Table 2.

The contents of 8 elements in soil

Elements	Elements contents (mg kg−1)				Environmental quality standard for soilsa	Risk control standard for soil contamination of agricultural landb
	Soil of AL	Soil of SB	Soil of RA	Soil of SG	First-class National Soil Environment Standard	Risk screening values#
Cr	12.02 ± 0.49	12.43 ± 0.52	17.72 ± 0.65	11.80 ± 0.24	90	150
Ni	6.47 ± 0.36	6.25 ± 0.24	8.80 ± 0.48	6.18 ± 0.23	40	60
Cu	5.38 ± 0.32	5.61 ± 0.47	8.62 ± 2.79	5.22 ± 0.32	35	50
Zn	20.67 ± 4.97	22.60 ± 4.48	23.72 ± 5.84	20.62 ± 3.2	100	200
As	4.44 ± 0.41	4.62 ± 0.43	5.19 ± 0.43	4.37 ± 0.18	15	40
Cd	0.16 ± 0.02	0.17 ± 0.01	0.21 ± 0.02*	0.16 ± 0.02	0.2	0.3
Hg	0.16 ± 0.17*	0.13 ± 0.17	0.40 ± 0.30*	0.19 ± 0.08*	0.15	1.3
Pb	12.84 ± 1.22	12.07 ± 0.68	15.71 ± 2.03	12.84 ± 0.96	35	70

Annotation: * means exceeding national Grade 1 soil standards; ^# all the screened values were selected for non-paddy fields and the minimum value at the lowest pH; ^a reference (AEPA, 1995); ^b reference (Environment, 2018). Values were highlight with bold, which means higher than the standards instead of representing a statistical difference