Pathogen releases due to inadequate wastewater treatment infrastructure in small-town Alabama

Olivia August Harmon , Megan E.J. Lott, Riley Johnson, Donnie Wilkie, Melu Woldu, Mark Elliott, Leigh-Anne Krometis, Musa Manga, Courtney Woods, Kevin White, Emily McGlohn, Joe Brown

Residents of the Alabama Black Belt lack safe and reliable wastewater treatment. Health risks of inadequate treatment are well-established, community-level contamination alone cannot characterize how sanitation failures translate into exposure risks, and few studies have identified pathogens associated with exposure. We surveyed of sanitation-related pathogen releases in a small town in Hale County, Alabama, lacking sanitation infrastructure. We enrolled 24 households with on-site sanitation, 18 utilizing direct discharge, and 10 in a neighboring sewered community for comparison. We visited each household three times over 9 months. We collected yard soil and wastewater from direct-discharge effluent, on-site systems, and a sewage lagoon. We cultured samples for total coliform and Escherichia coli and analyzed via multi-parallel qPCR for 39 pathogen targets, 2 fecal markers, and 2 human source tracking markers. In soils from households served by sewerage, we detected 4 pathogens, 1 fecal marker, and 0 human source markers, 5 pathogens, 1 fecal marker, and 2 human source markers in soils from households with on-site sanitation, and 9 pathogens, 2 fecal markers, and 2 human source markers in soils from households utilizing direct discharge. These findings suggest that failing or absent wastewater treatment infrastructure contributes to environmental pathogen releases in this setting.