Abstract
A total of 80 rooibos tea samples from a range of brands were purchased from various registered retail shops in South Africa. The samples were bought during 2019 winter (40) and summer (40) period which are classified as 6 natural rooibos, 18 herbal rooibos samples, and 16 flavor rooibos samples and subjected for heavy metal analysis such as chromium (Cr), iron (Fe), arsenic (As), cadmium (Cd), and lead (Pb) using inductively coupled plasma mass spectrometer (ICP-MS). Human health risks were determined by estimating the daily intake non-cancer hazard quotient (THQ) and hazard index (HI) via oral exposure to toxic elements based on daily tea consumption. The concentration range of the determined heavy metals in rooibos tea samples were as follows: Cr (0.17–11.98 mg/kg), Fe (31–450 mg/kg), As (ND–0.51 mg/kg), Cd (0.09–0.17 mg/kg), and Pb (0.06–2.73 mg/kg). Cr was found in higher amount when compared to the World Health Organization (WHO) permissive limit (1.3 mg/kg). The concentrations of all studied heavy metals during winter and summer period were compared using two-way Anova, and no significant differences (p = 0.832) were observed for the two seasons. Both the target risk quotient (THQ) and the hazard index (HI) levels in all analyzed tea were well below 1, implying that intake of rooibos tea with analyzed heavy metals should not cause a threat to human health. On the other hand, the continuous intake due to the high concentrations of trace metals such as Cr may pose a serious chronic health risk due to accumulation in body tissues over time. The study, therefore, suggests constant monitoring of these heavy metals in teas in order to limit the risk of exceeding the permissive limits.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Affholder M-C, Prudent P, Masotti V, Coulomb B, Rabier J, Nguyen-The B, Laffont-Schwob I (2013) Transfer of metals and metalloids from soil to shoots in wild rosemary (Rosmarinus officinalis L.) growing on a former lead smelter site: human exposure risk. Sci Total Environ 454-455:219–229. https://doi.org/10.1016/j.scitotenv.2013.02.086
Aigberua AO, Izah SC, Isaac IU (2018) Level and health risk assessment of heavy metals in selected seasonings and culinary condiments used in Nigeria. Biol Evid 8:6–20. https://doi.org/10.5376/be.2018.08.0002
Al-Oud S (2003) Heavy metal contents in tea and herb leaves. Pak J Biol Sci 6:208–212. https://doi.org/10.3923/pjbs.2003.208.212
Bamuwamye M, Ogwok P, Tumuhairwe V, Eragu R, Nakisozi H, Ogwang PE (2017) Human health risk assessment of heavy metals in Kampala (Uganda) drinking water. J Food Res 6:6–16. https://doi.org/10.5539/jfr.v6n4p6
Barone G, Giacominelli-Stuffler R, Storelli MM (2016) Evaluation of trace metal and polychlorinated biphenyl levels in tea brands of different origin commercialized in Italy. Food Chem Toxicol 87:113–119. https://doi.org/10.1016/j.fct.2015.12.008
Bhat R, Moskovitz G (2009) Herbal medicinal teas from South Africa. Phyton (Buenos Aires) 78: 67-73. 10.32604/phyton.2009.78.067
Brzezicha-Cirocka J, Grembecka M, Ciesielski T, Flaten TP, Szefer P (2017) Evaluation of macro-and microelement levels in black tea in view of its geographical origin. Biol Trace Elem Res 176:429–441. https://doi.org/10.1007/s12011-016-0849-2
Cao H, Qiao L, Zhang H, Chen J (2010) Exposure and risk assessment for aluminium and heavy metals in Puerh tea. Sci Total Environ 408:2777–2784. https://doi.org/10.1016/j.scitotenv.2010.03.019
Cao S, Duan X, Zhao X, Ma J, Dong T, Huang N, Sun C, He B, Wei F (2014) Health risks from the exposure of children to As, Se, Pb and other heavy metals near the largest coking plant in China. Sci Total Environ 472:1001–1009. https://doi.org/10.1016/j.scitotenv.2013.11.124
Chang K, Atici C (2015) Implications of maximum residue levels (MRLs) on tea trade. The Food and Agriculture Organization of the United Nations, Rome, pp 1–10 http://www.fao.org/3/i4481e/i4481e.pdf
Chary NS, Kamala C, Raj DSS (2008) Assessing risk of heavy metals from consuming food grown on sewage irrigated soils and food chain transfer. Ecotoxicol Environ Saf 69:513–524. https://doi.org/10.1016/j.ecoenv.2007.04.013
Chien L-C, Hung T-C, Choang K-Y, Yeh C-Y, Meng P-J, Shieh M-J, Han B-C (2002) Daily intake of TBT, Cu, Zn, Cd and As for fishermen in Taiwan. Sci Total Environ 285:177–185. https://doi.org/10.1016/S0048-9697(01)00916-0
Coelho LM, Pessoa DR, Oliveira KM, Sousa P, Silva L, Coelho N (2016) Potential exposure and risk associated with metal contamination in foods. Significance, Prevention and Control of Food Related Diseases: 99-123. https://doi.org/10.5772/62683.
Dabanović V, Šoškić M, Durovic D, Mugoša B (2016) Investigation of heavy metals content in selected tea brands marketed in podgorica, montenegro. Int J Pharm Sci Res 7:4798–4804. https://doi.org/10.13040/IJPSR.0975-8232.7(12).4798-04
Dordas C (2008) Role of nutrients in controlling plant diseases in sustainable agriculture. A review. Agron Sustain Dev 28:33–46. https://doi.org/10.1051/agro:2007051
Ferreira SL, Lemos VA, Silva LO, Queiroz AF, Souza AS, da Silva EG, dos Santos WN, das Virgens CF (2015) Analytical strategies of sample preparation for the determination of mercury in food matrices—a review. Microchem J 121:227–236. https://doi.org/10.1016/j.microc.2015.02.012
Flora G, Gupta D, Tiwari A (2012) Toxicity of lead: a review with recent updates. Interdiscip Toxicol 5:47–58. https://doi.org/10.2478/v10102-012-0009-2
Fu Q-L, Li L, Achal V, Jiao A-Y, Liu Y (2015) Concentrations of heavy metals and arsenic in market rice grain and their potential health risks to the population of Fuzhou, China. Hum Ecol Risk Assess 21:117–128. https://doi.org/10.1080/10807039.2014.884398
Ghuniem MM, Khorshed MA, Reda M, Mahmoud SM, Hammad G (2019a) Assessment of the potential health risk of heavy metal exposure from the consumption of herbal, black and green tea. Biomed J Sci & Tech Res 16:11810–11817. https://doi.org/10.26717/BJSTR.2019.16.002806
Ghuniem MM, Souaya ER, Khorshed MA, Souaya ER (2019b) Optimization and validation of an analytical method for the determination of some trace and toxic elements in canned fruit juices using quadrupole inductively coupled plasma mass spectrometer. J AOAC Int 102:262–270. https://doi.org/10.1080/03067319.2019.1599878
Iloms E, Ololade OO, Ogola HJ, Selvarajan R (2020) Investigating industrial effluent impact on municipal wastewater treatment plant in Vaal, South Africa. Int J Environ Res Public Health 17:1096. https://doi.org/10.3390/ijerph17031096
Ipeaiyeda A, Dawodu M (2011) Leaching of manganese, iron, copper and zinc from tea (Camellia sinensis) in tea mugs. EJEAFChe 10:2240–2247
Iswaldi I, Arráez-Román D, Rodríguez-Medina I, Beltrán-Debón R, Joven J, Segura-Carretero A, Fernández-Gutiérrez A (2011) Identification of phenolic compounds in aqueous and ethanolic rooibos extracts (Aspalathus linearis) by HPLC-ESI-MS (TOF/IT). Anal Bioanal Chem 400:3643–3654. https://doi.org/10.1007/s00216-011-4998-z
Jaganyi D, Ndlovu T (2001) Kinetics of tea infusion. Part 3: The effect of tea bag size and shape on the rate of caffeine extraction from Ceylon orange pekoe tea. Food Chem 75:63–66. https://doi.org/10.1016/S0308-8146(01)00186-8
Jaishankar M, Tseten T, Anbalagan N, Mathew BB, Beeregowda KN (2014) Toxicity, mechanism and health effects of some heavy metals. Interdiscip Toxicol 7:60–72. https://doi.org/10.2478/intox-2014-0009
Joubert E, Gelderblom W, Louw A, de Beer D (2008) South African herbal teas: Aspalathus linearis, Cyclopia spp. and Athrixia phylicoides—a review. J Ethnopharmacol 119:376–412. https://doi.org/10.1016/j.jep.2008.06.014
Karak T, Bhagat R (2010) Trace elements in tea leaves, made tea and tea infusion: a review. Food Res Int 43:2234–2252. https://doi.org/10.1016/j.foodres.2010.08.010
Karak T, Kutu FR, Nath JR, Sonar I, Paul RK, Boruah RK, Sanyal S, Sabhapondit S, Dutta AK (2017) Micronutrients (B, Co, Cu, Fe, Mn, Mo, and Zn) content in made tea (Camellia sinensis L.) and tea infusion with health prospect: a critical review. Crit Rev Food Sci Nutr 57:2996–3034. https://doi.org/10.1080/10408398.2015.1083534
Karimzadeh L, Bagheri GA, Pour Ali A, Gholipour M, Mohammadi Z, Moshrefi B, Esfahanizadeh MH, Salehifar E (2013) Evaluation of lead, cadmium and copper in black tea leaves in Mazandaran factories, spring and summer 2011. J Mazandaran Univ Med Sci 23:2–10
Liu NT, Lefcourt AM, Nou X, Shelton DR, Zhang G, Lo YM (2013) Native microflora in fresh-cut produce processing plants and their potentials for biofilm formation. J Food Prot 76:827–832. https://doi.org/10.4315/0362-028X
Martinez VD, Vucic EA, Becker-Santos DD, Gil L (2011) Lam WL (2011) Arsenic exposure and the induction of human cancers. J Toxicol 2011:1–13. https://doi.org/10.1155/2011/431287
McGaw LJ, Eloff JN (2008) Ethnoveterinary use of Southern African plants and scientific evaluation of their medicinal properties. J Ethnopharmacol 119:559–574. https://doi.org/10.1016/j.jep.2008.06.013
Mohagheghian A, Mahvi AH, Shekoohiyan S, Koolivand A, Nazmara S, Aslani H, Brahmand MB, Dobaradaran S (2015) Determination of copper, nickel and chromium contents in cultivated tea in north of Iran. Environ Eng Manag J 14:2409–2413. https://doi.org/10.30638/eemj.2015.257
Nazir R, Khan M, Masab M, Rehman HU, Rauf NU, Shahab S, Ameer N, Sajed M, Ullah M, Rafeeq M (2015) Accumulation of heavy metals (Ni, Cu, Cd, Cr, Pb, Zn, Fe) in the soil, water and plants and analysis of physico-chemical parameters of soil and water collected from Tanda Dam Kohat. Int J Pharm Sci Res 7:89
Neda Sadat SB, Gholam Reza M, Akbari H, Chimehi E, Mohammad Bagher M (2020) Determination of the concentration of heavy metals and their assessment of related potential health risk for dry black teas in Kashan, Iran. J Chem Health Risks 10:103–115. https://doi.org/10.22034/JCHR.2020.1891622.1094
Nkansah MA, Opoku F, Ackumey AA (2016) Risk assessment of mineral and heavy metal content of selected tea products from the Ghanaian market. Environ Monit Assess 188:332. https://doi.org/10.1007/s10661-016-5343-y
Olowoyo J, Okedeyi O, Mkolo N, Lion G, Mdakane S (2012) Uptake and translocation of heavy metals by medicinal plants growing around a waste dump site in Pretoria, South Africa. S Afr J Bot 78:116–121. https://doi.org/10.1016/j.sajb.2011.05.010
Owolabi IA, Mandiwana KL, Panichev N (2016) Speciation of chromium and vanadium in medicinal plants. S Afr J Chem 69:67–71. https://doi.org/10.17159/0379-4350/2016/v69a8
Patrick-Iwuanyanwu K, Udowelle N (2017) Monitoring of essential and toxic metals in imported herbal teas marketed in selected cities in Southern Nigeria: a health risk assessment study. J Appl Sci Environ Manag 21:1189–1196. https://doi.org/10.4314/jasem.v21i6.33
Roberts TL (2014) Cadmium and phosphorous fertilizers: the issues and the science. Procedia Eng 83:52–59. https://doi.org/10.1016/j.proeng.2014.09.012
Salahinejad M, Aflaki F (2010) Toxic and essential mineral elements content of black tea leaves and their tea infusions consumed in Iran. Biol Trace Elem Res 134:109–117. https://doi.org/10.1007/s12011-009-8449-z
Sarfo D, Quarshie E, Ahialey E, Denutsui D, Kaka E, Yankey R, Adotey D (2012) Levels of metals in commercially available tea from some selected markets in Ghana. Elixir Food Sci 53:12165–12168
Seenivasan S, Manikandan N, Muraleedharan NN (2008) Chromium contamination in black tea and its transfer into tea brew. Food Chem 106:1066–1069. https://doi.org/10.1016/j.foodchem.2007.07.02
Shanker AK, Cervantes C, Loza-Tavera H, Avudainayagam S (2005) Chromium toxicity in plants. Environ Int 31:739–753. https://doi.org/10.1016/j.envint.2005.02.003
Shekoohiyan S, Ghoochani M, Mohagheghian A, Mahvi AH, Yunesian M, Nazmara S (2012) Determination of lead, cadmium and arsenic in infusion tea cultivated in north of Iran. Iranian J Environ Health Sci Eng 9:37. https://doi.org/10.1186/1735-2746-9-37
Shen F-M, Chen H-W (2008) Element composition of tea leaves and tea infusions and its impact on health. Bull Environ Contam Toxicol 80:300–304. https://doi.org/10.1007/s00128-008-9367-z
Singh HP, Mahajan P, Kaur S, Batish DR, Kohli RK (2013) Chromium toxicity and tolerance in plants. Environ Chem Lett 11:229–254. https://doi.org/10.1007/s10311-013-0407-5
Sofuoglu SC, Kavcar P (2008) An exposure and risk assessment for fluoride and trace metals in black tea. J Hazard Mater 158:392–400. https://doi.org/10.1016/j.jhazmat.2008.01.086
Soliman N (2016) Metals contents in black tea and evaluation of potential human health risks to consumers. Health Econ Outcome Res: Open Access 2:1–4. https://doi.org/10.4172/2471-268X/1000109
Stander MA, Joubert E, De Beer D (2019) Revisiting the caffeine-free status of rooibos and honeybush herbal teas using specific MRM and high resolution LC-MS methods. J Food Compos Anal 76:39–43. https://doi.org/10.1016/j.jfca.2018.12.002
Thirulogachandar A, Rajeswari M, Ramya S (2014) Assessment of heavy metals in gallus and their impacts on human. Int J Sci Res Publ 4:1–8
USEPA (2013) Regional Screening Level (RSL) Summary table (TR= 1E− 6, HQ= 1). United State Environmental Protection Agency, pp. Regional Screening Levels (RSLs)
van Wyk B-E, Gericke N (2000) People’s plants: a guide to useful plants of Southern Africa. Briza publications
van Wyk B-E, Bosch van O, Gericke N (1997) Medicinal plants of South Africa. Briza, Pretoria; South Africa
Walpole SC, Prieto-Merino D, Edwards P, Cleland J, Stevens G, Roberts I (2012) The weight of nations: an estimation of adult human biomass. BMC Public Health 12:439. https://doi.org/10.1186/1471-2458-12-439
Wei H, Le Z, Shuxian L, Dan W, Xiaojun L, Lan J, Xiping M (2015) Health risk assessment of heavy metals and polycyclic aromatic hydrocarbons in soil at coke oven gas plants. Environ Eng Manag J 14:487–496. https://doi.org/10.30638/eemj.2015.051
WHO 2006: Using indicators to measure country pharmaceutical situations: fact book on WHO level I and level II monitoring indicators. , Geneva: WHO, Harvard Medical School, Harvard Pilgrim Health Care, Department of Technical Cooperation for Essential Drugs and Traditional Medicine; WHO Boston Collaborating Center on Pharmaceutical Policy
Zhao H, Zhao F (2019) The authenticity identification of teas (Camellia sinensis L.) of different seasons according to their multi-elemental fingerprints. Int J Food Sci Technol 54:249–255. https://doi.org/10.1111/ijfs.13935
Zhu F, Wang X, Fan W, Qu L, Qiao M, Yao S (2013) Assessment of potential health risk for arsenic and heavy metals in some herbal flowers and their infusions consumed in China. Environ Monit Assess 185:3909–3916. https://doi.org/10.1007/s10661-012-2839-y
Acknowledgements
The authors would like to thank the University of Johannesburg for the Faculty of Science Postgraduate Bursary awarded to the first author. Our sincere gratitude also goes to the Department of Biochemistry for providing her facilities for laboratory analysis.
Availability of data and materials
Not applicable.
Author information
Authors and Affiliations
Contributions
Oluwaseun Mary Areo: conceptualization and writing—original draft. Patrick Berka Njobeh: supervision, funding acquisition, project administration, and writing—review and editing. All authors read and approved the final manuscript.
Corresponding author
Ethics declarations
Ethical approval
Not applicable.
Consent to participate
Not applicable.
Consent to publish
Not applicable.
Conflict of interest
The authors declare no competing interests.
Additional information
Responsible Editor: Philippe Garrigues
Publisher’s note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Supplementary Information
ESM 1
(DOCX 25 kb)
Rights and permissions
About this article
Cite this article
Areo, O.M., Njobeh, P.B. Risk assessment of heavy metals in rooibos (Aspalathus linearis) tea consumed in South Africa. Environ Sci Pollut Res 28, 59687–59695 (2021). https://doi.org/10.1007/s11356-021-14968-2
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s11356-021-14968-2