Concentrations Of Heavy Metals In Soils-Chinese Herbal Medicines And Bioaccessibility Of Arsenic And Mercury In Traditional Chinese Medicines

The concentrations of Arsenic(As), Cadmium(Cd), Mercury(Hg) and Lead (Pb) in soil, Chinese herbal medicines and Chinese patent medicines were investigated respectively. Furthermore, an In Vitro gastrointestinal digestion test was used to assess the bioaccessibility of arsenic and mercury in some Chinese herbal medicines which accumumate higher concentrations of arsenic and Hg and each patent medicine. After gastrointestinal digestion, preliminary Health Risk Assessment (HRA) of arsenic and mercury was conducted comparing to ADI(Acceptable Daily Intake) from WHO(World Hygienic Organization). The resules showed as follows:(1) Concentrations of heavy metals in soils from herbal medicine cultivated regionsHNO₃-H₂O₂ digested acidic systerm was selected for the higher recovery of Pb, Cd, arsenic and Hg using the reference materials of soil. Soil samples were digested in high pressure vessels to measure the concentrations of arsenic, Hg, Pb and Cd. Arsenic and Hg were determined with HG-AFS, Pb and Cd were measured with GF-AAS. Compared with Environmental Quality Standard for soils-GB15618-1995, the concentrations of heavy metals in soils from herbal medicine cultivated regions were lower than the Quality Standard II class and did not exceed the safety limitation.(2) The concentrations of heavy metals in Chinese herbal medicinesThe results showed that different herbal medicine have different Bioconcentration Factor. The area of Bioconcentration Factor result were:Pb 0.009-0.07, Cd 0.20- 1.17, arsenic 0.008-0.04, Hg 0.72-2.97.The concentrations of heavy metals in herbal medicines from each working procedure were determined. The concentrations of four heavy metals in the great majority(about 95%) of herbal medicines could match with green standards of medicinal plants and preparations for foreign trade and economy (WM2/T-2003), there was little difference among the concentrations of heavy metals in herbal medicines during the whole process. However, the concentrations of Pb, Cd, arsenic and Hg increaesd in some samples (about 20%) sample step by step. Therefore, the processing may become the main source of heavy metals in some herbal medicines. (3) Concentrations of arsenic and Hg in the Chinese patent medicines with realgar or cinnabarThe concentrations of arsenic and Hg in Chinese patent medicine with realgar or cinnabar were 9.9×10²-1.2×10⁵mg/ kg and 5.0×10³-3.5×10⁴ mg/kg respectively, much higher than the standards (WM2/T-2003).(4) Bioaccessibility of arsenic and Hg in Traditional Chinese medicines (TCMs)Bioaccessibilities of arsenic and Hg in powder of herbal medicines were 5.75%-85.31% and 10.96%-68.04% at the gastric phase, were 7.84%-66.03% and 5.78%-43.11% at intestine phase respectively. Moreover, bioaccessibilities of arsenic and Hg in the hot exreactable solition of herbal medicines were 11.29%-51.31% and 5.24%-46.37% at the stomach phase, and were 17.57%-44.19% and 2.48%-23.07% at intestine phase respectively. In general, bioaccessibilities of arsenic and Hg in the stomach phase were higher than thoes of intestine phase, and arsenic and Hg showed higher bioaccessibilities in herbal medicine powder than in decoctions.In Chinese patent medicines with realgar, arsenic bioaccessibilities were 0.20%-2.17% in stomach phase, and 0.26% - 2.43% in intestine phase. In Chinese patent medicines with both realgar and cinnabar, arsenic bioaccessibilities was 0.37%-5.23% in stomach phase, and 0.36% - 5.94% in intestine phase. Hg bioaccessibilities were 0.002%-0.057% in stomach phase, and 0.002%-0.048% in intestine phase.(5) Preliminary Health Risk Assessment of heavy metalds in TCMsThe health risk of arsenic and Hg decreased according to the ranking: total concentrations in herbal medicine > available concentrations of powder > available concentrations of extractable solution of herbal medicines. Hg in herbal medicines had little risk to human health, but arsenic in some herbal samples showed much higher risk to human health.And in most of (about 70%) Chinese patent medicines, arsenic showed high health risk, but Hg had little health rish to human.In conclusion, TCMs could be contaminated with exterior source of heavy metals from every working procedures, and the preparation and processing procedure were the main sources of heavy metals accumulated in some herbal medicines. Realgar added in Chinese patent medicines may make a serious health risk to human body. However, there was no significant health risk of Chinese patent medicine with cinnabar.