EVALUATING SEDIMENT CONTAMINATION FROM BOATING ACTIVITY IN BOCA CIEGA BAY

Activities associated with commercial and recreational boating introduce contaminants to the surrounding environment. In areas with heavy boating activities, associated contaminants are often incorporated into sediments. The purpose of this research is to determine if there is an association between boating activities and sediment contamination in Boca Ciega Bay, and the controls on contaminant distribution. X-ray fluorescence (XRF) analysis of sediment provides the elemental composition, including the concentration of metal contaminants such as copper, zinc, arsenic, and lead. Sediment grain size influences the potential for contamination. As grain size decreases, the surface area increases resulting in higher concentrations of contaminants. Determining the correlation between sediment grain size and contaminant concentrations facilitates the evaluation of the distribution of contaminants throughout Boca Ciega Bay. Three sites with high densities of boats were selected, two marinas and a channel, with sediment samples collected in close proximity and along transects further from the potential input source. This sampling technique provides data representative of changes in sediment contamination with changes in distance from contaminant sources. Sediment cores were analyzed for short-lived radioisotopes to provide dating to determine when sediments were deposited to determine changes in contamination (XRF) over the past ~100 years. This data is used to evaluate the effectiveness of regulations on levels of contamination of sediments. This research allows for the assessment of contaminant transport, distribution, the magnitude of contaminant source inputs, as well as historical changes in contaminant input to the marine environment. 

For more information: kvmurray@eckerd.edu

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