新疆于田绿洲弃耕地浅层地下水化学特征

The chemical characteristics of shallow groundwater in abandoned cropland on Yutian Oasis in Xinjiang

在于田绿洲弃耕地典型地段布设两条基本平行的地下水采样带,用GPS定位,共设置13个样点,现场采样并送实验室分析,以研究其化学特征。运用统计分析发现,地下水离子平均含量,阳离子K^＋＋Na^＋〉Mg^2＋〉Ca^2＋,阴离子Cl^-〉HCO3^-〉SO4^2-〉CO3^2-,就变异系数而言,CO32^-和SO42^-较大,其余离子均介于30%-65%; 地下水埋深、溶解性总固体和电导率的变异系数较大,均大于50%,pH值的变异系数最小,为3.06%,且pH值的变化范围在8.35-9.28之间,呈弱碱性。通过主成分分析发现,影响研究区浅层地下水化学特征的主成分共有3个,第一主成分F1与K^＋＋Na^＋、Cl^-和CO3^2-具有显著的相关性,第二主成分F2与埋深和SO42-具有较显著的相关关系,第三主成分F3与Mg^2＋相关关系显著,且这3个主成分已涵盖所有8项指标信息的83%以上。线性回归分析显示,溶解性总固体与K^＋＋Na^＋和Cl^-的相关关系显著,且拟合方程具有显著的统计学意义。

Two sampling belts are laid in a typical lot on Yutian Oasis, which are almost paralleling. With GPS positionirtg, 13 points are set along the belts to collect samples of groundwater, which were sent to laboratory to study their chemical characteristics. Using statistical analysis, it was found out that the average level of ions of shallow groundwater in the study area is K^＋ ＋ Na^＋ 〉 Mg^2＋ 〉 Ca^2＋ and Cl^- 〉 HCO3^- 〉 SO4^2- 〉 CO3^2- . The coefficients of variation of CO3^2- and SO4^2- are both bigger, and the other ions are all between 30% and 65%. For those of buried depth of groundwater, TDS and EC are bigger, and all bigger than 50 %. The coefficient of variation of pH value is the least, only 3.06 %, and the pH values range between 8.35 and 9.28, which are all bigger than 7 and all weak alkaline. Through principal component analysis, it was also found out that principal components that impact the study area are 3 in all： The first principal component FI has significant relationship with K ^＋ ＋ Na^ ＋ , Cl^- and CO32- ; The second principal component F2 has significant relationship with buried depth and SO4^2- ; The third principal component F3 has significant relationship with Mg^2 ＋ . And the three principal components have covered more than 83 % information of the eight indexes. Linear regression analysis shows that there is a significant correlation between TDS and K ^＋ ＋ Na ^＋ and Cl^- , and the fitting equations have significant statistical significance.