Work

Exploring Environmental Influences on Mono(2‐Ethylhexyl) Phthalate (MEHP) Exposure in Common Bottlenose Dolphins ( Tursiops truncatus ) in Sarasota Bay, FL, USA

Year: 2026

Type: article

Abstract: Phthalates, endocrine‐disrupting, persistent organic pollutants widely used in plastic manufacturing, can readily enter aquatic environments and contaminate estuaries. As apex predators, resident bottlenose dolphins ( Tursiops truncatus ) provide critical insights into ecosystem health. Prior work documented phthalate exposure in the long‐term resident bottlenose dolphin community of Sarasota Bay, Florida, with evidence of temporal and spatial variability, particularly for mono(2‐ethylhexyl) phthalate (MEHP), a metabolite of the commonly used plasticizer di(2‐ethylhexyl) phthalate (DEHP). We predicted that environmental factors, such as large‐scale storm events, rainfall, and harmful algal blooms (HABs), may influence this variability. Urine samples collected from 138 free‐ranging dolphins during 1993–2024 were screened for phthalate metabolites, reliable biomarkers of exposure. MEHP was the most common metabolite, detected in 78.3% of samples (Regression on Order Statistics mean = 6.19 ng mL −1 , s.d. = 11.29 ng mL −1 , range = 0.04–76.6 ng mL −1 ), and concentrations did not vary significantly by sex or age ( p > 0.05). MEHP concentrations were positively correlated with rainfall occurring 3 days prior to sampling ( p = 0.01), and concentrations were significantly lower among dolphins sampled within 6 months of a major storm event ( p = 0.007). No significant associations between MEHP and HABs were discerned ( p > 0.05). Such findings suggest increased phthalate‐contaminated runoff during short‐term rainfall events, as well as the dilution or offshore transport of phthalates via storm‐related processes. Despite documented toxicity of MEHP to humans and other marine species, health impacts on Sarasota Bay dolphins remain poorly understood. As sentinels of estuarine health, long‐term exposure may signal chronic ecotoxicological risks, and observed environmental influences highlight the need for continued monitoring, research, and mitigation.

Source: GeoHealth

DOI: 10.1029/2026gh002199