Table 1.

Matrix of elements determination using SEM–EDS

Element/line		C (%) ± UNC
		Buk 2 pond	Buk 3 pond
C	K-ser	8.05 ± 0.77	12.6 ± 1.1
Ca	K-alpha	1.72 ± 0.12	1.89 ± 0.19
O	K-ser	51.9 ± 4.3	57.8 ± 4.5
Fe	K-alpha	1.45 ± 0.18	1.58 ± 0.29
Mg	K-ser	1.48 ± 0.11	1.62 ± 0.16
Al	K-ser	2.85 ± 0.17	3.12 ± 0.14
Si	K-ser	29.8 ± 1.3	14.9 ± 0.6
S	K-ser	<0.3	0.52 ± 0.06

Data are presented as mean ± UNC

SEM–EDS scanning electron microscope with energy-dispersive detector, UNC uncertainty (calculated according to Smith 2002)