Ação de compostos emergentes e rejeito hospitalar em Danio rerio e Allium cepa

Abstract

The dumping of chemical substances, both urban, industrial and hospital waste is the main responsible for the high concentrations of toxic substances in the environment. The adverse effects and risks that these substances can cause to the ecosystem have become the subject of scientific research. Chemical substances present in tailings can be metabolized, stored as well as interact directly with the DNA of eukaryotic cells, promoting pre-oncogenic events and epimutations. To assess the impact of the socalled emerging contaminants (EDC's) on the eukaryotic genome, it is possible to use micronucleus (MN) and nuclear abnormalities (AN) tests through onion root meristematic cells (Allium cepa) and fish blood cells (Danio rerio). The aim of this dissertation was to investigate cellular, genotoxic and clastogenic alterations in onion root meristematic cells, through exposure in three sampling efforts of hospital waste at three different times. The collected samples were analyzed in a gas chromatograph coupled to a mass spectrometer (GC-MS QP 2010) in order to qualify the constituents present in the tailings. Through analysis of semi-permanent slides stained by the Shiff method, nuclear and micronucleus abnormalities were computed in 3000 Allium cepa meristematic cells exposed to hospital waste for 96 hours. Likewise, fish and onions were subjected to samples from treatment in PhotoElectroPhenton, containing Bisphenol, considered one of the main emerging contaminants. The results obtained with the tailings show that the mitotic index in the cells evaluated in the three samples collected were 2,8%, 2,7% and 3,16% respectively. Compared with the negative control group which was 13.2% and 4.9% in the positive control. Low rates of dividing cells are indicative of tailings-induced cell cycle damage. Nuclear abnormality (AN) events in treatments 2 and 3 differed statistically when compared to positive and negative controls. Nuclear alterations that report genotoxic damage present the following results in 3,000 cells for the three samples: amount of MN was normal for the first sample (0.33%), in the second sample the amount of MN was higher (0,46%); binucleate and Lobbed-type cells in the first sample (0,21%) and in the second (0,30%). Cells undergoing apoptosis were also counted, and make up the cells treated with sample 1 (2,7%) and the second sample (4,1%). In fish, the number of cells with MN in the samples in BPA pH 3 and 5 was significantly higher than in the fish of the negative control, however the sample in pH5 was less error-inducing than the sample pH 3. In the GC-MS analysis several main peaks were observed and different retention times identified. In treatment 1 T (3,44) and treatment 2, T (3,47), Propoxur was one of the products found to offer clastogenic potential as it is a synthetic carbamate, composed of aromatic ether and acetylcholinesterase inhibitor, widely used as a pesticide.