Sentinels of synthetics - a comparison of phthalate exposure between common bottlenose dolphins (Tursiops truncatus) and human reference populations

PLoS One. 2020 Oct 15;15(10):e0240506. doi: 10.1371/journal.pone.0240506. eCollection 2020.

Abstract

Phthalates are chemical esters used as additives in common consumer goods, such as plastics, household cleaners, and personal care products. Phthalates are not chemically bound to the items to which they are added and can easily leach into the surrounding environment. Anthropogenic drivers, such as coastal plastic pollution and wastewater runoff, increase the exposure potential for coastal marine fauna. Phthalate exposure in free-ranging bottlenose dolphins has been the focus of recent study, with indications of heightened exposure to certain phthalate compounds. The objective of this study was to compare urinary phthalate metabolite concentrations among bottlenose dolphins (Tursiops truncatus) sampled in Sarasota Bay, FL, to levels reported in human samples collected as part of the Centers for Disease Control and Prevention's (CDC) National Health and Nutrition Examination Survey (NHANES). Monoethyl phthalate (MEP) and mono-(2-ethylhexyl) phthalate (MEHP) were the most prevalent metabolites detected in dolphin urine (n = 51; MEP = 29.41%; MEHP = 54.90%). The geometric mean (GM) concentration of MEP was significantly lower for dolphins (GM = 4.51 ng/mL; 95% CI: 2.77-7.34 ng/mL) compared to humans (p<0.05), while dolphin concentrations of MEHP (GM = 4.57 ng/mL; 95% CI: 2.37-8.80 ng/mL) were significantly higher than levels reported in NHANES (p<0.05). Health impacts to bottlenose dolphins resulting from elevated exposure to the MEHP parent compound (diethyl-2-ethylhexyl phthalate, DEHP) are currently unknown. However, given the evidence of endocrine disruption, reproductive impairment, and abnormal development in humans, pursuing investigations of potential health effects in exposed bottlenose dolphins would be warranted.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Bottle-Nosed Dolphin / metabolism
  • Bottle-Nosed Dolphin / urine*
  • Environmental Exposure / adverse effects
  • Environmental Exposure / analysis*
  • Environmental Pollutants / adverse effects
  • Environmental Pollutants / urine*
  • Female
  • Humans
  • Male
  • Nutrition Surveys
  • Phthalic Acids / adverse effects
  • Phthalic Acids / urine*
  • Reference Standards

Substances

  • Environmental Pollutants
  • Phthalic Acids
  • phthalic acid

Grants and funding

Funding to support this work was provided by an anonymous donor ([LH], no grant number), the College of Charleston’s School of Education, Health, and Human Performance Dean's Discretionary Funding, ([LH], no grant number), the College of Charleston’s Department of Health and Human Performance Research and Development Funds ([LH], no grant number), and the Masters of Environmental and Sustainability Studies’ Student Association ([MD], student travel funds, no grant number). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. CSS Inc. provided support in the form of salaries for authors [EP], but did not have any additional role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript. Dolphin Quest Inc. provided support for bottlenose dolphin health assessments but had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. The specific roles of these authors are articulated in the ‘author contributions’ section.