Table 1.

Certified NIST elemental analysis of standard reference material [61,62]

Element	San Joaquin Valley Soil	Montana Soil
	Mass Fraction (%)
Aluminum	7.50 ± 0.06	6.44 ± 0.08
Calcium	1.89 ± 0.05	1.25 ± 0.03
Iron	3.50 ± 0.11	3.38 ± 0.10
Magnesium	1.51 ± 0.05	0.853 ± 0.042
Phosphorus	0.062 ± 0.005	0.106 ± 0.015
Potassium	2.03 ± 0.06	2.11 ± 0.11
Silicon	29.66 ± 0.23	28.97 ± 0.18
Sodium	1.16 ± 0.03	1.14 ± 0.06
Sulfur	0.089 ± 0.002	0.240 ± 0.006
Titanium	0.342 ± 0.024	0.283 ± 0.010
	Mass Fraction (μg/g)
Arsenic	17.7 ± 0.8	626 ± 38
Cadmium	0.38 ± 0.01	21.8 ± 0.2
Copper	34.6 ± 0.7	2950 ± 130
Lead	18.9 ± 0.5	5532 ± 80
Manganese	538 ± 17	22,124 ± 876
Mercury	1.40 ± 0.08	32.6 ± 1.8
Zinc	106 ± 3	6952 ± 91