Li Ning, Li Yan, Zhou Shenglu, Zhang Huanchao, Wang Genmei
College of Forestry, Nanjing Forestry University, Nanjing, China.
Key Laboratory of Geographic Information Science of the Ministry of Education, School of Geographic Sciences, East China Normal University, Shanghai, China.
Front Plant Sci. 2022 Jul 11;13:911447. doi: 10.3389/fpls.2022.911447. eCollection 2022.
As a developed economic region in China, the problem of heavy metals (HMs) pollution in the Yangtze River Delta has become increasingly prominent. As an important evergreen broad-leaved tree species in southern China, the camphor tree cannot only be used as a street tree but also its various tissues and organs can be used as raw materials for Chinese herbal medicine. In order to explore whether heavy metal contamination in the region threatens the safety of camphor trees as pharmaceutical raw materials, we collected the bark and leaves of the tree most commonly used for pharmaceuticals in Yixing City. Based on the determination of HMs content, the health risks after human intake are evaluated, the sources and contributions of HMs are analyzed, and then the health risks of pollution sources are spatially visualized. The results showed that under the influence of human activities, the camphor trees in the study area had obvious enrichment of HMs, and the over-standard rate of Pb in the bark was as high as 90%. The non-carcinogenic risks of bark and leaves are acceptable, but the carcinogenic risks are not acceptable. The bark had the highest average carcinogenic risk, approaching six times the threshold. The results of Pb isotope ratio analysis showed that the average contribution rate of industrial activities to HMs in camphor trees in the study area was the highest, reaching 49.70%, followed by fossil fuel burning (37.14%) and the contribution of natural sources was the smallest, only 13.16%. The locations of the high-risk areas caused by the three pollution sources in the study area are basically similar, mainly concentrated in the northwest, northeast, and southeast, which are consistent with the distribution of industries and resources in the study area. This study can provide a reference for the precise prevention of HMs pollution of camphor and the safe selection of its pharmaceutical materials.
作为中国经济发达地区，长江三角洲的重金属污染问题日益突出。樟树作为中国南方重要的常绿阔叶树种，不仅可作行道树，其各组织器官还可作为中药材原料。为探究该地区重金属污染是否威胁樟树作为药材原料的安全性，我们采集了宜兴市最常用于制药的樟树的树皮和树叶。基于重金属含量测定，评估人体摄入后的健康风险，分析重金属的来源及贡献，进而对污染源的健康风险进行空间可视化。结果表明，在人类活动影响下，研究区域内的樟树存在明显的重金属富集现象，树皮中铅的超标率高达90%。树皮和树叶的非致癌风险可接受，但致癌风险不可接受。树皮的平均致癌风险最高，接近阈值的6倍。铅同位素比值分析结果显示，研究区域内樟树中重金属的工业活动平均贡献率最高，达49.70%，其次是化石燃料燃烧（37.14%），自然源的贡献最小，仅为13.16%。研究区域内由这三种污染源导致的高风险区域位置基本相似，主要集中在西北、东北和东南部，与研究区域内的产业和资源分布一致。本研究可为樟树重金属污染的精准防治及其药材原料的安全选择提供参考。
