Efeitos Ecotoxicológicos do córrego barro preto mediante ensaios de toxicidade aguda em Solanum lycopersicum e Artemia salina

Abstract

INTRODUCTION: There are a large number of bioassays designed to determine the toxicity of contaminants against the effects on aquatic beings. Organisms commonly used in toxicity testing include representative groups of marine, river or terrestrial ecosystems, such as plants, invertebrates and fish. AIMS: to evaluate the phytotoxicity of the water of the Barro Preto stream, located in Trindade-GO, through the germination process and the development of seedlings of Solanum lycopersicum, as well as its acute toxicity using the microcrustacean Artemia salina. METHODOLOGY: The experiment was carried out in the Botany laboratory of the Centro Universitário Goyazes, using water samples from three points of the Barro Preto stream, in addition to the control (distilled water) for the phytotoxicity test with tomato seeds ( Solanum lycopersicum) and positive and negative controls in the acute toxicity test with Artemia salina. In addition, a macroscopic evaluation of the points where water was collected from the Barro Preto stream was carried out using the Environmental Impact Index of Nascentes. In the germination test, the evaluation was carried out by calculating the germination percentage, percentage of normal and abnormal seedlings and germination speed index (IVG). In the acute toxicity test, the percentage of mortality of Artemia salina was evaluated. RESULTS: The investigation of the physical characteristics of the four selected points of the Córrego Barro Preto revealed that of these points 3 and 4 showed a poor degree of preservation (class E), while points 1 (this being the source of the Barro Preto stream) and 2 were, respectively, in a reasonable (class B) and poor (class D) environmental condition. The germination tests indicated that stream water did not affect the germination rate of tomato seeds, however, it was possible to observe that germinated tomato seeds submitted to treatment with water from point 3 had a higher percentage of abnormalities. Regarding the acute toxicity test with A. Salina, it was observed that artemias submitted to treatment with water from points 2, 3 and 4 of Córrego Barro Preto presented 100% mortality after 24 hours. CONCLUSION: Due to the experimental conditions applied in this study, the water from the Barro Preto stream did not influence the germination of tomato seeds, however, it promoted a high percentage of abnormal seedlings, as well as mortality of the microcrustaceum A. salina, especially at point 3, suggesting that the presence of different types of residues dissolved in the water of the stream can cause morphological and functional alterations in the development of tomato seedlings, possibly due to its toxicity.