Abstract
Green tea is one of the most widely consumed beverages worldwide, also in Morocco. It has numerous health benefits due to its various bioactive compounds. However, there are concerns about the contamination of green tea by some toxic heavy metals, such as lead (Pb) and cadmium (Cd). The aim of this study was to investigate the contamination levels of Pb and Cd in green tea samples taken from six different brands in Morocco by using graphite furnace atomic absorption spectrometry. Cd was detected in 59 out of 76 samples in the range of 0.002–0.743 μg/g, accounting for 77.63% of the analyzed samples, with a mean value of 0.121 ± 0.006 μg/g. For the rest of the samples (22.37%), Cd were below the limit of detection (LOD). For Pb, 67 samples (88.16%) were reported to have Pb levels ranging from 0.002 to 1.155 μg/g, with a mean value of 0.159 ± 0.006 μg/g. For the remaining samples (11.84%), Pb levels were < LOD. Samples from brand D had the highest content of Pb (1.145 μg/g) and Cd (0.728 μg/g) among the samples analyzed. Pb levels in all green tea samples were far below the standard limits set by the World Health Organization (WHO) (10 μg/g) and China (5 μg/g). However, for Cd levels, 3 green tea samples exceeded the recommended maximum limit (0.3 μg/g) set by WHO. Both the Target Hazard Quotient (THQ) values for individual elements and the Hazard Index (HI) values for Cd and Pb were far below 1.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
Data availability
The diverse data generated and analyzed during this work are available from the corresponding author on request.
References
Aksuner N, Henden E, Aker Z et al (2012) Determination of essential and non-essential elements in various tea leaves and tea infusions consumed in Turkey. Food Addit Contam B 5:126–132. https://doi.org/10.1080/19393210.2012.675592
Arfaeinia H, Dobaradaran S, Moradi M et al (2019) The effect of land use configurations on concentration, spatial distribution, and ecological risk of heavy metals in coastal sediments of northern part along the Persian Gulf. Sci Total Environ 653:783–791. https://doi.org/10.1016/j.scitotenv.2018.11.009
Barman T, Barooah AK, Goswami BC et al (2020) Contents of chromium and arsenic in tea (Camellia sinensis L.): extent of transfer into tea infusion and health consequence. Biol Trace Elem Res 196:318–329. https://doi.org/10.1007/s12011-019-01889-y
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
Bergasa O, Ramírez R, Collado C et al (2007) Study of metals concentration levels in Patella piperata throughout the Canary Islands, Spain. Environ Monit Assess 127:127–133. https://doi.org/10.1007/s10661-006-9266-x
Bora K, Sarkar D, Konwar K et al (2019) Disentanglement of the secrets of aluminium in acidophilic tea plant (Camellia sinensis L.) influenced by organic and inorganic amendments. Food Res Int 120:851–864. https://doi.org/10.1016/j.foodres.2018.11.049
Brzezicha-Cirocka J, Grembecka M, Szefer P (2016) Monitoring of essential and heavy metals in green tea from different geographical origins. Environ Monit Assess 188:183. https://doi.org/10.1007/s10661-016-5157-y
Chand P, Sharma R, Prasad R et al (2011) Determination of essential & toxic metal and its transversal pattern from soil to tea brew. FNS 02:1160–1165. https://doi.org/10.4236/fns.2011.210155
Chen Y, Xu J, Yu M et al (2010) Lead contamination in different varieties of tea plant (Camellia sinensis L.) and factors affecting lead bioavailability. J Sci Food Agric 90:1501–1507. https://doi.org/10.1002/jsfa.3974
Chen C, Xun P, Nishijo M et al (2015) Cadmium exposure and risk of pancreatic cancer: a meta-analysis of prospective cohort studies and case–control studies among individuals without occupational exposure history. Environ Sci Pollut Res 22:17465–17474. https://doi.org/10.1007/s11356-015-5464-9
Collado C, Ramírez R, Bergasa O et al (2006) Heavy metals (Cd, Cu, Pb and Zn) in two species of limpets (Patella rustica and Patella candei crenata) in the Canary Islands, Spain. WIT Trans Ecol Environ 95:45–53. https://doi.org/10.2495/WP060051
Conti ME, Cecchetti G (2003) A biomonitoring study: trace metals in algae and molluscs from Tyrrhenian coastal areas. Environ Res 93:99–112. https://doi.org/10.1016/S0013-9351(03)00012-4
Cravo A, Bebianno MJ (2005) Bioaccumulation of metals in the soft tissue of Patella aspera: application of metal/shell weight indices. Estuar Coast Shelf Sci 65:571–586. https://doi.org/10.1016/j.ecss.2005.06.026
de Oliveira LM, Das S, da Silva EB et al (2018) Metal concentrations in traditional and herbal teas and their potential risks to human health. Sci Total Environ 633:649–657. https://doi.org/10.1016/j.scitotenv.2018.03.215
Di Lorenzo A, Curti V, Tenore GC et al (2017) Effects of tea and coffee consumption on cardiovascular diseases and relative risk factors: an update. Curr Pharm Des 23:2474–2487. https://doi.org/10.2174/1381612823666170215145855
Donkora A, Kuranchiea C, Osei-Fosu P et al (2015) Assessment of essential minerals and toxic trace metals in popularly consumed tea products in Ghana, a preliminary study. Res J Chem Environ Sci 3:49–55
Edwards JR, Prozialeck WC (2009) Cadmium, diabetes and chronic kidney disease. Toxicol Appl Pharmacol 238:289–293. https://doi.org/10.1016/j.taap.2009.03.007
EFSA (2011) Statement on tolerable weekly intake for cadmium. EFSA J 9(2):1975. https://doi.org/10.2903/j.efsa.2011.1975
EFSA (2012) Lead dietary exposure in the European population. EFSA J 10:2831. https://doi.org/10.2903/j.efsa.2012.2831
El Jai A, Juan C, Juan-García A et al (2021) Multi-mycotoxin contamination of green tea infusion and dietary exposure assessment in Moroccan population. Food Res Int 140:109958. https://doi.org/10.1016/j.foodres.2020.109958
El Youssfi M, Sifou A, Ben Aakame R et al (2022) Trace elements in foodstuffs from the Mediterranean basin—occurrence, risk assessment, regulations, and prevention strategies: a review. Biol Trace Elem Res. https://doi.org/10.1007/s12011-022-03334-z
Ettler V (2016) Soil contamination near non-ferrous metal smelters: a review. Appl Geochemistry 64:56–74. https://doi.org/10.1016/j.apgeochem.2015.09.020
FAO (2018) Committee on commodity problems. Intergovernmental group on tea. Twenty-third session. CCP:TE 18/CRS1. Hangzhou, the People’s Republic of China, 17–20 May 2018. www.fao.org/3/BU642en/bu642en.pdf.
Faraji Ghasemi F, Dobaradaran S, Saeedi R et al (2020) Levels and ecological and health risk assessment of PM2.5-bound heavy metals in the northern part of the Persian Gulf. Environ Sci Pollut Res 27:5305–5313. https://doi.org/10.1007/s11356-019-07272-7
Gallagher CM, Meliker JR (2010) Blood and urine cadmium, blood pressure, and hypertension: a systematic review and meta-analysis. Environ Health Perspect 118:1676–1684. https://doi.org/10.1289/ehp.1002077
Garza A, Vega R, Soto E (2006) Cellular mechanisms of lead neurotoxicity. Med Sci Monit 12:RA57–RA65
Ghale Askari S, Oskoei V, Abedi F et al (2020) Evaluation of heavy metal concentrations in black tea and infusions in Neyshabur city and estimating health risk to consumers. Int J Environ Anal Chem. https://doi.org/10.1080/03067319.2020.1842388
Hadayat N, De Oliveira LM, Da Silva E et al (2018) Assessment of trace metals in five most-consumed vegetables in the US: conventional vs. organic. Environ Pollut 243:292–300. https://doi.org/10.1016/j.envpol.2018.08.065
Han W-Y, Zhao F-J, Shi Y-Z et al (2006) Scale and causes of lead contamination in Chinese tea. Environ Pollut 139:125–132. https://doi.org/10.1016/j.envpol.2005.04.025
Huang H, Kfoury N, Orians CM et al (2019) 2014–2016 seasonal rainfall effects on metals in tea (Camelia sinensis (L.) Kuntze). Chemosphere 219:796–803. https://doi.org/10.1016/j.chemosphere.2018.12.075
IARC (2006) Inorganic and organic lead compounds. IARC monographs on the evaluation of carcinogenic risks to humans. International Agency for Research on Cancer, Lyon
IARC (1993) Beryllium, cadmium, mercury and exposures in the glass manufacturing industry. Views and expert opinions of an IARC Working Group on the Evaluation of Carcinogenic Risks to Humans, Lyon, 9–16 February 1993. World Health Organization, Geneva
Idani E, Geravandi S, Akhzari M et al (2020) Characteristics, sources, and health risks of atmospheric PM10-bound heavy metals in a populated middle eastern city. Toxin Rev 39:266–274. https://doi.org/10.1080/15569543.2018.1513034
JECFA (2011) Evaluation of certain food additives and contaminants. Seventy-third report of the Joint FAO/WHO Expert Committee on Food Additives. World Health Organization, Geneva
Julin B, Wolk A, Johansson J-E et al (2012) Dietary cadmium exposure and prostate cancer incidence: a population-based prospective cohort study. Br J Cancer 107:895–900. https://doi.org/10.1038/bjc.2012.311
Karak T, Bhagat RM (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, Abollino O, Bhattacharyya P et al (2011) Fractionation and speciation of arsenic in three tea gardens soil profiles and distribution of As in different parts of tea plant (Camellia sinensis L.). Chemosphere 85:948–960. https://doi.org/10.1016/j.chemosphere.2011.06.061
Karak T, Bora K, Paul RK et al (2017) Paradigm shift of contamination risk of six heavy metals in tea (Camellia sinensis L.) growing soil: a new approach influenced by inorganic and organic amendments. J Hazard Mater 338:250–264. https://doi.org/10.1016/j.jhazmat.2017.05.036
Kelepertzis E, Galanos E, Mitsis I (2013) Origin, mineral speciation and geochemical baseline mapping of Ni and Cr in agricultural topsoils of Thiva Valley (central Greece). J Geochem Explor 125:56–68. https://doi.org/10.1016/j.gexplo.2012.11.007
Khalil N, Morrow LA, Needleman H et al (2009) Association of cumulative lead and neurocognitive function in an occupational cohort. Neuropsychology 23:10–19. https://doi.org/10.1037/a0013757
Khalili Doroodzani A, Dobaradaran S, Zarei S et al (2022) Maternal and fetal exposure to metal (loid)s, maternal nutrition status, and impact on prenatal growth in an energy rich zone and an urban area along the Persian Gulf. Environ Pollut 309:119779. https://doi.org/10.1016/j.envpol.2022.119779
Khan N, Mukhtar H (2019) Tea polyphenols in promotion of human health. Nutrients 11:39. https://doi.org/10.3390/nu11010039
Koch W, Kukula-Koch W, Komsta Ł et al (2018) Green tea quality evaluation based on its catechins and metals composition in combination with chemometric analysis. Molecules 23:1689. https://doi.org/10.3390/molecules23071689
Levin SM, Goldberg M (2000) Clinical evaluation and management of lead-exposed construction workers. Am J Ind Med 37:23–43. https://doi.org/10.1002/(SICI)1097-0274(200001)37:1%3c23::AID-AJIM4%3e3.0.CO;2-U
Li L, Fu Q-L, Achal V, Liu Y (2015) A comparison of the potential health risk of aluminum and heavy metals in tea leaves and tea infusion of commercially available green tea in Jiangxi. China Environ Monit Assess 187:228. https://doi.org/10.1007/s10661-015-4445-2
Liao WC, Wu WH, Lai ST et al (2012) Kinetics investigation of antioxidant capacity and total phenols of low-temperature steeping Bi Luo Chun green tea. Int J Food Sci Technol 47:2009–2014. https://doi.org/10.1111/j.1365-2621.2012.03064.x
Mannani N, Tabarani A, Abdennebi EH, Zinedine A (2020) Assessment of aflatoxin levels in herbal green tea available on the Moroccan market. Food Control 108:106882. https://doi.org/10.1016/j.foodcont.2019.106882
Mao JT, Nie W-X, Tsu I-H et al (2010) White tea extract induces apoptosis in non-small cell lung cancer cells: the role of peroxisome proliferator-activated receptor-γ and 15-lipoxygenases. Cancer Prev Res (phila) 3:1132–1140. https://doi.org/10.1158/1940-6207.CAPR-09-0264
Masindi V, Muedi KL (2018) Environmental contamination by heavy metals. In: Saleh HE-DM, Aglan RF (eds) Heavy metals. InTech
Nagata C, Nagao Y, Nakamura K et al (2013) Cadmium exposure and the risk of breast cancer in Japanese women. Breast Cancer Res Treat 138:235–239. https://doi.org/10.1007/s10549-013-2414-4
Nakhlé KF, Cossa D, Khalaf G, Beliaeff B (2006) Brachidontes variabilis and Patella sp. as quantitative biological indicators for cadmium, lead and mercury in the Lebanese coastal waters. Environ Pollut 142:73–82. https://doi.org/10.1016/j.envpol.2005.09.016
Navas-Acien A, Guallar E, Silbergeld EK, Rothenberg SJ (2007) Lead exposure and cardiovascular disease—a systematic review. Environ Health Perspect 115:472–482. https://doi.org/10.1289/ehp.9785
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
Nookabkaew S, Rangkadilok N, Satayavivad J (2006) Determination of trace elements in herbal tea products and their infusions consumed in Thailand. J Agric Food Chem 54:6939–6944. https://doi.org/10.1021/jf060571w
Oh J, Jo S-H, Kim JS et al (2015) Selected tea and tea pomace extracts inhibit intestinal α-glucosidase activity in vitro and postprandial hyperglycemia in vivo. Int J Mol Sci 16:8811–8825. https://doi.org/10.3390/ijms16048811
Park RM, Stayner LT, Petersen MR et al (2012) Cadmium and lung cancer mortality accounting for simultaneous arsenic exposure. Occup Environ Med 69:303–309. https://doi.org/10.1136/oemed-2011-100149
Peng C, Zhu X, Hou R et al (2018) Aluminum and heavy metal accumulation in tea leaves: an interplay of environmental and plant factors and an assessment of exposure risks to consumers. J Food Sci 83:1165–1172. https://doi.org/10.1111/1750-3841.14093
Pollack AZ, Mumford SL, Mendola P et al (2015) Kidney biomarkers associated with blood lead, mercury, and cadmium in premenopausal women: a prospective cohort study. J Toxicol Environ Health Part A 78:119–131. https://doi.org/10.1080/15287394.2014.944680
Pourfadakari S, Spitz J, Dobaradaran S (2022) Metal (liod)s levels of commercially green tea (Camellia sinensis) and salt in Germany and their non-carcinogenic risks. Toxin Rev 41:1096–1104. https://doi.org/10.1080/15569543.2021.1974484
Pourret O, Lange B, Bonhoure J et al (2016) Assessment of soil metal distribution and environmental impact of mining in Katanga (Democratic Republic of Congo). Appl Geochemistry 64:43–55. https://doi.org/10.1016/j.apgeochem.2015.07.012
Qin F, Chen W (2007) Lead and copper levels in tea samples marketed in Beijing, China. Bull Environ Contam Toxicol 79:247–250. https://doi.org/10.1007/s00128-007-9008-y
Qu C-S, Ma Z-W, Yang J et al (2012) Human exposure pathways of heavy metals in a lead-zinc mining area, Jiangsu Province, China. PLoS ONE 7:e46793. https://doi.org/10.1371/journal.pone.0046793
Ramadan G, El-Beih NM, Talaat RM, Abd El-Ghffar EA (2017) Anti-inflammatory activity of green versus black tea aqueous extract in a rat model of human rheumatoid arthritis. Int J Rheum Dis 20:203–213. https://doi.org/10.1111/1756-185X.12666
Rehman K, Fatima F, Waheed I, Akash MSH (2018) Prevalence of exposure of heavy metals and their impact on health consequences. J Cell Biochem 119:157–184. https://doi.org/10.1002/jcb.26234
Saeed M, Naveed M, Arif M et al (2017) Green tea (Camellia sinensis) and l-theanine: Medicinal values and beneficial applications in humans—a comprehensive review. Biomed Pharmacother 95:1260–1275. https://doi.org/10.1016/j.biopha.2017.09.024
Schimidt HL, Garcia A, Martins A et al (2017) Green tea supplementation produces better neuroprotective effects than red and black tea in Alzheimer-like rat model. Food Res Int 100:442–448. https://doi.org/10.1016/j.foodres.2017.07.026
Schunk PFT, Kalil IC, Pimentel-Schmitt EF et al (2016) ICP-OES and micronucleus test to evaluate heavy metal contamination in commercially available Brazilian Herbal Teas. Biol Trace Elem Res 172:258–265. https://doi.org/10.1007/s12011-015-0566-2
Sharma RK, Agrawal M, Marshall FM (2008) Heavy metal (Cu, Zn, Cd and Pb) contamination of vegetables in urban India: a case study in Varanasi. Environ Pollut 154:254–263. https://doi.org/10.1016/j.envpol.2007.10.010
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
Sifou A, Benabbou A, Ben Aakame R et al (2021) Trace elements in breakfast cereals and exposure assessment in Moroccan population: case of lead and Cadmium. Biol Trace Elem Res 199:1268–1275. https://doi.org/10.1007/s12011-020-02265-x
Suzuki T, Pervin M, Goto S et al (2016) Beneficial effects of tea and the green tea catechin epigallocatechin-3-gallate on obesity. Molecules 21:1305. https://doi.org/10.3390/molecules21101305
Tang G-Y, Zhao C-N, Xu X-Y et al (2019) Phytochemical composition and antioxidant capacity of 30 Chinese teas. Antioxidants (basel) 8:180. https://doi.org/10.3390/antiox8060180
Tao C, Song Y, Chen Z et al (2021) Geological load and health risk of heavy metals uptake by tea from soil: What are the significant influencing factors? CATENA 204:105419. https://doi.org/10.1016/j.catena.2021.105419
Thomas LD, Michaëlsson K, Julin B et al (2011) Dietary cadmium exposure and fracture incidence among men: a population-based prospective cohort study. J Bone Miner Res 26:1601–1608. https://doi.org/10.1002/jbmr.386
UNEP/FAO/COI/IAEA (1995) Reagent and laboratory ware clean-up procedure for low level contaminate monitoring. Reference method for marine pollution studies N°65
US EPA (2011) Exposure Factors Handbook: 2011 Edition. National Center for Environmental Assessment, Washington, DC; EPA/600/R-09/052F
US EPA (2015) Regional Screening Levels (RSLs) - User’s Guide. https://www.epa.gov/risk/regional-screening-levels-rsls-users-guide. Accessed 23 Jul 2022
WHO (2007) WHO guidelines for assessing quality of herbal medicines with reference to contaminants and residues. World Health Organization, Geneva
Yang W-Y, Staessen JA (2018) Letter to editor: Blood pressure, hypertension and lead exposure. Environ Health 17:16. https://doi.org/10.1186/s12940-018-0364-3
Yang CS, Zhang J, Zhang L et al (2016) Mechanisms of body weight reduction and metabolic syndrome alleviation by tea. Mol Nutr Food Res 60:160–174. https://doi.org/10.1002/mnfr.201500428
Zhang J, Yang R, Chen R et al (2018) Accumulation of heavy metals in tea leaves and potential health risk assessment: a case study from Puan County, Guizhou Province. China Int Environ Res Public Health 15:133. https://doi.org/10.3390/ijerph15010133
Zhang J, Yang R, Li YC et al (2020) Distribution, accumulation, and potential risks of heavy metals in soil and tea leaves from geologically different plantations. Ecotoxicol Environ Safe 195:110475. https://doi.org/10.1016/j.ecoenv.2020.110475
Zhao Y, Asimi S, Wu K et al (2015) Black tea consumption and serum cholesterol concentration: systematic review and meta-analysis of randomized controlled trials. Clinical Nutr 34:612–619. https://doi.org/10.1016/j.clnu.2014.06.003
Zheng H, Li J-L, Li H-H et al (2014) Analysis of trace metals and perfluorinated compounds in 43 representative tea products from South China. J Food Sci 79:C1123–C1129. https://doi.org/10.1111/1750-3841.12470
Zhong W-S, Ren T, Zhao L-J (2016) Determination of Pb (Lead), Cd (Cadmium), Cr (Chromium), Cu (Copper), and Ni (Nickel) in Chinese tea with high-resolution continuum source graphite furnace atomic absorption spectrometry. J Food Drug Anal 24:46–55. https://doi.org/10.1016/j.jfda.2015.04.010
Acknowledgements
The first author is most grateful to faculty of sciences of rabat (FSR) for facilities and the technical assistance given.
Funding
I confirm that this research article received no particular grant from any funding agency in the public, private, or not-for-profit sectors.
Author information
Authors and Affiliations
Contributions
All authors contributed to this study. Material preparation, collection of samples and analysis were performed by AS, MEY, AZ, MEH, RBA, and NM. AA, SA, and MH made the necessary corrections about the language. The first draft of the manuscript was written by AS and all authors commented on previous versions of the manuscript. All authors read, understood and approved the final manuscript.
Corresponding author
Ethics declarations
Conflict of interest
The authors of this article affirm that they have no conflict of interest.
Additional information
Publisher's Note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Supplementary Information
Below is the link to the electronic supplementary material.
Rights and permissions
Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.
About this article
Cite this article
Sifou, A., Youssfi, M.E., Zinedine, A. et al. Dietary intake and health risk assessment of lead and cadmium in green tea from Morocco. J Consum Prot Food Saf 18, 189–198 (2023). https://doi.org/10.1007/s00003-023-01422-3
Received:
Revised:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s00003-023-01422-3