Demographic information and phthalate metabolite concentrations (µg/L) detected in bottlenose dolphins (Tursiops truncatus) urine sampled from Barataria Bay, LA during 2011-2023 and Sarasota Bay, FL during 2010-2019, 2022-2024

Exposure to phthalate esters has previously been documented in bottlenose
dolphins (Tursiops truncatus) inhabiting an urban estuary (Sarasota Bay,
FL, USA; 2010-2019). Phthalates are chemicals commonly added to plastic
products and consumer goods to enhance qualities such as flexibility,
fragrance, and stability. These chemicals are known to leach out of
plastic products and into the marine environment, leaving wildlife
vulnerable to reproductive, developmental, and metabolic health effects.
Environmental phthalate exposure has been shown to vary relative to human
activity and urbanization. To evaluate potential differences in dolphin
exposure risk, urinary phthalate metabolite concentrations were compared
between free-ranging bottlenose dolphins from an urban (Sarasota Bay, FL,
USA; 2010-2023; n= 71 ) and rural estuary (Barataria Bay, LA, USA;
2011-2023; n = 45). The magnitude of MEHP detection did not differ
significantly between sampling sites (p = 0.97); however, MEHP was
detected more frequently in Sarasota Bay dolphins (73.24%; n=52; 95% CI:
61.20-82.73) than Barataria Bay dolphins (33.33%; n = 15; 95% CI: 20.00 -
48.95%). Further, dolphins from Sarasota Bay may be exposed to a greater
diversity of phthalates compared to Barataria Bay dolphins as indicated by
differences in the detected phthalate metabolite profile. Notably,
Barataria dolphins were also affected by the Deepwater Horizon oil spill,
warranting additional studies of potential phthalate sources and health
implications among these dolphins.