Role and possible mechanisms of earthworm Eisenia fetida in the elimination of microcystin-LR in soil

•MC-LR elimination in soil conforms to the availability-adjusted first-order model.•E. fetida accelerates the elimination rate but not the final elimination efficiency.•MC-LR elimination mainly due to biodegradation rather than bioaccumulation.•E. fetida enhances TOC, enzyme activity, and microbial bioactivity in soil.•Indigenous and earthworm-derived bacteria facilitate MC-LR biodegradation.