South Australia’s Port River Estuary, an urban and industrial hotspot, is home to a resident population of Indo-Pacific Bottlenose dolphins (Tursiops aduncus). This population has been experiencing a decrease in calf survival over the past five years and has recently succumbed to an unusual wasting syndrome, triggering an Unusual Mortality Event (UME). This event caused the mortality of 8 residents over a 13-month period. Most animals displayed wasting 2-4 weeks before death or disappearance, ulcerative cutaneous skin lesions, evidence of immune suppression, and delayed sexual development in males. Thorough post-mortem investigation and infectious disease testing in 5 of these individuals could not detect a consistent cause of mortality. The Port River Estuary has historically been subject to high concentrations of anthropogenic contaminants including per and polyfluorinated alkyl substances (PFAS) in abiotic and biotic samples (Gaylard, 2016). This study uses post mortem investigations to assess for associations between liver PFAS concentration, health, and organ morphology in 13 stranded T. aduncus from the Port River Estuary and outside regions. Pathological findings and histomorphology of major endocrine and immune organs (adrenal gland, spleen, thyroid gland and reproductive organs) are used in the analysis. Age, sex, geographic location, reproductive status, and body condition are considered in the interpretation of results. The results of this study will assist to improve our understanding on the effects of PFAS accumulation on the health of an apex marine predator.