Waalewijn-Kool et al.
Supporting Information
Bioaccumulation and toxicity of silver nanoparticles and silver nitrate to
the soil arthropod Folsomia candida
Pauline L. Waalewijn-Koola, Kim Kleina, Rebeca Mallenco Forniésa and Cornelis A.M. van
Gestela
a
Department of Ecological Science, Faculty of Earth and Life Sciences, VU University,
De Boelelaan 1085, 1081 HV Amsterdam, The Netherlands
E-mail contact: kees.van.gestel@vu.nl
Ag-NP characterization
Dispersion/sonication
Silver nanoparticles (3-8 nm) were obtained in a stable water dispersion (1000 mg Ag/l) from
Amepox© (Łódź, Poland). Samples were sonicated for 30 seconds in a low power US bath.
Dynamic Light Scattering
Figure SI-1. Particle size distribution of Ag-NP measured by Dynamic Light Scattering
(DLS) after 10 minutes. The graph shows the result of three replicate analyses and indicates
that in aqueous suspensions some aggregation of the Ag-NP takes place; see also Figure SI-2.
Transmission Electron Microscopy
Figure SI-2. Transmission Electron Microscopy (TEM) of Ag-NP; primary particles are 3-8
nm in size, and occur frequently as separate particles but also in aggregates or clusters.
Figure SI-3. Ag concentrations in Folsomia candida after 28 days exposure in Lufa 2.2 soil
spiked with different concentrations of AgNO3 or Ag-NP at a measured concentration of 673
mg Ag/kg dry soil.
Table SI-1. Properties of the soils used for the toxicity tests on Ag-NP and AgNO3 with
Folsomia candida. Average silver concentrations (n=2, ± SD) measured in Lufa 2.2 soil
spiked with Ag-NP and AgNO3 are presented in the second column. Recoveries (%) are
given in between brackets. pHwater values (n=2) of Lufa 2.2 soil freshly spiked with Ag-NP
and AgNO3 are presented in the third column. The last column contains Ag concentrations
measured in the pore water (mg Ag/l) of the test soils (n=1). Pore water was collected 3 days
after saturation of the soils with Milli-Q water.
Sample
(nominal)
Control
measured [Ag]
pHwater
(mg Ag/kg d.w.)
porewater [Ag]
(mg Ag/l)
0.088 ± 0.010
5.98
0.00
673 ± 105 (79.2)
5.78
0.08
50 mg Ag/kg
50.3 ± 0.415 (101)
5.93
0.04
75 mg Ag/kg
75.6 ± 5.82 (101)
5.83
0.07
110 mg Ag/kg
106 ± 8.74 (96.0)
5.92
0.09
170 mg Ag/kg
153 ± 20.5 (89.8)
5.80
0.31
250 mg Ag/kg
260 ± 35.2 (104)
5.72
0.17
380 mg Ag/kg
431 ± 17.4 (113)
5.76
5.65
Ag-NP
850 mg Ag/kg
AgNO3
Table SI-2. Properties of the soils used for the Ag-NP and AgNO3 uptake and elimination
kinetics study with Folsomia candida. Average silver concentration (n=2, ± SD) measured in
Lufa 2.2 soil spiked with Ag-NP and AgNO3 are presented in the second column. Recoveries
(%) are presented in between brackets. pHCaCl2 values (n=2) of Lufa 2.2 soil freshly spiked
with Ag-NP and AgNO3 are presented in the third column. Ag concentrations measured in the
pore water (mg Ag/l) of the test soils are presented in the last column (n=2, ± SD). Pore water
was collected 3 days after saturation of the soils with Milli-Q water.
Sample
(nominal)
measured [Ag]
pHCaCl2
(mg Ag/kg d.w.)
porewater [Ag]
(mg Ag/l)
Control
0.00
5.23
0.00
Ag-NP*
168 ± 3.02
4.53
0.138
30 mg Ag/kg
29.2 ± 3.11 (97.3)
5.12
0.021 ± 0.002
60 mg Ag/kg
53.3 ± 1.47 (88.8)
5.06
0.048 ± 0.004
AgNO3
*
no nominal value available
Table SI-3. Ag concentrations (μg Ag/g d.w.) measured in Folsomia candida (n=10, ± SD) at
different time points during the uptake (14 days) and elimination phase (14 days) in Lufa 2.2
soils, spiked with AgNO3 at 30 and 60 mg Ag/kg d.w. and with Ag-NP at 168 mg Ag/kg d.w.
Time
AgNO3
AgNO3
Ag-NP
(days)
(30 mg Ag/kg)
(60 mg Ag/kg)
(168 mg Ag/kg)
1
6.69 ± 2.54
28.3 ± 7.96
23.9 ± 5.18
2
2.35 ± 0.38
9.06 ± 2.08
24.6 ± 3.20
4
17.5 ± 6.29
24.7 ± 5.53
47.0 ± 9.12
10
53.8 ± 11.5
60.5 ± 13.5
192 ± 27.8
14
74.9 ± 11.6
75.9 ± 11.0
121 ± 25.1
14.5
98.8 ± 11.9
102 ± 14.9
152 ± 26.0
15
28.9 ± 3.89
62.0 ± 11.8
95.0 ± 16.8
16
32.6 ± 6.77
35.4 ± 12.1
57.2 ± 9.21
18
25.8 ± 5.32
23.7 ± 3.97
51.0 ± 10.6
24
36.1 ± 4.81
98.1 ± 14.6
57.9 ± 14.2
28
55.0 ± 16.4
51.0 ± 15.9
123 ± 16.0