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2012年4-5月以胶州湾地区为研究地点,分析和研究了该地区地下水、河水、海水中224Ra和226Ra的分布特征及其影响因素。结果表明,232Th和238U浓度较高的花岗岩地区地下水和河水中224Ra和226Ra的活度均比其他地区高;受到海水混合的影响,沿岸地区地下水和河水由于水体盐度升高,224Ra和226Ra从固体颗粒的解吸量增加,从而导致活度较高;受河流输入(溶解态和悬浮颗粒解吸)以及海底地下水排泄(Submarine groundwater discharge,SGD)影响,胶州湾近岸海水224Ra活度相对较高,之后224Ra自身衰变以及外海水的混合稀释,使224Ra活度分布呈现随着离岸距离增加活度逐渐降低的特点;而226Ra活度在胶州湾内则保持一个较高水平,只出现个别226Ra低值分布区,主要原因是外海水与陆源淡水的226Ra活度较为接近且226Ra半衰期较长。
From April to May in 2012, taking Jiaozhou Bay as a research site, the distribution and influencing factors of 224Ra and 226Ra in the groundwater, river water and seawater in the area were analyzed and studied. The results showed that the activities of 224Ra and 226Ra in the groundwater and river water of granite area with higher concentration of 232Th and 238U were higher than those in other areas. Due to the influence of seawater mixing, the salinity of groundwater and river water in coastal area increased, and 224Ra and 226Ra The desorption amount of solid particles increased, resulting in higher activity. The activity of 224Ra in the coastal water of Jiaozhou Bay was relatively high due to input of rivers (desorption of dissolved and suspended particles) and Submarine groundwater discharge (SGD) After 224Ra decay and the mixed dilution of seawater, the activity distribution of 224Ra showed a decreasing activity as the offshore distance increased. However, 226Ra activity maintained a high level in Jiaozhou Bay with only a few 226Ra values Distribution, mainly due to the 226Ra activity of the open seawater and terrestrial freshwater is relatively close and 226Ra half-life is longer.