Table 4.

Total and CaCl₂-extractable heavy metals of pot soil collected at pak choi harvest under amendment of biowastes before and after pyrolysis.

Amend-ment	Total (mg kg−1)				CaCl2-extractable (mg kg−1)
	Cu	Zn	Pb	Cd	Cu	Zn	Pb	Cd
CK	21.90 ± 0.79e	66.50 ± 6.85cd	19.69 ± 1.76bc	0.19 ± 0.02 d	0.07 ± 0.02c	1.01 ± 0.02 d	0.01 ± 0.01bc	0.04 ± 0.00c
UWS	21.30 ± 1.14Ae	60.15 ± 8.78Bd	18.16 ± 0.83Bc	0.17 ± 0.01Ad	0.11 ± 0.01Ab	0.52 ± 0.17Ae	0.02 ± 0.00Ab	0.02 ± 0.01Ad
WSB	22.28 ± 1.44Ae	79.05 ± 7.18Ac	22.23 ± 1.74Ab	0.18 ± 0.01Ad	0.11 ± 0.01Ab	0.41 ± 0.08Ae	0.02 ± 0.01Ab	0.02 ± 0.00Ad
USM	32.69 ± 1.16Bd	126.6 ± 14.11Bb	21.03 ± 2.26Ab	0.18 ± 0.01Bd	0.80 ± 0.06Aa	6.26 ± 0.14Aa	0.04 ± 0.00Aa	0.01 ± 0.00Ae
SMB	48.80 ± 2.50Ab	206.5 ± 15.10Aa	22.69 ± 0.97Ab	0.23 ± 0.01Ac	0.12 ± 0.05Bb	2.99 ± 0.15Bb	0.01 ± 0.00Bc	0.01 ± 0.00Ae
USS	39.38 ± 2.31Bc	104.75 ± 7.92Ab	24.84 ± 2.51 Bab	0.39 ± 0.03Bb	0.14 ± 0.05Ab	3.19 ± 0.21Ab	0.01 ± 0.00Ac	0.08 ± 0.00Aa
SSB	58.56 ± 4.31Aa	109.6 ± 8.69Ab	30.14 ± 3.94Aa	0.45 ± 0.01Aa	0.09 ± 0.03 Abc	1.13 ± 0.05Bc	0.01 ± 0.00Ac	0.06 ± 0.00Bb

Data as mean ± standard deviation of four replicates of a treatment. CK, control; UWS and WSB, USM and SMB, and USS and SSB, wheat residue, swine manure and sewage sludge respectively before and after pyrolysis. In a single column, different uppercase letters following a single pair of amendment and different lowercase letters across the column represents a significant difference at p < 0.05 between before and after pyrolysis, and among all the treatments, respectively(One-way ANOVA followed by Turkey test).