Dissolved trace metal speciation in estuarine and coastal waters: comparison of
WHAM/Model VII predictions with analytical results
Anthony Stockdale*†‡, Edward Tipping† and Stephen Lofts†
†Centre for Ecology and Hydrology, Lancaster Environment Centre, Bailrigg, Lancaster LA1
4AP, UK
‡School of Earth and Environment, University of Leeds, Leeds, LS2 9JT, UK
*Corresponding author. E-mail address: tony@biogeochemistry.org.uk
Supplementary data
Figures S1 to S4. Comparisons of measured and modelled metal free ion concentrations
where EDTA is included in the model predictions.
Martino et al, 2004
Slaveykova et al, 2009
Turner et al, 1998
-17
-18
-19
-20
-7
1
Gledhill et al, 1998
-16
WHAM calculated free ion (log mol L )
Fe
1
WHAM calculated free ion (log mol L )
-15
-8
-9
-10
-11
Ni
-21
-11
-10
-9
-8
-7
Free ion derived from measurements (log mol L 1)
-21
-20
-19
-18
-17
-16
-15
Free ion derived from measurements (log mol L 1)
-7
-8
-9
-10
Muller et al, 2001
Kozelka and Bruland, 1998
Skrabal et al, 2006
WHAM calculated free ion (log mol L 1)
1
WHAM calculated free ion (log mol L )
-10
Zn
-11
Cd
-11
Kozelka and Bruland, 1998
Slaveykova et al, 2009
Muller, 1999
-12
-11
-10
-9
-8
-7
Free ion derived from measurements (log mol L 1)
-12
-11
-10
Free ion derived from measurements (log mol L 1)
1
WHAM calculated free ion (log mol L )
Hg
1
WHAM calculated free ion (log mol L )
-27
-28
-11
-29
-30
Slaveykova et al, 2009
Muller, 1999
Kozelka and Bruland, 1998
-12
-31
-32
Han et al, 2006
Pb
-13
-32
-31
-30
-29
-28
-27
Free ion derived from measurements (log mol L 1)
-13
-12
-11
Free ion derived from measurements (log mol L 1)
Figure S1. Comparison of WHAM/Model VII calculated free ion concentrations and free ion
concentrations determined experimentally. EDTA is included in the modelling at a concentration of 5 ×
108 mol L1. Note the different scales for each metal. Data from separate studies are shown as
different symbols. See Table 1 in the main manuscript for the analytical methods used. The solid line
represents the 1:1 line and the shaded area represents one order of magnitude either side of the 1:1
line. Where data include error bars these represent points where DOM concentrations have been
estimated. The ranges represent the free ion concentrations calculated from scenarios where DOM
concentrations are at the upper and lower estimates (where variations are small, the bars appear as a
solid line behind the data symbol).
WHAM calculated free ion (log mol L )
1
1
WHAM calculated free ion (log mol L )
-8
-10
-12
-14
All analysis methods
-16
-10
-12
-14
Slaveykova et al, 2009
Standard addition
voltammetry
1
-8
-10
-12
Jones and Bolan, 2007
Kozelka and Bruland, 1998
Louis et al, 2009
-14
-16
-14
-12
-10
-8
Free ion derived from measurements (log mol L 1)
WHAM calculated free ion (log mol L )
1
Hollow fibre - permeation
liquid membrane
-16
-16
-14
-12
-10
-8
Free ion derived from measurements (log mol L 1)
WHAM calculated free ion (log mol L )
-8
-16
Ion selective
electrode
-8
-10
-12
Eriksen et al, 2001
Delgadillo-Hinojosa et al, 2008
Boyd et al, 2005
-14
-16
-16
-14
-12
-10
-8
-16
Free ion derived from measurements (log mol L )
1
WHAM calculated free ion (log mol L )
-14
-12
-10
-8
Free ion derived from measurements (log mol L 1)
1
Competitive ligand methods
-8
-10
-12
Tang et al, 2001
Buck and Bruland, 2005
Shank et al, 2004
Muller, 1999
Muller et al, 2001
-14
-16
-16
-14
-12
-10
-8
-6
-4
Free ion derived from measurements (log mol L 1)
Figure S2. Comparison of WHAM/Model VII calculated Cu free ion concentrations and free ion
concentrations determined experimentally. EDTA is included in the modelling at a concentration of 5 ×
108 mol L1. Measurements from studies using the same technique are grouped together. The solid
line represents the 1:1 line and the shaded area represents one order of magnitude either side of the
1:1 line. Where data include error bars these represent points where DOM concentrations have been
estimated. The ranges represent the free ion concentrations calculated from scenarios where DOM
concentrations are at the upper and lower estimates.
Martino et al, 2004
Slaveykova et al, 2009
Turner et al, 1998
-16
-17
-18
-19
-20
-7
1
Gledhill et al, 1998
WHAM calculated free ion (log mol L )
Fe
1
WHAM calculated free ion (log mol L )
-15
-8
-9
-10
-11
-12
-13
Ni
-21
-10
-9
-8
-7
Free ion derived from measurements (log mol L 1)
-21
-20
-19
-18
-17
-16
-15
Free ion derived from measurements (log mol L 1)
-7
Muller et al, 2001
Kozelka and Bruland, 1998
Skrabal et al, 2006
-8
-9
-10
Zn
WHAM calculated free ion (log mol L 1)
1
WHAM calculated free ion (log mol L )
-10
-11
Cd
-11
Kozelka and Bruland, 1998
Slaveykova et al, 2009
Muller, 1999
-12
-11
-10
-9
-8
-7
Free ion derived from measurements (log mol L 1)
-12
-11
-10
Free ion derived from measurements (log mol L 1)
1
WHAM calculated free ion (log mol L )
Hg
1
WHAM calculated free ion (log mol L )
-27
-28
-29
-11
Slaveykova et al, 2009
Muller, 1999
Kozelka and Bruland, 1998
-12
-30
-31
-13
-32
-33
Han et al, 2006
-32
-31
-30
-29
-28
-27
Free ion derived from measurements (log mol L 1)
-14
Pb
-13
-12
-11
Free ion derived from measurements (log mol L 1)
Figure S3. Comparison of WHAM/Model VII calculated free ion concentrations and free ion
concentrations determined experimentally. EDTA is included in the modelling at a concentration of 1 ×
106 mol L1. Note the different scales for each metal. Data from separate studies are shown as
different symbols. See Table 1 in the main manuscript for the analytical methods used. The solid line
represents the 1:1 line and the shaded area represents one order of magnitude either side of the 1:1
line. Where data include error bars these represent points where DOM concentrations have been
estimated. The ranges represent the free ion concentrations calculated from scenarios where DOM
concentrations are at the upper and lower estimates (where variations are small, the bars appear as a
solid line behind the data symbol). Note different y-axis for Ni, Hg and Pb.
WHAM calculated free ion (log mol L )
1
1
WHAM calculated free ion (log mol L )
-8
-10
-12
-14
All analysis methods
-16
-10
-12
-14
Slaveykova et al, 2009
Standard addition
voltammetry
1
-8
-10
-12
-14
-16
-14
-12
-10
-8
Free ion derived from measurements (log mol L 1)
WHAM calculated free ion (log mol L )
1
Hollow fibre - permeation
liquid membrane
-16
-16
-14
-12
-10
-8
Free ion derived from measurements (log mol L 1)
WHAM calculated free ion (log mol L )
-8
Jones and Bolan, 2007
Kozelka and Bruland, 1998
Louis et al, 2009
-16
Ion selective
electrode
-8
-10
-12
-14
Eriksen et al, 2001
Delgadillo-Hinojosa et al, 2008
Boyd et al, 2005
-16
-16
-14
-12
-10
-8
-16
1
WHAM calculated free ion (log mol L )
-14
-12
-10
-8
Free ion derived from measurements (log mol L 1)
Free ion derived from measurements (log mol L 1)
Tang et al, 2001
Buck and Bruland, 2005
Shank et al, 2004
Muller, 1999
Muller et al, 2001
-8
-10
-12
-14
Competitive ligand methods
-16
-16
-14
-12
-10
-8
-6
-4
1
Free ion derived from measurements (log mol L )
Figure S4. Comparison of WHAM/Model VII calculated Cu free ion concentrations and free ion
concentrations determined experimentally. EDTA is included in the modelling at a concentration of 1 ×
106 mol L1. Measurements from studies using the same technique are grouped together. The solid
line represents the 1:1 line and the shaded area represents one order of magnitude either side of the
1:1 line. Where data include error bars these represent points where DOM concentrations have been
estimated. The ranges represent the free ion concentrations calculated from scenarios where DOM
concentrations are at the upper and lower estimates.