恩施富硒茶园土壤重金属和氟含量及风险评价

Contents and Risk Assessment of Heavy Metal and Fluorine in Selenium Enriched Tea Garden Soils in Enshi Area

探讨了恩施地区富硒(Se)茶园土壤重金属及氟(F)元素含量,并结合土壤环境质量标准、有机茶产地环境条件标准及F的土壤健康标准,运用单因子污染指数法及综合污染指数法对恩施地区10个典型茶园土壤污染状况进行了评价,以期为该区茶园土壤重金属和F污染风险评价提供参考。结果表明:铅(Pb)和铬(Cr)含量均在土壤背景值范围内,3个茶园土壤镉(Cd)含量超过土壤环境质量二级标准,土壤F含量普遍偏高;Pb和Cr的单因子污染指数平均值小于1,说明土壤未受该元素污染;F和Cd的单因子污染指数平均值均大于1,大部分土壤处于污染水平;从综合污染指数来看,土壤以轻度污染为主,有必要加强土壤F和Cd的风险防治工作以保证有机茶的品质安全。通过对富Se茶园土壤、茶叶中Cd、Pb、Cr、Se、F含量进行相关性分析可知,土壤中Cd、Pb、Cr、Se含量之间没有显著的相关性,茶叶Se含量与土壤Cr全量,茶叶Cd含量与土壤有效态Cd含量、Se全量,茶叶Cr含量与土壤有效态Se含量,茶叶F含量与土壤有效态F含量均呈显著或极显著正相关,茶叶Pb含量与土壤有效态F含量呈显著负相关。

The contents of heavy mental and fluorine（ F） were investigated in selenium（ Se） enriched tea garden soil in Enshi,and the pollution risk of heavy mental and F were assessed using the single factor pollution index and comprehensive pollution index in 10 typical tea gardens by reference to the soil environment quality standards,organic tea growing conditions and soil health standard of F. The results showed that the lead（ Pb） and chromium（ Cr） contents were in the range of soil background values,while the cadmium（ Cd） contents were above the second level criterion of soil environment quality standards.The F contents were generally higher. The average single factor pollution indexes of Pb and Cr were below one,indicating that most of the soil samples were clean. The average single factor pollution indexes of Cd an F were above one,indicating that most of soils were polluted by the two elements. For comprehensive pollution index,a light pollution was observed for most soil samples. It would be necessary to strengthen the risk assessment of Cd and F to ensure the quality and security of organic tea. The results of correlation relationships analysis of elements（ Cd,Pb,Cr,Se and F） contents in soil and tea,no significant correlations were found between soil total elements contents; while the positive significant correlations were observed between the Se content in tea leaf and total Cr content in soil,Cd content in tea leaf and total Se content,effective Cd content in soil,the Cr content in tea leaf and effective Se content in soil,and the F content in tea leaf and effective F content in soil,respectively; the Pb content in tea leaf was negatively correlated with effective F content in soil.