Use of the Tradescantia pallida purpurea as bioindicator of toxic agents in the water. Natália Barreto dos Santos, Claudia de Moura, Ana Beatriz Carollo Rocha-Lima, Débora-Jâ de Araujo Lobo, Paulo Hilário Nascimento Saldiva, Luciana Bizeto

Abstract

The pollution came gradually at first and is now increasing rapidly in one of the most important rivers for the people of São Paulo, the Tietê River. The use of bio-indicator allows to evaluate and characterize the health of the environment by providing a more accurate knowledge of environmental quality. The aim of this study was to analyze and compare the toxicity of a water sample collected in the Tiete River in the city of Cabreúva, on the border with Araçariguama, state of São Paulo, comparing it to the positive, white and negative controls, using Tradescantia pallida purpurea species as a bio-indicator of water quality. For this, approximately 20 stems of the plant species Tradescantia pallida purpurea were collected for performing a positive, white and negative control. The stems or "cuttings" were placed in tap water constituting the adaptive phase and were later transferred to the controls and to the collected water sample from the Tietê river, remaining there for 8 hours. After this period, they were transferred back to tap water characterizing the recovery period. Ten blades with inflorescences were prepared for each sample of collected water and the micronuclei was counted in 1200 cells, comparing them with the positive, white and negative controls. It was verified a high prevalence of micronuclei in the experimental sample in relation to the other controls, including positive (formaldehyde). The frequency of micronuclei found in the experimental sample, compared with controls, indicates a high prevalence of toxic substances in the analyzed water.