Plastics in the environment are of increasing pollution concern for wildlife, including dolphins. Phthalates are a group of man-made chemicals commonly used in the manufacturing of plastic and other consumer goods (for example, cosmetics and personal care products), and are leached into the environment because they are not chemically bonded to these materials. Because of this, phthalates are readily available for human and wildlife exposure. Concern over phthalates stems from experimental laboratory animal and human epidemiologic studies demonstrating associations between phthalate exposure and adverse health effects including endocrine disruption and reproductive impairment.
Macro- and microplastics (particles < 5mm in diameter) are ubiquitous in the marine environment and quantities appear to be growing. In addition, there are potential sources of phthalates in storm-water and other effluents that reflect increased population pressures in coastal zones. This suggests that marine wildlife may be vulnerable to chronic chemical plasticizer exposure. Once exposed, phthalates are rapidly broken down into metabolites that have been detected in urine and blubber of large whales. To date, phthalates, or their metabolites, have not been measured in bottlenose dolphins.
We are collecting urine and blubber samples from Sarasota Bay bottlenose dolphins to develop phthalate detection methods for this species, quantify phthalate exposure among Sarasota Bay dolphins, and determine if blubber can be a reliable sampling matrix to monitor environmental phthalate exposure. During the 2016 health assessment, nine samples were collected, including from animals that were recaptured on subsequent days. We are currently in the process of developing detection methods for both matrices, and plan to produce the first measure of these chemicals in bottlenose dolphins. Moving forward, we will continue to collect these samples from Sarasota Bay dolphins to help determine the correlation between urine and blubber concentrations. If blubber proves to be a reliable detection matrix, we hope this study will motivate additional, larger-scale exposure studies to examine differences in phthalate exposure across geographic and temporal space. Funding for this research was provided by the College of Charleston.
This article appeared on page 17 of the 2017 SDRP Annual Report, Nicks n Notches.