|Abstract Title:||Novel Mercury Sequestration Technology to Suppress the Methylmercury and Bioaccumulation in Sediment|
|Presenter Name:||Daniel Griffin|
|Session:||Mercury in Freshwater Ecosystems|
|Co-Authors:||Daniel Griffin,Chris Stransky,Khalil Abusaba,Chase Gerbig,Alexander Gabriel,Se Hye Kim,Jon Miller|
Abstract Information :
MercLok? has been developed by Albemarle Corporation to address soil, sediment and groundwater impacts from mercury (Hg). Using MercLok?, rapid sequestration of multiple mercury species and long-term stability have been validated in bench and field studies in a wide range of soils and subsurface conditions. Objectives of these studies were to assess the treatment effectiveness of MercLok? at (1) decreasing methylmercury (MeHg) in sediment porewater and (2) reducing bioaccumulation of Hg in exposed biota as a result of MeHg suppression in the water system. Treatment of sediment with MercLok? reduced the fraction of MeHg relative to total Hg in porewater from 25.4% to 0.47%. The bioaccumulation exposure experiment was conducted over a 28-day period using freshwater Lumbriculus worms. The concentration of total Hg and lipids were measured in tissues at Day 14 and 28. Tissue concentrations of Hg on Day 28 were 3.8 to 4.7 times lower in MercLok? treated sediments compared to unamended, with similar values at Day 14 in sediments contaminated with 10 to 100 mg/kg Hg. The relationship between concentrations of MeHg in the sediments and Hg in worm tissues (Biota to Sediment Accumulation Factors, BSAFs) were also evaluated to directly assess the effectiveness of MercLok? at reducing partitioning of Hg into the worm tissues. BSAF values on Day 28 ranged from 12.6 - 22.9 in unamended sediments and 0.6 - 1.5 in amended sediments. BSAF values were substantially greater (up to 24x at Day 28) for unamended versus amended sediments. BSAF values greater than 1.0 indicate that the MeHg preferentially partitioned from the sediment into the worm tissues. A notable increase in effectiveness of the MercLok? treatment was also observed over time with greater BSAF ratios between unamended and amended sediment on Day 28 compared to that observed on Day 14.