材料期刊网

河流的水化学特征受地质、气候和人类活动等多种因素的支配，可能通过水?环境?粮食?健康的转移链构成对流域经济和社会的持续影响．为此，分别于2015年4月和10月采集了龙江?柳江?西江流域38个点位共70份水样，测定所有样品的主要物理化学指标，运用阴阳离子三角图和相关性分析来探究水体中主要阴阳离子的含量分布及其来源，结合Gibbs图和端元图来分析水化学组成的控制过程．结果表明，龙江?柳江?西江流域水体整体呈弱碱性，四月份和十月份的TDS均值分别为204．81 mg·L－1和234．20 mg·L－1，低于世界主要大河的均值，EC、TZ－、TZ＋、TDS和TH的均值空间分布都表现为龙江段＞西江段＞柳江段，含量最高的阴阳离子分别为HCO－3和Ca2＋，流域的水化学类型为HCO－3?Ca2＋型；Ca2＋、Mg2＋与HCO－3主要来源于碳酸盐岩的溶解， Cl－、NO－3和SO2－4主要来源于酸沉降、城镇生活污水和地下水的输入，K＋和Na＋主要来源于硅酸盐岩的溶解和人类活动的排放；该流域水体表现为典型的喀斯特地区水质特性，水化学组成主要由碳酸盐岩风化作用所控制，不同的下伏岩层分布决定了各江段控制作用的强弱，也决定了流域水化学组成的空间差异性，碳酸和硫酸共同参与了碳酸盐岩的风化作用，但以碳酸为主．总体而言，对龙江?柳江?西江流域水化学特征及其成因的上述认识，有助于制定水资源管理措施和水环境保护战略．

Chemical characteristics of river water are dominated by various factors such as geology, climate and human activity, which may constitute a lasting impact on the watershed economy and society through the transfer chain of water?environment?food?health. For this purpose, seventy water samples were collected from thirty?eight sites in the Longjiang?Liujiang?Xijiang watershed in April and October, 2015, and major physical and chemical indicators of all samples were measured. Ternary diagrams of anions and cations and Pearson correlation analysis were applied to explore the concentration distribution and sources of the major ions ( Cl-, NO-3 , SO2-4 , HCO-3 , K+, Na+, Mg2+and Ca2+) , and Gibbs charts combined with major ion element ratio analysis method were used to analyze the controlling process of hydrochemical composition. The results indicated that water of the selected rivers was slightly alkaline, and the total dissolved solids ( TDS ) concentrations (204.81 mg·L-1 in April and 234. 20 mg·L-1 in October) were higher than the average value of rivers worldwide. The spatial distribution of average values of electrical conductivity ( EC) , anionic charge ( TZ-) , cationic charge ( TZ+) , total dissolved solids and total hardness ( TH) followed the order of Longjiang reach>Xijiang reach>Liujiang reach in different rivers reaches. The major anion and cation were HCO-3 and Ca2+, respectively, and the hydrochemical type belonged to HCO-3?Ca2+type. Ion source analysis demonstrated that Ca2+, Mg2+ and HCO-3 were mainly derived from dissolution of carbonate rocks, and Cl-, NO-3 and SO2-4 were mainly derived from acid deposition, urban sewage discharge and groundwater, and K+ and Na+ were mainly derived from dissolution of silicate rocks and anthropogenic inputs. Water of the selected river watershed showed typically hydrochemical characteristics of karst terrain, and the hydrochemical composition was mainly controlled by chemical weathering of carbonate rocks. Different distribution of the underlying rock stratums determined the intensity of the controlling effects on different rivers reaches, and also determined the spatial variances of hydrochemical composition. Moreover, both carbonic acid and sulfuric acid contributed to the chemical weathering, but carbonic acid dominated. In general, the study on hydrochemical characteristics and its sources of Longjiang?Liujiang?Xijiang watershed will be conducive to the development of water resources management measures and water environmental protection strategies.