The use of biochar to reduce soil PCB bioavailability to Cucurbita pepo and Eisenia fetida

► Two concentrations of weathered PCB-contaminated soil were amended with (0, 0.2, 0.7, 2.8, and 11.1% w/w) of biochar. ► Biochar additions decreased the uptake of PCBs into plant tissue by 89% after 50 days. ► Biochar amendment significantly decreased the bioavailability of PCBs to earthworms by 88% after 50 days of exposure. ► Biochar has potential to serve as a mitigation technology at Brownfield sites.