GEH1202:        Human Mercury and Antibiotic Resistant Bacterial Sampling Along the Indian River Lagoon


Speaker:          Emily Jensen


This project served as a pilot analysis on the human population to compliment previous and ongoing dolphin analysis of mercury and antibiotic resistant organisms (ARO) in the Indian River Lagoon, FL.  Both mercury contamination and AROs continue to be significant public health issues and this study linked the coastal environment, a sentinel species, and public health. The study also suggests that   there is a need for more regionally specific exposure estimates and public health advisories to protect high risk groups.


Attend this session to understand the relationship between mercury concentration and fish consumption in high risk sub-populations, including coastal residents and recreational anglers.





Objectives: We previously described high levels of mercury in skin and blood of Atlantic bottlenose dolphins from the Indian River Lagoon, FL and suggested that these animals may serve as sentinels for public health. Therefore, we assessed mercury exposure through fish consumption among individuals living near the Indian River Lagoon (IRL), FL who are potentially exposed to high levels of mercury in their diets.   Results were compared to existing data on the Indian River Lagoon bottlenose dolphin population in order to fully understand the link between human and dolphin health in this unique environment.


Methods:  We surveyed 59 adult residents at the Florida Oceanographic Society Center, Harbor Branch Oceanographic Institute, and around common fishing areas.  Questionnaires provided information on species-specific fish consumption during the 3 months before the survey. Hair samples were collected from all participants to be analyzed for total mercury. 


Results:  Residents’ mean hair mercury concentration was 1.5 ppm (n=59; range, 0.04-16.18 ppm); 42% of participants had levels >1 ppm, which approximately corresponds to the US EPA’s reference dose.  Hair mercury levels were positively associated with fish consumption and significantly higher in those who consumed seafood from the Indian River Lagoon.  In particular, those who consumed tuna filets/steak, grouper, and salmon had higher mercury concentrations in their hair, which follows the nationally reported averages in tissue of these fish species.  However, the mean concentration of mercury in human hair was lower than that in the skin of IRL dolphins (7 ppm).  


Conclusions:  Study participants had relatively elevated mercury concentrations in their hair.  This group represents a highly exposed sub-population with an exposure profile that differs from fish consumers in other regions of the United States and the general population, suggesting a need for more regionally specific exposure estimates and public health advisories.