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Description
The relationship between microbial water pollution and discharges from people experiencing homelessness living in or near riverine environments has not been well studied. The aim of this thesis was to quantify and characterize pollution from homeless encampments to a tributary of the San Diego River (Forester Channel) during dry weather conditions. To do so, chemical and microbial pollutants and water quality parameters were measured in grab samples collected directly upstream and downstream of an active riverine homeless encampment. Samples were also sequenced to investigate changes in the 16S rRNA bacterial communities upstream and downstream of the encampment. Indicators of fecal pollution were found, but there was limited evidence of human-associated fecal pollution. On average, E. coli and enterococci concentrations were higher downstream of the active homeless encampments than they were upstream, but the difference was only statistically significant for E. coli. Furthermore, the human-associated fecal marker, HF183, was not detected in any of the upstream or downstream samples. There were also no considerable shifts in the relative abundance of microbial phyla, class, order, family, or genera between the upstream and downstream sample locations. As such, based on the lack of detectable levels of HF183, the lack of consistent, significant changes in the measured concentrations of physical-chemical pollutants associated with feces, the low caffeine/sucralose ratios observed, and the lack of a considerable shift in the relative abundance of bacterial communities upstream and downstream of the encampment, there is a lack of evidence to suggest that the homeless encampment was contributing fecal pollution to Forester Creek during dry weather conditions.
