Mutagenic Activity Assessment of Cristais River, São Paulo, Brazil, Using the Blue Rayon/Salmonella Microsome and the Tradescantia pallida Micronuclei Assays

Abstract

Cristais River, located in the metropolitan region of Sao Paulo city, is used as source of drinking water and mutagenic activity was observed in the extracts obtained from its waters. This effect was associated to a discharge of a textile dye processing plant that contains, among other mutagenic compounds, the dyes C.I. Disperse Blue 373, C.I. Disperse Violet 93 and C.I. Disperse Orange 37. The objective of this work was to assess the mutagenic activity using the blue rayon hanging technique (BR)/Salmonella microsome assay and the Tradescantia-MCN mutagenicity test exposed in the field for 24 hours before and after the discharge of the cited industrial effluent. The BR/Salmonella microsome assay showed to be sensitive to detect the mutagenicity, after the textile dye processing plant discharge. The Trad-MCN assay, using plant cuttings exposed directly in the river showed an increased response after the industrial discharge. Due to its simplicity and low cost, the Trad-MCN assay seems to be a good alternative for screening surface waters for mutagenic activity. Both techniques have the advantage of better represent the environmental conditions because the extraction/exposure is performed in the field during 24 hours.