Table 4.

Summary statistics of the heavy metal contents in soil (N = 1822).

Content	Cr (mg/kg)	Pb (mg/kg)	Cd (mg/kg)	Hg (mg/kg)	As (mg/kg)	Cu (mg/kg)	Zn (mg/kg)	Ni (mg/kg)
Mean	69.64	42.89	0.20	0.31	6.67	35.50	111.16	29.99
Median	71.10	42.65	0.18	0.21	6.38	33.45	107.00	30.40
Std	27.53	15.43	0.09	0.32	2.57	15.13	34.90	15.61
CV (%)	39.53	35.98	45.00	103.23	38.53	42.62	31.40	52.05
Min	9.16	15.60	0.03	0.02	0.88	7.14	34.30	3.81
Max	326.00	263.00	1.83	2.26	19.10	160.00	714.00	293.00
Background value	56.1	36.2	0.161	0.076	5.75	23.1	86.6	20.7
Critical value [46]	150	250	0.3	0.3	30	50	200	40