Data was compiled and treated from 60 toxicity tests using marine organisms under effect of 4 reference substances: copper, chrome, zinc and DSS, available in the literature and data from the Ecotoxicity Laboratory from CTTMar/UNIVALI. By ranking values of CL50/CE50, it was shown that microcrustaceans copepods and mysids are the most sensitive organisms to all tested substances. Sea urchins and mollusks also exhibited a high sensibility, but are mutually exclusive, showing therefore a specificity to the type of contaminant. Through a preliminary risk analysis, using the sensibility ranking and data from the acceptable limits from CONAMA N° 20 1986 resolution, these substances exhibit a probability effect of up to 60% on the marine aquatic biota.