黄河干流铀同位素的沿程变化及入海通量

Variation of dissolved uranium isotopes along the main channel of the Yellow River and the fluxes from the river to the sea

通过分析黄河干流溶解铀的沿程变化特征和下游利津站溶解铀浓度的季节性变化,估算了溶解铀的逐月及全年入海通量。研究结果表明,溶解铀浓度从上游至下游总体呈现出沿程逐步增加的趋势,^(234)U/^(238)U放射性活度比在上游源头附近比较高,其余河段^(234)U/^(238)U放射性活度比维持在较稳定的水平(1.3~1.7)。黄河下游利津站溶解铀浓度的变化范围为2.72±0.18μg/L至7.57±0.66μg/L之间,平均值为5.49±0.28μg/L,并且呈现出夏、秋季低于春、冬季的变化规律。黄河下游水沙、溶解铀的月际入海通量年内变化显著,主要集中丰水期特别是调水调沙时期。利津站的径流量是影响溶解铀入海通量的主要因素。2010年、2013和2014年利津站溶解铀的入海通量分别为1.04×10~5kg/a、1.31×10~5kg/a和6.41×10~4kg/a,占世界河流年入海通量的1%左右。

The variation of uranium isotopes along the main channel of the Yellow River and the fluxes of dissolved uranium from the river to the sea have been studied. Dissolved uranium concentration exhibited an increasing trend from the upper reaches to the lower reaches along the main channel of the Yellow River. Except the high value near the source,the（234） U /（238） U activity ratios kept in a relatively stable level in the Yellow River（ 1. 3 - 1. 7）. Dissolved uranium concentrations at station Lijin ranged from 2. 72 ± 0. 18 μg / L to 7. 57 ± 0. 66 μg / L,averaged 5. 49 ± 0. 28μg /L,with a seasonal variation of lower concentrations in summer and fall compared with winter and spring. Monthly fluxes of water,sediment and dissolved uranium changed notably,and concentrated in the periods of the Water-Sediment Regulation Scheme and rainfall flood. Monthly flux of dissolved uranium was mainly controlled by water discharge at station Lijin. The fluxes of dissolved uranium at station Lijin were 1. 04 × 10^5 kg / a,1. 31 × 10^5 kg / a and 6. 41 ×10^4kg / a in 2010,2013 and 2014,respectively,which accounted for 1% of the dissolved uranium flux of the whole world rivers.