广州流溪河河水主要化学组成时空分布特征及控制因素  

Spatial and temporal variations of the river water chemistry in the Liuxihe River,Guangzhou,Guangdong

作　　者：徐谨立 王志兵 王希杰 韦刚健[2] 谢露华[2] 曾提[2] XU Jin-li;WANG Zhi-bing;WANG Xi-jie;WEI Gang-Jian;XIE Lu-hua;ZENG Ti(School of Lisiguang,China University of Geosciences,Wuhan 430074,China;State Key Laboratory of Isotope Geochemistry,Guangzhou Institute of Geochemistry,Chinese Academy of Sciences,Guangzhou 510640,China)

机构地区：[1]中国地质大学(武汉)李四光学院,湖北武汉430074 [2]中国科学院广州地球化学研究所同位素地球化学国家重点实验室,广东广州510640

出　　处：《地球化学》2021年第2期211-218,共8页Geochimica

基　　金：广州市科技计划科学研究专项(201607020008);中国科学院大学生创新实践训练计划(201716500221)。

摘　　要：本次研究报道了位于广州市典型热带-亚热带河流流溪河上游、中游和下游3个站点(东星、乌石和江高)河水的主要化学成分在近1年的持续变化时间序列。结果显示,3个站点河水的阳离子均主要来自硅酸盐的化学风化输出,但贡献率略有差异,其中在上游的东星站贡献率最大,下游的江高站次之,中游的乌石站相对较少。相较之下,阴离子的来源更为多样,其中F^(−)主要来自于岩石风化,Cl^(−)、SO_(4)^(2−)和NO_(3)^(−)更多地受到海洋源降雨或咸潮作用的影响。流域内主要化学风化反应以钾长石、钠长石和钙长石的溶解为主。从上游到下游,Si/TZ^(+*)比值和Si/(Na^(*)+K)比值逐渐降低,说明上游硅酸盐岩风化较下游更为强烈。从上游到下游,随工农业生产活动的增加,人类活动对河流水化学组成的贡献逐渐增大,岩石风化输出的相对贡献逐渐减小。This paper reports the time series associated with the main chemical compositions of Liuxihe River’s upper,middle,and lower reaches in Guangzhou city,Guangdong.Continuous observations were carried out monthly from 2016 to 2017 at three stations in the upper(Dongxing),middle(Wushi),and lower streams(Jianggao).The spatial and temporal variations of the in-field observed physical and chemical parameters,such as temperature,conductivity,pH,and dissolved oxygen,were studied along with the main chemical compositions,such as those of the main anions and major elements,to understand the source variations of the dissolved materials in the Liuxihe River and their controlling mechanism.Results indicate that the primary dissolved elements or metals in the Liuxihe River are mainly derived from the chemical weathering of silicates.At Dongxing station,the river water has the most significant contribution from silicate weathering,followed by that at Jianggao station;at Wushi station,such contributions are slightly less.In contrast,the sources of anions are more diverse;F^(−)is mainly formed due to rock weathering,while Cl^(−),SO_(4)^(2−),and NO_(3)^(−)are largely affected by rainfall and salty tides from the ocean.The chemical weathering reaction in the basin is dominated by the dissolution of potassium feldspar,albite,and anorthite.The Si/TZ^(+*)ratio and the Si/(Na^(*)+K)ratio gradually decrease upstream to downstream,indicating that silicate rock weathering is stronger upstream than that observed downstream.Likewise,from the upper to the lower streams,the impact of human activities is gradually enhanced with the increase in industrial and agricultural activities.Consequently,the relative contribution of rock weathering to river hydrochemistry is gradually decreased.

关 键 词：水化学组成 化学风化 物质来源 流溪河 

分 类 号：P593[天文地球—地球化学] X142[天文地球—地质学]