Recently, biomarkers in earthworms were widely used for assessing the effect of pollutants on the environment. There is necessary for using earthworms and their biomarkers based on sensitivity and their presence in field, but testing usually focused on Eisenia fetida. Therefore, after a year field study to identify and determine the dispersal of earthworm species in Hyrcanian zone (case study, chaloos), Aporrectodea rosea and Aporrectodea trapezoides were selected and put in front of E. fetida. The species were exposed to lethal (14 d) and sublethal concentrations (7, 14 and 28 d) of cadmium (Cd) nitrate in OECD soil. For this purpose, apoptosis, lipid peroxidation (MDA), Total Antioxidant Capacity (TAC), lethal toxicity (LC50), weight loss and subcellular partitioning were assessed as biomarkers to compare species sensitivities. Acute toxicity for Cd was E. fetida > A. trapezoides > A. rosea (p< 0.05). Cadmium caused significant inhibition in TAC and weight loss at upper treatments, and significant increase in apoptosis and lipid peroxidation in all three earthworm species (p< 0.05). Subcellular partitioning in all three species for Cd were: Cytosol> Granules> Debris (P<0.05). Comparison of biomarker responses showed E. fetida was less susceptible to Cd exposure than A. rosea and A. trapezoides. Therefore, this study confirms the employment of A. trapezoides and A. rosea is more suitable than E. fetida for the soil Cd toxicity tests duo to their sensitivity and dispersal in the field.
