哈萨克斯坦东部水体氢、氧同位素和水化学特征

Characteristics of hydrochemistry and hydrogen,oxygen isotopes of waters in Kazakhstan

哈萨克斯坦是中亚干旱-半干旱地区最大的内陆国家,东部以阿尔泰山、天山与我国相隔,区内河流众多,是该国水资源的主要来源地,额尔齐斯河、伊犁河是中哈两国重要的跨境河流。通过对哈萨克斯坦东部不同区域河水和湖水的主要离子、氢、氧同位素分析,初步研究了该区域的水化学和同位素空间分布特征及其对地表水循环的指示意义。结果表明:哈萨克斯坦东部河水离子组成以HCO_3-Ca为主,局部有HCO_3-Na水型分布。湖水以SO_4-Na为主,有少量HCO_3-Ca和SO_4-Ca型水。研究区内水体Ca^(2+)、Na^+、SO_4^(2-)均表现出南北低中间高的空间特征。河水氢、氧同位素变化范围分别为-123.46‰^-71.22‰和-16.09‰^-10.21‰,湖水氢、氧同位素变化范围分别为-97.82‰^-9.20‰和-12.74‰~2.44‰。额尔齐斯河河水与周围补给水体的氢、氧同位素差异显著,表明其主要来源于上游补给。河水和湖水氢、氧同位素关系式分别为δD=7.546×δ^(18)O+3.507和δD=5.737×δ^(18)O-24.14,且河水氢、氧同位素与经、纬度显著相关,反映了明显的内陆效应,而湖水氢、氧同位素的变化则主要反映了水体的蒸发程度,水体氢、氧同位素变化敏感地示踪了该区域水体的来源与循环特征。

Main ions and hydrogen, oxygen isotopes were measured in lake water, fiver water and rain water collect- ed in Kazakhstan from July 2012, in order to analyze the spatial distribution characteristics and further explore the environmental significance. The results showed that the ions of water reflect the environment characteristics of differ- ent area of Kazakhstan. Ca2~ and HCO3 are the dominant ions of fiver water, while few water samples are HCQ and Na~ ions types impacted by the evaporation. The quality types of lakes in Kazakhstan are mainly SO4-Na and SO4-Ca ions types, impacted by long time evaporation. The arid climate condition induces that most lakes become slight sa- line lakes. The ion concentrations of Ca2＋, Na＋, SO]- in the central area are much higher than that in the north and south areas. The hydrogen, oxygen isotopes of fiver water in Kazakhstan rang from-123.46‰to-71.22‰ and-16.09‰ to-10.21‰ respectively. The equivalent values of lake water are from-97.82‰ to-9.20‰ and -12.74‰to 2.44‰. The values of hydrogen, oxygen isotopes in the Ertix River are significantly different from that of adjacent rivers, indicating that the water source of Ertix River is mainly from the upper reach. The relationship between hydrogen and oxygen isotopes of fiver water and lake water are ~ D=7.546 ×δ 18O＋3.507 and D=5.737×δ 18O-24.14. Moreover, the values of hydrogen and oxygen isotopes are decreased from the south to the north. These suggest that river water is mainly supplied by glaciers and precipitation and the hydrogen, oxygen isotopes of lake water mainly reflected the degree of water evaporation. The results indicate that hydrogen, oxygen isotopes are good tracers for the water source and hydrological cycle in Kazakhstan.