Evaluation of the quality of the sediments from sao sebastiao channel, by using toxicity tests with the sea-urchin lytechinus variegatus - Zamboni, A J; Nipper, M G; Bícego, Márcia Caruso (Simposio Latino-Americano de Saude de Ecossistemas Aquaticos e Significados Ecologicos de Bioensaios, 1994)