Sensibilidade do Ouriço Arbacia lixula (Echinodermata: Echinoidea) em Testes de Toxicidade

Abstract

Sensitivity of the sea urchin Arbacia lixula (Echinodermata: Echinoidea) in toxicity tests This study investigates the sea urchin Arbacia lixula in terms of embryonic and larval development time, development tolerance in different salinities and maintenance water temperatures, its repeatability in the presence of reference toxicants used in toxicity tests, and its sensitivity in comparison with other species of sea urchin normally used in Brazil. The embryonic development of A. lixula at 25°C rapidly reached the larval stage pluteus in less than 24 hours, therefore it was not necessary to extend the period of the experiments. However, it presents some disadvantages such as a fertilization membrane that is not very clear, and often with a fertilization rate from 70 to 80%. The experiments to determine the viability of the embryos in different salinities and temperatures demonstrated a wide tolerance, with a normal development of 24 h between the salinities of 29 and 39 and 20 h for 30 o C of temperature. The toxicity tests carried out with the reference toxicant resulted in values for variation coefficients lower than 30% for chromium and zinc, demonstrating that the tests are repeateable. When compared with other sea-urchin species (Lytechinus variegatus and Echinometra lucunter), A. lixula presented sensitivity of the same order and scale, and similar results were obtained for the environmental samples (sediment elutriate).