title: Effects of a textile azo dye on mortality, regeneration, and reproductive performance of the planarian,Girardia tigrina.
abstract: BACKGROUND
  Many dyes can be considered emerging contaminants. The most widely used dyes belong to the class of azo compounds, some of which are known to have toxic and genotoxic properties. They are used in great quantities in textile activities and are of environmental concern because of their potential discharge in water. Planarians have been successfully used as test organisms in hazard evaluation of different chemicals, and we demonstrate the suitability ofGirardia tigrinafor laboratory testing. The aim of this work was to evaluate the suitability of the planarian speciesG. tigrinato assess the ability of the azo textile dye disperse red 1 to cause acute toxicity and adverse effects in the regeneration and reproduction of newborn and adult specimens.
  
  
  RESULTS
  Disperse red 1 presented a median LC50of 75 and 152 mg/L, respectively, for newborns and adults ofG. tigrina, showing that newborns are twice as susceptible to the dye. Uncoordinated movements, irregular twists, colored skin, increased mucous production, and regenerative delays were observed after dye exposure at sub-lethal concentrations.
  
  
  CONCLUSIONS
  A no-observed-adverse-effect concentration (NOAEC) of 0.1 mg/L could be determined for disperse red 1 based on the fecundity test. Zinc seems to be a suitable positive control for monitoring the sensitivity inG. tigrinatests within only 24 h of exposure. This study demonstrates the applicability ofG. tigrinatests in the hazard evaluation of water contaminants, such as azo dyes.
authors.affiliation: School of Technology, State University of Campinas - UNICAMP, Paschoal Marmo Street 1888, Limeira, SP 13484-332 Brazil.
authors.forename: Alyson Rogério
authors.initials: AR
authors.lastname: Ribeiro
authors.affiliation: School of Technology, State University of Campinas - UNICAMP, Paschoal Marmo Street 1888, Limeira, SP 13484-332 Brazil.
authors.forename: Gisela de Aragão
authors.initials: GA
authors.lastname: Umbuzeiro
keywords: Azo dye; Disperse red 1; Girardia tigrina; Planarians; Regeneration; Reproductive performance