I₁

I₂

I₃

I₄

As

−0.072

−0.253

0.957

−0.093

Cd

0.457

0.735

0.089

0.214

Cr

0.912

0.512

−0.125

0.019

Cu

0.543

0.073

0.611

0.231

Hg

0.013

0.013

0.216

0.078

Pb

0.647

0.815

0.028

0.978

Zn

0.832

0.621

−0.214

0.872

方差贡献率/%

28.14

13.2

11.3

15.2

累积方差贡献率

27.38

62.1

55.7

81.6