Search for water quality markers and biomarkers of effects on growth and reproduction of Japanese medaka in treated wastewater by comprehensive analysis of chemical substances using TOF-MS and by metabolomics

Abstract

 In this study, to estimate water quality markers and biomarkers on fish reproduction in treated wastewater, a growth test was carried out for Japanese medaka exposed to effluents of secondary treatment and of microbial carrier process, followed by a Target screening analysis on endogenous metabolites in liver and reproduction test for grown medaka. In addition to a general water quality analysis, a Non-target analysis on chemical substances by LC-QTOF/MS was carried out for test waters. A relationship between the water quality parameters and the impacts observed on growth, on reproduction, and on composition of endogenous metabolites was determined by statistical analysis. Decreases in fertilized egg number and fertility were observed in the reproduction test using secondary treated wastewater. Lager changes in metabolites were observed in female fish than in male. Phosphocreatine was among those metabolites that particularly increased in female fish exposed to secondary treated wastewater. The fertilized egg number showed high correlation to the concentration of NH_4-N and of the compound observed at m/z 362.1523 by LC-QTOF/MS. Fertility showed high correlation to the fluorescence intensity (Ex : 345 nm/ Em : 430 nm) and the concentration of the compound observed at m/z 517.0774.