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通过对2011~2014年采集的青海湖及周边水体样品(岩层间隙水、井水、泉水、河流水、降水和湖表水)镭同位素活度及离子含量测定,得到镭同位素的空间分布特征。223Ra的活度范围是0~2.30 dpm/100L,224Ra的活度范围是0~97.49 dpm/100L,226Ra的活度范围是33.30~126.70 dpm/100L,228Ra的活度范围是22.50~209.40 dpm/100L。降水只有半衰期最长的226Ra有活度,其余镭同位素皆低于检测值。无论是长半衰期还是短半衰期,间隙水和井水都拥有比较高的活度值,河水和湖表水则比较低。短半衰期镭同位素的分布特征呈现由湖岸向湖中心快速降低的规律,无地表径流注入的湖岸距离5~6 km就检测不到其活度,证明在这个距离短半衰期镭同位素基本衰变完毕;5号采样点活度是平均活度值的一倍,接近18 dpm/100L,可能有深层地下水的渗出。12号与13号采样点由于靠近布哈河口,受到水平涡动扩散的影响,所以矿化度有所下降,短半衰期的活度值有所上升,除此之外短半衰期的镭同位素的变化趋势基本与矿化度呈负相关;除12号、13号采样点受到布哈河的影响外,228Ra的活度的变化基本与Ca2+、HCO-3、Mg2+、K+呈现正相关,与NO-3基本呈负相关。
The spatial distribution characteristics of radium isotopes were obtained from the radium isotope activity and ion content of Qinghai Lake and the surrounding water samples collected from 2011 to 2014 (interlaminar water, well water, spring water, river water, precipitation and lake water). The activity range of 223Ra is 0-2.30 dpm / 100L, the activity range of 224Ra is 0-97.49 dpm / 100L, the activity range of 226Ra is 33.30-126.70 dpm / 100L, the activity range of 228Ra is 22.50-209.40 dpm / 100L. Only 226Ra with the longest half-life of precipitation had activity, and the rest of the radium isotopes were lower than the detection value. Whether long or short half-life, interstitial water and well water have relatively high activity values, while river and lake waters are relatively low. The distribution of short-lived radium isotopes showed a rapid decrease from the lakeshore to the center of the lake. No activity was detected at the lakeshore where the surface runoff was injected from 5 to 6 km, indicating a complete decay of the radium isotope at the short half-life of this distance. 5 The sampling point activity is double the average activity value, which is close to 18 dpm / 100L. There may be deep seepage of groundwater. As the sampling points 12 and 13 are affected by the horizontal eddy diffusion near the mouth of the Buha River, the degree of salinity decreases and the activity value of short half-life increases. In addition, the change of the short half-life radium isotope The trend of the activity was negatively correlated with the degree of salinity. The activity of 228Ra was positively correlated with Ca2 +, HCO-3, Mg2 + and K + except for the Buha River at No. 12 and No. 13 sampling points, 3 is basically negative correlation.