C - Lublin

Soil Solution. Soil solution was approximated by 0,002 M CaCl 2 extraction
(CaCl 2 ) (soil: solution ratio was 1:2 for B horizon and 1:4 for O horizon), and soil
saturation extracts (BSE, at moisture content equal to 100% of water holding
capacity). For organic horizon (O) soil solution approximated with CaCl 2 had
lower pH and higher values of dissolved organic carbon DOC in contaminated
soils, which resulted in higher Pb and Cd concentrations. For B horizon values of
pH and Pb concentrations were similar for both methods, whereas DOC and Cd
concentrations were higher in the case of CaCl 2 extraction.
Results demonstrated that terms “reactive pool” and “soil solution” are
operationally defined and values of metal concentrations depend on extraction
method used. It means that for “soil solution” concentration prediction metal
concentration in test soil should be determined using the same type of extract as for
TF database.
C Pb in BSE (KOLA
mmol/l
-3
-4
-5
-6
a
1:5
5:1
-6 -5 -4 -3
C Pb calculated
log C =-0,456+0,67*log Q
mmol/l
C Cd in BSE (KOLA
mmol/l
-2
-3
-4
-5
b
1:5
5:1
-6
-6 -5 -4 -3 -2
C Cd calculated
log C =-3,59+0,19*log Q,
mmol/l
Fig. 2. Agreement between metal concentration measured in BSE (Kola field data)
and those predicted with TF. TF based on field partitioning data for German soils,
a – Pb, b- Cd (Pampura et al., 2002).
Transfer functions validation. Applicability of TF linking concentration in BSE
and reactive metal pool in soil (extracted with 1M NH 4 NO 3 ) was checked by
comparison of Kola field data (metal concentration in BSE) with values predicted
with TF (Fig. 2). Transfer functions are based on metal field partitioning data
(German soils, Pampura et al., 2002). In this case the simplest form of TF function
was used without considering any soil characteristics (Fig. 2). Lines designated as
1:5 correspond to the ratio 1:5 between observed and calculated values of metal
concentrations in soil solution.
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