Waalewijn-Kool et al.
Supplemental Data
The effect of pH on the toxicity of ZnO nanoparticles to Folsomia candida in amended field soil
Pauline L. Waalewijn-Kool,† Maria Diez Ortiz,‡ Stephen Lofts,§ and Cornelis A.M. van Gestel*†
†Department of Ecological Science, Faculty of Earth and Life Sciences, VU University, De Boelelaan
1085, 1081 HV Amsterdam, The Netherlands
‡Centre for Ecology and Hydrology, Maclean Building, Benson Lane, Crowmarsh Gifford, Wallingford,
Oxfordshire OX10 8BB, UK
§Centre for Ecology and Hydrology, Lancaster Environment Centre, Library Avenue, Bailrigg,
Lancaster, LA1 4AP, UK
* To whom correspondence may be addressed
1
Table S1. pHCaCl2 of the three test soils spiked with 30 nm ZnO, 200 nm ZnO and ZnCl2.
30 nm ZnO
200 nm ZnO
ZnCl2
Nominal conc.
soil 1
soil 2
soil 3
soil 1
soil 2
soil 3
soil 1
soil 2
soil 3
Control
4.31
5.71
6.39
100
4.24
5.42
6.66
4.06
5.48
6.34
4.31
5.58
6.81
200
4.28
5.45
6.79
4.27
5.54
6.30
4.01
5.51
6.83
400
4.43
5.44
6.70
4.37
5.63
6.20
4.03
5.41
6.61
800
4.63
5.49
6.55
4.44
5.75
6.06
3.96
5.28
6.41
1600
5.05
5.88
6.33
4.88
5.82
6.12
-
5.13
6.16
3200
5.48
5.90
6.27
5.53
5.88
6.13
-
-
-
6400
5.76
5.90
6.26
5.67
5.99
6.09
-
-
-
(mg Zn/kg d.w.)
-
test concentrations not included in this study
2
Table S2a. Average zinc concentrations (± SD, n=2) measured in soil 1 (pHCaCl2 = 4.31) spiked with
30 nm ZnO, 200 nm ZnO and ZnCl2. Zinc concentrations in the soil are corrected for the zinc levels
measured in the controls. Recoveries (%) are presented in brackets.
Nominal conc.
30 nm ZnO
200 nm ZnO
ZnCl2
Control
10.3 ± 1.5
10.3 ± 1.5
10.3 ± 1.5
100
119 ± 7.2 (119)
93.5 ± 12.0 (94)
104 ± 4.3 (104)
200
209 ± 6.6 (105)
242 ± 11.1 (121)
260 ± 1.1 (130)
400
450 ± 2.8 (113)
491 ± 42.7 (123)
434 ± 29.3 (108)
800
746 ± 27.2 (93)
662 ± 50.3 (83)
793 ± 63.5 (99)
1600
1760 ± 106 (110)
1280 ± 10.3 (80)
3200
3547 ± 507 (111)
3005 ± 376 (94)
6400
6084 ± 886 (95)
7419 ± 573 (116)
(mg Zn/kg d.w.)
3
Table S2b. Average zinc concentrations (± SD, n=2) measured in soil 2 (pHCaCl2 = 5.71) spiked with
30 nm ZnO, 200 nm ZnO and ZnCl2. Zinc concentrations in the soil are corrected for the zinc levels
measured in the controls. Recoveries (%) are presented in brackets.
Nominal conc.
30 nm ZnO
200 nm ZnO
ZnCl2
Control
5.1 ± 0.5
5.1 ± 0.5
5.1 ± 0.5
100
108 ± 2.9 (108)
106 ± 4.9 (106)
110 ± 9.9 (110)
200
286 ± 17.7 (143)
217 ± 4.0 (108)
247 ± 1.5 (123)
400
514 ± 44.8 (129)
511 ± 26.8 (128)
476 ± 1.0 (119)
800
825 ± 76.9 (103)
936 ± 97.7 (117)
891 ± 43.6 (111)
1600
1607 ± 9.7 (100)
1697 ± 186 (106)
1416 ± 86.2 (89)
3200
3960 ± 116 (124)
3610 ± 126 (113)
6400
7039 ± 375 (110)
7009 ± 382 (110)
(mg Zn/kg d.w.)
4
Table S2c. Average zinc concentrations (± SD, n=2) measured in soil 3 (pHCaCl2 = 6.39) spiked with
30 nm ZnO, 200 nm ZnO and ZnCl2. Zinc concentrations in the soil are corrected for the zinc levels
measured in the controls. Recoveries (%) are presented in brackets.
Nominal conc.
30 nm ZnO
200 nm ZnO
ZnCl2
Control
5.8 ± 1.4
5.8 ± 1.4
5.8 ± 1.4
100
110 ± 20.2 (110)
113 ± 10.9 (113)
120 ± 13.3 (120)
200
252 ± 23.5 (126)
279 ± 20.5 (139)
219 ± 11.5 (109)
400
534 ± 22.6 (133)
512 ± 8.7 (128)
567 ± 35.8 (142)
800
770 ± 18.0 (96)
819 ± 21.6 (102)
957 ± 165 (120)
1600
1755 ± 77.1 (110)
1785 ± 65.5 (112)
1702 ± 254 (106)
3200
3381 ± 567 (106)
2577 ± 63.6 (112)
6400
6855 ± 549 (106)
6598 ± 392 (103)
(mg Zn/kg d.w.)
5
Table S3. Calcium concentrations measured in the pore water (mg/L) of the three test soils spiked
with 30 nm ZnO, 200 nm ZnO and ZnCl2. Pore water was collected one week after saturation of the
soils with Milli-Q water.
Nominal conc.
30 nm ZnO
200 nm ZnO
ZnCl2
(mg Zn/kg)
soil 1
soil 2
soil 3
soil 1
soil 2
soil 3
soil 1
soil 2
soil 3
Control
15.3
21.4
61.7
100
16.4
20.3
48.1
11.9
19.8
50.6
48.9
51.7
33.8
200
16.3
20.2
47.5
12.0
19.7
50.1
67.6
80.5
60.5
400
16.2
20.0
46.3
12.2
19.6
49.2
105
138
114
800
15.9
19.7
44.0
12.5
19.3
47.4
180
253
221
1600
15.2
19.0
39.3
13.2
18.6
43.8
484
434
3200
13.9
17.5
29.8
14.7
17.3
36.6
6400
11.4
14.6
10.9
17.6
14.8
22.2
6
Table S4. TOC concentrations (mg/L) in the pore water from the test soils treated with 30 nm ZnO,
200 nm ZnO and ZnCl2.
30 nm ZnO
200 nm ZnO
ZnCl2
Nominal conc.
soil 1
soil 2
soil 3
soil 1
soil 2
soil 3
soil 1
soil 2
soil 3
Control
443
449
517
100
507
467
533
479
460
526
319
318
534
200
472
459
510
433
421
543
282
282
484
400
436
447
481
423
447
540
259
296
477
800
434
518
480
394
459
533
294
357
473
1600
409
501
541
416
461
542
336
487
3200
442
507
555
428
463
544
6400
467
493
444
444
460
504
Average*
452
485
506
431
453
533
318
491
(mg Zn/kg d.w.)
* without
control
7
288
Table S5. Zn2+ ion concentrations (M) in the pore water calculated with WHAM7 using calcium and
zinc levels (mg/L), soil pH and TOC level (mg/L) of the pore water.
30 nm ZnO
200 nm ZnO
ZnCl2
Nominal conc.
soil 1
soil 2
soil 3
soil 1
soil 2
soil 3
soil 1
soil 2
soil 3
Control
2.41E-06
3.82E-09
7.10E-09
100
1.45E-05
1.65E-07
1.38E-08
1.39E-05
1.33E-07
6.16E-08
4.83E-05
8.41E-06
4.04E-09
200
2.24E-05
3.41E-07
2.29E-08
2.76E-05
2.45E-07
8.19E-08
1.65E-04
5.12E-05
1.70E-07
400
4.03E-05
9.33E-07
8.80E-08
4.40E-05
3.69E-07
4.35E-07
6.55E-04
3.74E-04
4.40E-06
800
4.93E-05
1.17E-06
5.26E-07
1.38E-05
4.67E-07
1.71E-06
2.94E-03
8.03E-04
7.71E-05
1600
2.97E-05
6.16E-07
1.53E-06
1.46E-05
1.39E-06
5.99E-06
3.03E-03
1.24E-03
3200
1.80E-05
4.46E-06
1.84E-06
7.07E-06
3.96E-06
1.07E-05
6400
6.50E-06
1.41E-05
1.08E-06
1.34E-05
8.02E-06
1.19E-05
(mg Zn/kg d.w.)
8
500
250
30 nm ZnO
400
200
30 nm ZnO
200
300
150
200
100
100
50
30 nm ZnO
150
number of juveniles per test jar
100
50
0
0
0
0
2000
4000
6000
0
8000
500
2000
4000
6000
2000
4000
6000
8000
120
200
200 nm ZnO
200 nm ZnO
400
0
8000
200 nm ZnO
100
150
80
300
100
60
200
40
50
100
20
0
0
0
2000
600
4000
6000
0
0
8000
2000
4000
200
ZnCl 2
6000
8000
0
2000
200
ZnCl2
500
4000
6000
8000
1500
2000
ZnCl2
160
150
400
120
300
100
80
200
50
40
100
0
0
0
0
200
400
600
800
[Zn] soil (mg Zn/kg d.w.)
SOIL 1
1000
0
500
1000
1500
[Zn] soil (mg Zn/kg d.w.)
SOIL 2
0
500
1000
[Zn] soil (mg Zn/kg d.w.)
SOIL 3
Fig. S1. Effect of 30 nm ZnO (top), 200 nm ZnO (middle) and ZnCl2 (below) on the reproduction
(number of juveniles) of Folsomia candida after 28-d exposure in Dorset soil 1 (pHCaCl2 = 4.31), soil 2
(pHCaCl2 = 5.71) and soil 3 (pHCaCl2 = 6.39) based on measured concentrations of zinc in the soil (mg
Zn/kg d.w.). Line shows fit obtained with a logistic model.
9
500
250
30 nm ZnO
400
200
300
150
200
100
100
50
200
30 nm ZnO
30 nm ZnO
150
number of juveniles per test jar
100
0
50
0
0
10
500
20
30
0
0
10
200
200 nm ZnO
400
160
300
120
200
80
100
40
0
0
20
30
40
50
0
10
120
200 nm ZnO
20
30
40
30
40
200 nm ZnO
100
80
60
0
10
600
20
30
40
20
0
0
10
200
ZnCl 2
20
30
0
40
200
ZnCl 2
500
10
20
ZnCl 2
160
150
400
120
300
100
80
200
50
40
100
0
0
0
0
50
100
150
200
[Zn] pore water (mg Zn/l)
SOIL 1
250
0
50
100
150
200
[Zn] pore water (mg Zn/l)
SOIL 2
250
0
50
100
150
[Zn] pore water (mg Zn/l)
SOIL 3
Fig. S2. Effect of 30 nm ZnO (top), 200 nm ZnO (middle) and ZnCl2 (below) on the reproduction
(number of juveniles) of Folsomia candida after 28-d exposure in Dorset soil 1 (pHCaCl2 = 4.31), soil 2
(pHCaCl2 = 5.71) and soil 3 (pHCaCl2 = 6.39) based on soluble Zn concentrations in the pore water (mg
Zn/L). Line shows fit obtained with a logistic model.
10
30 nm ZnO
500
250
30 nm ZnO
400
200
300
150
200
100
100
50
200
30 nm ZnO
150
number of juveniles per test jar
100
1.E-06
1.E-05
1.E-04
200 nm ZnO
0
1.E-03
1.E-09
1.E-07
1.E-05
200 nm ZnO
500
0
1.E-03
50
1.E-09
1.E-07
1.E-05
200 nm ZnO
200
150
80
300
60
100
200
40
50
100
1.E-06
1.E-05
1.E-04
ZnCl 2
20
1.E-09
600
1.E-07
1.E-05
0
1.E-03
1.E-09
1.E-07
200
ZnCl 2
1.E-05
ZnCl2
500
100
80
200
50
40
100
1.E-04
1.E-02
free [Zn2+] (µM)
SOIL 1
200
120
300
1.E-06
0
1.E-03
160
150
400
0
1.E+00
120
100
400
0
1.E-03
0
1.E-03
1.E-09
1.E-07
1.E-05
1.E-03
0
1.E-01
1.E-09
free [Zn 2+] (µM)
SOIL 2
1.E-07
1.E-05
1.E-03
0
1.E-01
free [Zn2+] (µM)
SOIL 3
Fig. S3. Effect of 30 nm ZnO (top), 200 nm ZnO (middle) and ZnCl2 (below) on the reproduction
(number of juveniles) of Folsomia candida after 28-d exposure in Dorset soil 1 (pHCaCl2 = 4.31), soil 2
(pHCaCl2 = 5.71) and soil 3 (pHCaCl2 = 6.39) based on free Zn2+ concentrations in the pore water
calculated with WHAM7 (µM). Line shows fit obtained with a logistic model.
11