Case Study of the Relationship between Aqua Regia and Real Total Contents of Harmful Trace Elements in Some European Soils

Table 4

Adjusted 𝑅² values of more reliably characterised chemical elements obtained using different regression models without elimination of measurements.

Element	Model
	Linear	2nd order polynomial	Logarithmic	Exponential
As	0.996	0.996	0.815	0.831
Ba	0.814	0.822	0.707	0.639
Be	0.988	0.989	0.853	0.860
Cd	1.000	1.000	0.707	0.725
Co	0.997	0.997	0.811	0.841
Cr	0.749	0.825	0.769	0.570
Cu	0.998	0.999	0.883	0.871
Hg	0.994	0.997	0.808	0.850
Mn	0.999	0.999	0.763	0.794
Mo	0.997	0.997	0.779	0.802
Ni	0.992	0.992	0.715	0.753
Pb	0.986	0.985	0.854	0.903
Sb	0.967	0.989	0.702	0.895
Sn	0.990	0.993	0.788	0.736
V	0.924	0.923	0.768	0.832
Zn	0.996	0.996	0.801	0.793

The maximum adjusted 𝑅² values are in bold. The values of 𝐹-test were significant (𝑃<0.00005) for all these models.