Table 2.

Mean concentrations of 10 metals at four different metal recyclers (MRs).

Metal	MR1 (n = 12)	MR2 (n = 14)	MR3 (n = 21)	MR4 (n = 12)
As	1.11 ± 0.58	9.18 ± 8.05	8.23 ±13.04	0.53 ± 0.47
Ag	0.49 ± 0.12	2.28 ± 2.67	2.36 ± 3.56	0.66 ± 0.34
Cd	0.53 ± 0.07	1.62 ± 0.89	2.95 ± 5.16	0.98 ± 1.14
Co	1.25 ± 1.23	14.85 ± 6.47	3.64 ± 6.04	0.59 ± 0.41
Cr	50.13 ± 46.12	354.6 ± 288.7	54.59 ± 74.6	9.35 ± 4.06
Fe	5091 ±10,058	15,869± 8070	13,144±16,585	1985 ±824.0
Mn	45.00 ± 24.95	365.7 ± 215.8	301.7 ± 280.7	33.43 ±10.85
Ni	93.09 ± 95.54	769.8 ± 668.6	86.53 ± 142.0	14.24 ± 7.98
Pb	16.05 ± 11.21	67.78 ± 69.71	93.51 ± 97.23	52.23 ±40.07
Se	1.17 ± 0.62	1.73 ± 0.48	1.51 ± 2.76	0.54 ± 0.81

Notes. Unit: ng/m³

Concentrations are shown as Mean ± SD (standard deviation)