吉林省西部氟病区苏打盐碱土氟的赋存形态及分布特征

为了研究吉林省西部氟病流行区农田土壤的氟形态及其分布特征,采用连续浸提法,对该区域内45个表层土壤和6个剖面土壤的氟含量进行了测定,并与土壤理化性质进行相关分析。结果表明,表层土壤全氟含量变化范围为200~450 mg/kg,平均值为266.17 mg/kg,低于全国土壤氟背景值和对照黑土,但是其生物有效性强,水溶态氟和交换态氟平均含量分别为13.73、8.49 mg/kg,均高于对照黑土。土壤剖面中,残余态氟和全氟含量呈40~60 cm0~20 cm20~40 cm;铁锰结合态氟分布较均匀;其他形态氟则随着土层加深呈降低趋势。交换态氟与其他形态氟间呈显著或极显著的正相关关系,为各形态氟相互转换的过渡形式。pH与水溶态氟、有机束缚态氟、铁锰结合态氟呈极显著或显著正相关,与交换态氟呈极显著负相关;碳酸钙、CEC分别与水溶态氟和交换态氟呈极显著正相关;另外,有效磷与交换态氟呈显著正相关;有机质与水溶态氟、铁锰结合态氟和有机束缚态氟呈显著或极显著正相关;游离氧化铁和游离氧化铝分别与交换态氟和铁锰结合态氟呈显著或极显著正相关。降低苏打盐碱土pH是降低氟生物有效性的首选方法。通过对以上土壤参数进行分析,为今后降低该区域土壤中氟的生物有效性提供技术支持。

Fluorine Speciation and Distribution Characteristics in Sodic Soil of Fluorosis Area in Western Jilin Province

The objectives of this study were to research fluorine speciation and distribution characteristics in the cultivated soils in fluoride epidemic area in western Jilin Province. In total 45 surface soil samples and 6 soil profile samples were collected and fluorine contents in soils were measured by the method of consecutive extraction, and correlation analysis was conducted to determine the relationships between soil fluorine speciation and soil physic-chemical properties. The results showed that the average content of total fluorine in surface soils was 266.17 mg/kg with the range of 200 - 450 mg/kg, which was lower than the background value of China and control treatment of black soil. Fluorine in tested soils had a strong biological activity because higher contents of water soluble fluorine and exchangeable fluorine (13.73 mg/kg and 8.49 mg/kg respectively) compared with black soil. In soil profiles, the distribution of residual fluorine and total fluorine was 40 - 60 cm>0 - 20 cm>20 - 40 cm; Fe/Mn oxides fluorine changed little in each profile, other fluorine forms decreased with soil depth increasing. There was a significant or extremely significant positive correlation between exchangeable fluorine and other fluorine forms, which indicated that exchangeable fluorine was the transition form when fluorine mutually transformed. pH was significantly positively correlated with water soluble fluorine, organic fluorine and Fe/Mn oxides fluorine but significantly negatively correlated with exchangeable fluorine. Significant positive correlation were observed between CaCO3 and water soluble fluorine, CEC and exchangeable fluorine. Moreover, available P was significantly positively correlated with exchangeable fluorine. Soil organic matter was significantly positively correlated with water soluble fluorine, Fe/Mn oxides fluorine and organic fluorine. Free iron oxidewas significantly positively correlated with exchangeable fluorine, free iron aluminum was significantly positively correlated with Fe/Mn oxides fluorine. Decrease soil pH is the best method to reduce fluorine biological effectiveness in Soda saline soil. The results provided technical support in reducing fluorine bioavailability in fluoride epidemic area.