| 摘要: |
| 于1986年1月，采取大体积取样，Co-APDC螯合共沉淀富集分离，银片上自沉积和α-计算分析，研究长江口区可溶态210Pb的来源、分布和逗留时间、结果表明，全区平均放射性比度为7.5 dpm/m3，从河向海纵向分布呈口内段和近外海两端高，而低谷出现在中间的口门外最大浊度及稀释带高生产力区。210Pb明显因悬浮颗粒物的吸附絮凝沉降和浮游生物的吸收利用被清除。经探析，该区210Pb主要来源是大气气溶胶的沉降；水体中226Ra母体衰变的仅占0.68％；径流水携带的几乎可以忽略。全区可溶态的210Pb和稳定Pb的逗留时间为3.33d，而在最大浊度带仅为2.65d，比大洋区小3－4个数量级。说明该区水体对可溶态Pb及其性质类似的重金属和污染物质具很强的自净能力。 |
| 关键词: 可溶态210Pb 来源 分布 逗留时间 长江口 |
| DOI： |
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| 基金项目:中法合作长江口生物地球化学研究项目 |
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| SOURCE, DISTRIBUTION AND RESIDENCE TIME OF SOLUBLE 210Pb IN THE CHANGJIANG RIVER ESTUARY AREA |
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Lin Yian1, Martin，J．M2, Thomas，A.J2
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1.Second Institute of Oceanogrophy, SOA, Hangzhou 310012;2.Institut De Biogeochimie Marine Ecole Nomale Superieure Unite Associee Au CNRS, Paris, France 92120
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| Abstract: |
| In January 1986, Changjiang River Estuary area 210Pb was studied by using separation and enrichment with Co-APDC co-precipitating from 20 liter filtrate water, followed by electrodeposition and alpha counting. The average 210Pb activity was 7.5 dpm/m3 in the Changjiang River Estuary area. The high concentration appears in the river section and near-water area; the low activity was in the maximum turbidity band and diluted water-seawater front band (i. e., high primary productivity area). It was obvious that the 210Pb in water was scavenged e?iciently because Pb2+ can be absorbed, flocculated and settled by particles and can be assimilated and utilized by plankton. The source of 210Pb in the Changjiang River Estuary primarily comes from the decay of 222Rn in the atmosphere; the second the decay of 226Ra in water mass, but the latter only is 0.68 percent in gross 210Pb. The residence times of the soluble 210Pb and stable Pb were estimated to be 3.33 days in the whole Estuary and only 2.65 day in the maximum turbidity band, three to four orders of magnitude shorter than that in the ocean. The results showed that the water mass of the Changjiang River Estuary area has larger capacity for scavenging soluble Pb. |
| Key words: Soluble, 210Pb, Source, Distribution, Residence time, Changjiang River Estuary |
