HYDROCHEMICAL CHARACTERISTICS OF GROUNDWATER AND GENESIS OF MINERAL WATER AT LAOSHAN MOUNTAIN AND SURROUNDING AREAS, QINGDAO

The Laoshan Mountain and its surrounding areas are rich in mineral water under the joint control of structural faults and weathering granite crust. In this paper, 14 hydrogeological wells are selected from the area surrounding the Laoshan Mountain for revealing the hydrogeological characteristics and concerned problems. The main hydrogeological problems are concentrated in the middle and lower reaches of rivers where human activities are frequent and active. Both industrial and agricultural pollution leads to the excess of nitrate in groundwater, in addition to saltwater intrusion occurred in the nearshore areas. A mineral water well located in the weathered crust of granite was discovered this time in the Lanseguigu District. The groundwater in the well belongs to the type of HCO₃·SO₄-Ca·Na. The contents of strontium (Sr) and metasilicic acid (H₂SiO₃) of the groundwater are 0.66 and 25.49 mg/L respectively, which are both higher than the standard content for drinking natural mineral water. The formation of the mineral water is closely related to the geological environment of the Laoshan area and mineral compositions of surrounding rocks. The strontium-metasilicic acid mineral water is formed by the dissolution of strontium and silica from granite into water by a long term water-rock interaction. This discovery is significant and may provide a new mineral water producing area in the Laoshan region of Qingdao.