater reduction in As and Cd mobility. Biochar has contaminated land remediation potential, but its long-term impact on contaminants and soil biota needs to be assessed.