One potential impact of environmental contaminants occurs when endocrine-disrupting compounds alter bone density. As a PhD candidate at Portland State University, I have been awarded a 3-year fellowship from the U.S. Environmental Protection Agency to continue and expand my doctoral research on bone density in bottlenose dolphins. Since starting my graduate program, I have established the first-ever normative distribution of bone density values for bottlenose dolphins utilizing a comprehensive archive of skeletal specimens. I have also developed a custom ultrasound device to clinically assess live, wild bottlenose dolphins in capture-release health assessments. The unique natural laboratory setting of Sarasota Bay and the support of the Sarasota Dolphin Research Program fostered the environment necessary to develop and test the novel technology required to pursue this line of research. Pilot data collected during the 2014 and 2015 health assessments, and the opportunity to demonstrate feasibility and proof of concept of the use of ultrasonic bone densitometry on live dolphins was instrumental in obtaining this fellowship.
The study will use bottlenose dolphins as a model species to investigate the effects of endocrine disrupting compounds on bone density. Environmental contaminants adversely affect health, both through direct damage and through effects on growth and development. Exposure to contaminants is known to reduce bone density, alter bone mineral composition, and result in abnormal bone growth in laboratory animal research. Bottlenose dolphins are an ideal model to further investigate these issues as they are long-lived mammals known to be affected by exposure to contaminants that also affect humans. Bone density can potentially provide a record of an animal’s chronic environmental contaminant exposure and provide a mechanism to model similar effects that would be expected in humans under similar exposure conditions.
Bone density profiles will continue to be established for dolphins in the Sarasota Bay community during future health assessments in order to further comparisons to dolphins residing in areas of higher environmental contaminant exposure. In order to further the field of bottlenose dolphin bone densitometry, ultrasound device development is in progress to facilitate assessment of additional skeletal target sites. Current assessments using the initial prototype device are limited to the bones of the dolphin flipper, and additional measurements of bones in other areas of the body, such as vertebrae in the tailstock, may open new research opportunities.
This article appeared on page 17 of the 2017 SDRP Annual Report, Nicks n Notches.