不同预处理条件对土壤可溶性氟测定结果的影响研究

The effect research of the soil soluble fluoride determination results under different pretreatment conditions

土壤可溶性氟是地下水中氟的重要来源，明确高氟水地区土壤中可溶性氟的分布情况，对于防治地方性氟中毒有重要意义。预处理条件对土壤可溶性氟的测定起着至关重要的作用。本文以陕西渭南高氟地下水地区的土壤为例，探讨土壤浸提土液比、土壤浸提时间、温度和振荡速度、以及土壤筛分粒径等预处理参数对测定结果的影响。试验结果表明，浸提土液比、时间、温度和振荡速度、以及土壤筛分粒径等参数均对土壤可溶性氟测定结果产生影响。通过综合比较，对于供试土壤可溶性氟在测定过程中，浸提土液比宜选择1：10，浸提时间50min为宜（黏土宜延长浸提时间），浸提温度45℃，振荡速度为180r／min，其筛分径可在0．5～2．5mm之间（黏土可选择2．5mm）；土壤样品测试前前处理方式宜选择0．45μm过滤纸以及0．22μm水系过滤头过滤，其中砂壤土样品测试前处理方式亦可采用8500r／min转速离心，然后使用0．22μm水系过滤头过滤。本试验为陕西渭南区域氟问题的相关研究奠定基础，对于分析土壤氟污染以及评估周边区域氟中毒情况有着重要的实践意义。

Determining soil soluble fluoride content can control endemic fluorosis indirectly, as soil soluble fluoride is a main source of high fluoride groundwater. Pretreatment conditions play a vital role in determin- ing soil soluble fluoride. The impact of soil water ration, soil extraction time, temperature and shaking speed, soil sieve particle size on determining soil soluble fluoride were studied in this paper. Soil samples were collected from Weinan city, Shanxi province. Results show that the soil water ration, soil extraction time, temperature and shaking speed, soil sieve particle size all have effect on the result of determining soil soluble fluoride. By comparing different treatments, the suitable pretreatment conditions for tested soil soluble fluoride in Weinan are as follows： soil water ratio is 1： 10, extraction time is 50 min and can be longer for clay soil, temperature is 45℃, shaking speed is 180r/min, soil sieve particle size can be from 0.5mm to 2.5mm for sandy soil and 2.5ram for clay soil Before soil extraction was tested, soil extraction should be filtered by 0.45μm fiher paper and 0.22μm water system filter. For sandy soil, soil extraction can also be centrifuged at 8 500r/rain speed and filtered by 0.22μm water system filter. This study served as a base of fluoride related research in Weinan, and played an important role in analyzing the soil fluo- rine pollution and assessing the surrounding areas fluorosis.