The release and leaching of metal pollutants into coastal and estuarine environments has been greatly curtailed, capped deposits however can still reenter the ecosystem by natural perturbation or human activity. To assess the potential of legacy pollution sites, this research investigated the ability of the native bivalve Mercenaria mercenaria as a natural bioindicator within infield XRF analysis. The quahog exhibiting a sedentary borrowing habitat and long lifespan (&gt;10yrs) make them ideal in-situ biomonitors. Quahogs have the ability to bioconcentrate heavy metals into their shells and to exchange/adsorb them on their outer shell surface from the benthic media.<br/>Quahogs harvested from sites in Narragansett Bay RI had their shells assessed by XRF and correlated with ICP analysis for their heavy metal content to that of their habitat. The cation exchange capacity and adsorption of Cu, Pb and Cd ions of the whole shell’s outer surface at various buffered pHs (2.5, 4, 5 and 8) was assessed. These pH’s reflecting the burrowing sediment profile and were also accessed for their potential to rerelease metals into the water column by ICP analysis. Experimental XRF shows shell surface accumulation could be qualitatively seen at 10ppm for Cu and Pb while Cd was limited to 25ppm from sea water samples.

Assessing legacy pollution by shell surface XRF analysis of sedentary shellfish

255th National Meeting (2018)

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