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.