Professor's Research Shows Dolphins Exposed to Chemicals

A new study published in GeoHealth shows that bottlenose dolphins in Sarasota Bay, Florida, are exposed to man-made chemical additives commonly found in cleaning products, pesticides, cosmetics, personal care products and plastic.

The study by researchers from the College of Charleston, Chicago Zoological Society, the National Oceanic and Atmospheric Administration (NOAA), and the National Institute of Standards and Technology (NIST) shows that metabolites of these chemicals, otherwise known as phthalates, have been found in the urine of 71 percent of dolphins sampled in Sarasota Bay. This is the first time that phthalate metabolites have been detected in the urine of any wild marine mammal.

In humans, phthalate exposure is linked with hormonal and reproductive issues. Scientists are not sure what health impacts these compounds may have on dolphins.

Leslie Hart testing samples. (Photo provided by Chicago Zoological Society’s Sarasota Dolphin Research Program)

Leslie Hart ’03 (M.E.S), College of Charleston public health professor and lead author of the study, says because dolphins are sensitive gauges of their surroundings, detection of phthalate exposure in these dolphins suggests some level of environmental contamination. She believes that understanding what dolphins are exposed to gives researchers – and the public – a better idea of what is in the environment.

“I think this research is critically important for our understanding of how humans can significantly impact the marine environment,” says Hart. “Previous studies have detected phthalates and their metabolites in various other marine organisms, so we were not particularly surprised to discover that dolphins are also exposed. However, we were surprised to find levels of some metabolites comparable to concentrations detected in people.”

Hart says the man-made chemicals are added to many consumer goods and are therefore ubiquitous.

“Understanding that these potentially hazardous chemicals are ending up in our marine environment is a call to action,” she says. “Now that we know they are there, we should be responsible for cleaning them up and preventing future contamination. Reducing the consumer demand for products containing these chemicals can help motivate innovation to develop healthier alternative additives, which in the long run can protect both ocean and human health.”

Researchers say more studies will be needed to discover how these chemicals are getting into Sarasota Bay, and how they may impact the health of the bottlenose dolphins living there. Samples were collected from 17 wild dolphins in the waters in and around Sarasota Bay in 2016 and 2017. The bay is a subtropical coastal lagoon enclosed by barrier islands to the west and the mainland of Manatee and Sarasota Counties to the east.

Other researchers on the project include:

Barbara Beckingham– College of Charleston Department of Geology and Environmental Geosciences

Randall S. Wells– Chicago Zoological Society’s Sarasota Dolphin Research Program

Moriah Alten Flagg – College of Charleston Department of Health and Human Performance

Kerry Wischusen ’18-College of Charleston Department of Chemistry and Biochemistry

Amanda Moors – National Institute of Standards and Technology

John Kucklick – National Institute of Standards and Technology

Emily Pisarski – JHT Inc.

Ed Wirth – National Oceanic and Atmospheric Administration/National Ocean Service/National Center for Coastal Ocean Science