title: Influence of Intrinsic Colloid Formation on Migration of Cerium through Fractured Carbonate Rock.
abstract: Migration of colloids may facilitate the transport of radionuclides leaked from near surface waste sites and geological repositories. Intrinsic colloids are favorably formed by precipitation with carbonates in bicarbonate-rich environments, and their migration may be enhanced through fractured bedrock. The mobility of Ce(III) as an intrinsic colloid was studied in an artificial rainwater solution through a natural discrete chalk fracture. The results indicate that at variable injection concentrations (between 1 and 30 mg/L), nearly all of the recovered Ce takes the form of an intrinsic colloid of >0.45 μm diameter, including in those experiments in which the inlet solution was first filtered via 0.45 μm. In all experiments, these intrinsic colloids reached their maximum relative concentrations prior to that of the Br conservative tracer. Total Ce recovery from experiments using 0.45 μm filtered inlet solutions was only about 0.1%, and colloids of >0.45 μm constituted the majority of recovered Ce. About 1% of Ce was recovered when colloids of >0.45 μm were injected, indicating the enhanced mobility and recovery of Ce in the presence of bicarbonate.
authors.affiliation: Zuckerberg Institute for Water Research, Jacob Blaustein Institutes for Desert Research, Ben Gurion University of the Negev , Midreshet Ben Gurion, 08990 Israel.
authors.forename: Emily L
authors.initials: EL
authors.lastname: Tran
authors.affiliation: Nuclear Research Center of the Negev , P.O. Box 9100, Beer Sheva 84190, Israel.
authors.forename: Ofra
authors.initials: O
authors.lastname: Klein-BenDavid
authors.affiliation: Geological Survey of Israel , Jerusalem, 95501 Israel.
authors.forename: Nadya
authors.initials: N
authors.lastname: Teutsch
authors.affiliation: Zuckerberg Institute for Water Research, Jacob Blaustein Institutes for Desert Research, Ben Gurion University of the Negev , Midreshet Ben Gurion, 08990 Israel.
authors.forename: Noam
authors.initials: N
authors.lastname: Weisbrod
mesh_terms: D002119:Calcium Carbonate / Q000737:chemistry; D002563:Cerium / Q000737:chemistry*; D003102:Colloids / Q000737:chemistry*; D005844:Geology / Q000379:methods; D011868:Radioisotopes; D011891:Rain; D012996:Solutions; D064091:Waste Disposal Facilities
chemical_list: D003102:Colloids; D011868:Radioisotopes; D012996:Solutions; D002563:Cerium; D002119:Calcium Carbonate