招远金矿区水体中硫同位素特征及其对污染来源的指示

稳定同位素因其指纹效应已成为分析矿区污染来源的重要技术手段。文章以招远金矿区为例，应用硫同位素联合水化学分析、聚类分析及氢氧同位素分析招远金矿区水污染特征和成因。通过分析可知，矿区内地表水和地下水主要接受大气降水补给，水力联系密切。水化学类型以SO₄—Ca和SO₄—Na型为主，阴离子以SO₄2-为主，地表水和地下水的NO₃-和Cl-在空间上变异性较大。地表水硫酸盐含量普遍偏高，硫酸盐污染较为严重，高值区出现在玲珑金矿、金翅岭金矿和张星镇附近；而地下水高值区都出现在玲珑金矿附近，且SO₄2-浓度沿着径流方向逐渐降低。地表水中硫酸盐δ34S值介于1.8‰~9.8‰，地下水中硫酸盐δ34S值介于2.7‰~9.6‰，地表水和地下水硫酸盐含量受玲珑金矿硫化、玲珑花岗岩和胶东岩群影响明显。在地下水径流途中，有地表水入渗污染地下水的现象。另外，工业废水的排放也是硫酸盐含量升高的主要原因。研究表明:硫同位素在金矿区硫酸盐污染的来源和特征方面有很好的指示作用，是评价矿山开采对地下水污染的有效工具。

Characteristics of sulfur isotope in water bodies near the Zhaoyuan gold mine area and its indicative function of pollution sources

Stable isotopes have become an important technical method for analyzing pollution sources in mining areas due to their fingerprint effect. In the Zhaoyuan gold mine area, most of the studies were based on experiments or hydrochemical data combined with hydrogeological conditions. It is difficult to analyze the compositions of pollution sources. This paper is the first time to analyze the hydrochemical characteristics and pollution causes of the Zhaoyuan gold mine area by combining the 2H, 18O and 34S isotopes of water bodies and hydrochemical methods. 32 samples were collected, including 16 groundwater samples, 10 surface water samples, 3 beneficiation wastewater samples, 2 tailing leachate samples and 1 pit water sample. Based on the analyses, the surface water and groundwater with close hydraulic connection in the mining area are mainly recharged by precipitation. The main hydrochemical components are from the oxidation of sulfide minerals, the dissolution of silicate minerals and the influence of human activities. The main hydrochemical types are of SO₄—Ca and SO₄—Na, the main anion is SO₄2-, and the variation of NO₃- and Cl- in surface water and groundwater is large in space. The contents of sulfate in the surface water are generally high, and the sulfate pollution is serious. The high value areas appear near the Linglong gold mine, Jinchiling gold mine and Zhangxing Town, while the high value areas of groundwater appear near the Linglong gold mine, and the concentrations of SO₄2- decreases gradually along the runoff direction. The value of δ34S in the surface water ranges between 1.8‰ and 9.8‰, and that in groundwater, between 2.7‰ and 9.6‰. The groundwater and surface water are obviously affected by the Linglong granite, Jiaodong rock group and sulfide of Linglong gold deposit. In the process of groundwater runoff, there is the phenomenon of groundwater pollution caused by surface water infiltration. In addition, the discharge of industrial and domestic sewage is also the main reason for the increase of sulfate contents. Sulfur isotope can trace the source and characteristics of sulfate pollution in the gold mining area, and it is an effective tool for tracing and evaluating the groundwater pollution caused by mining activities.