Avaliação de risco ambiental de pesticidas para ecossistemas aquáticos - representatividade das espécies padrão de invertebrados

Mestrado em Engenharia do Ambiente - Gestão Ambiental - Instituto Superior de AgronomiaWith the main aim of verifying whether Daphnia magna is sufficient for the evaluation of the environmental risk of pesticides to aquatic ecosystems, toxicity values of 218 insecticides were analyzed. For each one the relative tolerance (Trel) value was calculated to compare the sensitivity of species from different taxonomic groups with that of D. magna. The taxonomic groups were grouped in arthropods, non-arthropod invertebrates, fish, algae/macrophytes and based on Trel values the species sensitivity distribution (SSD) were defined. For the arthropods the influence of the mode of action (MOA) on vulnerability to the insecticide was also analyzed. Still in the arthropods group, for each species, the class, order and family they belong to were identified. To check the necessity of inclusion of a second species studies of relationship were performed, between D. magna, Americamysis bahia and Chironomus riparius. As far as the SSD curves are concerned, for the different groups the most sensitive one was the arthropods group in both values of EC50 and NOEC. Taking into consideration MOA the group of neonicotinoids was the most sensitive one in EC50 case and the GABA – gated chloride channel antagonists in NOEC. The most sensitive taxonomical group was Mysida and it was the combination of Daphnia plus A. Bahia that generated the greater percentage of protection