Evaluation of EROD and CYP3A4 activities in earthworm Eisenia fetida as biomarkers for soil heavy metal contamination

► EROD and CYP3A4 activities can be detected in earthworms Eisenia fetida. ► Metals induced significant changes in both biomarkers at lower concentrations. ► Inverted U-shaped dose responses were observed in EROD and CYP3A4. ► Induction potency on EROD and CYP3A4 follows the order: Cd > Cu > Pb > Zn. ► EROD is more sensitive than CYP3A4 as a biomarker for heavy metal contamination.