|Abstract Title:||Effects of Activated Carbon-based Amendments on the Bioavailability of Methyl Mercury to Aquatic Invertebrates|
|Presenter Name:||Susan Kane Driscoll|
|Session:||Mercury in Contaminated Sites|
|Co-Authors:||Susan Kane Driscoll,Konrad Kulacki,Cynthia Gilmour,Guilherme Lotufo,Daniel Farrar,Steven Brown|
Abstract Information :
The Berry?s Creek Study Area is a tidal tributary of the Hackensack River and is the subject of an ongoing remedial investigation. Studies were conducted to evaluate the effect of activated carbon (AC) amendments on the bioaccumulation of methylmercury (MeHg) in marsh sediments by Leptocheirus plumulosus, a representative benthic test organism. In one study, effects of two types of AC amendments (powdered AC and SediMiteTM, a pelletized agglomerate of powdered AC) were compared to an unamended control sediment. In another study, the effects of powdered AC in a newly amended sediment and a powdered AC-amended sediment aged under field conditions for 20 months were compared to an unamended control. Samples were collected periodically for analysis of sediment (MeHg and sediment organic carbon), porewater (MeHg), and tissues (MeHg and lipids). In both experiments, concentrations of MeHg in porewater were significantly lower in all AC treatments compared to the unamended control. Concentrations of MeHg in porewater were reduced by up to 50-fold in the freshly amended AC treatment, but only reduced by up to 4-fold in the aged AC treatment. Two to three-fold reductions in tissue concentrations were observed in the freshly amended AC treatments, and significant differences between freshly amended AC treatments and unamended controls were observed on Day 7 and 14 in the first study, and on Day 7, 14 and 21 in the second study. Concentrations of MeHg in tissue from the aged AC treatment were significantly higher than in the unamended control, possibly reflecting significant increases in MeHg in the aged AC treated sediment over the course of the experiment. After normalizing tissue concentrations to sediment concentrations (i.e., accounting for differences in sediment MeHg concentrations) results indicate that both fresh and aged AC decreased bioavailability of MeHg (up to ~3- to 4-fold) in comparison to unamended sediment.