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Table 3 Panel A: Half-lives (DT50) and DT90 values of QE, QA, 3-OH-QA, and 3-OH-CQO. Panel B: Half-lives (DT50) and formation fractions of metabolites resulting from sequential fitting

From: Degradation and sorption of the herbicides 2,4-D and quizalofop-P-ethyl and their metabolites in soils from railway tracks

Panel A
  pH Corg T [°C]/ DT50/DT90 [days], best fita
  (CaCl2) [%] M [%] QE QA 3-OH-QA 3-OH-CQO
Soils from railway tracks
 EB 7.7 0.15 20/49 21/> 1000 FOMC 96/414 DFOP 37/122 SFO 335/> 1000 FOMC
 MBS 7.6 0.31 20/54 0.22/1.4 DFOP 113/488 DFOP 35/116 SFO 24/> 1000 FOMC
 MR 7.6 ≈ 0.04 20/67 0.21/0.98 FOMC >1000/> 1000 SFO 630/> 1000 SFO 445/> 1000 SFO
 CS 7.5 < 0.06 20/55 0.69/68 FOMC 371/> 1000 SFO 189/628 SFO 474/> 1000 FOMC
    DT50 [days], modeling endpointsb
 Geom. mean, 20 °C, pF 2   ≈ 0.1   4.0 276 101 246
Agricultural soils [17]
 Min–max 5.0–8.2c 0.8–4.6 20–22/40–70 0.3–1.1 7–182 7–69 42–258
 Geom. mean, 20 °C, pF 2   2.8/1.9/1.5/2.1d   0.4 24 18 63
Panel B  
  sequence of fitting DT50 [days]
QEe
Formation fraction [%] DT50 [days]
QAe
Formation fraction [%] DT50 [days]
3-OH-QAe
 
EB QE → QA → 3-OH-QA → sink 28 FOMC 100 92 SFO 0.5 180 SFO  
MBS QE → QA → 3-OH-QA → sink 0.20 DFOP 100 105 SFO 3.0 91 SFO  
MR QE → QA → sink 0.21 DFOP 98 968 SFO    
CS QE → QA → sink 1.1 FOMC 100 746 SFO    
  1. T: temperature, M: moisture in % of water holding capacity
  2. aSFO: single first-order kinetics, DFOP: double first-order in parallel model, FOMC: first-order multi-compartment model. χ2 values < 10%
  3. bCalculated according to [26], for details see Additional file 1: Table S5 and Additional file 2: Kinetic fits
  4. cMeasured in H2O
  5. dIn degradation studies with QE/QA/3-OH-QA/3-OH-CQO
  6. eBest fit. χ2 values ≤ 12%, except for 3-OH-QA in MBS (16%)