To assess the risk of chemical contaminants it is desirable to derive toxicity data from representative species of the ecosystem intended to be protected. However, species of occurrence in Brazil are rarely used in toxicity tests, especially for marine and estuarine environments. To address this need, we evaluated the toxicity of different toxicants such as metals and organic compounds to marine invertebrates of Brazilian occurrence, representative from tropical regions and cultivated in laboratory. We used two epibenthic test species of Brazilian occurrence, Parhyale hawaiensis, a deposit feeding amphipod and Nitocra sp, a harpacticoid copepod. Nitocra sp. was more sensitive than other copepods to zinc, and more sensitive than P. hawaiensis to disperse dyes. Sensitivity species distribution revealed that Nitocra sp. and P. hawaiensis were similarly responsive as other marine species to zinc, and Nitocra sp. was among of the most sensitive species. Moreover, our study highlighted that organic compounds are poorly explored in toxicity evaluation with marine organisms; therefore, more studies need to be carried out to assess the toxicity of different substances using marine and estuarine organisms representative of tropical ecosystems.

O trabalho consiste na implementação de melhorias em ensaios de toxicidade aguda em microplaca com o anfípode marinho Parhyale hawaiensis, visando o atendimento dos protocolos internacionais que requerem que o coeficiente de variação entre os ensaios realizados seja menor que 30%. Foram utilizados como substâncias teste os metais: zinco, cobre e cádmio. A variabilidade entre osensaios de toxicidade aguda em microplaca para os três metais estudados encontram-se abaixo do valor máximo recomendado (menor que 30%). Conclui-se que as mudanças realizadas nos procedimentos de preparo e montagem de testes contribuiram positivamente para obtenção de resultados satisfatórios.