Country | Average activity concentration (Bq/kg) | References | ||
226Ra | 232Th | 40K | ||
Yemen | 45 | 106 | 1235 | Present study |
India | 82 | 112 | 1908 | [16] |
Yemen | 54 | 127 | 1743 | [17] |
Spain | 84 | 42 | 1138 | [18] |
Saudi Arabia | 75 | 71 | 987 | [19] |
Egypt | 137 | 82 | 1082 | [20] |
Greek | 74 | 85 | 881 | [21] |
Turkey | 70 | 83 | 1234 | [22] |
Iran | 74 | 69 | 1130 | [23] |
Italy | 112 | 107 | 1063 | [24] |
Brazil | 45 | 106 | 1320 | [25] |
Japan | 43 | 72 | 1004 | [26] |
World average | 50 | 50 | 500 | UNSCEAR 2000 [8] |