Assessing the potential for rhizoremediation of PCB contaminated soils in northern regions using native tree species

► We assessed the abilities of willow and spruce to promote microbial PCB degradation. ► We examined effects of crushed roots on soil PCB content, toxicity and microflora. ► Willow-treated soil showed greater loss of PCBs than spruce, salicylate or controls. ► The Microtox bioassay indicated that willow treatment resulted in less toxic soil. ► Salix alaxensis (willow) may be an effective plant for rhizoremediation of PCBs.