Can polyethylene passive samplers predict polychlorinated biphenyls (PCBs) uptake by earthworms and turnips in a biochar amended soil?

A pot experiment was carried out in which aged polychlorinated biphenyls (PCBs) contaminated soil was amended with biochar, and three phases: earthworms, turnips and polyethylene (PE) passive samplers, were added simultaneously in order to investigate changes in bioavailability of PCB following biochar amendment. Two biochars were used: one made from rice husk in Indonesia using local techniques and the other made from mixed wood shavings using more advanced technology. The biochars were amended at 1 and 4% doses. The overall accumulation of PCBs to the phases followed the order: earthworm lipid > PE > turnip. The rice husk biochar reduced PCB accumulation to a greater degree than the mixed wood biochar for all phases, however there was no effect of dose for either biochar. Earthworm uptake was reduced between 52% and 91% for rice husk biochar and by 19% to 63% for mix wood biochar. Turnip uptake was not significantly reduced by biochar amendment. Phase to soil accumulation factors (PSAF) were around 0.5 for turnips, approximately 5 for PE and exceeded 100 for earthworms. This study demonstrates that both biochars can be a sustainable alternative for in situ soil remediation and that PE can be used as tool to simulate the uptake in earthworms and thus remediation effectiveness.