6 research outputs found

    Genotoxicity biomonitoring of sewage in two municipal wastewater treatment plants using the Tradescantia pallida var. purpurea bioassay

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    The genotoxicity of untreated and treated sewage from two municipal wastewater treatment plants (WTP BN and WTP SJN) in the municipality of Porto Alegre, in the southern Brazilian state of Rio Grande do Sul, was evaluated over a one-year period using the Tradescantia pallida var. purpurea (Trad-MCN) bioassay. Inflorescences of T. pallida var. purpurea were exposed to sewage samples in February (summer), April (autumn), July (winter) and October (spring) 2009, and the micronuclei (MCN) frequencies were estimated in each period. The high genotoxicity of untreated sewage from WTP BN in February and April was not observed in treated sewage, indicating the efficiency of treatment at this WTP. However, untreated and treated sewage samples from WTP SJN had high MCN frequencies, except in October, when rainfall may have been responsible for reducing these frequencies at both WTPs. Physicochemical analyses of sewage from both WTPs indicated elevated concentrations of organic matter that were higher at WTP SJN than at WTP BN. Chromium was detected in untreated and treated sewage from WTP SJN, but not in treated sewage from WTP BN. Lead was found in all untreated sewage samples from WTP SJN, but only in the summer and autumn at WTP BN. These results indicate that the short-term Trad-MCN genotoxicity assay may be useful for regular monitoring of municipal WTPs

    Genotoxicity on Tradescantia pallida var. purpurea plants exposed to urban and rural environments in the metropolitan area of Porto Alegre, southern Brazil

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    The Trad-MCN bioassay was used to investigate the genotoxicity on Tradescantia pallida var. purpurea plants exposed to variations in the environmental conditions in urban and rural sites in the metropolitan area of Porto Alegre, southern Brazil, over a one-year period. In spring 2009 and in summer, autumn and winter 2010, potted plants of T. pallida var. purpurea were exposed at two sites with different characteristics: the urban area of the municipality of Estância Velha, with leather and footwear industrial activity, and a Site of Special Environmental Interest in the rural area of the municipality of Novo Hamburgo. Other plants comprised the control group and were kept indoors. Frequencies of micronuclei (MCN) were determined in early tetrads of pollen mother cells and expressed as MCN/100 tetrads. Climate data were also registered during the experiment. MCN frequencies in the urban area were significantly higher (up to 8.13) than those found in the rural area (up to 1.26) and in the control group (up to 1.10), which did not differ statistically from each other over the year. The higher MCN frequencies observed in the urban site can be attributed to air pollution, but also may have been influenced by microclimatic and daily thermal variation differences between sites. Higher temperatures recorded in spring and summer may have influenced MCN frequencies observed in the urban site. No clear relation was observed between rainfall and MCN frequencies. Similar and high relative humidity percentages were registered over the period of the study. Considering that the bioindicator plant presents an integrated response to abiotic factors such as pollutants and weather conditions, it can be used as an additional tool that can point to synergistic effects of environmental variables on organisms
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