A Regional Scale Investigation on Groundwater Arsenic in Different Types of Aquifers in the Pearl River Delta, China

Table 2

Principal component (PC) loadings for groundwater samples in granular aquifers.

Item	PC1	PC2	PC3	PC4	PC5	PC6	PC7
pH	0.105	0.755	0.163	0.174	0.025	−0.011	−0.043
EC	0.766	0.432	0.196	0.102	0.386	−0.053	0.003
DO	−0.274	−0.206	−0.163	−0.134	−0.045	0.500	−0.312
Eh	−0.015	−0.248	−0.051	−0.055	0.069	0.707	0.219
K^+	0.314	0.286	0.046	−0.044	0.804	−0.035	0.038
Na^+	0.942	0.151	0.065	0.053	0.107	−0.085	0.027
Ca^2+	0.324	0.753	0.239	0.158	0.314	−0.233	−0.043
Mg^2+	0.812	0.277	0.079	0.067	0.100	0.174	−0.059
	0.240	0.186	0.571	0.519	−0.113	0.260	−0.072
Fe	0.125	0.060	0.244	0.672	−0.141	−0.324	0.123
	0.363	0.712	0.431	0.272	−0.026	−0.109	−0.048
Cl^−	0.945	0.092	0.010	0.039	0.178	−0.057	0.030
	0.399	0.541	−0.131	0.064	0.420	−0.168	0.026
F^−	0.135	0.717	−0.098	−0.100	−0.223	−0.031	0.203
	0.236	−0.174	−0.072	−0.157	0.814	0.068	−0.048
TDS	0.675	0.530	0.294	0.138	0.350	−0.129	−0.026
TH	0.535	0.692	0.217	0.148	0.283	−0.125	−0.054
I^−	−0.021	0.136	0.361	0.684	0.088	0.039	0.186
	0.048	0.203	0.900	0.064	0.031	0.016	0.023
Al	−0.034	0.019	−0.011	0.047	−0.018	0.096	0.905
Mn	0.058	0.075	−0.127	0.851	−0.070	0.044	−0.116
	0.252	0.338	0.218	0.376	−0.156	0.541	0.063
As	0.101	0.022	0.890	0.116	−0.021	−0.147	−0.004
Eigenvalue	4.6	3.9	2.7	2.3	2.1	1.4	1.1
Explained variance (%)	19.9	17.1	11.7	10.1	9.2	6.2	4.8
Cumulative% of variance	19.9	37.0	48.8	58.9	68.1	74.3	79.1