Determination of mercury, cadmium and lead contents in different tea and teas infusions (Camelia sinensis, L.)
Keywords:mercury, cadmium, lead, teas, tea infusions, Camellia sinensis, L.
The present paper deals with assessing the level of contamination of green (n = 14) and black - fermented (n = 10) teas of different origins (country of origin) (China, India, Japan, Nepal and Taiwan), which are normally available in Slovakia. The contents of the studied contaminants (mercury, cadmium and lead) were observed in samples of dried teas and their infusions. The contaminant contents were investigated by atomic absorption spectrometry with Zeeman background correction and a graphite furnace GF-AAS (Cd, Pb). The total mercury content was analyzed by CV-AAS method. Concentrations of the studied contaminants in the dried tea samples were as follows: green tea: Hg: 0.0027 ±0.0010 mg.kg-1 (median ± standard deviation); Cd: 0.161 ±0.084 mg.kg-1, Pb: 0.875 ±0.591 mg.kg-1, black tea: Hg: 0.0022 ±0.0014 mg.kg-1, Cd: 0.397 ±0.077 mg.kg-1, Pb: 1.387 ±0.545 mg.kg-1. The contents of the contaminants in the tea infusions were as follows: green tea: Hg: 0.03 ±0.04 μg.L-1, Cd: 0.278 ±0.068 μg.L-1, Pb: 1.975 ±0.503 μg.L-1, black tea: Hg: 0.050 ±0.080 μg.L-1, Cd: 0.291 ±0.054 μg.L-1, Pb: 1.955 ±1.264 μg.L-1. According to the currently valid maximum limits for a particular contaminant in Slovakia, it can be stated that the health standards were not exceeded in any of the tea samples. The limit value of the lead content (2.0 mg.kg-1 DM) was exceeded (by 12.4%) only in one sample of the dried black tea from China (Yunnan - Golden Snow), however it is the limit value valid in China. The results of the analysis of 24 tea samples show that even regular consumption does not pose a health risk to consumers.
Árvay, J., Tomáš, J., Hauptvogl, M., Kopernická, M., Kováčik, A., Bajčan, D., Massányi, P. 2014. Contamination of wild-grown edible mushrooms by heavy metals in a former mercury-mining area. Journal of Environmental Science and Health – part B, vol. 49, no. 11, p. 815-827.
Bobková, A., Fikselová, M., Bobko, M., Lopašovský, Ľ., Tóth, T., Zeleňáková, L. 2015. Selected parameters of quality and safety of herbal tea. Potravinárstvo, vol. 9, no. 1, p. 183-189. https://doi.org/10.5219/451
Cabrera, C., Gimenez, R., Lopez, M. C. 2003. Determination of tea components with antioxidant activity. Journal of Agricultural and Food Chemistry, vol. 51, no. 15, p. 4427-4435.
Cao, H. B., Qiao, L., Zhang, H., Chen, J. J. 2010. Exposure and risk assessment for aluminium and heavy metals in Puerh tea. Science of the Total Environment, vol. 408, no. 14, p. 2777-2784.
De Sole, P., Rossi, C., Chiarpotto, M., Ciasca, G., Bocca, B., Alimonty, A., Bizzarro, A., Rossi, C, Masullo, C. 2013. Possible relationship between Al/ferritin complex and Alzheimer´s disease. Clinical Biochemistry, vol. 46, no.
-2 p. 89-93.
Dong, F., He, P. M., Lin, Z. 2007. Review on antioxidant activity of Pu-Erh tea. Food Science, vol. 28, no. 5,
Franklin, R. E., Duis, L., Brown, R., Kemp, T. 2005. Trace elements content of selected fertilizers and micronutrient source materials. Communications in Soil Science and Plant analysis, vol. 36, no. 11-12, p. 1591-1609.
Han, W. Y., Liang, Y. R., Yang, Y. J., Shi, Y. Z., Ma, L. F., Ruan, J. Y. 2006b. Effect of processing on the Pb and Cu pollution of tea. Jornal of Tea Science Research, vol. 26, p. 95-101.
Han, W. Y., Zhao, F. J., Shi, Y. Z., Ma, L. F., Ruan, J. Y. 2006a. Scale and causes of lead contamination in Chinese tea. Environmental Pollution, vol. 139, no. 1, p. 125-132.
Karimi, G., Hasanzadeh, M. K., Nili, A., Khashayarmanesh, Z., Samiei, Z., Nazari, F. 2008. Concentrations and health risk of heavy metals in tea samples marketed in Iran. Pharmacologyonline, vol. 3, 164-174.
Chen, Y. M., Tsao, T. M., Lius, C. C., Linc, K. C., Wang, M. K. 2011. Aluminium and nutrients induce changes in the profiles of phenolic substances in tea plants (Camellia sinensis CV TTES, No. 12 (TTE)). Journal of the Science of Food and Agriculture, vol. 91, no. 16, p. 1111-1117.
Chung, F. L., Schwartz, J., Herzog, C. R., Yang, Y. M. 2003. Tea and cancer prevention: Studies in animals and humans. The Journal of Nutrition, vol. 133, no. 10, p. 3268-3274.
Jeszka-Skowron, M., Krawczyk, M., Zgola-Grześkowiak, A. 2015. Determination of antioxidant aktivity, rutin, quercetin, phenolic acids and trace elements in tea infusions: Influence of citric acid addition on extraction of metals. Journal of Food Composition nad Analysis, vol. 40, p. 70-77.
Lv, H. P., Lin, Z., Tan, J. F., Guo, L. 2013. Contents of fluoride, lead, copper, chromium, arsenic and cadmium in Chinese Pu-erh tea. Food Research International, vol. 53, no. 2, p. 938-944.
Marcos, A., Fisher, A., Rea, G., Hill, S. J. 1998. Preliminary study using trace element concentrations and a chemometrics approach to determine geographical origin of tea. Journal of Analytical Atomic Spectrometry, vol. 13, p. 521-525.
MOAC, 2002. Ministry of Agiculture in China. Green Food: Tea. NY/T 288-2002, Beijing. Available at: http://gcz.qingdaoagri.gov.cn/qdguochazhan/jxpd/ShowArticle.asp?ArticleID=1232.
MOAC, 2003. Ministry of Agriculture in China. The limits for chromium, cadmium, mercury, arsenic and fluoride in tea. NY 659-2003, Beijing. Available at: https://food.chemlinked.com/regulatory-database/ny659-2003-maximum-limits-chromium-cadmium-mercury-arsenic-and-fluoride-teas.
Moreda-Pineiro, A., Fisher, A, Hill, S. J. 2003. The classification of tea according to region of origin using pattern recognition techniques and trace metal data. Journal of Food Composition and Analysis, vol. 16, no. 2, p. 195-211.
Musilová, J., Bystrická, J. 2010. Proteins of potatoe tubers in relation to the content of cadmium in their tubers. Potravinárstvo, vol. 4, no. 4, p. 48-55.
Naldi, M., Fiori, J., Gotti, R., Periat, A., Veuthey, J. L., Guillarme, D., Andrisano, V. 2014. UHPLC determination of catechins for the quality control of green tea. Journal of Pharmaceutical and Biomedical Analysis, vol. 88, p. 307-314.
Nookabkaew, S., Rangkadilok, N., Satayavivad, J. 2006. Determination of trace elements in herbal tea products and their infusions consumed in Thailand. Journal of Agricultural and Food Chemistry, vol. 54, no. 18, 6939-6944.
Nováková, L., Spáčil, Z., Sifrtová, M., Opletal, L., Solich, P. 2010. Rapid qualitative and quantitative ultra high performance liquid chromatography method for simultaneous analysis of twenty nine common phenolic compounds of various structures. Talanta, vol. 80, no. 15, p. 1970-1979. https://doi.org/10.1016/j.talanta.2009.10.056
PKSR, 2006. Potravinový kódex Slovenskej republiky, výnos č. 18558/2006-SL. Nyjvyššie prípustné množstvá kontaminantov v potravinách platné v Slovenskej republike, z 11. Septembra 2006. [online]. Available at: http://www.svssr.sk/dokumenty/legislativa/18558_2006.pdf.
Qin, F., Chen, W. 2007. Lead and copper levels in tea samples marketed in Beijing. Bulletin of Environmental Contamination Toxicology, vol. 79, no. 2, p. 247-250.
Roman, A., Popiela, E. 2011. Studies of chosen toxic elements concentration in multiflower bee honey. Potravinárstvo, vol. 5, no. 2, p. 67-69.
Salahinejad, M., Aflaki, F. 2010. Toxic and essential mineral elements content of black tea leaves and their tea infusions consumed in Iran. Biological Trace Element Research, vol. 134, no. 1, p. 109-117.
Sharangi, A. B. 2009. Medicinal and therapeutic potentialities of tea (Camellia sinensis, L.) – a review. Food Research International, vol. 42, no. 5-6, p. 529-535.
Sofuoglu, S. C., Kavcar, P. 2008. An exposure and risk assessment for fluoride and trace metal in black tea. Jornal of Hazardous Materials, vol. 158, no. 2-3, p. 392-400.
Svoboda, L., Havlíčková, B., Kalač, P. 2006. Contents of cadmium, mercury and lead in ideble mushrooms growing in a historical silver-mining area. Food Chemistry, vol. 96, no. 4., p. 580-585.
The United Kingdom Tea Council Ltd, 2015. [online]. Available at: http://www.tea.uk/ (accessed 29.07.15).
Timoracká, M., Vollmannová, A., Ismael, D. S. 2011. Minerals, trace elements and flavonoids content in white and coloured kidney bean. Potravinárstvo, vol. 5, no. 1, p. 56-60. https://doi.org/10.5219/116
Yao, L. H., Jiang, Y. M., Shi, J., Tomás-Barberán, F. A., Datta, N., Singanusong, R. 2004. Flavonoids in food and their health benefits. Plant Foods for Human Nutition., vol. 59, no. 3, p. 113-122.
Zhang, D. Y., Shao, W. F., Liu, Z. H., Liu, Y. L., Huang, Y. W. 2009. Research on the anti-diabetes and anti-hyperlipidemia function of monomers in Pu-erh tea. Journal of Tea Science, vol. 29, no. 1, p. 41-46.
Zimmermann, B. F., Gleichenhagen, M. 2011. The effect of ascorbic acid, citric acid and low pH on the extraction of green tea: how to get most out o fit. Food Chemistry, vol. 56, no. 3, p. 8130-8140.
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