Benthica has developed a method for remediating mercury in sediments.  More specifically, it is a means that decreases methylmercury production in the sediment and its subsequent release to the overlying water.  The method uses iron oxide as a preferred electron acceptor to sulfate.  Several beneficial processes occur simultaneously, all contributing to decreased production and release.  The sulfate-reducing bacteria (SRB), the ones that produce most of the MeHg, are out competed by the iron-reducing bacteria (IRB), which limits the amount of food they have and thereby decreases their activity and associated methylmercury production.  The SRB are pushed deeper in the sediment, which decreases the diffusive flux of sulfate to the SRB, which further decreases their activity.  Any MeHg that SRB do produce now has to diffuse further upward to reach the water column, which decreases the concentration gradient and flux.  More importantly, the diffusing MeHg is strongly sorbed to the iron oxide as it diffuses upward, which drastically decreases the flux.  The iron oxide also sorbs phosphate that would otherwise be released to the overlying water and stimulate primary productivity.  The resulting decrease in primary productivity decreases the amount of detrital algae that settles to the sediment and which is a carbon source for sediment microbial activity. The iron oxide also does not negatively impact benthic invertebrates.  Follow the "Mercury Data" tab to see the data.

Some of this data was presented at the 2006 ICMGP in Madison Wisconsin.  More recently this approach was presented at the 2015 Battelle Contaminated Sediment Symposium in New Orleans, LA.  If you and your group are interested in more information on this technology, please contact Dr. Klein to arrange a more interactive presentation and discussion at your facility.