Determining the connectivity of tribal communities to wastewater treatment facilities for use in environmental contamination and exposure assessments by wastewater-based surveillance

Background Limited information is available on the connectivity of Tribal communities to wastewater treatment facilities (WWTFs). This is important for understanding current sanitation infrastructure which drives public health and community construction, knowledge of potential routes of exposure through lack of infrastructure and/or discharging facilities, and opportunities to assess community health through wastewater-based surveillance (WBS). Objectives The objective of this work was to assess current wastewater infrastructure for 574 Federally Recognized Indian Tribes (FRITs) in the United States (US) to determine the number and location of facilities on or adjacent to Tribal reservations and Off-Reservation Trust Lands, with the goal of determining the feasibility of employing wastewater-based surveillance within these communities and to identify areas with inadequate sanitation infrastructure. Methods Here, we identified available National Pollutant Discharge Elimination System (NPDES) wastewater discharge permits in the Environmental Protection Agency’s Environmental Compliance History Online database to assess proximity to and within spatial boundaries of Tribal lands. These data were coupled to race data and tribal spatial boundary information from the US Census Bureau. Results 94 FRITs have registered NPDES permits within Tribal boundaries including a total of 522 facilities. 210 of these are American Indian (AI)-serving (>50% AI) with the ability to reach 135,000 AI-people through the wastewater network to provide community health assessments via WBS. Of the remaining facilities, 153 predominantly serve non-Tribal populations raising concerns about infrastructure placement and indigenous sovereignty. 523 FRITs were identified as without permitted discharging WWTFs, which may suggest inadequate or alternative infrastructure. Impact statement Here, multiple data sources including permit information from the Environmental Protection Agency’s National Pollution Discharge Elimination System and US Census Bureau data were used to determine the number of wastewater treatment facilities on or adjacent to Tribal lands and how many community members were connected to those municipal systems. This information was used to assess which Tribal communities may be a viable option for wastewater public health surveillance techniques and were used to answer supplemental questions related to basic sanitation and environmental justice concerns.