Biological and chemical remediation of CCA treated eucalypt poles after 30 years in service.

The aim of this study was to evaluate the efficacy of biological and chemical remediation of chromated copper arsenate (CCA) treated Corymbia citriodora poles, removed from service after 30 years. The presence of arsenic (As), chromium (Cr) and copper (Cu) was quantified by inductively coupled plasma optical emission spectrometry (ICP-OES). Twelve species of decay fungi were used for the biological remediation assay. For chemical remediation oxalic, citric, maleic and ethylenediamine tetraacetic (EDTA) acids were used for 24 and 48 h. In biological remediation, copper-tolerant brown-rot fungi, Wolfiporia cocos, Antrodia xantha and Fibroporia radiculosa, performed the best results, with the highest removals for As (59-85 %) and Cr (38-61 %). Cu was the most easily extracted, with removals above 60 % among the tested fungi, with the best results (90-98 %) for F. radiculosa, Coniophora puteana, Antrodia vaillantii and Postia placenta. In chemical remediation, the extraction time of 48 h was the most effective, and oxalic acid generally reached the highest removals. The EDTA + oxalic acid combination reached the highest value for Cu extraction (98 %).