Elemental Analysis and Natural Radioactivity Levels of Clay by Gamma Ray Spectrometer and Instrumental Neutron Activation Analysis

Table 4

Comparison of ²²⁶Ra, ²²⁸Ra, and ⁴⁰K and radiation hazard parameter in clay from around the world [31].

Country	^226Ra	^232Th	^40K
Australia	41	89	681	220
China	41	52	717	171
Egypt	20	14	204	56
Finland	78	62	962	241
Greece	49	24	670	135
Germany	59	67	673	207
India	48	52	381	152
Netherlands	39	41	560	141
Sweden	96	127	962	352
Norway	104	62	1058	276
Sri Lanka	35	72	585	183
Egypt, present work	36	28	208	101