title: Bioaccessibility of mercury in selected Ayurvedic medicines.
abstract: Five Ayurvedic medicines with mercury concentrations of 85mg/kg and higher were characterized with respect to their speciation and their bioaccessibility. X-ray absorption spectroscopy revealed that the mercury in the Ayurvedic medicines was inorganic and best matched to cinnabar, even in samples that had been hypothesized to contain mercury through plant sources only. The bioaccessibility (bioaccessible concentrations and percent bioaccessibility) was measured using two methods: a two-phase physiologically based extraction test (PBET gastric, G and gastric+intestinal phase, GI); and the fed organic estimation human simulation test (FOREhST). The percent bioaccessibility of mercury in all Ayurvedic samples was very low (<5%), corresponding to the low solubility of cinnabar, but it increased with increasing dissolved organic carbon content of the bioaccessibility solutions (PBET-G<PBET-GI<FOREhST). Filtration of FOREhST solutions reduced the bioaccessible mercury concentrations to undetectable values for most of the Ayurvedic samples. Incorporation of percent relative bioaccessibility of mercury into risk calculations decreased daily intake estimates by 29-900 times, and reduced them to acceptable levels for three of the five medicines.
authors.affiliation: Environmental Sciences Group, Department of Chemistry and Chemical Engineering, Royal Military College of Canada, K7K 7B4, Canada.
authors.forename: Iris
authors.initials: I
authors.lastname: Koch
authors.forename: Maeve
authors.initials: M
authors.lastname: Moriarty
authors.forename: Jie
authors.initials: J
authors.lastname: Sui
authors.forename: Allison
authors.initials: A
authors.lastname: Rutter
authors.forename: Robert B
authors.initials: RB
authors.lastname: Saper
authors.forename: Kenneth J
authors.initials: KJ
authors.lastname: Reimer
mesh_terms: D001682:Biological Availability; D004784:Environmental Monitoring / Q000379:methods*; D041981:Gastrointestinal Tract / Q000378:metabolism*; D006801:Humans; D007194:India; D008419:Materia Medica / Q000032:analysis / Q000493:pharmacokinetics*; D008515:Medicine, Ayurvedic; D017669:Mercury Compounds / Q000032:analysis / Q000493:pharmacokinetics*; D010936:Plant Extracts / Q000032:analysis / Q000493:pharmacokinetics; D018570:Risk Assessment / Q000379:methods; D013052:Spectrometry, X-Ray Emission; D056928:X-Ray Absorption Spectroscopy
chemical_list: D008419:Materia Medica; D017669:Mercury Compounds; D010936:Plant Extracts