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

Table 3

Specific activities and radiological indices for the clay studied samples.

Sample number	^226Ra	^232Th	^40K
1	40 ± 3.1	12.5 ± 0.6	47 ± 6.9	62	28	0.2
2	49 ± 2.5	50 ± 2.5	241 ± 12.1	135	65	0.4
3	44 ± 3.2	43 ± 2.1	251 ± 12.6	108	50	0.3
4	45 ± 3.3	60 ± 3.3	283 ± 15	66	31	0.2
5	34 ± 2.4	45 ± 3.2	132 ± 10.0	103	49	0.3
6	36 ± 2.1	31 ± 1.8	167 ± 9.5	150	71	0.4
7	30 ± 1.5	21 ± 10	263 ± 13.1	78	38	0.2
8	30 ± 1.5	20 ± 10	279 ± 13.9	78	38	0.2
9	39 ± 2.5	18 ± 1.8	125 ± 6.3	75	34	0.2
10	35 ± 1.8	52 ± 2.6	136 ± 6.8	73	35	0.2
11	27 ± 1.4	21 ± 10	222 ± 11.1	104	40	0.2
12	39 ± 2.3	18 ± 0.8	240 ± 13.5	82	39	0.3
13	32 ± 1.6	30 ± 1.6	250 ± 12.5	86	41	0.2
14	38 ± 3.5	18 ± 2.8	260 ± 14.9	219	103	0.6
15	30 ± 2.4	29 ± 2.6	214 ± 11.7	97	46	0.3
16	38 ± 1.9	12 ± 0.6	245 ± 12.2	72	39	0.2
17	37 ± 1.9	07 ± 0.4	171 ± 8.6	156	74	0.5
18	31 ± 2.7	19 ± 2.0	210 ± 11.5	74	35	0.2
Min	30 ± 1.5	07 ± 0.4	47 ± 6.90	62	28	0.2
Max	49 ± 2.5	60 ± 3.3	279 ± 14	219	103	0.6
Average	36.3 ± 1.5	28.1 ± 0.8	208 ± 11	101	47.5	0.3