Based on the Kaiser criterion only two PCs can be retained and have eigenvalues greater than 1 (Kaiser 1958). However, after a number of tests, three PCs were extracted explaining 84% of the total variance in the data set (Table 1).
PC loadings and explained variance for three components with Varimax rotation
Parameter . | PC1 . | PC2 . | PC3 . |
---|---|---|---|
Ca2+ | 0.168 | 0.650 | 0.667 |
Mg2+ | 0.524 | 0.625 | 0.428 |
Na+ | 0.916 | 0.104 | 0.182 |
K+ | 0.824 | 0.139 | 0.123 |
HCO3− | 0.007 | 0.933 | −0.139 |
Cl− | 0.783 | −0.001 | 0.381 |
SO42− | 0.331 | −0.099 | 0.878 |
Eigenvalue | 3.69 | 1.40 | 0.79 |
Explained variance (%) | 52.67 | 20.10 | 11.30 |
Cumulative % of variance | 52.67 | 72.72 | 83.98 |
Parameter . | PC1 . | PC2 . | PC3 . |
---|---|---|---|
Ca2+ | 0.168 | 0.650 | 0.667 |
Mg2+ | 0.524 | 0.625 | 0.428 |
Na+ | 0.916 | 0.104 | 0.182 |
K+ | 0.824 | 0.139 | 0.123 |
HCO3− | 0.007 | 0.933 | −0.139 |
Cl− | 0.783 | −0.001 | 0.381 |
SO42− | 0.331 | −0.099 | 0.878 |
Eigenvalue | 3.69 | 1.40 | 0.79 |
Explained variance (%) | 52.67 | 20.10 | 11.30 |
Cumulative % of variance | 52.67 | 72.72 | 83.98 |
Variables with PC loadings greater than 0.6 are considered to be significant and are marked in bold.