【摘要】 选取闽中地区8个代表性茶园,分别采集茶园土壤及相应的茶树各器官样品,采用ICP-MS法测定茶园土壤、茶树各器官及茶汤中铅含量,研究茶园土壤及茶树各器官中铅的分布状况,分析了其与土壤理化性质之间的关系;结合目标危害系数法（THQ）评价由于饮茶摄入铅导致的人体健康风险,并估算茶叶中铅的限量值和最大饮茶量。结果表明,研究区茶园土壤全铅均值为82.91 mg·kg^-1,是福建省土壤铅含量背景值的2.38倍,存在明显的富集现象;茶园土壤有效铅含量均值15.20 mg·kg^-1,铅的活化率均值17.57%;茶园土壤铅污染指数为0.40～4.05,有两个样点超过限量标准。不同样点的茶树各器官铅含量和富集系数差异较大,总体顺序表现为侧根>主茎>主根≈侧茎>老叶>新叶,铅大部分被根和茎固定,茶树根系从土壤中吸收的铅不会导致茶叶铅含量超标。土壤全铅和有效铅与茶树老叶、侧茎和主茎之间呈极显著正相关,土壤铅含量及有效性是影响茶树铅吸收主要因素;土壤全磷和速效磷与土壤有效铅、茶树各器官铅含量、铅富集系数及转移系数大多呈显著负相关,说明磷能降低土壤铅的生物有效性,从而降低茶树对铅的吸收。茶汤中铅含量均值为22.84μg·L^-1,低于《GB5749-2006生活饮用水卫生标准》中铅限量含量;茶叶铅溶出率范围为12.53%～26.85%,均值为20.98%;茶汤和茶叶中铅的目标危险系数（THQ）分别为2.06×10^-2和1.07×10^-1,比推荐限量标准低1～2个数量级,该区域合理饮茶的健康风险较小;当茶叶中铅含量达到82.36 mg·kg^-1或人体每日饮茶达到550.98 g时,通过饮茶摄入的铅才有可能导致健康风险。更多还原

【Abstract】 The content and distribution of lead（Pb） in the soil and parts of a tea plant from 8 representative tea plantations in central Fujian were determined using the inductively coupled plasma mass spectrometry（ICP-MS）. Correlations among the soil physiochemical properties were studied. A preliminary assessment on the health risk of Pb in the brewed tea made from the plants grown in the same areas were conducted according to the method of target hazard quotient（THQ） to arrive at the proposed safety limits of Pb in tea leaves and plantation soil. In the soil, the average Pb content was found to be 82.91 mg·kg^-1, which was 2.38 times higher than the standard for the province, indicating a substantial accumulation of the metal ion in the region. The average available Pb in soil was 15.20 mg·kg^-1 and the activation rate of Pb was 17.57 %. The Pb pollution indices of the plantation soils ranged from 0.40 to 4.05, averaging 1.18, with two specimens scored beyond the national standards. On the tea plants, the amount and enrichment coefficients of Pb differed in different tissues that generally ranked in the order of lateral roots>main stem>taproot≈side-stems>old leaves>young leaves. It appeared that most of the Pb absorbed by a tea plant tended to accumulate in the roots and stems, and that the Pb uptake in the leaves, which are the raw material made into teas, might not exceed the safety limit under normal conditions. The Pb contents in the old leaves, side-stems, and main stem of a plant correlated significantly or extremely significantly with the total and available Pb in soil.The total available phosphorus inversely correlated with the available Pb, Pb in the tea organs, Pb enrichment coefficient, and Pb transfer coefficient in soil. The average Pb content in the brewed tea was 22.84 μg·L^-1, which was well below the safety standard for drinking water（GB5749-2006）. As the solubility of Pb in water being 20.98%, the target THQ for brewed tea being 2.06×10^-2, and that for tea leaves being 1.07×10^-1（which are one to two order of magnitude lower than those for safety standards）, only minimal risk for personal consumption was expected. Nonetheless, when the Pb content in tea leaves was up to 82.36 mg·kg^-1 or the daily tea drinking reached 550.98 g, the risk index will be greater than 1, and a risk on human health may become a realistic concern.更多还原