南秦岭大巴山区河流、泉水、井水的含硒量及其分布规律

Selenium Content in the Water of the Rivers, Springs and Wells in the Daba Mountain Area of the South Qinling Mountains and Its Distribution Pattern

地处南秦岭大巴山地区的紫阳县是我国著名的富硒区。通过对南秦岭大巴山区几条主要河流、泉水、井水的含硒量及其分布区地层和岩石的含硒量及其相关关系分析,结果表明大巴山地区河流、泉水、井水的含硒量与含水层及其流域分布的岩石特征、岩石的含硒量及其硒的淋失率等密切相关。其河流、泉水、井水的含硒量为0.05～15 μg/L。其中泉水的含硒量为0.1～1.9 μg/L,井水的含硒量为0.05～15 μg/L,河流的含硒量为0.3～0.7 μg/L。本区含硒量最高的水体为下寒武统鲁家坪组碳质板岩分布区汇水侧的井水,其含量为2～15μg/L。富硒而淋失率低、但淋失量高的下寒武统鲁家坪组分布区的泉水和井水的含硒量高,是今后大巴山紫阳县潜在的富硒矿泉水的寻找和开发的方向。含硒量低的志留纪砂岩和粉砂岩、奥陶纪白云岩、白云质灰岩以及中、晚寒武世灰岩和砾屑灰岩分布区的泉水和井水的含硒量低。

Ziyang county in Daba Mountain, which lies in the South Qinling Mountains, is considered a famous area rich in selenium in China. The relations between the selenium content of the water of the main rivers, springs and wells, as well as the lithologic characters, the selenium content of the rocks in this area are studied in this paper. The results show that the selenium content of the water is closely related to the lithologic characters, the selenium content and its leaching rate of the acquifer and the water drainage region. The selenium content in the water of this area is about 0. 05-15 μg/L; specifically, it is 0. 1-1. 9μg/L for springs, 0. 05~15 μg/L for wells and 0. 3~0. 7 μg/L for rivers. The selenium content has the highest values in the wells in the car-bonaceous slate area on the catchment side of the Lower Cambrain Lujiaping Formation, which range from 2 to 15 μg/L. The springs and wells in the above area are rich in selenium, and have a low leaching rate but the amount of leaching is large. It will be a potential source for searching for and exploring selenium-mineral water in Daba Mountain in future. In the areas distributed by Silurian siltstone and sandstone, Ordovician dolomite and dolomitic limestone, as well as Middle-Upper Cambrain limestone and calcirudite, the selenium content of the water in springs and wells is low.