St. Johns River
• The St. Johns River (SJR) is an St. Marys River important resource for northeast Florida. Nassau River • There is a history of industry along the river that has been a source of PAHs SJR pollutants, specifically polycyclic aromatic PCBs hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs). • Past studies have detected levels of PAHs and PCBs in the sediment that exceed the sediment quality thresholds for biological effects [Cooksey; SJR].
Polycyclic Aromatic Hydrocarbons (PAHs)
• Most toxic component of oil-related products • In 1991 Pepper Industries’ creosote tanks leaked near Talleyrand • High contamination of low molecular weight PAHs in Rice creek (2002) – Naphthalene – Anthracene
Polychlorinated Biphenyls (PCBs)
• Synthetic chemicals used in industry until they were banned in the 1970’s • PCB spill in early 1980s during a fire at the American Electric Company – 800 ppb • Rice Creek ~780 ppb • Trout River ~325 ppb • Probable effect level (PEL) 200 ppb Exposure
• Exposure to both PAHs and PCBs is demonstrated to cause an array of negative health effects (Whitehead et al., 2012; Aas et al., 2000) • PAHs – Toxicopathic lesions, including neoplasms (Meyers et al., 2008) • PCBs – Can alter endocrine and immune function (Gelsleichter et al., 2006) • Possible population level effects due to reduced growth, reproduction, and immune health
Biomarker
Toxicological biomarkers are quantifiable indicators of exposure to environmental contaminants, i.e. PAHs and PCBs.
Responses to Exposure
PAH Cytochrome P450 1a1 (CYP) Exposure Glutathione-S-Transferase (GST)
Evidence of Evidence of Exposure Metabolism
PAH Metabolites Evidence of Cellular Damage Lipid DNA Adduct Excretion Peroxidation (LPO) Formation Study Organism
• Atlantic stingray (Dasyatis sabina) • Indicator species – Interacts with sediments – Relatively high position on the food chain – Minimal movement patterns
Goal
The goal of this study was to evaluate the potential health effects of PCBs and PAHs on the Atlantic stingray in the St. Johns River. To accomplish this goal, our objectives were to measure and compare PAH and PCB biomarker levels of Atlantic stingrays collected from known contaminated sites in the SJR and reference sites.
Research Questions
1. Are biomarker levels in the St. Johns River higher than those in the Nassau River and St. Marys River? 2. Are there high biomarker levels in close proximity to known contaminated sites? Materials & Methods
Data Collection Seine Net • Individuals collected began in December, 2014
Otter Trawl Trotline Assays
• Stingrays were euthanized for liver and bile collection • Liver – An ethoxyresorufin-o-deethylase (EROD) assay was used to measure CYP activity – A Gultatione-S-Transferase Assay Kit was used to measure GST activity – A Lipid Peroxidation Assay Kit was used to quantify LPO • Bile – Analyzed for Fluoresence Aromatic Coumpounds (FACs) • Naphthalene • Pyrene Gull Bladder • Benzo(a)Pyrene Liver
Data Analysis
• Standard deviations were used to determine relative biomarker levels – Negligible (White): < 1 SD below the mean – Low (Green): between 1 SD below the mean and 1 SD above the mean – Moderate (Yellow): 1-2 SD above the mean – High (Red): > 2 above the mean • Bartlett’s Test and Student’s t-test were used to determine if biomarker levels were significantly different between the SJR and the reference sites
Results
• Each biomarker had individuals with high levels except for CYP • The PAH metabolite biomarkers did not have any negligible levels Research Questions
1. Are biomarker levels in the St. Johns River higher than those in the Nassau River and St. Marys River? 2. Are there high biomarker levels in close proximity to known contaminated sites? Biometabolizing Enzymes
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1. Are biomarker levels in the St. Johns River higher than those in the Nassau River and St. Marys River? – Not significantly higher 2. Are there high biomarker levels in close proximity to known contaminated sites? Research Questions
1. Are biomarker levels in the St. Johns River higher than those in the Nassau River and St. Marys River? – Not significantly higher 2. Are there high biomarker levels in close proximity to known contaminated sites? CYP
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1. Are biomarker levels in the St. Johns River higher than those in the Nassau River and St. Marys River? – Not significantly higher 2. Are there high biomarker levels in close proximity to known contaminated sites? – Need more data Conclusions
• Preliminary data indicates that pollutant biomarker levels in SJR stingrays were not significantly higher than individuals from reference locations • However, the appearance of high levels of biomarkers in individuals caught in close proximity to known contaminated areas suggests continuous exposure
Significance
• First study to examine pollutant mediated effects of exposure in populations of Atlantic stingrays residing in the SJR using multiple biomarkers • Relative biomarker levels are indicators of ecosystem health • Further dredging of the SJR can resuspend and redistribute pollutants – Important to gather baseline pre- dredge biomarker levels to determine the effects of dredging on stingrays and the health of the SJR
Future Directions
• Greater sample size – Specifically in the known contaminated sites • Expand study beyond Northeast Florida – Construction phase of the Savannah Harbor Expansion Project began in January, 2015 – Possible model of environmental impact on dredging in the SJR
Acknowledgements
We would like to thank the UNF Coastal Biology Program for partially funding this research, my lab mates, and everyone at the Florida Fish and Wildlife Conservation Commission for collecting stingrays. Russel Brodie Hannah Hart Samantha Ehnert Justin Ryan Ford Chris Solomon Matt Julia Amy Carrissa