title: To what extent can portable fluorescence spectroscopy be used in the real-time assessment of microbial water quality?
abstract: The intrinsic fluorescence of aquatic organic matter emitted at 350 nm when excited at 280 nm correlates widely with water quality parameters such as biochemical oxygen demand. Hence, in sewage-impacted rivers and groundwater, it might be expected that fluorescence at these wavelengths will also correlate with the microbial water quality. In this paper we use a portable fluorimeter to assess the relationship between fluorescence intensity at this wavelength pair and Escherichia coli enumeration in contrasting river catchments of poor water quality: in KwaZulu-Natal, S. Africa and the West Midlands, UK. Across all catchments we demonstrate a log correlation (r = 0.74) between fluorescence intensity and E. coli over a seven-log range in E. coli enumerations on non-perturbed (unfiltered) samples. Within specific catchments, the relationship between fluorescence intensity and E. coli is more variable, demonstrating the importance of catchment-specific interference. Our research demonstrates the potential of using a portable fluorimeter as an initial screening tool for indicative microbial water quality, and one that is ideally suited to simple pollution scenarios such as assessing the impact of faecal contamination in river or groundwater at specific sites.
authors.affiliation: Connected Waters Initiative Research Centre, UNSW Australia, Sydney NSW2052, Australia.
authors.forename: Andy
authors.initials: A
authors.lastname: Baker
authors.affiliation: School of Earth Sciences, University of Melbourne, Parkville, 3010 Melbourne, Victoria, Australia.
authors.forename: Susan A
authors.initials: SA
authors.lastname: Cumberland
authors.affiliation: School of Geography, Earth and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK.
authors.forename: Chris
authors.initials: C
authors.lastname: Bradley
authors.affiliation: Pollution Research Group, University of KwaZulu-Natal, South Africa.
authors.forename: Chris
authors.initials: C
authors.lastname: Buckley
authors.affiliation: School of Civil Engineering, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK.
authors.forename: John
authors.initials: J
authors.lastname: Bridgeman
mesh_terms: D004784:Environmental Monitoring / Q000379:methods*; D013019:South Africa; D013050:Spectrometry, Fluorescence; D014871:Water Microbiology; D014873:Water Pollutants / Q000032:analysis*; D060753:Water Quality
chemical_list: D014873:Water Pollutants
keywords: Fluorimetry; Groundwater; Microbial water quality; Organic matter fluorescence; River