西南氟病区典型高氟土壤的地球化学特征及氟富集原因

贵阳市高氟土壤的成土母岩主要为三叠系松子坎组泥质灰岩与泥质白云岩。研究区内表层土壤最高值是全国均值的8.2倍,深层土壤最高值是全国均值的12倍。土壤中氟富集的主要原因为土壤粘粒组分吸收富集了基岩风化过程中释放出来的氟,在基岩氟含量较高的地区,这一过程导致土壤氟含量达到极高水平。在碳酸盐岩区发育程度不同的土壤氟含量差别较大,氟主要富集在土壤粘化层,土壤中含粘土矿物和非晶质矿物越多的层位,氟含量越高。

Element Geochemistry and Fluoride Enrichment Mechanism in High-fluoride Soils of Endemic Fluorosis-affected Areas in Southwest China

Pedogenic parent rocks of high-fluoride soils were mainly derived from argillaceous limestone and argillaceous dolomite of the Songzikan Formation in Guiyang.The value of fluoride in surface soils is 8.2 times higher than the average value for Chinese soils.The value of fluoride in deep soils is 12 times higher than the average value for Chinese soils.The fluoride mobility increased with rock weathering and it was absorbed on soil clay particles.This is the main reason of fluoride enrichment in soils,which leads to soils having a high fluoride value in the high-fluoride pedogenic parent rock areas.Fluoride values in soils varied greatly because of various carbonates,and fluoride was enriched in near-surface soil,especially in clay and amorphous minerals in the soils.