Table 3.

Estimated molar fraction of spike (x_spike) and amendment (x_amendment) in the plant samples grown on soil with spiked amendment, and corresponding mass fractions of Ni stemming from the spike and the amendment as a whole. The given uncertainty represents standard deviation between replicates (n = 5 per group)

Soil	xspike/%	xamendment/%	w (Ni)/ng g−1
			Total	From spike	From amendment
S1	0.87 ± 0.23	19.3 ± 5.0	35,000 ± 19,000	310 ± 154	6700 ± 3400
S6	0.350 ± 0.081	7.7 ± 1.8	33,000 ± 22,000	110 ± 53	2400 ± 1100