鲁北平原高氟深层地下水的探究

Study on Deep Groundwater with High-flouride in Lubei Plain

在山东省北部(鲁北)地区,当地群众由于长期饮用高氟深层地下水,极易导致地氟病,严重影响当地群众的身体健康。根据取样分析,研究区深层地下水氟离子含量大致呈现由南向北、由东向西依次增大的趋势,并且同一地段不同深度、不同岩性的氟离子含量也不尽相同,粘土中氟离子含量普遍大于粉砂层中的含量,高氟地下水多为弱碱性水,高氟地下水Na/Ca比高,高氟水与Na/Ca呈对数相关,相关性较好;高氟水水化学类型一般为HCO_3·Cl-Na型。从地质环境、水文地质环境、水文地球化学角度初探了鲁北平原深层高氟地下水的水文地球化学成因,认为鲁北深层高氟水的形成及分布规律主要受沉积环境、径流条件以及开采量的影响。由于沉积物来源的不同、水化学特征的迥异以及深层地下水的大量开采,粘土层压密释水过多补给,同时由于粘土层由南向北厚度逐渐增大,地下水径流进一步变缓,造成氟离子含量逐步增高,形成了南北部相差较大的氟离子分布特征。

In Lubei plain, long - term consumption of deep groundwater with high - flouride will cause endemic fluorosis, which affects the health of local people seriously. The enrichment of fluorine in groundwater is a complicated process. According to the analysis of samples, the content of flouride in deep groundwater takes on an ascend trend from south to north and from east to west in the study area. Even in the same position, the content of fluoride is not the same for different lithology. Content of fluoride in clay is higher than that in silty sand generally. High- flouride groundwater used to be weak alkalinity water, and the ratio of Na/Ca is higher. High - flouride water and the ratio of Na/Ca is a logarithm relation, and they corre- lated well. The hydrochemical type is generally HCO3· Cl- Na in high- flouride water. From the aspects of geological environment, hydrogeological environment and hydro geochemistry in Lubei plain, hydro - geochemical cause of underground with high- flouride in Lubei plain has been studied. It is concluded that the accumulation and distribution law of high- flouride water are mainly affected by depositional environment, runoff condition and yield. Such reasons make the content of fluoride rise gradually as different sources of sediments, different hydrochemical characteristics, exploitation of deeper groundwater which make the clay layer consolidated to release more water and the increase of clay layer in amount/total thickness from south to north resulting to slower groundwater runoff. All the reasons mentioned above lead to the quite different distribution characteristics of fluoride between south and north parts.