Arsenic Exposure Affects Embryo Development of Sea Urchin, Paracentrotus lividus (Lamarck, 1816)

Toxicity tests were performed with embryos of Paracentrotus lividus to investigate the toxicological effect of two arsenic species: arsenate (As-V), expected to be more toxic, and dimethyl-arsinate (DMA) expected to be less toxic. Exposures to toxicants were performed at different developmental stages in order to identify the most sensitive phase of embryological development. Statistical analysis revealed a high significance of each factor (Molecule, Concentration and Time of exposure) and their interaction for the dependent variable Percentage of normal-shaped plutei. In particular, the 8 cell stage was the most sensitive to arsenic; at a concentration of 50 mu g L-1 DMA proved to be more toxic than As-V, resulting in nearly 50 % of normal-shaped plutei against the 74 % recorded for As-V. Starting the administration of arsenic at the morula stage, arsenate proved to be significantly more toxic when compared to DMA.