安溪土壤—茶叶铅含量关系与土壤铅临界值研究

摘要

在福建安溪等地79个茶园采集了表层、亚表层土壤样和对应的茶叶样品,测定了茶叶铅含量和土壤常量组分、铅等微量元素组成. 相关分析表明,茶叶与土壤铅含量呈显著正相关(P<0.01),由此可建立一元线性回归方程,计算茶叶对土壤铅的迁移系数( Ft ). 研究得出,茶叶铅迁移系数受土壤中Pb、Mn、P、Zn 浓度的影响. 依据茶叶铅质量标准,推算出茶园土壤铅安全临界值,结果表明,通常情况下由茶树根系从土壤中吸收的铅不会导致茶叶铅含量超标. 以土壤铅存在形态及其生物有效性的理论研究成果为指导,结合影响茶叶铅迁移系数的土壤理化指标,建立的多元回归方程能更好地表征茶叶铅含量与土壤理化指标间的相互关系.%Top ( 0~20 cm) and sub-layer ( 20~40 cm) soil samples as well as corresponding tea leaf samples were collected at seventy-nine tea gardens in Anxi County and other areas, Fujian Province. Lead concentrations of tea leaves as well as soil geochemical indica-tors including macro-and micro-elements were determined. There is a significant correlation between the lead concentration of tea leav-es and that of the corresponding soils. Therefore, a linear regression model was established, and transfer factors( Ft ) for lead from soils to tea leaves was calculated. It seems that Ft values are affected by the concentrations of lead, manganese, phosphorus and zinc in soils. The critical value of soil lead for tea production was derived from the regression model and Ft value according to tea quality crite-ria. The result demonstrates that the lead values of tea uptake from soils would not exceed tea quality criteria (5×10-6) under normal soil lead concentration. Multivariable linear regression model can preferably explain the relationship between lead concentration in tea leaves and soil physicochemical indicators.