[Toxicologic effects of cadmium on gametes and embryonal kinetics of paracentrotus lividus].

Abstract

The adverse effects of cadmium chloride or cadmium sulphate on both fertilization of sea urchin eggs by spermatozoa and cadmium treated embryos have been studied. Cd treated ova can be fertilized by control spermatozoa. On the contrary, the preliminary treatment of spermatozoa with CdCl2 or CdSO4 succeeds in reducing the fertilization rate of control eggs at concentrations as low as 2 micrograms/ml. Cd sulphate appears to be more noxious than Cd chloride. The study of the residual motility of sea urchin embryos exposed to either CdCl2 or CdSO4 has evidenced a fairly effect at 21 hours after fertilization. On the contrary, concentrations of 25 micrograms/ml Cd chloride or Cd sulphate significantly affect the motility of 48 hours embryos. Higher levels of cadmium, for example, 150 or 200 micrograms/ml, completely block the translation of developing organisms. In this instance, Cd chloride is more effective than Cd sulphate. In addition, a few embryos are affected by malformations and are underdeveloped. These results are interpreted on the basis of the inhibitory effect of cadmium on the CaCO3 uptake by tissues and structures which physiologically need to be calcified in order to develop and function. Further, they give support to the predictive significance of the toxicological tests on the sea urchin plutei in monitoring environmental hazards.