铁观音茶园土壤-茶树体系中镉的评价及迁移研究

Evaluation and transport of Cadmium in soil-tea tree system in Tieguanyin tea plantation

采集福建省泉州市安溪县祥华乡、剑斗镇、感德镇及湖头镇7个茶园的21个表层及垂直剖面土壤样品和28个茶树样品,使用电感耦合等离子体质谱仪(ICP-MS)测定样品中镉的含量,采用单因子指数法、地累积指数法、潜在生态风险指数法评价了茶树样品中镉的污染程度和潜在风险;采用相关分析法、生物富集系数法与转移系数法对土壤-茶树体系中镉的迁移特征进行了分析.结果显示,剑斗镇和湖头镇采样点所有的垂直剖面土壤中镉含量均超过福建省土壤元素背景值,其中S7采样点在0~20 cm深度土壤中镉的含量为2.37 mg/kg,为福建省土壤元素背景值的45倍.地累积指数法显示S7采样点处0~20 cm土壤的地累积指数为4.870,已达到重度污染,S7与S6采样点20~40 cm深度土壤均呈现中度污染.富集系数法结果表明,根对土壤中镉的富集能力最强,且由相关分析法可知,根中镉的来源是表层土壤,该研究为铁观音茶叶的种植管理和镉污染的研究提供基础数据.

Twenty-one surface and vertical profile soil samples and 28 tea tree samples were collected from 7 tea gardens in Xianghua Township, Jiandou Town, Gande Town and Hutou Town, Anxi County, Quanzhou City, Fujian Province.The Cd content in each sample was determined by inductively coupled plasma mass spectrometry(ICP-MS).Degree of pollution and potential risk of Cd exposure from tea plant samples were evaluated by single factor, ground accumulation, and potential ecological risk indices.The characteristics of Cd transfer between soil and tea plants were analyzed by correlation analysis and determination of bioenrichment and transfer coefficients.Cd content in all samples collected in Jiandou town and Hutou Town exceeded the background value of soil Cd content in Fujian Province.Cd content in 0~20 cm depth soil at the S7 site was 2.37 mg/kg, 45 times the background value in soil in Fujian Province.The ground accumulation index for soil of 0~20 cm depth at the S7 sampling site was 4.870,indicating severe pollution.Soil at 20~40 cm depth at the S7 and S6 sampling sites was moderately polluted.Enrichment coefficient analysis showed that roots had the strongest ability to enrich Cd in soil below the surface.Correlation analysis revealed that the source of Cd in roots was surface soil.