Combined Toxicological Effects of Cd-HA-TiO2 on Chlorella

Chlorella was selected to test the combined toxicological effects of Cd-HA-TiO2.The present results showed that the 96h-EC50 of single Cd，Cd-HA and Cd-TiO2 were 0.166， 0.185~0.207 and 0.185~0.199mg/L， respectively，indicating that the toxicity of cadmium would be attenuated in the presence of HA or TiO2. This was mainly due to the reduction of free Cd ion through combination of HA and TiO2. However，the 96h-EC50 of Cd-HA-TiO2 was decreased to 0.063~0.089 mg/L，indicating that the toxicity of cadmium was significantly increased in the presence of HA and TiO2 existed. Chlorella showed highest CAT level after exposure to Cd-HA-TiO2 compared to other conditions. In addition，the bio-accumulation level of Cd was highest after exposure to Cd-HA-TiO2. This may explain that the highest toxicity was observed on the Cd-HA-TiO2 exposure group.