STUDY OF SUBLETHAL AND LETHAL EFFECTS (REPRODUCTION AND TERATOGENISIS) OF THE PHARMACEUTICAL COMPOUND TRICLOSAN TO Daphnia similis, Ceriodaphnia dubia, and Ceriodaphnia silvestrii (CLADOCERA, CRUSTACEA) / Estudos dos efeitos letais e subletais (reprodução e teratogênese) do farmáco triclosan para Daphnia similis, Ceriodaphnia dubia, Ceriodaphnia silvestrii (Cladocera, crustacea)




Until recently, the knowledge of contamination on aquatic ecosystems was restricted to metals and pesticides, with little emphasis on pharmaceuticals. Despite being found in concentrations of nanograms to micrograms per litre, these compounds can cause lethal and development defects on living organisms. Ecotoxicological studies have been performed to identify effects of these substances. However, the data available is not sufficient, especially for species in tropical and sub-tropical environments. Lethal and sublethal effects, such as growth and reproduction, are determined through acute and chronic toxicity tests, but developmental effects are hardly evaluated in these tests. Thus, researchers have been developing refined methods, such as the direct exposure of embryos to chemicals in tests of teratogenisis. These tests are restricted to Cladocera. The purpose of study was to evaluate lethal and sublethal effects of an antimicrobial compound, Triclosan (5-chloro-2[2,4-dichloro-phenol) to Daphnia similis, Ceriodaphnia dubia and C. silvestrii. Acute toxicity tests with Daphnina similis and Ceriodaphnia silvestrii were conducted with natural reconstituted water, with and without photoperiod, aiming to estimate more rigorous effects in tropical and subtropical environments. Acute toxicity tests were conducted with reconstituted water (Milli-Q) without photoperiod to observe the toxicity of Triclosan without external interferences. Embryonic stages of development in D. similis, C. dubia and C. silvestrii were identified to optimize teratogenesis tests. Acute toxicity testes were performed with D. similis, C. dubia, C. silvestrii and cronic toxicity testes with D. similis and C. silvestrii. Eggs were cultivated "in vivo" at temperature of 20°C (D. similis) and 25°C (C. dubia and C. silvestrii), and observed every hour until full development. Subsequently, the conditions of the teratogenisis tests were established and tests were performed with D. similis. The EC50,48H of Triclosan for D.similis and C. silvestrii in natural reconstituted water with photoperiod was 0.23 and 0.10 mg.L-1, respectively, and 0.13 mg.L-1 for C. silvestrii, without photoperiod. The EC50;48H values to D. similis, C. dubia and C. silvestrii for the tests with reconstituted water (Milli-Q) without photoperiod, were: 0.218, 0.088 and 0.083 mg.L-1, respectively. The CEO for D. similis was 0.1 mg.L-1 and the IC50 value (malformation) for neonates was 0.057 mg.L-1. The CEO was 0.04 mg.L-1 for C.silvestrii, not being verified malformations in neonates. Seven stages were observed in the embryonic development of cladocerans with duration (hours) of 51 (± 5) to D. similis, 34 (± 3) to C. dubia and 36 (± 2) to C. silvestrii. The IC50 value (malformation) in the teratogenesis test was 0.075 mg.L-1 to D. similis, which is close to the value obtained for chronic toxicity.


desenvolvimento embrionário ecotoxicologia teratogênese fármaco desenvovimento embrionário fármaco teratogênese ecotoxicologia

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