华南西部火山岛地区滨海浅层地下水的水质现状研究

Study on current state of shallow underground water quality along shoreline of volcanic islands in western South China

雷州半岛与海南岛一峡相隔,气候和地质环境相似。近年来,随着经济社会的快速发展,沿海地下水抽用频繁,发展和环境的矛盾日益突出。为了解滨海地区地下水的分布、变化及其与环境的关系,在雷州半岛和海南岛滨海地区进行了浅层地下水井钻凿和地下水潮周期化学连续取样及实验测试。对数据的分析与评价结果表明:全部监测井为Na-Cl型,除个别监测井外,大多数监测井浅层地下水的溶解性固体总量(total amount of dissolved solids,TDS)和氯离子、硫酸盐、钠离子等含量较高,其中TDS和氯离子含量最高,分别接近39.00 g/L和20.00 g/L,取样时段内波动较大,类型以偏酸性重碳酸盐为主转为以偏碱性钠离子和氯化物为主;受制于地质环境条件,地下水自我调节能力以"一般"和"弱"居多,水质为IV—V级,且不随测次而变化,表明至少在短期内不会改变。滨海地区浅层地下水水质既与地质环境条件关系密切,也与人类活动有关,还可能受到深层承压古海水释放的影响。影响地下水水质的因素较为复杂,需要进一步加强综合研究和监测。

Separated by Qiongzhou Strait, Leizhou Peninsula and Hainan Island have similar climate and geolog-ical environment. Recently, with the quick development of economy and society, the extract and usage of under-ground water is becoming frequent and the problems of development against environment protection have become prominent. In order to understand the distribution, variation of underground water and the link between distribu-tion ,variation and environment, the authors drilled shallow underground monitoring wells, and then sampled and analyzed the samples in laboratory along Leizhou Peninsula and Hainan Island shorelines. The analysis results show that beside few wells, the concentration of total amount of dissolved solids （TDS） and the main ions （ Cl~ , SO4 and Na＋ ） in underground water are at high level. TDS and Cl have maximum concentration nearly to 39. 00 g/L and 20. 00 g/L respectively, and also are featured with relatively frequent vibration, revealing that the type of underground water changed from weak acidic and bicarbonate to Cl types and are related with tidal cy-cles. Constrained by geological environment, the resilience of shallow underground in most wells falls into average or weak grade and the water quality is IV - V types, which will not change at least in shortterm. Therefore, theunderground water quality has close relationship with geological environment and human activities, and it is proba-bly affected by the release of deep ancient seawater. The influence factors of the underground water quality are complicated, so more attention should be paid to the further monitoring and research.