A multibiomarker approach in rats to assess the impact of pollution on Sinos River, Southern Brazil

Abstract

The aim of this study was to determine the feasibility of combining water quality analysis with different biomarkers to characterise the relationship between anthropogenic contamination and biotic response in the Sinos River, southern Brazil. Wistar rats were studied using three biomarkers combined with physical, chemical and microbiological analysis to assess the effects of pollution at four sampling sites. The induction of oxidative stress was quantified by MDA levels in peripheral blood, lymphocyte DNA damage was determined using the comet assay, and histopathological changes were analysed in the liver. After sampling, animals were allowed to drink the river water during a 48 hours period. No increase in oxidative stress and DNA damage was observed. However, liver damage was observed in the animals exposed to water samples, indicating that the Sinos River is contaminated with hepatotoxic substances. Water analyses confirmed that water quality decreased downriver.Keywords: genotoxicity, pollution, biomarkers, oxidative stress, tissue damage. Análise de múltiplos biomarcadores em ratos para determinar o impacto da poluição do rio dos SinosResumo O objetivo deste estudo foi determinar a viabilidade de combinar a análise da qualidade da água com o estudo de biomarcadores para caracterizar a relação entre contaminação antropogênica e resposta biótica no rio dos Sinos, sul do Brasil. Ratos Wistar machos foram estudados usando três biomarcadores combinados com análises físicas, químicas e microbiológicas para determinar os efeitos da poluição em quatro locais de amostragem de água. A indução do estresse oxidativo foi quantificada pelos níveis de MDA no sangue periférico, o dano do DNA linfocitário foi determinado usando o ensaio cometa, e as alterações histopatológicas foram analisadas no fígado. As amostras da água do rio dos Sinos (dos quatro pontos selecionados) foram administradas por via oral (como água para beber) por 48 horas. Nenhum aumento do estresse oxidativo ou do dano do DNA foi observado. Entretanto, dano do tecido hepático foi verificado nos animais expostos à ingestão das amostras da água, indicando que o rio dos Sinos está contaminado com substâncias hepatotóxicas. As análises das amostras de água confirmaram a redução da qualidade da água em direção à foz do rio.Palavras-chave: genotoxicidade, poluição, biomarcadores, estresse oxidativo, dano tecidual.

Surface water quality in the Sinos River basin, in Southern Brazil: tracking microbiological contamination and correlation with physicochemical parameters

“…BOD 5 , the main parameter in the characterization of pollution in bodies of water (Von Sperling 2005), presented a concentration (6.42 mg/l) above that recommended by law (up to 5 mg/l O 2 ) in the lower stretch, characterizing pollution of these waters. The main cause for this is the increased flow of effluents, predominantly organic (Macedo 2009;Rechenmacher et al 2010). However, in the upper stretch, BOD 5 concentrations observed were less than 1 mg/l, indicating probable environmental conservation and improved water quality, with reduced interference from human actions, as already observed by other studies (Blume et al 2010;FEPAM 2014).…”

Integrated Environmental Assessment of streams in the Sinos River basin in the state of Rio Grande do Sul, Brazil

“…The Pampa stream presents high levels of domestic pollution along its course, often comparable to untreated domestic wastewaters (Nascimento and Naime, 2009), and the contamination of the EstânciaVelha/Portão stream has been assigned to domestic and industrial wastewater discharges (Naime and Fagundes, 2005).…”

Evaluation of phytotoxicity of municipal landfill leachate before and after biological treatment

“…However, in these locations, there is still generation and treatment of leachate, which is ultimately released in the water resources. The water quality in the basin is influenced by the direct discharge of domestic and industrial sewage, which have the potential to cause toxic effects on genetic and cellular levels (Blume et al, 2010;Scalon et al, 2010;Rechenmacher et al, 2010;Costa and Droste, 2012). Although the release of leachate poses an environmental risk, the effectiveness of its treatment and its toxicity in the Sinos River Basin were not assessed.…”