**Field and Model Study to Define Baseline Conditions of Beached Oil Tar Balls along Florida's First Coast**

#### **Peter Bacopoulos, James David Lambert, Mary Hertz, Luis Montoya and Terry Smith**

**Abstract:** Anecdotal data are currently the best data available to describe baseline conditions of beached oil tar balls on Florida's First Coast beaches. This study combines field methods and numerical modeling to define a data-driven knowledge base of oil tar ball baseline conditions. Outcomes from the field study include an established methodology for field data collection and laboratory testing of beached oil tar balls, spatial maps of collected samples and analysis of the data as to transport/wash-up trends. Archives of the electronic data, including GPS locations and other informational tags, and collected samples are presented, as are the physical and chemical analyses of the collected samples. The thrust of the physical and chemical analyses is to differentiate the collected samples into highly suspect oil tar balls *versus* false/non-oil tar ball samples. The numerical modeling involves two-dimensional hydrodynamic simulations of astronomic tides. Results from the numerical modeling include velocity residuals that show ebb-dominated residual currents exiting the inlet via an offshore, counter-rotating dual-eddy system. The tidally derived residual currents are used as one explanation for the observed transport trends. The study concludes that the port activity in the St. Johns River is not majorly contributing to the baseline conditions of oil tar ball wash-up on Florida's First Coast beaches.

Reprinted from *J. Mar. Sci. Eng.* Cite as: Bacopoulos, P.; Lambert, J.D.; Hertz, M.; Montoya, L.; Smith, T. Field and Model Study to Define Baseline Conditions of Beached Oil Tar Balls along Florida's First Coast. *J. Mar. Sci. Eng.* **2014**, *2*, 160-170.

#### **1. Introduction**

Florida's First Coast beaches have experienced occurrences of oil tar ball wash-up as anecdotally evidenced by the local beach communities of Jacksonville. There has also been the question and concern of the local port (Mayport—St. Johns River) contributing to oil tar ball washup on the beaches of Florida's First Coast, and, historically, it was practice of ships to dump their bilge (containing fresh and used oil) just offshore before entering the inlet to port into Jacksonville. In addition to this local societal context, there is also a scientific purpose to generate a sample of baseline conditions of beached oil tar balls for Florida's First Coast. This scientific purpose is motivated by the speculation of Cuba drilling for oil [1] and the possibility of an oil spill disaster that would directly affect Florida's First Coast [2,3].

Much previous work on oil tar ball transport and wash-up came about from the post-evaluation of the Deepwater Horizon oil spill (2010) in the Gulf of Mexico, as related to various aspects including tar ball characterization [4] and spill tracking via beach observation [5]. Tar ball characterizations have been done for other regions of the world (e.g., California, USA [6] and Malaysia's east coast [7]). However, there is no previous work related to oil tar ball transport and wash-up along Florida's First Coast. The objective of this study was to define baseline conditions of beached oil tar balls along Florida's First Coast. Defining these baseline conditions will provide a dataset to use for comparison for future oil spill/tar ball events.
