Approved Abstracts

A new testing platform for tropical marine environment: Acute and chronic evaluations



Author(s): School of Pharmaceutical Sciences, University of São Paulo; Oceanographic Institute, University of São Paulo; School of Technology, University of Campinas; Oceanographic Institute, University of São Paulo; School of Technology, University of Campinas;
Presenter: Amanda dos Santos

The majority of the ecotoxicological tests for tropical marine and estuarine regions, especially in South America, are being performed with acclimated exotic standardized species from temperate areas. However, toxicity tests with representative organisms of these areas are essential for deriving reliable and relevant criteria and assessing the quality of this environment. Lately, we joined efforts to develop the circumtropical marine amphipod Parhyale hawaiensis as a species for ecotoxicity evaluation in marine environments. We developed and published protocols for culture and miniaturized acute toxicity test for testing water and sediment. As well as methods for internal dose analysis of organic and inorganic compounds. We explored molecular and regenerative responses of P. hawaiensis after exposure to toxicants. We are investigating genotoxicity endpoints, such as comet analysis and micronuclei in hemocytes. Furthermore, to verify impacts at higher biological levels, we developed a chronic toxicity protocol assessing endpoints as survival, reproduction, and growth. Aiming to use as less sample and testing volumes as possible we tested different conditions such as number of organisms, medium volume, and amount of food per replicate, and monitored physical-chemical parameters, time required for sexual maturity, and time required for neonates hatching. After selection of the most promising condition, we performed two independent experiments with zinc sulphate (concentrations of 0.02 to 2.0 mg Zn/L) and 3,4-dichloroaniline (concentrations of 0.01 to 1.0 mg/L) as proof of concept. One-way analysis of variance (ANOVA) and Dunnett’s test were used to analyze the data (p≤0.05) and to establish the no observed effect concentration (NOEC). For both toxicants, we observed significant reductions in survival, reproduction, and growth. For zinc, the NOEC for survival was 0.2 mg Zn/L and for reproduction and growth, 0.1 mg Zn/L. As for 3,4-DCA the NOEC for survival and reproduction was 0.3 mg/L, and for growth 0.01 mg/L. Data with other marine test organisms are being retrieved from the literature for sensitivity comparisons. In addition, thinking in other responses with ecological relevance, we are working on the description of hemocytes from P. hawaiensis’ hemolymph to provide data for the development of immunotoxicological endpoints. The immune system is a critical determinant enabling the organism to survive, to minimize the costs of an infection and to keep good reproduction and growth. Therefore, we are successfully expanding the information and tools to make P. hawaiensis a robust model organism in ecotoxicology. Financial Support: Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - Brasil (CAPES) - Finance code 001, Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) and Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP, processes n. 20/04628-8, 2017/16168-9 and 2020/06112-9).

Keywords: Amphipod; Toxicity; Miniaturization

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