Our previous community-based participatory research at Northeast Cape (NEC) on St. Lawrence Island (SLI)found elevated levels of polychlorinated biphenyls (PCBs) organochlorine pesticides (OCPs) and mercury(Hg) in sediments and biota within the watershed at the formerly used defense (FUD) site. We found elevatedOCPs and PCBs in serum of the SLI people due to both long-range transport and military-derived sources withthe highest levels of PCBs in people who have traditional and familial connections with NEC includingsubsistence. Concentrations of persistent organic pollutants (POPs) in our resident fish model the sticklebackclosely mirror concentrations in the blood serum of SLI residents indicating their efficacy as sentinel specieson SLI. Despite extensive remediation at NEC short-lived lower trophic level fish in the Suqitughneq (Suqi)River remain contaminated with PCBs OCPs and Hg originating from the FUD site at levels that exceed EPAfish consumption guidelines for cancer risk. Elevated contaminant levels and disrupted health in Suqi River fishindicate potential health threats for residents and that site remediation is incomplete. Our overarching goal is toadvance scientific understanding of the exposure pathways and long-term human health consequencesassociated with contaminant exposure from FUD sites and inform interventions necessary to protect the healthand long-term well-being of the people of SLI as they re-establish their traditional community at NEC. In Aim 1we propose to build on our prior discoveries and continue our collaboration with the communities of SLI toinvestigate potential exposure pathways and biological impacts of persistent contamination associated with theFUD site at NEC on SLI. We will analyze PCBs OCPs and Hg in the water of the Suqi and Tapisaggak riversas well as in traditional foods and air samples to assess ingestion and inhalation as potential exposurepathways. We will build on work with stickleback as a sentinel species to determine biological effects ofcontaminants on endocrine function and organ-specific histopathology. In Aim 2 we will characterize andquantify body burden of contaminants and linkages to health outcomes in people associated with NEC. In Aim3 we will inform decisions and interventions to protect the health of the people of SLI and enable re-establishment of the traditional community at NEC. We will provide information that will lead to improvedremediation provide data and traditional knowledge to inform public health consultations and assessmentsand develop a community-based public health action plan and interventions to protect health ensure equity indecision-making and restore the NEC community. This study will have local and circumpolar arcticimplications for Indigenous communities. Locally we will provide data and implement actions necessary for re-establishing the community at NEC. Given that thousands of such Cold War military sites exist throughout theArctic often in close proximity to Indigenous communities our project may serve as a model for environmentaland health monitoring and policy action by other Arctic Indigenous Peoples.