Sample

Ash

Enrichment Factor

K⁴⁰

Ra²²⁶

Th²³²

Po²¹⁰

Witbank

Fly ash

25%

3.9 ± 0.8

3.8 ± 0.3

4 ± 0.7

4.1 ± 0.1

Bottom ash

3.8 ± 0.8

3 ± 0.3

3.8 ± 0.7

0.9 ± 0.1

Waterberg

Fly ash

33%

3.5 ± 0.8

3.1 ± 0.6

3 ± 0.2

4 ± 0.6

Bottom ash

3.3 ± 0.6

2.9 ± 0.4

3.9 ± 0.1

0

Sasolburg

Fly ash

41%

2.6 ± 1

2.7 ± 0.8

2.4 ± 0.5

3.2 ± 0.2

Bottom ash

2.2 ± 0.3

2.1 ± 0.8

2.3 ± 0.7

0.0

Spain: Teruel UPT [25]

Fly ash

22%

4.6 ± 0.9

3.5 ± 0.3

3.5 ± 0.2

4 ± 0.3

Bottom ash

3.6 ± 0.7

2.8 ± 0.7

3.1 ± 0.1

0.9 ± 0.6

Spain: Litoral UPT [25]

Fly ash

16%

4.8 ± 0.1

7.1 ± 0.8

6.7 ± 0.1

9 ± 0.1

Bottom ash

4 ± 0.1

5.4 ± 0.8

4.9 ± 0.1

0.2 ± 0.3

Spain: Compostilla II [24]

Fly ash

37%

3.3 ± 0.2

2.8 ± 0.3

2.8 ± 0.3

4 ± 1

Bottom ash

3.2 ± 0.2

2.5 ± 0.2

2.7 ± 0.3

0.2 ± 0.1

Spain: Teruel [24]

Fly ash

28%

4 ± 2

3.4 ± 0.3

3.5 ± 0.3

4 ± 1

Bottom ash

3 ± 1

2.7 ± 0.3

3.1 ± 0.3

1 ± 0.2

Spain: Litoral [24]

Fly ash

15%

4 ± 3

9 ± 3

8 ± 3

11 ± 8

Bottom ash

4 ± 2

8 ± 3

7 ± 4

0.2 ± 0.1