BIOAVAILABILITY AND BULK HEAVY METAL CONCENTATIONS IN TORRECILLA LAGOON-PUERTO RICO

Numerous studies have primarily relied on the use of bulk heavy metal concentrations as controls of foraminiferal distributions. Sediments with high bulk concentrations does not translate directly to those metals being bioavailable and thereby able to influence macro- or microorganisms. Thus, assessing bulk sediments typically overestimates the concentrations of the target contaminants assumed to cause morphological deformities as well as benthic foraminiferal distributions.

Sediments from Torrecilla Lagoon show bulk sediment Cu⁺² concentrations to be an order of magnitude higher than those found in the carbonate fraction (more bioavailable). Statistical analysis shows that bulk concentrations have a positive correlation with deformities and with key stress tolerant taxa while having a negative correlation with the more bioavailable fraction. These results bring forward evidence of the confounding results when relying on bulk concentrations and to begin examining heavy metal speciation in sediments.