Tryptophan-like fluorescence as a measure of microbial contamination risk in groundwater

Nowicki, Saskia; Lapworth, Dan J. ORCID: https://orcid.org/0000-0001-7838-7960; Ward, Jade S.T.; Thomson, Patrick; Charles, Katrina. 2018 Tryptophan-like fluorescence as a measure of microbial contamination risk in groundwater. Science of the Total Environment, 646. 782-791. https://doi.org/10.1016/j.scitotenv.2018.07.274

Before downloading, please read NORA policies.

Preview

Text TLF_STOTEN_Accepted_Manuscript.pdf - Accepted Version Available under License Creative Commons Attribution Non-commercial No Derivatives 4.0. Download (2MB) | Preview

Abstract/Summary

Microbial water quality is frequently assessed with a risk indicator approach that relies on Escherichia coli. Relying exclusively on E. coli is limiting, particularly in low-resource settings, and we argue that risk assessments could be improved by a complementary parameter, tryptophan-like fluorescence (TLF). Over two campaigns (June 2016 and March 2017) we sampled 37 water points in rural Kwale County, Kenya for TLF, E. coli and thermotolerant coliforms (total n = 1,082). Using three World Health Organization defined classes (very high, high, and low/intermediate), risk indicated by TLF was not significantly different from risk indicated by E. coli (p=0.85). However, the TLF and E. coli risk classifications did show disagreement, with TLF indicating higher risk for 14% of samples and lower risk for 13% of samples. Comparisons of duplicate/replicate results demonstrated that precision is higher for TLF (average relative percent difference of duplicates = 14%) compared to culture-based methods (average RPD of duplicates >= 26%). Additionally, TLF sampling is more practical because it requires less time and resources. Precision and practicality make TLF well-suited to high-frequency sampling in low resource contexts. Interpretation and interference challenges are minimised when TLF is measured in groundwaters, which typically have low dissolved organic carbon, relatively consistent temperature, negligible turbidity and pH between 5 and 8. TLF cannot be used as a proxy for E. coli on an individual sample basis, but it can add value to groundwater risk assessments by improving prioritization of sampling and by increasing understanding of spatiotemporal variability.

Item Type:	Publication - Article
Digital Object Identifier (DOI):	https://doi.org/10.1016/j.scitotenv.2018.07.274
ISSN:	0048-9697
Additional Keywords:	GroundwaterBGS, Groundwater, Point source pollution, Groundwater protection, International development
Date made live:	26 Sep 2018 10:56 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/521039

Actions (login required)

View Item

Document Downloads

More statistics for this item...