Characteristics of heavy metal accumulation and risk assessment in understory Panax notoginseng planting system
Characteristics of heavy metal accumulation and risk assessment in understory Panax notoginseng planting system
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DOI：
10.1007/s10653-022-01392-9
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发表时间：
2022-10-02
影响因子：
4.2
通讯作者：
Fan, Wei
中科院分区：
文献类型：
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作者：
Huang, Zhenhua;Shen, Zhida;Fan, Wei
云南省是名贵中药材三七的主产区，但地处中国地区土壤重金属含量较高的地质区。由于连作障碍和过量使用化学物质而频繁的土地置换，使得三七在农田种植时容易受到重金属的污染。林下三七是为解决耕地短缺问题而发展起来的一种新型生态种植模式，其特点是无化学物质投入。然而，这种新开发的种植制度迫切需要了解土壤-植物重金属特征和风险评估。本研究旨在评价云南省澜沧县土壤耕作层(0~20 cm)、下土层(20~40 cm)和不定植植物中8种重金属的污染状况。污染指数(P-I)表明，耕层重金属污染程度为Cd>；铅>；镍>；铜>；锌>；铬>；汞>；As；耕作层潜在生态风险指数(PERI)为轻度，下层为中等。根中Cd、As、铅、汞、铜的超标率分别为5.33%、5.33%、13.33%、26.67%和1.33%，只有叶片中Cd和Hg的超标率分别为10%和14%。根、叶中Cd、Hg的富集力最强，而Pb2+的富集力最弱。UPN根和叶中8种重金属的危害指数(HI)和目标危害商(THQ)均小于1，证明UPN对人体健康无危害，为UPN的安全性评价和推广提供了科学依据。
Yunnan Province is the main planting area of the precious Chinese herbal medicines (CHM) Panax notoginseng; however, it locates the geological area with high soil heavy metals in China. The frequent land replacement due to continuous cropping obstacles and excessive application of chemicals makes P. notoginseng prone to be contaminated by heavy metals under the farmland P. notoginseng (FPn) planting. To overcome farmland shortage, understory P. notoginseng (UPn) was developed as a new ecological planting model featured by no chemicals input. However, this newly developed planting system requires urgently the soil-plant heavy metal characteristics and risk assessment. This study aimed to evaluate the pollution status of eight heavy metals in the tillage layer (0-20 cm), subsoil layer (20-40 cm) and the plants of UPn in Lancang County, Yunnan Province. Pollution index (P-i) showed that the contamination degree of heavy metals in the tillage layer and subsoil layer was Cd > Pb > Ni > Cu > Zn > Cr > Hg > As and Pb > Cd > Cu > Ni > Cr > Hg > Zn > As, respectively. Potential ecological risk index (PERI) for the tillage layer and subsoil layer was slight and middle, respectively. The exceeding standard rate of Cd, As, Pb, Hg, Cu in the UPn roots was 5.33%, 5.33%, 13.33%, 26.67% and 1.33%, respectively, while only Cd and Hg in the UPn leaves exceeded the standard 10% and 14%, respectively. The enrichment abilities of Cd and Hg in the roots and leaves of UPn were the strongest, while that of Pb was the weakest. The Hazard index (HI) and target hazard quotient (THQ) of eight heavy metals in the roots and leaves of UPn were less than 1.Therefore, our results prove that Upn has no human health risk and provide a scientific basis for the safety evaluation and extension of UPn.