铅在植物-环境体系中的吸收、分布和迁移规律的稳定同位素示踪法研究

以低浓度的稳定铅同位素为示踪剂,采用电感耦合等离子质谱法,通过盆栽实验,考察了在不同的pH值环境和不同铅源引入方式下,茶树植株对铅的吸收情况以及铅在植株体内的分布及迁移规律.结果表明:茶树植株对大气铅源污染的反应比土壤铅源污染灵敏;大气铅源污染有往顶端(芽)迁移的趋势,而土壤铅源污染则主要聚集在根部;低pH条件增强植株对铅的吸收且能促使植株体内的铅的往高处迁移.本实验方法危害小,更接近植株承受低浓度污染的实际情况,能区分实验引入铅源和环境引入铅源.

INVESTIGATION OF ADSORPTION, DISTRIBUTION AND MIGRATION OF LEAD BETWEEN ENVIRONMENT AND PLANT BY STABLE LEAD ISOTOPIC TRACER

Low concentration isotopic lead tracer (SRM982) was adopted, ICP-MS was used as a detection tool. By pot test, the chemical action of lead in tea under the condition of different pH and different modes of lead exposure was studied. Simulated rain water (C_(pb) = 0.5mg·l~(-1)) was used to pot soil and spray leaf to investigate the adsorption, distribution and migration of lead in two systerms: atmosphere-tea and soil-tea. The results are: 1. the reaction to lead pollution from atmosphere is more sensitive than that from soil; 2. the migration and distribution in tea of lead pollution from atmosphere and from soil is different, the former has the trend of conveying to bud while the latter focus mainly in root; 3. pH has an evidently effect on the migration of lead in tea, generally, low pH facilitates migration to upper parts. This method has the advantages that tea beared low polution, and the hazard to plant is less than traditional ways. In addition, lead from environment and from tracer can be separated.