摘要
宁南西吉存在范围较大的高氟地下水区,属于高氟水重灾区。以宁南含水层沉积物为研究对象开展室内实验,探讨了pH、Ca2+、Na+、HCO-3和Ca2+/OH-协同作用对沉积物中氟释放的影响及定量关系。结果表明,相对于HCO-3,pH值对F-释放的促进作用更高,相对增量为10%~50%。低Ca2+/Na+比提高了沉积物所释放F-的活度,有利于地下水中F-的聚集。不同岩性对pH值的缓冲能力不同,从而决定F-的释放。整体而言,粉质粘土、泥岩和粘土F-释放的浓度相对其他岩性要高。泥岩和粉质粘土的F-释放受pH影响较大。沉积物中Al、Fe、Mn、Si组分含量、总F-浓度与不同条件下淋滤出的F-浓度也具备较好的相关性。沉积物的F-含量对地下水中F-聚集有较大的影响。
High fluoride groundwater occurs extensively in Xiji county of southern Ningxia.In order to evaluate the key factors controlling fluoride release,experiments were carried out to study the impacts of pH,Ca2 +,Na+,HCO3 in combination with Ca2 +and OH-on the release of F-from typical sediments of aquifers in Xiji.Results showed that the promotive effect of pH on fluoride release was 10% ~ 50% higher than the effect of HCO3.In addition,the low ratio of Ca2 +to Na+improved the F-activity,and therefore enhanced fluoride release from the sediments,which is conducive to fluoride enrichment in groundwater.Different lithological sediments display different buffering capacity of pH,which determines the release of F-.Overall,silty clay,mudstone,and clay released more fluoride in comparison with other lithological sediments.Besides,mudstone and silty clay are more prone to the effect of pH.In all of the sediments,contents of Al,Fe,Mn,Si and total F-showed a good correlation with concentration of released F-.Therefore,F-content of sediments played a significant role in F-enrichment in the groundwater.
出处
《水文地质工程地质》
CAS
CSCD
北大核心
2013年第5期117-123,共7页
Hydrogeology & Engineering Geology
基金
国家自然科学基金项目(41222020,41172224)
中国地质调查局项目(1212010813104)
关键词
高氟地下水
西吉
氟释放
富集
水-岩相互作用
high fluoride groundwater
Xiji
F-release
enrichment
water-rock interaction
