不同上覆水氟浓度对湖泊沉积物氟释放与微生物群落的影响

Effect of different fluoride concentrations of the overlying water on the release of fluoride and microbial communities of lake sediments

通过模拟沙湖沉积物-水系统,以沙湖原水氟离子(F^(-))浓度为1倍浓度(0.69 mg/L),设置0.5倍浓度、1倍浓度、1倍浓度灭菌、2倍浓度和4倍浓度共5个实验组,探究不同上覆水F^(-)浓度背景下沙湖沉积物中F^(-)的迁移.结果表明,沉积物F^(-)的释放量随上覆水F^(-)浓度的增加而呈下降的趋势,其中2倍和4倍浓度组的沉积物由释放F^(-)转变为吸附F^(-).碱性水体有利于沉积物F^(-)的释放,即随着pH增大,F^(-)释放量也会增加.微生物的Beta多样性层次聚类分析表明,F^(-)会抑制Paenisporosarcina与Thiobacillus的相对丰度,但对Fusibacter的生命活动具有促进作用.根据各浓度组间优势菌属相对丰度与环境因子的冗余分析可得,Acinetobacter、Thiobacillus相对丰度与pH呈负相关;Fusibacter相对丰度与F^(-)浓度呈显著正相关,而Thiobacillus的相对丰度则与F^(-)表现出弱负相关.通过对各浓度组中重要离子的分析发现,0.5倍组和4倍组中F^(-)的迁移受Ca^(2+)、HCO_(3)^(-)和SO_(4)^(2-)浓度影响较大;相关性分析表明0.5倍浓度组的Ca^(2+)、HCO_(3)^(-)浓度与F^(-)浓度呈极显著正相关,而4倍组中F^(-)浓度和Ca^(2+)、HCO_(3)^(-)浓度呈负相关,SO_(4)^(2-)浓度和F^(-)浓度的相关性则是0.5倍组呈负相关,4倍组呈极显著正相关.本文在不同上覆水F^(-)浓度背景下全面探究了沙湖沉积物中F^(-)释放和迁移机理,为沙湖及其他含氟地表水的氟污染防治提供理论支持.

We simulated the sediment-water system of Lake Shahu.The raw fluoride(F^(-))concentration of the Lake Shahu water was set to 1-fold concentration(0.69 mg/L).Five concentration-gradient groups(0.5-fold,1-fold,1-fold sterilization,2-fold and 4-fold)were tested to investigate the migration of F^(-) in Lake Shahu sediments under different F^(-) concentrations of the overlying water.Results showed that the release of F^(-) from the sediments decreased with the gradient of F^(-) concentrations,and the sediments adsorbed F^(-) in the 2-fold and 4-fold groups.Alkaline waters were favorable for the release of F^(-) from the sediments.As the pH level increased,the release of F^(-) also increased.Results from analysis of the beta diversity hierarchical clustering of the microorganisms showed that F^(-) inhibited the relative abundances of Paenisporosarcina and Thiobacillus,but promoted the vital activities of Fusibacter.According to the redundancy analysis of the dominant genera and environmental factors,Acinetobacter and Thiobacillus were negatively correlated with the pH level.Fusibacter had a significant positive correlation with F^(-) concentrations,while Thiobacillus showed a weak negative correlation with F^(-).Analysis of the significant ions in each group indicated that the migration of F^(-) in the 0.5-fold and 4-fold groups was strongly influenced by Ca^(2+),HCO_(3)^(-),and SO_(4)^(2-) concentration.Correlation analysis showed that Ca^(2+)and HCO_(3)^(-) concentrations had a highly significant positive correlation with F^(-)concentration in the 0.5-fold concentration group,and a negative correlation was found between F^(-) and Ca^(2+) or HCO_(3)^(-) concentrations in the 4-fold group.Correlation between SO_(4)^(2-) and F^(-) concentrations in the 0.5-fold group showed a negative correlation,and the 4-fold group showed a highly significant positive correlation.This study comprehensively investigated the mechanisms of the release and migration of F^(-) in the sediments of Lake Shahu under different F^(-) concentrations of the overlying water.Thus,a theoretical support is provided for the control of F^(-) pollution in Lake Shahu and other fluorinated surface waters.