滇池沉积柱中有机质和营养盐对天然放射性核素分布的影响  

Effects of Organic Matter and Nutrients on Natural Radionuclides in Sediment Core from Dianchi Lake

作　　者：万难难 胡淑捷 冉勇[1,2] WAN Nannan;HU Shujie;RAN Yong(State Key Laboratory of Organic Geochemistry,Guangzhou Institute of Geochemistry,Chinese Academy of Sciences,Guangzhou 510640,China;CAS Center for Excellence in Deep Earth Science,Guangzhou 510640,China;University of Chinese Academy of Sciences,Beijing 100049,China;National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China,Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management,Institute of Eco-environmental and Soil Sciences,Guangdong Academy of Sciences,Guangzhou 510650,China)

机构地区：[1]中国科学院广州地球化学研究所,有机地球化学国家重点实验室,广州510640 [2]中国科学院深地科学卓越创新中心,广州510640 [3]中国科学院大学,北京100049 [4]广东省科学院生态环境与土壤研究所,华南土壤污染控制与修复国家地方联合工程研究中心,广东省农业环境综合治理重点实验室,广州510650

出　　处：《地球与环境》2023年第3期354-362,共9页Earth and Environment

基　　金：国家自然科学基金项目(41773137);国家自然科学基金-广东省自然科学基金联合项目(U1701244);有机地球化学国家重点实验室基金项目(SKLOG2015A01)。

摘　　要：为明确柱状沉积物中有机质和营养盐对天然放射性核素垂直分布存在的影响,本文以中国西南部的淡水湖泊滇池的柱状沉积物为例,阐述了天然放射性核素在滇池沉积物中的分布特征和影响因素,说明了滇池沉积有机质和营养盐对天然放射性核素的影响。分别应用多通道能谱仪(GX6020)和Vario EL III Elementar分析仪对样品中的天然放射性核素、总有机碳(TOC)和总氮TN进行测定,应用钼酸铵分光光度法测定总磷TP的含量。同时,还对有机质、营养盐和天然放射性核素进行了皮尔森相关性分析。研究结果显示:沉积物中^(210)Pb_(ex)指示的年代区间为1955~2017年;沉积物中^(40)K、^(232)Th、^(238)U、^(226)Ra和^(210)Pb_(ex)比活度依次为:185±13.2~798±61.0 Bq/kg、46.2±0.19~101±0.47 Bq/kg、54.5±3.99~136±10.4 Bq/kg、28.5±0.20~66.5±0.50 Bq/kg和98.1±4.54~312±14.0 Bq/kg;TOC、TN和TP含量分别为:7.88~60.3 mg/g,1.11~7.35 mg/g和1.43~2.78 mg/g。滇池湖泊内循环作用促进沉积物中碳氮磷的释放,为水生生物的生长提供营养物质,进而增加沉积物中水生来源有机质的贡献。本研究揭示了沉积有机质和营养盐对^(40)K、^(232)Th和^(226)Ra的稀释作用以及对^(210)Pb_(ex)的清洗效应,为今后湖泊沉积有机质和营养盐对天然放射性核素的研究提供了数据支持。To determine the effect of organic matter and nutrients on the vertical distribution of natural radionuclides in sediment core,this paper took Dianchi Lake,a freshwater lake in southwest China as an example.The distribution characteristics and influencing factors of natural radionuclides in sediment of Dianchi Lake were described,which illustrated the effect of sedimentary organic matter and nutrients on natural radionuclides in Dianchi Lake.The natural radionuclides,total organic carbon(TOC)and total nitrogen(TN)in the samples were determined by multi-channel energy spectrometer(GX6020)and Vario EL III Elementar analyzer,respectively.The content of total phosphorus(TP)was determined by ammonium molybdate spectrophotometry.Pearson correlation analysis of organic matter,nutrients and natural radionuclides was also carried out.The results were as follows:the CRS dating results of ^(210)Pb_(ex) of the sediments showed that the age range was from 1955 to 2017.The specific activity ranges of ^(40)K,^(232)Th,^(238)U,^(226)Ra and ^(210)Pb_(ex) were as follows:from 185±13.2 Bq/kg to 798±61.0 Bq/kg,from 46.2±0.19 Bq/kg to 101±0.47 Bq/kg,from 54.5±3.99 Bq/kg to 136±10.4 Bq/kg,from 28.5±0.20 Bq/kg to 66.5±0.50 Bq/kg,and from 98.1±4.54 Bq/kg to 312±14.0 Bq/kg.TOC,TN,and TP contents ranged from 7.88 to 60.3 mg/g,from 1.11 to 7.35 mg/g,and from 1.43 to 2.78 mg/g,respectively.The internal loop of Dianchi Lake promoted the release of carbon,nitrogen,and phosphorus in sediment,and provided nutrients for the growth of aquatic organisms,thus increasing the contribution of aquatic organic matter in sediment.This study revealed the dilution effect of sedimentary organic matter and nutrients on ^(40)K,^(232)Th and ^(226)Ra and the cleaning effect of ^(210)Pb_(ex),which can providedata support for future research on natural radionuclides by lake sedimentary organic matter and nutrients.

关 键 词：滇池 有机质 营养盐 天然放射性核素 

分 类 号：X524[环境科学与工程—环境工程]