九龙江河口区溶解态、颗粒态铀同位素的地球化学行为

Abstract

对九龙江河口区枯、丰水期水体中溶解态、颗粒态铀同位素地球化学行为的研究表明，溶解态铀与盐度存在良好的正相关关系，证实枯、丰水期该河口区水体中的铀均是保守行为。在低盐度区域（Ｓ＜１０），~２３８Ｕ主要以颗粒态形式存在，颗粒态~２３８Ｕ所占份额随盐度增加而降低。~（２３８）Ｕ之条件分配系数介于 １． ２ × １０~３～１． ５ ×１０~５ｄｍ~３／ｋｇ之间，它与盐度呈负相关关系，但与悬浮颗粒物浓度无相关关系存在。枯水期悬浮颗粒物上~２３４Ｕ／~２３８Ｕ_Ａ．Ｒ．与盐度的负相关关系为河口区悬浮颗粒物中~２３４Ｕ的优先沥取理论提供了有力的证据。 【英文摘要】 The geochemical behavior of dissolved and particulate uranium isotopes during spring and dry seasons in Jiulongjiang estuary have been studied. Conservation behavior during estuary mixing in both seasons is shown by linear uranium-salinity plots.~238U in low salinity region(S<10) is largely incorporated into filterable particles. The percentages of particulate to total~238U in seawaters decrease with salinity. The conditional distribution coefficiences for ~238U ranged from 1. 2 × 10~3~1.5 × 10~5dm~3/kg, wh...