An Assessment of Ambient Water Quality and Challenges with Access to Water and Sanitation Services for Individuals Experiencing Homelessness in Riverine Encampments

Abstract

Individuals experiencing unsheltered homelessness face significant barriers to accessing water, sanitation, and hygiene services, but the risks associated with this lack of access and barriers to service provision have been largely understudied. We analyzed water samples upstream and downstream of three homeless encampments in the San Diego River watershed and interviewed service providers from public and nonprofit sectors to assess local perceptions about challenges and potential solutions for water and sanitation service provision in this context. Water upstream from encampments contained detectable levels of caffeine and sucralose. Escherichia coli concentrations downstream of the encampments were significantly greater than concentrations upstream, but there was no significant change in the concentrations of other pollutants, including caffeine and sucralose. The HF183 marker of Bacteroides was only detected in one sample upstream of an encampment and was not detected downstream. Overall, there was insufficient evidence to suggest that the encampments studied here were responsible for contributing pollution to the river. Nevertheless, the presence of caffeine, sucralose, and HF183 indicated that there are anthropogenic sources of contamination in the river during dry weather and potential risks associated with the use of this water by encampment residents. Interviews with service providers revealed perceptions that the provision of water and sanitation services for this population would be prohibitively expensive. Interviewees also reported perceptions that most riverbank residents avoided contact with service providers, which may present challenges for the provision of water and sanitation service unless trust is first built between service providers and residents of riverine encampments.

Keywords: caffeine; dry weather; fecal pollution; social science and engineering collaboration; sucralose; water quality.

FIG. 1.

Upstream and downstream sampling locations in the San Diego River and its tributaries.

FIG. 2.

Cumulative distribution of reported open defecation sites as a function of distance from the river in 2017 and 2018. Fifty percent of sites were located within 60 m from the river margin in both years. Source of data: San Diego River Park Foundation (2019).

FIG. 3.

Log₁₀ differences between concentrations of fecal indicator bacteria (Escherichia coli and fecal enterococci) and viral fecal indicator PhiX174 for samples collected directly upstream and directly downstream of homeless encampments along the banks of: (a) Alvarado Creek near SDSU (N = 8); (b) Forester Channel (N = 8); and (c) the San Diego River at Fashion Valley (N = 4). Boxes show the interquartile range and the median, and whiskers show the minimum and maximum data points that are within 1.5 times the interquartile range. Plots also show mean values ( × ) and any outlier data points (_°) that are less than or greater than 1.5 times the interquartile range.

FIG. 4.

Percent differences between general water quality parameters for samples collected during dry weather conditions directly upstream and directly downstream of homeless encampments along the banks of: (a) Alvarado Creek near SDSU (N = 8); (b) Forester Channel (N = 8); and (c) the San Diego River at Fashion Valley (N = 4). Boxes show the interquartile range and the median, and whiskers show the minimum and maximum data points that are within 1.5 times the interquartile range. Plots also show mean values ( × ) and any outlier data points (_°) that are less than or greater than 1.5 times the interquartile range.

FIG. 5.

Time series plots showing: (a) the log₁₀ differences in the concentrations of E. coli and fecal enterococci; (b) the percent changes in the concentrations of caffeine and sucralose; and (c) the change in the caffeine/sucralose ratios, at the Forester Channel site. For (a, b), negative values indicate concentrations were higher upstream than they were downstream and positive values indicate concentrations were higher downstream than they were upstream.