SUPPLEMENTAL DATA
Manuscript title: Development of a duration-based water quality guideline for magnesium
pulses in a tropical freshwater creek
Authors: Alicia C Hogan, Melanie A Trenfield, Andrew J Harford and Rick A van Dam
Address: Environmental Research Institute of the Supervising Scientist, Supervising Scientist
Division, Australian Government Department of Sustainability, Environment, Water,
Population and Communities, Darwin Northern Territory, Australia.
No. figures: 4
No. tables: 3
No. pages: 9
1
4-h pulse
Percent growth rate (as % of control)
120
MgCl2
MgSO4
100
80
60
IC50 - 6500 mg L-1
40
20
0
0
2000
4000
6000
8000
10000
12000
14000
Magnesium (mg L-1)
Percent growth rate (as % of control)
8-h pulse
MgCl2
100
MgSO4
80
60
IC50 - 6530 mg L-1
40
20
0
0
2000
4000
6000
8000
10000
12000
14000
Magnesium (mg L-1)
Percent growth rate (as % of control)
24-h pulse
MgSO4
100
MgCl2
80
IC10 (as MgSO4) = 3940 mg L-1
60
IC10 (as MgCl2) = 3550 mg L-1
IC50 (as MgCl2) = 6750 mg L-1
40
20
0
0
2000
4000
6000
8000
10000
12000
14000
-1
Magnesium (mg L )
Figure S.1 Toxicity of magnesium chloride (MgCl2) to Chlorella sp. relative to the toxicity of magnesium
sulfate (MgSO4). Figures represent toxicity over 4-h (top), 8-h (middle) and 24-h (bottom) pulse
exposures. Mg IC10s/IC50s were based on 3 parameter sigmoidal models (4-h MgCl2, r2 = 0.99; 8-h
MgCl2, r2 = 0.99; 24-h MgCl2, r2 = 0.94; 24-h MgSO4, r2 = 0.67).
2
Percent growth rate (as % of control)
4h MgSO4
100
4h MgCl2
80
60
IC50 = 2180 mg L-1
40
20
0
0
2000
4000
6000
8000
10000
12000
14000
Magnesium (mg L-1)
Figure S.2 Toxicity of a 4-h pulse exposure of magnesium chloride (MgCl2) to Lemna aequinoctialis
relative to the toxicity of magnesium sulfate (MgSO4). The Mg IC50 based on the MgCl2 data was
calculated using a 3 parameter sigmoidal model (r2 = 0.99).
3
4-h pulse
MgSO4
100
MgCl2
Percent survival
80
60
IC50 - 5185 mg L-1
40
20
0
0
2000
4000
6000
8000
10000
12000
-1
Magnesium (mg L )
8-h pulse
MgSO4
100
MgCl2
Percent survival
80
60
IC50 - 5725 mg L-1
40
20
0
0
2000
4000
6000
8000
10000
12000
-1
Magnesium (mg L )
24-h pulse
MgSO4
100
MgCl2
Percent survival
80
60
IC50 - 3050 mg L-1
40
20
0
0
2000
4000
6000
8000
10000
12000
Magnesium (mg L-1)
Figure S.3 Toxicity of magnesium chloride (MgCl2) to Mogurnda mogurnda relative to the toxicity of
magnesium sulfate (MgSO4). Figures represent toxicity over 4-h (top), 8-h (middle) and 24-h (bottom)
pulse exposures. Mg IC50s based on the MgCl2 data were calculated using the following models: 4-h –
3 parameter sigmoidal model (r2 = 0.79); 8-h – linear interpolation (a model could not be fitted); and 24-h
– 3 parameter logistic model (r2 = 0.95).
4
Table S1 Algal growth in final 24 h of test
Test code
Pulse duration
Mg (mg L-1)
Mean growth rate
SEM
(doublings d-1)
1202G
1233G
1203G
1232G
1189G
1192G
1199G
1234G
4h
4h
8h
8h
24 h
24 h
24 h
24 h
0.8
1.03
0.04
3900
1.03
0.13
1.1
0.97
0.07
4100
1.06
0.05
6000
1.66
0.10
0.9
0.7
0.07
4100
0.67
0.04
1.1
0.56
0.09
4000
0.88
0.05
5900
1.27
0.04
0.9
1.09
0.10
930
1.31
0.13
1900
1.43
0.09
4300
1.69
0.09
0.9
0.79
0.10
940
1.23
0.11
1900
1.27
0.07
4200
1.52
0.14
0.9
0.6
0.03
1400
0.64
0.04
3200
0.95
0.20
4300
1.08
0.15
0.9
1.31
0.07
1900
1.24
0.12
3800
1.34
0.18
6700
1.17
0.11
5
Table S2 Lemna aequinoctialis growth for each 24 h period of the test based on plant number
Test code
Pulse
Mg (mg L-1)
0 – 24 h
24 – 48 h
48 – 72 h
72 – 96 h
0.8
0.60 (0.04)
0.49 (0.04)
0.29 (0.04)
0.64 (0.01)
199
0.65 (0.04)
0.45 (0.04)
0.17 (0.06)
0.62 (0.04)
413
0.65 (0.04)
0.48 (0.04)
0.15 (0.08)
0.61 (0.07)
814
0.44 (0.14)
0.66 (0.14)
0.17 (0.06)
0.58 (0.04)
1650
0.73 (0.43)
0.34 (0.41)
0.27 (0.07)
0.57 (0.08)
3280
0.80 (0.12)
0.04 (0.14)
0.17 (0.07)
0.25 (0.15)
4150
0.94 (0.08)
0.03 (0.08)
0.10 (0.06)
0.03 (0.03)
0.9
0.73 (0.04)
0.37 (0.04)
0.30 (0.08)
0.64 (0.10)
208
0.76 (0.11)
0.36 (0.09)
0.38 (0.04)
0.55 (0.02)
412
0.76 (0.11)
0.44 (0.10)
0.27 (0.07)
0.55 (0.01)
822
0.65 (0.04)
0.53 (0.06)
0.23 (0.08)
0.61 (0.03)
1670
0.49 (0.14)
0.52 (0.16)
0.26 (0.10)
0.50 (0.11)
3280
0.32 (0.17)
0.49 (0.10)
0.00 (0.06)
0.25 (0.07)
4140
0.85 (0.04)
0.16 (0.09)
0.00 (0.09)
0.22 (0.07)
0.8
0.28 (0.06)
0.72 (0.08)
0.24 (0.09)
0.58 (0.08)
120
0.63 (0.15)
0.35 (0.18)
0.34 (0.10)
0.35 (0.05)
233
0.54 (0.16)
0.53 (0.13)
0.03 (0.07)
0.64 (0.09)
482
0.51 (0.05)
0.44 (0.04)
0.09 (0.09)
0.51 (0.18)
992
0.38 (0.16)
0.40 (0.15)
0.34 (0.09)
0.40 (0.05)
2030
0.34 (0.11)
0.40 (0.14)
0.36 (0.06)
0.11 (0.05)
4060
0.14 (0.14)
0.84 (0.17)
0.03 (0.06)
0.11 (0.06)
0.9
0.07 (0.07)
0.57 (0.12)
0.48 (0.07)
0.41 (0.02)
99.9
0.14 (0.14)
0.50 (0.16)
0.49 (0.14)
0.32 (0.04)
188
0.34 (0.06)
0.43 (0.13)
0.37 (0.20)
0.39 (0.01)
373
0.37 (0.09)
0.46 (0.05)
0.50 (0.07)
0.15 (0.03)
773
0.32 (0.17)
0.39 (0.05)
0.36 (0.07)
0.31 (0.08)
1600
0.32 (0.17)
0.56 (0.13)
0.19 (0.06)
0.18 (0.05)
2920
0.44 (0.14)
0.29 (0.10)
0.14 (0.07)
0.06 (0.08)
4090
0.14 (0.14)
0.81 (0.12)
0.03 (0.03)
0.00 (0.06)
duration
1097L
1108L
1011L
1018L
8h
8h
24 h
24 h
Mean population growth rate (k), (SEM)
6
Table S3 Hydra viridissima growth for each 24 h period of the test
Test code
Pulse
0 – 24 h
24 – 48 h
48 – 72 h
72 – 96 h
0.4
0.36 (0.02)
0.39 (0.07)
0.47 (0.05)
0.46 (0.02)
651
0.26 (0.04)
0.45 (0.09)
0.36 (0.02)
0.53 (0.02)
821
0.42 (0.08)
0.29 (0.07)
0.45 (0.05)
0.54 (0.06)
1030
0.33 (0.07)
0.25 (0.11)
0.51 (0.04)
0.50 (0.03)
1300
0.00 (0.09)
0.36 (0.18)
0.36 (0.08)
0.49 (0.08)
0.3
0.06 (0.03)
0.60 (0.03)
0.38 (0.04)
0.13 (0.06)
212
0.10 (0.00)
0.51 (0.02)
0.39 (0.06)
0.24 (0.13)
422
0.06 (0.03)
0.56 (0.03)
0.29 (0.02)
0.21 (0.11)
842
0.24 (0.03)
0.37 (0.06)
0.31 (0.02)
0.23 (0.13)
0.8
0.25 (0.11)
0.45 (0.03)
0.37 (0.03)
0.43 (0.05)
247
0.26 (0.04)
0.53 (0.04)
0.38 (0.01)
0.42 (0.02)
496
0.30 (0.09)
0.42 (0.08)
0.34 (0.10)
0.43 (0.08)
773
0.24 (0.16)
0.47 (0.09)
0.37 (0.09)
0.33 (0.07)
1000
0.17 (0.09)
0.31 (0.08)
0.48 (0.05)
0.42 (0.04)
1300
0.00 (0.37)
0.56 (0.27)
0.14 (0.14)
0.33 (0.04)
0.8
0.17 (0.12)
0.49 (0.13)
0.32 (0.02)
0.30 (0.04)
230
0.22 (0.12)
0.42 (0.12)
0.31 (0.02)
0.38 (0.05)
473
0.15 (0.08)
0.53 (0.08)
0.33 (0.07)
0.41 (0.05)
710
0.06 (0.06)
0.63 (0.06)
0.33 (0.06)
0.38 (0.07)
906
0.00 (0.14)
0.48 (0.04)
0.25 (0.11)
0.49 (0.07)
0.8
0.06 (0.03)
0.61 (0.04)
0.30 (0.08)
0.32 (0.08)
190
0.00 (0.00)
0.69 (0.00)
0.31 (0.01)
0.22 (0.03)
293
0.00 (0.00)
0.64 (0.03)
0.28 (0.08)
0.18 (0.08)
444
0.03 (0.03)
0.67 (0.04)
0.05 (0.08)
0.25 (0.04)
655
0.00 (0.00)
0.66 (0.02)
0.17 (0.04)
0.24 (0.07)
965
0.00 (0.56)
0.21 (0.32)
0.06 (0.06)
0.21 (0.12)
0.9
0.23 (0.07)
0.49 (0.07)
0.19 (0.02)
0.35 (0.08)
261
0.03 (0.03)
0.69 (0.00)
0.24 (0.07)
0.34 (0.04)
401
0.03 (0.03)
0.64 (0.08)
0.18 (0.07)
0.29 (0.01)
duration
979B
972B
1100B
1114B
1014B
1017B
4h
4h
8h
8h
24 h
24 h
Mean population growth rate (k) ± SEM
Mg (mg L-1)
7
Table S3 (cont.)
Test code
Pulse
0 – 24 h
24 – 48 h
48 – 72 h
72 – 96 h
590
0.00 (0.00)
0.68 (0.02)
0.15 (0.10)
0.37 (0.05)
795
0.00 (0.00)
0.69 (0.05)
0.03 (0.14)
0.38 (0.05)
1010
0.00 (0.00)
0.64 (0.06)
0.00 (0.06)
0.43 (0.08)
0.8
0.29 (0.05)
0.39 (0.06)
0.25 (0.01)
0.35 (0.01)
216
0.00 (0.00)
0.71 (0.02)
0.18 (0.04)
0.34 (0.04)
441
0.06 (0.03)
0.68 (0.04)
0.20 (0.04)
0.33 (0.06)
654
0.00 (0.00)
0.68 (0.02)
0.07 (0.04)
0.43 (0.03)
792
0.03 (0.50)
0.61 (0.04)
0.07 (0.03)
0.37 (0.04)
duration
1095B
24 h
Mean population growth rate (k) ± SEM
Mg (mg L-1)
8
A. 4-h pulse
99
Cumulative percent
95
90
Loc
7.665
Scale
0.6803
N
5
AD
0.344
P-Value >0.250
80
70
60
50
40
30
20
10
5
1
10
100
1000
10000
100000
1000000
Magnesium toxicity (mg/L)
B. 8-h pulse
99
Cumulative percent
95
90
Loc
6.676
Scale
0.8779
N
5
AD
0.189
P-Value >0.250
80
70
60
50
40
30
20
10
5
1
0.1
1
10
100
1000
10000
100000
1000000
Magnesium toxicity (mg/L)
C. 24-h pulse
99
Cumulative percent
95
90
Loc
Scale
N
AD
P-Value
5.832
0.8148
5
0.225
>0.250
80
70
60
50
40
30
20
10
5
1
0.1
1
10
100
1000
10000
100000
1000000
Magnesium toxicity (mg/L)
Figure S4. Species sensitivity distributions (SSDs; 2-parameter log-logistic) for Mg based on (A) 4-h,
(B) 8-h and (C) 24-h pulse exposure durations.
9