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UQ Water Forum, August 18-19 2015
Sustainable Water Program @ the Global Change Institute
Monitoring Bioavailability of Metals and Metalloids in
River Water Receiving Mine Water Discharge
Dr Trang Huynh, SMI
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Research Question
Can the in-situ and time-integrated Diffusive Gradients in Thin Films technique (DGT) replace the series gab samples to determine metal and metalloid concentrations in water receiving mine water discharge?
Dif
fusi
ve
gel
R
e
s
i
n
g
e
l
g
C
waterM2+diffusion
1 2 mm
CSOL
filter Piston holder
ML
LM2+
M2+
M2+
M2+
M2+
M2+
M2+
M2+
M2+
M2+
4
What I found…
0
20
40
60
80
100
120
140
160
As
(µg/
L)
Grab samples 0.45um Labile DGT conc.Mean + SD Mean - SDMean of Grab samples
0
40
80
120
160
200
1 2 3 4 5 6 7 8 9 10 11 12
Cd
(u
g/L)
Sampling times (12hrs interval)
0
50
100
150
200
250
300
0
3
6
9
12
15
Al (
µg/
L) f
or
on
ly IR
HB
Al (
µg/
L)
LOR
0.0
0.5
1.0
1.5
2.0
2.5
3.0
Cu
(µ
g/L)
DGT CCB DGT-IRCC DGT-IRDS DGT-IRHB
Grab CCB Grab IRCC Grab IRDS Grab IRHB
Mean Grab CCB Mean Grab IRCC Mean Grab IRDS Mean-IRHB
LOR
ANZECC (TV 95%)
0
20
40
60
80
100
120
140
1 2 3 4 5 6 7 8 9 10 11 12
Cu
(u
g/L
)
Times (12hrs interval)
Grab sample0.45um
Mean grabsamples
Labile DGT conc.
Inorganic Cu
Mean InorganicCu
Cu2+
Mean Cu2+
What Next?
DGT measurement will replace 3 steps for assessing metal/loid toxicant in water in the ANZECC decision tree
Decision tree for metal speciation guideline (ANZECC, 2000)
0.0
1.0
2.0
3.0
4.0
5.0
CCB IRCC IRDS IRHB
Cu
(µ
g/L)
Grab-total Grab dissolved
DGT ANZECC (TV 95%)
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Contact details:
Dr. Trang Huynh
Dr. Sue Vink
References:
Reducing Analytical and Water Quality Monitoring Costs using Diffusive
Gradients in Thin Films (DGT) Technique (ACARP Project C23027)
