Embryotoxicity of copper and zinc in tropical sea urchin Tripneustes gratilla

The study determined the individual toxicity of copper (Cu) and zinc (Zn) in sea urchin Tripneustes gratilla. Bioassay using inhibitions on fertilization, early cleavage, mid cleavage, late cleavage and blastulation as endpoints involved exposure of viable gametes to Cu and Zn for 0.5, 3, 6, 9 and 12 h, respectively. Inhibitions increased significantly with concentration of Cu and Zn. Probit analysis estimated EC50 values for Cu and Zn, respectively, at 32 and 67 mu g L-1 on fertilization; 31 and 93 mu g L-1 on early cleavage; 43 and 61 mu g L-1 on mid cleavage; 42 and 42 mu g L-1 on late cleavage; and 20 and 44 mu g L-1 on blastulation. Results showed that toxicity of Cu is significantly higher (p