科研之友
微信
新浪微博
Facebook
分享链接
摘要
Seven commercial cosmetic clays having different colour (white, green, pink and red) available in pharmacies and herbalists' shops in the Greek market have been examined for their trace element concentrations (Ag, As, Ba, Be, Cd, Ce, Co, Cr, Cs, Cu, Ga, Hf, Hg, La, Mo, Ni, Pb, Rb, Sb, Sc, Se, Sr, Tl, V, Y, Zn and Zr). According to EC Regulation 1223/2009 the presence of As, Be, Cd, Cr, Hg, Ni, P, Pb, Sb, Se, Te, Tl, Zr and their compounds is prohibited in cosmetics. The most abundant trace elements in the white clays were P (330 mu g/g), Pb (220 mu g/g) and Zr (11 mu g/g) and for the green clays were P (1250 mu g/g), As (43 mu g/g), Cr (31 mu g/g), Pb (30 mu g/g) and Ni (23 mu g/g). Red and pink clays had lower concentrations of these elements than their white and green counterparts. The green clays are three times enriched in As and the kaolinite-rich white clays are nine times enriched in Pb compared to the Average Shale. The main mineral phase in the white clays is either kaolinite or calcite, in green clays smectite, in pink clay kaolinite and talc and in red clays it is vermiculite. The specific activities of U-238, Ra-226, Ra-228, Th-228 and K-40 were determined by gamma-ray spectroscopy. The kaolinite-rich white clays are more enriched in U-238-series radionuclides (U-238 and Ra-226) than the smectitic green clays. In contrast, the green clays were more enriched in Th-232-series radionuclides (Ra-228 and Th-228) and K-40 than the white clays.
- 出版日期2014-3
