U and Th speciation in river sediments

Soil to plant transfer of 238U, 226Ra and 232Th on a uranium mining-impacted soil from southeastern China

“…For example, retention of radionuclides onto the soil particles will affect their availability for plant uptake. Martı´nez-Aguirre et al (1995) reported that Th exhibited a much lower mobility than U, which is consistent with our observations that 232 Th has smaller TF values. The magnitude and range of TFs of 238 U, 226 Ra and 232 Th found in this study appeared to be generally similar to values obtained in other studies where root uptake was the primary mechanism of accumulation (IAEA, 1994;IUR, 1994;Bettencourt et al, 1988;Frissel and Koster, 1988;Ko¨hler et al, 2000).…”

Environmental status of Daya Bay surface sediments inferred from a sequential extraction technique

“…Unlike some river sediments where the majority of the total U was associated with the non-residual fractions (Martínez-Aguirre et al, 1995;Martin et al, 1998), on average w80% of the total U in the Daya Bay surface sediments is present in the residual fraction. Co-precipitation with amorphous ferromanganese oxyhydroxides is the main process of U incorporation from the water column into the sediment particles (Martínez-Aguirre et al, 1995).…”

“…Co-precipitation with amorphous ferromanganese oxyhydroxides is the main process of U incorporation from the water column into the sediment particles (Martínez-Aguirre et al, 1995). The waste discharge from the operation of fertilizer industries was found to be an anthropogenic source of the enhanced U in sediments (Martínez-Aguirre et al, 1995).…”

“…Co-precipitation with amorphous ferromanganese oxyhydroxides is the main process of U incorporation from the water column into the sediment particles (Martínez-Aguirre et al, 1995). The waste discharge from the operation of fertilizer industries was found to be an anthropogenic source of the enhanced U in sediments (Martínez-Aguirre et al, 1995). In Daya Bay, the waste discharge from nuclear power plants may be a possible anthropogenic source of the sedimentary U, for the total content of U at stations 3 and 4, the two stations being located closest to the two nuclear plants, is clearly higher than at the other stations (Table 3).…”

Phosphate regulates uranium(VI) toxicity to Lemna gibba L. G3

“…Uranium attracts special interest because of the perceived chemo-and radiotoxicity risks it poses to the environment, mainly because it is relatively mobile because, and is readily soluble in the oxidation state VI (Martinez Aguirre et al, 1995;Kohler et al, 1996;Murakami et al, 1997). As a result, surface mine waters usually contain elevated uranium levels which may flow into local streams, and contaminate the receiving aquatic ecosystems including drinking water sources .…”