Tryptophan-like and humic-like fluorophores are extracellular in groundwater: implications as real-time faecal indicators.

ABSTRACT: Fluorescent natural organic matter at tryptophan-like (TLF) and humic-like fluorescence (HLF) peaks is associated with the presence and enumeration of faecal indicator bacteria in groundwater. We hypothesise, however, that it is predominantly extracellular material that fluoresces at these wavelengths, not bacterial cells. We quantified total (unfiltered) and extracellular (filtered at < 0.22 µm) TLF and HLF in 140 groundwater sources across a range of urban population densities in Kenya, Malawi, Senegal, and Uganda. Where changes in fluorescence occurred following filtration they were correlated with potential controlling variables. A significant reduction in TLF following filtration (ΔTLF) was observed across the entire dataset, although the majority of the signal remained and thus consi

SUBMITTER: Sorensen JPR 

PROVIDER: S-EPMC7505957 | biostudies-literature | 2020 Sep

REPOSITORIES: biostudies-literature