Table 10. PCA results of heavy metals in the Rongna River.

Component	Initial eigenvalues			Rotation sums of squared loadings			Element	Principal component
	Total	%of variance	Cumulative%	Total	%of variance	Cumulative%		1	2
1	5.52	61.30	61.30	5.52	61.30	61.30	Cu	0.98	0.16
2	1.80	19.98	81.27	1.80	19.98	81.27	Pb	0.55	-0.71
3	0.98	10.90	92.17				Zn	0.97	0.21
4	0.45	4.96	97.13				As	-0.56	0.69
5	0.22	2.45	99.58				Mn	0.97	0.23
6	0.03	0.39	99.97				Cd	0.79	0.51
7	0.002	0.021	99.99				Cr	0.48	-0.48
8	0.001	0.012	100.00				Ni	0.97	0.22
9	0	0	100.00				Hg	-0.52	0.38