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Organic nature of colloidal actinides transported in surface water environments.
Isoelectric focusing experiments of radiolabeled colloidal matter extracted from RFETS soils revealed that colloidal Pu is in the four-valent state and is mostly associated with a negatively charged organic macromolecule with a pH(IEP) of 3.1 and a molecular weight of 10-15 kDa, rather than with the more abundant inorganic colloids.
Causes of Salt Marsh Erosion in Galveston Bay, Texas
Abstract There is major salt marsh loss in Galveston Bay and other estuarine environments. In Galveston Bay, the causes of marsh loss include wave action, subsidence, eustatic sea-level rise, and
Concentration-dependent mobility, retardation, and speciation of iodine in surface sediment from the Savannah River Site.
Results demonstrate that the mobility of iodine species greatly depends on, in addition to the type of species, the iodine concentration used, presumably limited by the number of surface organic carbon binding sites to form covalent bonds.
Sequestration and remobilization of radioiodine (129I) by soil organic matter and possible consequences of the remedial action at Savannah River Site.
Results showed that 72-77% of the newly introduced I(-) or IO(3)(-) were irreversibly sequestered into the organic-rich riparian soil, while the rest was transformed by the soil into colloidal and truly dissolved organo-iodine, resulting in (129)I remobilization from the soil greatly exceeding the 1 pCi/L drinking water permit.
210Pb and 239,240Pu in the Northeast Water Polynya, Greenland: particle dynamics and sediment mixing rates
Abstract Distributions of the radionuclides 210Pb and 239,240Pu in sediment cores from the Northeast Water Polynya, Greenland, showed that these nuclides reached depths of 5–15 cm by particle mixing
Upper ocean carbon flux determined by the 234Th approach and sediment traps using size-fractionated POC and 234Th data from the Gulf of Mexico
Size-fractionated particulate 234Th and particulate organic carbon (POC) fluxes were measured in the Gulf of Mexico during 2000 and 2001 in order to obtain a better estimation of upper ocean organic
Novel molecular-level evidence of iodine binding to natural organic matter from Fourier transform ion cyclotron resonance mass spectrometry.
Electrospray ionization coupled to Fourier transform ion cyclotron resonance mass spectrometry (ESI-FTICR-MS) was applied to elucidate the interactions between inorganic iodine species (iodide and iodate) and a fulvic acid (FA) extracted from a SRS surface soil and provides novel evidence to better understand the reactivity and scavenging properties of NOM towards radioiodine and possible influence of N OM on (129)I migration.
A novel approach for the simultaneous determination of iodide, iodate and organo-iodide for 127I and 129I in environmental samples using gas chromatography-mass spectrometry.
A sensitive and rapid method was developed which enables determination of isotopic ratios of speciated iodine and was successfully applied to water samples from the contaminated Savannah River Site, South Carolina, and more pristine Galveston Bay, Texas.
Evaluation of a radioiodine plume increasing in concentration at the Savannah River Site.
Groundwater monitoring of the plume at the basins has shown that the migration of many of the high risk radionuclides originally present at this complex site has been attenuated, however, (129)I continues to leave the source at a rate that may have been exacerbated by the initial remediation efforts.
Bacterial production of organic acids enhances H2O2-dependent iodide oxidation.
The results indicate that as pH decreases (≤5.0), increasing H( 2)O(2) hydrolysis is the driving force behind iodide oxidation, however, at pH ≥ 6.0, spontaneous decomposition of peroxy carboxylic acids, generated from H(2).