基于镭同位素示踪方法的大风江河口水体滞留时间估算

Estimation of Water Residence Time in the Dafengjiang River Estuary Based on Radium Isotopes Tracing Model

为评估广西北部湾沿岸的重要入海河流河口区——大风江河口的水体更新速率,本研究对大风江河口水体中的^(224)Ra和^(223)Ra放射性活度进行测定,基于短长半衰期镭同位素的活度比值,对大风江河口的水体滞留时间进行估算,得出大风江河口枯季的平均水体滞留时间为(8.36±2.88)d。整体来讲,大风江河口的水体更新速率相对较慢,在其遭受陆源污染时应在相应时间尺度上进行污染防控,以期为大风江河口水体的物质交换和输运提供基础信息。

In order to evaluate the water renewal rate of the Dafengjiang River estuary,an important estuary area of the Beibu Gulf coast in Guangxi,the radio-activities of ^(224)Ra and ^(223)Ra in the Dafengjiang River estuary water were determined in this study.Based on the activity ratio of short and long half-life radium isotopes,the water retention time of Dafengjiang River estuary was estimated,and the average water retention time in dry season was(8.36±2.88)d.On the whole,the renewal rate of water body in the Dafengjiang River estuary is relatively slow,pollution prevention and control should be carried out at the corresponding time scale when it is subjected to terrestrial pollution.It is expected that this study can provide basic information for the material exchange and transportation of the Dafengjiang River estuary.