Table 4.

The DTPA extractable concentrations of PTEs of biological sewage sludge and produced biochar (mg/kg).

Metal	Sewage sludge	Biochar
Cd	0.3 ± 0.1	0.1 ± 0.0
Cr	0.62 ± 0.06	0.15 ± 0.00
Ni	3.21 ± 0.57	0.67 ± 0.27
Pb	13.46 ± 0.48	2.92 ± 0.38
Zn	316.40 ± 21.78	38.75 ± 3.11
Cu	17.01 ± 0.14	1.45 ± 0.43
Fe	187 ± 39.60	63.92 ± 8.95