Table 3 The results of linear combination fitting for the Pb L3-edge XANES spectra of roots (with iron plaque).

From: Biochar amendment immobilizes lead in rice paddy soils and reduces its phytoavailability

Biochar added

Weighted percentage (%) of the roots

Pb(NO3)2

Ferrihydrite

Pectin

Cysteine

Pb5PO4Cl

R-factor (×103)b

0%

7.4 ± 1.6

60.8 ± 3.4

21.4 ± 2.1

0

10.8 ± 2.5

0.21

5%

11.4 ± 1.0

47.1 ± 1.7

20.9 ± 1.9

21.6 ± 3.1

0

0.12

  1. The data show the proportion (%) of the reference spectra that resulted in the best fit to the sample dataa.
  2. aMean ± standard deviation. Weighting factors on each fit summed to 100 ± 3%.
  3. bNormalized sum of the squared residuals of the fit (R-factor = ∑(data-fit)2/∑data2).
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