Supporting Information to Predicting sorption of pesticides and ...

S1

Supporting Information to 466

467

Predicting sorption of pesticides and other multifunctional organic 468

chemicals to soil organic carbon 469

470

Guido Bronner* (1,2), Kai-Uwe Goss* (2) 471

(1) Institute for Biogeochemistry and Pollutant Dynamics (IBP), Swiss Federal Institute of 472

Technology (ETH) Zurich, Universitätstrasse 16, CH-8092 Zurich, Switzerland 473

(2) Helmholtz Centre for Environmental Research UFZ, Permoserstr. 15, 04318 Leipzig, 474

Germany, phone: +49 341 235 1411 (also current address) 475

*corresponding authors: [email protected], [email protected] 476

477

478

Content 479

SI-1 Correlation between log Koc und log Kow for non-polar and polar sorbates 480

SI-3 Physicochemical properties of the sorbates for the calibration data set 481

SI-2 Detailed procedure of the batch experiments. 482

SI-4 Physicochemical properties and experimental log KOC of sorbates for the 483

validation data set 484

SI-5 Cross correlation of the sorbate descriptors for the calibration data set. 485

SI-6 Properties of Pahokee Peat 486

SI-7 Theoretical Evaluation of the Equilibrium Assumption. 487

SI-8 Equilibration time of the batch sorption experiments. 488

SI-9 Long-term stability of the column packing in the dynamic experiments. 489

SI-10 Comparison of the experimental log Koc determined with the batch and the 490

column sorption experiments. 491

SI-11 Background sorption in the column sorption system. 492

SI-12 Performance of pp-LFER predictions for log Koc from the literature for the 493

calibration data set of this work. 494

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List of tables 495

496

Tab. SI– 1: Physicochemical properties of sorbates for the calibration data set. 497

Tab. SI– 2: Physicochemical properties experimental log KOC of sorbates for the validation 498

data set 499

Tab. SI– 3: Correlation between each single descriptor and the combination of the remaining 500

descriptors for both types of equation (cross correlation). 501

Tab. SI– 4: Properties of Pahokee Peat bulk material; * material dried at 60°C in vacuum 502

Tab. SI– 5: Diffusion coefficients of the sorbate into the sorbent particles that would allow to 503

obtain more than 80% of the equilibrium sorption for the given combination of 504

sorbent particle diameter and equilibration time (based on calculations for 505

spherical diffusion) 506

Tab. SI– 6: Background sorption in the column sorption system (HPLC system) 507

Tab. SI– 7: comparison of the fitted pp-LFER system coefficients for SOM/water partitioning 508

from the different literatures and from this work. 509

Tab. SI– 8: comparison of range of the compound descriptors of the calibration compounds 510

used to derive the pp-LFER equation for SOM/water partitioning in the literature 511

and in this work. 512

513

514

515

List of figures 516

517

Fig. SI– 1. Left: KOC - Kow plot for nonpolar sorbates. Right: Plot of log Koc values for polar 518

sorbates from this work (including pesticides, pharmaceuticals and hormones) versus 519

the respective log Kow values. Definition of nonpolar: mass fraction of oxygen + 520

nitrogen atoms in the molecule ≤ 12%. 521

Fig. SI– 2: Scanning electron microscope image of the peat material 522

Fig. SI– 3: Scanning electron microscope image of the SiC support material mixed with peat 523

Fig. SI– 4: Kinetik of batch experiments for the determination of the equilibration time. 524

Fig. SI– 5: Reproducibility of experimental sorption data after the peat column had been in use 525

for sorption experiments for one month and flushed with < 10’000 times the pore 526

volume. The average increase in log KOC in one month was 0.027; the root mean 527

square error (rmse) between the first and second measurment was 0.086. 528

Fig. SI– 6: Comparison of the Koc values for chemicals of the compound class alkyl benzenes 529

(benzene, toluene, ethylbenzene, propylbenzene, butylbenzene, pentylbenzene and 530

hexylbenzene) determined once with the batch method and once with the column 531

method. The log KOC obtained from the batch experiments were on average 0.045 532

higher than those obtained with the column method; the rmse between the two 533

methods was 0.058. 534

Fig. SI– 7: Comparison of experimental Koc values for the calibration data on Pahokee peat (this 535

work) with the predictions of 3 pp-LFER from the literature. Endo et al. 2009, 536

equation for Pahokee Peat at high concentrations (left) [1], Nguyen et al. 2007 537

(middle) [2], Niederer et al. 2006, equation for Leonardite humic acid (right) [3]. 538

539

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SI-1 Correlation between log Koc und log Kow for non-polar and 540

polar sorbates 541

542

543

0

1

2

3

4

5

6

7

8

0 1 2 3 4 5 6 7 8

exp. log Kow (Lw/Lo)

exp

. lo

g K

oc (

L/k

g)

this work N = 47

Nguyen et al.2007 N = 54

Karickhoff model(1981)

0

1

2

3

4

5

6

0 1 2 3 4 5 6

exp. log Kow (Lw/Lo)

exp

. lo

g K

oc (

L/k

g)

this work

N = 91

Karickhoff model

(1981)

544 Fig. SI– 1. Left: KOC - Kow plot for nonpolar sorbates. Right: Plot of log Koc values for polar sorbates from this work 545 (including pesticides, pharmaceuticals and hormones) versus the respective log Kow values. Definition of nonpolar: 546 mass fraction of oxygen + nitrogen atoms in the molecule ≤ 12%. 547 548

549

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SI-2 Detailed procedure of the batch experiments and chemical used. 550

For aliphatic compounds that are UV inactive thus not measurable by our column system, batch-551

experiments in at least duplicate were carried out. The coarse Pahokee Peat was pulverized with a 552

planetary mill (®pulverisette 5, FritschGmbH, Idar-Oberstein, Germany) for 40 minutes and then 553

sieved into 3 different fractions. Then, 0.02-0.7 g of the fraction 77-125 µm were added into a 554

10- or 20-ml vial and was dispersed in 5 ml of an aqueous solution containing 5 mM CaCl2 and 555

200 mg/l NaN3. A methanolic stock solution (10 µL) containing a mix of solutes of the same 556

compound class was added and the vial was immediately closed with a crimp cap and a silicon 557

septum lined with aluminum to prevent loss of solute. Stock solutions were prepared to meet the 558

following requirements: 1) the sum of the concentrations (in mol/L) in the water should not 559

exceed the solubility of the solute with the lowest solubility, 2) the sum of the sorbed 560

concentrations should be as near as possible to 5 mmol/kg OC and 3) the concentrations in the gas 561

phase have to be high enough to be quantified. Reference vials containing 5 ml aqueous solution 562

and 10 µl of a 10- to 100-fold dilution of the original methanolic stock solution were prepared for 563

each solute mix. For equilibration the vials were put on a horizontal shaker in the darkness for 3.5 564

days at a temperature of 25±2ºC. A separate experiment showed that the measured KOC did not 565

significantly change after two days Fig. SI– 4. The gas phase of the vials was measured by 566

headspace sampling coupled with GC-FID analysis. The evaluation of Koc values was based on 567

mass balance and concentration ratio between the vial with the peat and the reference vial. Due to 568

the anticipated non-linearity of sorption isotherms it was necessary to relate the sorption data of 569

all sorbates to one fixed reference concentration. Here, this reference concentration was chosen as 570

5 mmol/kg OC. Hence, our data that were measured in a range of 0.1 to 50 mmol/kg OC were 571

converted to 5 mmol/kg OC. This conversion was done based on the work of Endo et al. 2008 [1]. 572

573

Reference SI-2 574

[1] Endo, S.; Grathwohl, P.; Haderlein, S. B.; Schmidt, T. C. Environ. Sci. Technol. 2008, 42, 575

5897-5903. 576

577

578

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Chemicals. The chemicals were purchased from Sigma-Aldrich, Alfa-Aesar or Dr. Ehrenstorfer 579

GmbH and their purity was at least 97%; methanol (Lichrosolv quality) was purchased from 580

Merck. All solutes were either first dissolved in methanol (exception: PAHs were dissolved in 581

acetonitrile) and then diluted in 5 mM CaCl2 aqueous solution in order to keep the methanol 582

concentration below 1% (V/V) to avoid cosolvent effects (acetonitrile not exceeding 0.1%), or 583

directly dissolved in the same aqueous solution as used for the sorption experiments. 584

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SI-3 Physicochemical properties of the sorbates for the calibration 585

data set 586

587

Tab. SI– 1: Physicochemical properties of sorbates for the calibration data set. 588

CAS-RN Name Sorbate descriptors

exp.

log KOC

(L/kg)

E S A B V L

91-20-3 Naphthalene 1.34 0.92 0 0.20 1.09 5.16 2.48

573-98-8 1,2-Dimethylnaphthalene 1.43 0.92 0 0.20 1.37 6.44a) 3.64

83-32-9 Acenaphthene 1.60 1.04 0 0.20 1.26 6.47 3.22

86-73-7 Fluorene 1.59 1.03 0 0.20 1.36 6.92 3.63

85-01-8 Phenanthrene 2.06 1.29 0 0.29 1.45 7.63 4.26

110-83-8 Cyclohexene 0.40 0.20 0 0.10 0.80 3.02 1.84

591-49-1 1-Methylcyclohexene 0.39 0.20 0 0.10 0.94 3.48 2.08

108-90-7 Chlorobenzene 0.72 0.65 0 0.07 0.84 3.66 2.08

106-46-7 1,4-Dichlorobenzene 0.83 0.75 0 0.02 0.96 4.44 2.88

120-82-1 1,2,4-Trichlorobenzene 0.98 0.81 0 0 1.08 5.25 2.95

634-66-2 1,2,3,4-Tetrachlorobenzene 1.18 0.92 0 0 1.21 6.17 3.51

93-55-0 Propiophenone 0.80 0.95 0 0.51 1.15 4.97 1.99

1009-14-9 Pentanophenone 0.80 0.95 0 0.50 1.44 5.90 2.32

1671-75-6 Heptanophenone 0.72 0.95 0 0.50 1.72 6.88 3.16

91-23-6 2-Nitroanisole 0.73 1.47 0.22 0.30 1.09 5.60 1.89

555-03-3 3-Nitroanisole 0.87 1.20 0.14 0.25 1.09 5.59 2.11

100-17-4 4-Nitroanisole 0.97 1.21 0 0.24 1.09 5.85 2.28

88-73-3 2-Chloronitrobenzene 1.02 1.25 0.08 0.24 1.01 5.24 2.08

629-37-8 1-Nitrooctane 0.19 0.95 0 0.29 1.41

5.43

b) 2.47

98-95-3 Nitrobenzene 0.87 1.11 0 0.28 0.89 4.56 1.90

88-72-2 2-Nitrotoluene 0.87 1.11 0 0.28 1.03 4.88 1.82

121-14-2 2,4-Dinitrotoluene 1.18 1.27 0.07 0.51 1.21 6.27 2.23

118-96-7 2,4,6-Trinitrotoluene 1.40 1.70 0.13 0.59 1.38 7.03 1.92

100-66-3 Anisole 0.71 0.75 0 0.29 0.92 3.89 1.46

271-89-6 Benzofuran 0.89 0.83 0 0.15 0.91 4.36 2.04

4265-25-2 2-Methylbenzofuran 0.95 0.83 0 0.15 1.05 4.68 b

) 2.37

132-64-9 Dibenzofuran 1.41 1.02 0 0.17 1.27 6.72 3.51

110-02-1 Thiophene 0.69 0.56 0 0.15 0.64 2.82 1.33

93-58-3 Methyl benzoate 0.73 0.85 0 0.46 1.07 4.70 1.55

93-89-0 Ethyl benzoate 0.69 0.85 0 0.46 1.21 5.20 1.92

84-66-2 Diethyl phthalate 0.73 1.40 0 0.88 1.71 6.79 1.53

131-16-8 Di-n-propyl phthalate 0.71 1.40 0 0.88 1.99 7.70 a) 2.01

84-74-2 Di-n-butyl phthalate 0.67 1.40 0 0.88 2.27 8.60 a) 3.20

131-18-0 Di-n-pentyl phthalate 0.68 1.40 0 0.88 2.56 9.52 a) 3.73

91-15-6 1,2-Dicyanobenzene 0.71 1.95 0 0.27 1.29 5.64 c) 1.69

90-15-3 1-Naphthol 1.52 1.05 0.61 0.37 1.14 6.13 2.36

95-57-8 2-Chlorophenol 0.85 0.88 0.32 0.31 0.90 4.18 1.85

106-48-9 4-Chlorophenol 0.92 1.08 0.67 0.20 0.90 4.78 1.94

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CAS-RN Name Sorbate descriptors

exp.

log KOC

(L/kg)

E S A B V L

95-77-2 3,4-Dichlorophenol 1.02 1.14 0.85 0.03 1.02 5.71 2.40

95-95-4 2,4,5-Trichlorophenol 1.07 0.92 0.73 0.10 1.14 5.73 2.90

95-51-2 2-Chloroaniline 1.03 0.92 0.25 0.31 0.94 4.67 1.59

87-62-7 2,6-Dimethylaniline 0.97 0.89 0.20 0.46 1.10 5.03 1.38

120-72-9 Indole 1.20 1.12 0.44 0.22 0.95 5.51 2.04

50-28-2 Estradiol 1.80 1.77 0.86 1.10 2.20 11.11 2.76

15687-27-1 Ibuprofen 0.70 0.92 0.60 0.60 1.78 6.90 2.63 d)

80-05-7 Bisphenol A 1.61 1.56 0.99 0.91 1.86 8.95 2.49

543-59-9 1-Chloropentane 0.21 0.40 0 0.10 0.94 3.22 2.47

629-06-1 1-Chloroheptane 0.19 0.40 0 0.10 1.22 4.28 3.36

111-85-3 1-Chlorooctane 0.19 0.40 0 0.10 1.36 4.77 3.83

142-96-1 Di-n-butyl ether 0.00 0.25 0 0.45 1.29 3.92 1.65

693-65-2 Di-n-pentyl ether 0.00 0.25 0 0.45 1.58 4.80 b

) 2.78

112-58-3 Di-n-hexyl ether 0.00 0.25 0 0.45 1.86 5.74 b

) 3.60

592-76-7 1-Heptene 0.09 0.08 0 0.07 1.05 3.06 2.84

111-66-0 1-Octene 0.09 0.08 0 0.07 1.19 3.57 3.33

124-11-8 1-Nonene 0.09 0.08 0 0.07 1.33 4.07 3.84

872-05-9 1-Decene 0.09 0.08 0 0.07 1.47 4.58 b

) 4.39

111-13-7 2-Octanone 0.11 0.68 0 0.51 1.25 4.26 1.24

821-55-6 2-Nonanone 0.12 0.68 0 0.51 1.39 4.74 1.87

693-54-9 2-Decanone 0.11 0.68 0 0.51 1.53 5.25 2.37

112-12-9 2-Undecanone 0.10 0.68 0 0.51 1.67 5.73 2.82

628-05-7 1-Nitropentane 0.21 0.95 0 0.29 0.99 3.94 1.40

646-14-0 1-Nitrohexane 0.20 0.95 0 0.29 1.13 4.42 1.95

637-92-3 Ethyl tert-butyl ether -0.02 0.16 0 0.60 1.01 2.72 0.64

540-84-1 2,2,4-Trimethylpentane 0.00 0.00 0 0 1.24 3.11 3.60

919-94-8 Ethyl tert-pentyl ether 0.00 0.16 0 0.61 1.15 3.26 0.99

597-76-2 3-Ethyl-3-hexanol 0.20 0.30 0.31 0.60 1.29 4.29 1.05

19780-44-0 4-Ethyl-3-hexanol 0.17 0.36 0.33 0.57 1.29 4.18 1.28

104-76-7 2-Ethyl-1-hexanol 0.21 0.39 0.37 0.48 1.29 4.38 1.51

26675-46-7 Isoflurane -0.24 0.56 0 0.08 0.90 1.97 1.26

13838-16-9 Enflurane -0.24 0.54 0.01 0.10 0.90 2.01 1.19

151-67-7 Halothane 0.10 0.39 0.13 0.05 0.80 1.95 1.46

76-38-0 Methoxyflurane 0.11 0.67 0.07 0.14 0.91 2.86 1.44

71-43-2 Benzene 0.61 0.52 0 0.14 0.72 2.79 1.32

108-88-3 Toluene 0.60 0.52 0 0.14 0.86 3.33 1.77

100-41-4 Ethylbenzene 0.61 0.51 0 0.15 1.00 3.78 2.08

103-65-1 Propylbenzene 0.60 0.50 0 0.15 1.14 4.23 2.53

104-51-8 Butylbenzene 0.60 0.51 0 0.15 1.28 4.73 2.99

538-68-1 Pentylbenzene 0.59 0.51 0 0.15 1.42 5.23 3.51

1077-16-3 Hexylbenzene 0.59 0.50 0 0.15 1.56 5.72 3.93 a) experimental value determined for this work (detail will be published elwhere);

b) short range 589

extrapolation from homologous compounds; c) pers. communication M. Abraham;

d) log KOC of 590

the neutral species 591

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592

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References SI-3: source sorbate descriptors 593

Abraham, M. H. (1993). "Hydrogen Bonding XXVII. Solvation Parameters for Functionally 594

Substituted Aromatic Compounds and Heterocyclic Compounds, from Gas-Liquid 595

Chromatographic Data." J. Chromatogr. 644: 95-139. 596

Abraham, M. H. and W. E. Acree (2004). "Correlation and prediction of partition coefficients 597

between the gas phase and water, and the solvents dodecane and undecane." New Journal 598

Of Chemistry 28(12): 1538-1543. 599

Abraham, M. H., J. Andonian-Haftvan, et al. (1994). "Hydrogen Bonding. Part 34. The Factors 600

that Influence the Solubility of Gases and Vapours in Water at 298 K, and a New Method 601

for its Determination." J. Chem. Soc. Perkin Trans. 2(7): 1777-1791. 602

Abraham, M. H., H. S. Chadha, et al. (1994). "Hydrogen Bonding. 32. An Analysis of Water-603

Octanol and Water-Alkane Partitioning and the ∆log P Parameter of Seiler." J. Pharm. 604

Sci. 83: 1085-1100. 605

Abraham, M. H., A. Ibrahim, et al. (2006). "A data base for partition of volatile organic 606

compounds and drugs from blood/plasma/serum to brain, and an LFER analysis of the 607

data." Journal Of Pharmaceutical Sciences 95(10): 2091-2100. 608

Gunatilleka, A. D. and C. F. Poole (2000). "Models for Estimating the Non-Specific Toxicity of 609

Organic Compounds in Short Term Bioassays." Analyst 125: 127-132. 610

Sprunger, L. M., W. E. Acree, et al. (2008). "Mathematical correlations for gas-to-olive oil, gas-611

to-saline solution, and saline solution-to-olive oil partition coefficients based on the Goss 612

modified Abraham model." Qsar & Combinatorial Science 27(7): 890-900. 613

Torres-Lapasio, J. R., M. C. Garcia-Alvarez-Coque, et al. (2004). "Analysis of a solute polarity 614

parameter in reversed-phase liquid chromatography on a linear solvation relationship 615

basis." Anal. Chim. Acta 515(1): 209-227. 616

Tülp, H. C., K.-U. Goss, et al. (2008). "Experimental determination of LSER parameters for a set 617

of 76 diverse pesticides and pharmaceuticals." Environ. Sci. Technol. 42: 2034-2040. 618

Zissimos, A. M., M. H. Abraham, et al. (2002). "Calculation of Abraham Descriptors from 619

Experimental Data from Seven HPLC Systems; Evaluation of Different Methods of 620

Calculation." J. Chem. Soc. Perkin Trans. 2: 2001-2010. 621

622

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SI-4 Physicochemical properties and experimental log KOC of 623

sorbates for the validation data set 624

625

Tab. SI– 2: Physicochemical properties experimental log KOC of sorbates for the validation data 626

set 627 CAS-RN Name log KOC sorbate descriptors

(L/kg) E S A B V L

exp. ACD-Lab derived based on eq. 2 exp

15972-60-8 Alachlor 1.84 1.17 1.24 0.04 1.04 2.140 8.41

1912-24-9 Atrazine 1.82 1.51 1.28 -0.01 0.96 1.620 7.34

131860-33-8 Azoxystrobin 2.44 2.59 2.06 0.16 1.81 2.917 n.a.

741-58-2 Bensulide 3.47 1.64 1.56 0.53 1.47 2.873 n.a.

314-40-9 Bromacil 1.40 1.03 1.08 0.87 0.83 1.631 8.18

298-46-4 Carbamazepine 2.29 2.15 2.00 0.42 0.90 1.811 9.40

63-25-2 Carbaryl 2.31 1.00 1.30 0.46 0.75 1.541 7.81

10605-21-7 Carbendazim 2.96 2.00 1.67 0.56 0.50 1.361 n.a.

510-15-6 Chlorobenzilate 3.26 1.72 0.65 0.09 1.36 2.266 9.74

1897-45-6 Chlorothalonil 2.96 1.64 2.20 -0.25 0.44 1.515 7.65

210880-92-5 Clothianidin 2.05 2.21 2.21 0.86 0.75 1.576 9.50

21725-46-2 Cyanazine 1.76 1.73 1.60 0.27 1.04 1.774 8.29

57966-95-7 Cymoxanil 1.22 0.95 1.93 0.57 0.73 1.455 n.a.

94361-06-5 Cyproconazole 2.30 2.25 1.18 0.35 1.17 2.162 9.55

6190-65-4 Desethylatrazine 1.56 1.50 1.07 0.37 0.88 1.338 6.67

333-41-5 Diazinon 2.46 1.04 0.81 0.06 1.18 2.306 8.00

1085-98-9 Dichlofluanid 1.75 2.43 1.28 0.05 1.07 2.046 8.35

87674-68-8 Dimethenamid 1.75 1.27 1.25 0.02 1.18 2.065 8.22

88-85-7 Dinoseb 0.90 0.17 0.35 1.95 1.687 7.76

330-54-1 Diuron 2.56 1.50 1.59 0.50 0.63 1.599 n.a.

115-29-7 Endosulfan 2.89 2.44 0.82 0.41 0.96 2.082 9.38

26225-79-6 Ethofumesate 1.84 1.20 1.63 0.14 1.02 2.051 8.29

55-38-9 Fenthion 3.44 1.36 1.70 -0.01 0.70 1.988 8.49

79622-59-6 Fluazinam 1.95 1.60 0.44 1.28 1.45 2.364 10.01

103361-09-7 Flumioxazin 2.29 2.61 2.31 -0.04 1.33 2.416 12.00

85509-19-9 Flusilazole 3.02 1.47 1.68 0.34 0.88 2.274 9.33

98886-44-3 Fosthiazate 1.27 1.14 1.32 0.30 1.19 2.091 8.66

72963-72-5 Imiprothrin 2.18 1.65 1.40 0.21 1.37 2.463 9.81

28159-98-0 Irgarol 2.73 1.52 1.55 -0.23 0.97 1.975 8.74

34123-59-6 Isoproturon 1.65 1.20 1.54 0.39 0.88 1.777 n.a.

41394-05-2 Metamitron 1.99 1.89 1.79 0.30 0.94 1.500 8.64

67129-08-2 Metazachlor 1.69 1.62 1.34 0.16 1.24 2.087 8.78

950-37-8 Methidathion 2.16 2.07 1.87 -0.01 0.85 1.889 8.76

51218-45-2 Metolachlor 1.87 1.15 0.95 0.09 1.35 2.281 8.86

19937-59-8 Metoxuron 2.04 1.33 1.80 0.49 0.80 1.676 n.a.

21087-64-9 Metribuzin 1.48 1.61 1.13 0.32 0.86 1.620 7.64

150-68-5 Monuron 2.06 1.36 1.52 0.48 0.71 1.477 n.a.

15299-99-7 Napropamide 2.70 1.51 1.34 0.07 1.18 2.246 9.36

1836-75-5 Nitrofen 3.98 1.78 1.28 -0.30 0.85 1.802 9.25

26530-20-1 Octhilinone 2.75 0.89 1.82 0.10 0.58 1.786 7.88

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CAS-RN Name log KOC sorbate descriptors

(L/kg) E S A B V L

exp. ACD-Lab derived based on eq. 2 exp

34622-58-7 Orbencarb 3.19 1.33 1.17 -0.08 0.89 1.963 8.47

56-38-2 Parathion 3.23 1.33 1.65 0.06 0.72 1.998 8.41

13684-63-4 Phenmedipham 2.16 1.56 1.48 0.59 1.29 2.236 n.a.

32809-16-8 Procymidone 2.23 1.99 0.76 -0.01 1.18 1.862 8.76

1918-16-7 Propachlor 1.35 1.12 1.39 -0.03 0.89 1.659 6.83

60207-90-1 Propiconazole 2.77 2.15 1.41 0.07 1.18 2.343 10.11

114-26-1 Propoxur 1.53 0.72 1.11 0.38 0.86 1.654 n.a.

122836-35-5 Sulfentrazone 1.52 2.32 1.14 0.72 1.36 2.245 9.97

35256-85-0 Tebutam 1.91 0.80 1.03 0.04 1.11 2.100 7.52

886-50-0 Terbutryn 2.55 1.21 1.34 -0.12 0.96 1.943 8.38

117718-60-2 Thiazopyr 2.33 1.23 1.04 0.09 1.33 2.499 8.69

3380-34-5 Triclosan 4.02 1.85 1.81 0.92 0.30 1.809 8.96

17924-92-4 Zearalenone 3.32 1.25 1.68 0.87 1.24 2.463 11.95

64-85-7 Deoxycorticosterone 2.53 1.74 3.50 0.14 1.31 2.680 13.12

50-23-7 Hydrocortisone 1.79 2.03 3.49 0.71 1.9 2.798 13.72

57-83-0 Progesterone 3.02 1.45 3.29 0 1.14 2.622 12.05

58-22-0 Testosterone 2.24 1.54 2.59 0.32 1.19 2.383 11.27

50-33-9 Phenylbutazone 2.08 1.85 2.62 0.00 1.28 2.433 10.19

628

629

630

SI-5 Cross correlation of the sorbate descriptors for the calibration 631

data set. 632

633

Tab. SI– 3: Correlation between each single descriptor and the combination of the remaining 634

descriptors for both types of equation (cross correlation). 635

descriptor E S A B V

Eq. 1 r2 0.56 0.61 0.2 0.6 0.51

descriptor L S A B V

Eq. 2 r2 0.91 0.76 0.27 0.62 0.86

636

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S12

SI-6 Properties of Pahokee Peat 637

638

Pahokee Peat, was obtained from the International Humic Substances Society (IHSS) and 639

its properties are shown in Tab.SI-4. 640

641

642

Tab. SI– 4: Properties of Pahokee Peat bulk material; * material dried at 60°C in vacuum 643

soil organic

matter Identity IHSS

rel. amount in

bulk material

rel. amount

in dry

material * relative amount in ash free sample

H2O Ash C H O N S P

% (w/w) % (w/w) --------------------% (w/w)--------------------

Pahokee Peat II

bulk material PPII 2S103P 6.2 12.7 46.9 3.9 30.3 3.42 0.58 --

644 Source: Elemental analyses by Huffman Laboratories, Wheat Ridge, CO, USA; Isotopic analyses by Soil 645 Biochemistry Laboratory, Dept. of Soil, Water, and Climate, University of Minnesota, St. Paul, MN, USA 646 H2O content is the %(w/w) of H2O in the air-equilibrated sample (a function of relative humidity). 647 Ash is the %(w/w) of inorganic residue in a dry sample. 648 C, H, O, N, S, and P are the elemental composition in %(w/w) of a dry, ash-free sample. 649 The data for bulk source materials are reported on an as-stored basis, except that %H and %O are corrected for 650 water content. 651 nd means that an item was not determined. 652

653

654

655 656 Fig. SI– 2: Scanning electron microscope image of the peat material 657 658

659

660

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S13

661 662 Fig. SI– 3: Scanning electron microscope image of the SiC support material mixed with peat 663 664

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S14

SI-7 Theoretical Evaluation of the Equilibrium Assumption. 665

666

Realisation of a sorption equilibrium in the experimental system is a fundamental prerequisite for 667

the correct determination of sorption coefficients. The kinetically limiting step is diffusion of the 668

sorbate into the sorbent whereas diffusion through the aqueous phase is comparatively fast. The 669

time that is required for attaining equilibrium increases with decreasing diffusion coefficients and 670

it increases non-linearly with the diffusion path length. Hence, much smaller equilibration times 671

are needed if the sorbent is supplied in the form of thin films or particles where the maximal 672

diffusion path lengths are small. Gas chromatography nicely illustrates this effect: a sorbent film 673

thickness of 1 µm or less allows for a linear gas phase velocity of more than 30 m/min without 674

violating the equilibrium requirement. Therefore, considerable effort was spent to reduce the 675

particle size of our sorbents as much as possible. For Pahokee Peat we ended up with particles 676

smaller than 20 µm. The sorption kinetics of a typical particle of 12 µm diameter can be 677

calculated by using the appropriate equation for spherical diffusion [1]. If the sorption kinetics 678

model is combined with a convective-dispersive transport model (AQUASIM 2.0, [2] one can 679

calculate how small the diffusion coefficients into the sorbent can be without violating our 680

equilibrium assumption. The calculations revealed that the diffusion coefficient into spherical 681

sorbents of 12 µm diameter may be as small as 10-11

cm2/sec for the typical linear flow velocity 682

that was applied in our experiments (2.4 cm/min corresponding to a volume flow of 0.05 ml/min) 683

without violating our equilibrium assumption. As a comparison we note that diffusion 684

coefficients typically observed in peat are in the order of 10-9

cm2/sec [3,4]. These conditions can 685

be compared with those of batch sorption experiments that usually last between 2 and 30 days 686

and that use particle sizes in the range of 100 and 2000 µm diameter. Table 3 gives the diffusion 687

coefficients that would still allow to achieve more than 80% of the equilibrium sorption for the 688

given equilibration time and particle diameter in those batch experiments. 689

690

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S15

Tab. SI– 5: Diffusion coefficients of the sorbate into the sorbent particles that would allow to 691

obtain more than 80% of the equilibrium sorption for the given combination of sorbent particle 692

diameter and equilibration time (based on calculations for spherical diffusion) 693

particle diameter

(µm)

equilibration time

(days)

2 7 30

100 2E-11 cm2/sec 5E-12 cm

2/sec 1.5E-12 cm

2/sec

300 2E-10 cm2/sec 5E-11 cm

2/sec 1.5E-11 cm

2/sec

1000 2E- 9 cm2/sec 5E-10 cm

2/sec 1.5E-10 cm

2/sec

694

This comparison suggests that the conditions in our flow-through experiment allowed slower 695

sorption processes to come into equilibrium than most batch experiments do. 696

697

References SI-7 698

[1] Schwarzenbach, R. P.; Gschwend, P. M.; Imboden, D. M. Environmental Organic 699

Chemistry; 2. ed.; John Wiley & Sons: Hoboken, 2003. 700

[2] Reichert, P.; 2.0 ed.; Swiss Federal Institute of Environmental Science and Technology 701

(EAWAG): Dübendorf, 1998; p Computer Program for the Identification and Simulation 702

of Aquatic Systems. 703

[3] Piatt, J. J.; Brusseau, M. L. Environ. Sci. Technol. 1998, 32, 1604-1608. 704

[2] Chang, M.-L.; Wu, S.-C.; Chen, C.-Y. Environ. Sci. Technol. 1997, 31, 2307-2312. 705

706

707

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S16

SI-8 Equilibration time of the batch sorption experiments. 708

709

To evaluate the equilibration time of the batch experiments 10 vials were prepared for batch 710

sorption experiments with 5 sorbates of the alkylbenzene class and periodically we sacrificed 2 of 711

them and measured the sorbates in the headspace Fig. SI– 4. After 2 days the determined Koc 712

values were stable. 713

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

0 2 4 6 8 10 12 14

Time (days)

log

Ko

c (

L/k

g)

butylbenzene

propylbenzene

ethylbenzene

toluene

benzene

714 Fig. SI– 4: Kinetik of batch experiments for the determination of the equilibration time. 715

716

SI-9 Long-term stability of the column packing in the dynamic 717

experiments. 718

0

1

2

3

4

5

0 1 2 3 4 5log KOC (L/kg) second measurment

log K

oc (

L/k

g)

firs

t m

easu

rment.. calibration compounds

on PP (subset, n = 26)

1:1 line

719

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S17

Fig. SI– 5: Reproducibility of experimental sorption data after the peat column had been in use for sorption 720 experiments for one month and flushed with < 10’000 times the pore volume. The average increase in log KOC in one 721 month was 0.027; the root mean square error (rmse) between the first and second measurment was 0.086. 722 723

724

SI-10 Comparison of the experimental log Koc determined with the 725

batch and the column sorption experiments. 726

0

1

2

3

4

5

0 1 2 3 4 5

log KOC column experiments

log

KO

C b

atc

h e

xp

erim

en

ts

alkyl benzenes on PP

727 Fig. SI– 6: Comparison of the Koc values for chemicals of the compound class alkyl benzenes (benzene, toluene, 728 ethylbenzene, propylbenzene, butylbenzene, pentylbenzene and hexylbenzene) determined once with the batch 729 method and once with the column method. The log KOC obtained from the batch experiments were on average 0.045 730 higher than those obtained with the column method; the rmse between the two methods was 0.058. 731

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S18

SI-11 Background sorption in the column sorption system. 732

733

Tab. SI– 6: Background sorption in the column sorption system (HPLC system) 734

CAS-RN Name

Vnet

background

(ml)

Vnet, system

(ml)

Vnet,

background/

Vnet, system

110-83-8 Cyclohexene 0.018 0.101 0.180

591-49-1 1-Methylcyclohexene 0.059 0.200 0.296

71-43-2 Benzene 0.006 0.029 0.219

108-88-3 Toluene 0.008 0.079 0.100

100-41-4 Ethylbenzene 0.027 0.142 0.188

103-65-1 Propylbenzene 0.086 0.421 0.204

104-51-8 Butylbenzene 0.339 1.420 0.239

538-68-1 Pentylbenzene 0.729 3.832 0.190

1077-16-3 Hexylbenzene 2.043 11.930 0.171

108-90-7 Chlorobenzene 0.019 0.161 0.117

106-48-9 4-Chlorophenol 0.006 0.110 0.055

106-46-7 1,4-Dichlorobenzene 0.210 1.117 0.188

120-82-1 1,2,4-Trichlorobenzene 0.227 1.282 0.177

634-66-2 1,2,3,4-Tetrachlorobenzene 0.818 4.643 0.176

95-57-8 2-Chlorophenol 0.004 0.088 0.050

95-51-2 2-Chloroaniline 0.003 0.049 0.064

87-62-7 2,6-Dimethylaniline 0.003 0.031 0.087

120-72-9 Indole 0.007 0.136 0.051

109-97-7 1H-Pyrrole 0.002 0.007 0.242

91-23-6 2-Nitroanisole 0.005 0.097 0.048

555-03-3 3-Nitroanisole 0.007 0.159 0.045

100-17-4 4-Nitroanisole 0.007 0.207 0.032

88-73-3 2-Chloronitrobenzene 0.009 0.186 0.048

646-14-0 1-Nitrohexane 0.015 0.063 0.235

629-37-8 1-Nitrooctane 0.042 0.388 0.108

98-95-3 Nitrobenzene 0.003 0.097 0.036

88-72-2 2-Nitrotoluene 0.015 0.092 0.159

121-14-2 2,4-Dinitrotoluene 0.010 0.209 0.049

118-96-7 2,4,6-Trinitrotoluene 0.008 0.107 0.078

100-66-3 Anisole 0.008 0.043 0.196

271-89-6 Benzofuran 0.014 0.143 0.099

4265-25-2 2-Methylbenzofuran 0.041 0.318 0.129

132-64-9 Dibenzofuran 0.491 4.303 0.114

110-02-1 Thiophene 0.003 0.033 0.100

1009-14-9 Pentanophenone 0.030 0.278 0.110

1671-75-6 Heptanophenone 0.331 2.029 0.163

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S19

CAS-RN Name

Vnet

background

(ml)

Vnet, system

(ml)

Vnet,

background/

Vnet, system

93-58-3 Methyl benzoate 0.005 0.047 0.106

93-89-0 Ethyl benzoate 0.009 0.108 0.085

136-60-7 Butyl benzoate 0.076 0.282 0.269

84-66-2 Diethyl phthalate 0.007 0.047 0.140

131-16-8 Di-n-propyl phthalate 0.036 0.157 0.230

84-74-2 Di-n-butyl phthalate 0.325 2.194 0.148

131-18-0 Di-n-pentyl phthalate 3.062 9.391 0.326

91-15-6 1,2-Dicyanobenzene 0.002 0.060 0.034

91-20-3 Naphthalene 0.069 0.429 0.161

573-98-8 1,2-Dimethylnaphthalene 0.504 5.704 0.088

83-32-9 Acenaphthene 0.352 2.303 0.153

86-73-7 Fluorene 0.604 5.634 0.107

85-01-8 Phenanthrene 1.817 23.490 0.077

90-15-3 1-Naphthol 0.027 0.301 0.091

64-85-7 Deoxycorticosterone 0.056 0.454 0.123

50-28-2 Estradiol 0.064 0.744 0.086

50-23-7 Hydrocortisone 0.011 0.084 0.126

58-22-0 Testosterone 0.078 0.286 0.273

57-83-0 Progesterone 0.186 1.420 0.131

80-05-7 Bisphenol A 0.067 0.432 0.155

100-02-7 4-Nitrophenol 0.008 0.275 0.028

95-77-2 3,4-Dichlorophenol 0.035 0.330 0.108

95-95-4 2,4,5-Trichlorophenol 0.135 1.088 0.124

735

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S20

SI-12 Performance of pp-LFER predictions for log Koc from the 736

literature for the calibration data set of this work. 737

738

739

740 Fig. SI– 7: Comparison of experimental Koc values for the calibration data on Pahokee peat (this work) with the 741 predictions of 3 pp-LFER from the literature. Endo et al. 2009, equation for Pahokee Peat at high concentrations 742 (left) [1], Nguyen et al. 2007 (middle) [2], Niederer et al. 2006, equation for Leonardite humic acid (right) [3]. 743 744

745

746

Tab. SI– 7: comparison of the fitted pp-LFER system coefficients for SOM/water partitioning 747

from the different literatures and from this work. 748

749

l v b a s e c R2 SE n

Poole et Poole 1996 [4] 2.09 -2.27 -0.31 0 0.74 0.21 0.98 0.25 131

SE 0.1 0.11 0.09 0.04 0.09

Thanh et al. 2005 [2] 2.28 -1.98 0.15 -0.72 1.1 0.14 0.98 0.26 74

SE 0.14 0.14 0.15 0.14 0.10 0.10

Endo et al. 2009 [1]

(at low conc.) 3.71 -3.94 -0.1 1.27 0.31 -1.04 0.91 0.34 51

SE 0.22 0.35 0.25 0.29 0.2 0.24

Endo et al. 2009 [1]

(at high conc.) 3.51 -3.83 0.02 0.19 0.43 -0.82 0.90 0.35 51

SE 0.22 0.35 0.25 0.29 0.21 0.24

this work (Eq. 1) 2.99 -3.44 -0.21 -0.61 0.81 -0.29 0.92 0.25 79

SE 0.11 0.18 0.14 0.11 0.08 0.12

this work (Eq. 2) 0.54 1.20 -3.34 -0.42 -0.98 0.02 0.929 0.24 79

SE 0.05 0.20 0.1 0.14 0.13 0.12

SE: standard error 750

751

752

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S21

Tab. SI– 8: comparison of range of the compound descriptors of the calibration compounds used 753

to derive the pp-LFER equation for SOM/water partitioning in the literature and in this work. 754

755

V B A S E

Poole et Poole 1996 [4] min 0.47 0.00 0.00 0.34 0.20

max 1.95 0.88 1.10 2.17 4.00

range 1.48 0.88 1.10 1.83 3.80

Thanh et al. 2005 [2] min 0.71 0.00 0.00 0.40 0.37

max 2.30 1.05 0.97 1.90 2.85

range 1.59 1.05 0.97 1.50 2.48

Endo et al. 2009 [1] min 0.49 0.00 0.00 0.00 0.00

max 1.58 0.60 0.73 1.59 2.38

range 1.09 0.60 0.73 1.59 2.38

this work min 0.64 0.00 0.00 0.00 -0.24

max 2.56 1.10 0.99 1.95 2.06

range 1.91 1.10 0.99 1.95 2.29

756

757

758

759

References SI-12 760

[1] Endo, S.; Grathwohl, P.; Haderlein, S. B.; Schmidt, T. C. Environmental Science & 761

Technology 2009, 43, 3094-3100. 762

[2] Nguyen, T. H.; Goss, K.-U.; Ball, W. P. Environ. Sci Technol. 2005, 39, 913-924. 763

[3] Niederer, C.; Goss, K.-U.; Schwarzenbach, R. P. Environ. Sci Technol. 2006, 40, 5374-764

5379. 765

[4] Poole, S. K.; Poole, C. F. Analytical Communications 1996, 33, 417-419. 766

767

768

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