Quality water assessment of the Matadouro Stream, Ijui, Rio Grande do Sul, by physicochemical parameters and the Allium cepa test

Urban water resources are of great importance for the maintenance of the ecosystem and their quality needs to be evaluated to identify possible sources of contamination. The present study aimed to use the Allium cepa L. test and physical-chemical analysis to assess the water quality of stream Matadouro, Ijui, Rio Grande do Sul. The collections were carried out in four places of the urban stream and the samples used for physical-chemical analysis and Allium cepa test. The following parameters were evaluated: biochemical oxygen demand, chemical oxygen demand, total phosphorus, ammoniacal nitrogen, suspended solids and surfactants, trophic state index, mitotic index, and chromosomal aberrations. With regard to physical-chemical analysis, point 2 had the most changes, while point 1 (spring), the indicators showed better water quality. The trophic state index presented an average value of 59.17, classifying the stream in eutrophic degree. The mitotic index analysis showed that all points had stimulation of cell proliferation. Chromosomal aberrations were verified in all samples, however, higher in point 4. The Allium cepa test showed possible cytotoxic and genotoxic potential and, associated with the physical-chemical parameters, proved to be a good tool for assessing water quality. This study indicated that the urban stream is impacted by the surrounding actions, especially those related to domestic pollutants.