Epsilon Archive for Student Projects

Abstract

Drinking water pollution by faeces and associated enteric pathogens can cause serious health issues and
outbreaks of diseases. A fast and reliable indication of faecal pollution is necessary to prevent the consumption
of polluted water. This work aims at identifying faecal pigments in wastewater and discusses
the possibility of using on-line fluorescence monitoring of faecal pigments in water as a tool for the
detection of faecal pollution. Three faecal pigment standards, urobilinogen, urobilin, and stercobilin, as
well as wastewater in- and outflows from five German wastewater treatment plants (WWTPs) were
characterized by 2D fluorescence spectroscopy (using Excitation Emission Matrices), and by high performance
liquid chromatography (HPLC) coupled with absorption (DAD) and fluorescence detection
(FLD), as well as mass spectrometry (MS). Furthermore, tests on faecal pigment stability, reaction to
zinc addition, kinetics, and pH influence on faecal pigment fluorescence were performed. With the obtained
fluorescence data, a parallel factor analysis (PARAFAC) model for the detection and quantification
of urobilin and stercobilin in real water samples was developed. An addition of zinc to the pigments
in real water lead to a time-dependent fluorescence intensification of a factor >30 and red shift of the
pigments’ fluorescence spectra, which can be used as a tool to detect low concentrations of faecal pigments
in water. Urobilin and stercobilin were identified in all examined WWTP inflows. The results and
literature study indicated that a degradation of faecal pigments during wastewater treatment may have
taken place. In the wastewater of one treatment plant, fluorescein was detected. Fluorescence detection
and quantification of faecal pigments in wastewater was possible with the help of zinc addition or prior
enrichment, but more studies are needed to enhance the sensitivity of the method to be sensitive enough
to detect faecal pollution in concentrations relevant for drinking or surface water monitoring. It was
concluded that fluorescence detection of faecal pigments in water is promising as an early warning system,
but in this study it did not prove sensitive enough to be used as a stand-alone method.