Availability and Plant Uptake of Biosolid-Borne Metals

Table 2

Metal uptake rates (means where 𝑛=4) by corn grown on sand media amended, without biosolids (Standard) and with biosolids at different growth stages^†.

Metal	Plant tissue	Treatment	Time (weeks)
			0–2	2–4	4–8	8–12	12–16
			𝜇g g^−1 2 wk^−1
Cd	Shoot	Standard	0.5^a	0.2^b	n.d.^‡	n.d.^‡	n.d.^‡
		Biosolids	7.0^a	7.0^a	5.0^a	5.0^a	6.0^a
	Root	Standard	1.9^a	1.8^a	n.d.^‡	n.d.^‡	n.d.^‡
		Biosolids	36^b	37^b	25^b	38^b	79^a
Cr	Shoot	Standard	1.3^a	1.0^a	0.4^b	0.4^b	0.4^b
		Biosolids	1.9^a	1.6^b	0.5^c	0.5^c	n.d.^‡
	Root	Standard	3.6^a	1.7^b	0.7^c	0.7^c	0.7^c
		Biosolids	16^a	10^b	3.0^c	3.0^c	n.d.^‡
Cu	Shoot	Standard	13^a	10^a	3.0^b	3.0^b	3.0^b
		Biosolids	19^a	15^b	7.0^c	5.0^c	6.0^c
	Root	Standard	23^a	20^a	10^b	8.0^b	n.d.^‡
		Biosolids	71^a	54^b	22^c	16^c	12^c
Ni	Shoot	Standard	16^a	12^a	5.0^b	4.0^b	4.0^b
		Biosolids	52^a	35^b	10^c	11^c	n.d.^‡
	Root	Standard	20^a	19^a	6.0^b	5.0^b	n.d.^‡
		Biosolids	321^a	215^b	81^c	59^d	16e
Pb	Shoot	Standard	6.0^a	5.0^a	2.0^b	1.0^b	2.0^b
		Biosolids	15^a	12^b	5.0^c	4.0^c	5.0^c
	Root	Standard	6.0^a	5.0^a	1.0^b	1.0^b	n.d.^‡
		Biosolids	37^a	14^b	6.0^c	4.0^c	5.0^c
Zn	Shoot	Standard	30^b	30^b	21^b	19^b	63^a
		Biosolids	157^b	165^b	127^b	185^b	687^a
	Root	Standard	58^a	60^a	57^a	73^a	n.d.^‡
		Biosolids	235^a	179^b	81^c	76^c	31^c

†The differences of metal rates among the time periods were tested by one-way ANOVA. Within a row and between shoot and root, values followed by same letters were not significantly different at 𝑃<0.05.
^‡Metal uptake rate was not detected in this period.