Metal Population Reference Concentration (mg/kg) Cd The Canary Islands The present study <LOQ1 Japan [55] 0.018 ± 0.0003 Turkey [56] 2.3 ± 0.4 Taiwán [57] 0.07 Saudi Arabia [3] 1.1 India [33] 0.14 Pakistan [58] 0.0121 Co The Canary Islands The present study 0.44 ± 0.09 Japan [55] 0.506 ± 0.042 Turkey [56] 14.5 ± 7.1 Taiwán [57] 0.2 Saudi Arabia [3] 10.98 Pakistan [58] 1.14 Cr The Canary Islands The present study 0.38 ± 0.15 Turkey [56] 13.0 ± 1.7 Taiwan [57] 7.92 Saudi Arabia [3] 9.8 India [33] 4.76 Pakistan [58] 12.63 Cu The Canary Islands The present study 5.64 ± 1.19 Japan [55] 27.7 ± 0.7 Turkey [56] 16.5 ± 3.9 Taiwan [57] 0.3 Saudi Arabia [3] 18.1 India [33] 24.07 Pakistan [58] 21.39 Fe The Canary Islands The present study 33.29 ± 13.72 Japan [55] 134 ± 48 Taiwan [57] 0.9 Saudi Arabia [3] 250.46 Pakistan [58] 118.46 Mg The Canary Islands The present study 58.03 ± 38.53 Japan [55] 2070 ± 30 Taiwan [57] 135.3 Ni The Canary Islands The present study 2.82 ± 0.53 Japan [55] 8.06 ± 0.19 Turkey [56] 23.3 ± 9.6 Saudi Arabia [3] 16.8 India [33] 2.53 Pakistan [58] 6.78 Pb The Canary Islands The present study 0.026 ± 0.0259 Japan [55] 0.709 ± 0.020 Turkey [56] 17.9 ± 7.1 Taiwan [57] 2.01 Saudi Arabia [3] 1 India [33] 0.81 Pakistan [58] 0.37 Zn The Canary Islands The present study 5.04 ± 0.81 Japan [55] 36.6 ± 0.7 Turkey [56] 129.0 ± 12.9 Taiwan [57] 1.2 Saudi Arabia [3] 65.71 Pakistan [58] 25.47

1LOQ: Quantification limit

Table 5: Comparison of the Cd, Co, Cr, Cu, Fe, Mg, Ni, Pb and Zn concentrations in black tea: population of the Canary Islands against other populations.