Purpose To evaluate the pollution risks of five heavy metals (Cd, As, Pb, Cr, Hg) in Panax notoginseng cultivated farmland soil and the accumulation differences of these five heavy metals in plants.
Methods A total of 250 P. notoginseng plants and corresponding rhizosphere soil samples were collected from 10 different planting sites. The contents of five heavy metals in soil and plants were detected by inductively coupled plasma mass spectrometry, then, the exceeding rate, enrichment coefficient, and transport coefficient of five heavy metals in the rhizosphere soil of P. notoginseng and the aboveground and underground parts of plants were analyzed.
Results The heavy metal exceeding rate of P. notoginseng rhizosphere soil in the 10 sampling sites was Cd (75.56%)>As (40.23%)>Cr (8.89%)>Hg (0.00%)=Pb (0.00%), the exceeding heavy metals did not exceed control value, and four sampling sites belonged to slight pollution. The heavy metals that exceeded the standard in both the aboveground and underground parts of P. notoginseng plants were Cd, Cr and Pb, with Cd (67.90%)>Cr (22.22%)>Pb (10.84%) in the aboveground part and Cr (49.43%)>Cd (32.05%)>Pb (3.70%) in the underground part. Except for Hg, the underground parts of P. notoginseng showed a stronger enrichment ability for Cd, Pb, As and Cr than the aboveground parts. The enrichment coefficient for Cd in both aboveground and underground parts were greater than one.
Conclusion Most of the sampling sites are classified as slight pollution level, however, there is a potential risk of exceeding Cd, As and Cr in the underground part and the rhizosphere soil of the P. notoginseng, P. notoginseng plants accumulate these metals more in the underground part than that in the aboveground part, with the strongest ability for Cd. It is necessary to strengthen the monitoring of soil heavy metals and control the accumulation of Cd, As and Cr in the main medicinal parts before selecting P. notoginseng cultivation sites.
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