Assessing Sediment Composition, Organic Matter, Metal Contamination, and Ecological Risks in Port Everglades, Florida

Assessing Sediment Composition, Organic Matter, Metal Contamination, and Ecological Risks in Port Everglades, Florida

Alvin Sherman Library

Port sediments often accumulate heavy metals and organic pollutants from anthropogenic inputs. The planned expansion of Port Everglades (Fort Lauderdale, Florida, USA) raises concern that dredging may remobilize contaminated sediments, potentially affecting nearby benthic habitats, including coral reefs. To assess sediment quality, eighteen cores were collected from five port sites and one control site, along with additional surface sediments. Cores were sectioned at 10 cm intervals and analyzed for 14 metals (ICP-MS), percent organic matter, and grain size. Geo-accumulation index results indicated moderate to strong contamination by As and Mo, while ecological risk assessments suggested moderate to high overall metal contamination. Subsamples from four port sites and the control site contained As concentrations exceeding both the threshold effect level (TEL, 7.24 μg/g) and probable effect level (PEL, 41.6 μg/g). Mo geometric means also exceeded the continental crust background value (1.5 μg/g). Grain size analysis revealed a predominance of fine sand (125-250 μm). Organic matter content varied substantially, with the port's South Turning Basin comprised of a mean 55.2% in contrast to the port inlet mean of 0.7%. Correlation analyses indicate links among sediment size, organic content, and metal concentrations. These findings highlight the potential risks dredging poses to adjacent coral reef ecosystems and surrounding protected habitats.