Single and joint oxidative stress of cadmium and phenanthrene on the Bivalve Anadara subcrenata

Single and joint oxidative stress of cadmium (Cd) and phenanthrene (Phe) on Anadara subcrenata were investigated under laboratory conditions with biomarkers such as reactive oxygen species (ROS), malondialdehyde (MDA), superoxide dismutase (SOD) and total antioxidant capacity (TAOC). The results indicated that the ROS level in Anadara subcrenata exposed to Cd and Phe significantly (P < 0.05) increased during the early exposure stage, and the TAOC level and SOD activity were induced as the response of the antioxidant defense system, and this followed a damage, recovery or acclimation event. The MDA content was negatively correlated with SOD activity. As the time went on, the ROS level decreased gradually and was close to that in the control after 9 days; the TAOC level decreased accordingly, but the recovery rate of the SOD activity was slower than that of the TAOC level. High concentrations of Cd or Phe had a stronger oxidative stress effect on Anadara subcrenata. Phe had a stronger effect on the SOD activity of Anadara subcrenata. The joint effects of Cd and Phe on the levels of ROS and TAOC, SOD activity and MDA content in Anadara subcrenata are dependent on their concentration combination, which were called the double-dose dependent effects and time-dependent effects, respectively. The binary mixture treatments of 477.33 μg/L Cd and 48.08 μg/L Phe had the highest oxidative stress on Anadara subcrenata.