Table 10. A summary of the soil analyses for the Palmerton zinc smelter study (mean 1 SD; n = 4).
Total metals (g/g)
TCLP extracts (g/mL)
Water extracts (g/mL)
Element
Clean*
Contam.
DCR
Clean
Contam.
DCR
Clean
Contam.
DCR
31 1
29000 816
29500 577
0.21 0.11
588 29
1.9 0.8
0.066 0.014
16 2
1.2 0.8
Zinc
5.6 0.1
1850 58
1900 82
8.0 0.6
2.2 0.3
2.4 0.7
Lead
<0.31
<0.30
<0.30
16 1
248 10
252 10
0.72 0.04
0.26 0.07
0.014 0.017
0.54 0.08
Copper
<0.012
<0.012
155 6
160 0
4.0 0.2
0.29 0.03
Cadmium
<0.51
<0.0042
<0.0041
<0.0041
<0.0041
7.0 1.5
6.4 0.1
Silver
<1.7
<0.014
<0.014
<0.014
<0.014
<0.014
<0.014
5.2 0.4
78 5
85 4
<0.45
<0.45
<0.45
<0.45
<0.45
<0.45
0.22 0.01
1.01 0.06
0.94 0.03
0.00053 0.00005
0.00098 0.00015
Beryllium
<0.00045
<0.00045
<0.00045
<0.00045
13 1
24 3
21 2
<0.015
<0.015
<0.015
<0.015
<0.015
<0.015
0.015 0.006
1.5 0.1
1.5 0.1
Mercury
<0.0002
<0.0002
<0.0002
<0.0002
<0.0002
<0.0002
14 0
29 1
26 1
0.12 0.01
Nickel
<0.017
<0.017
<0.017
<0.017
<0.017
Antimony
<34
<36
<37
<0.30
<0.30
<0.30
<0.30
<0.30
<0.30
8.6 0.4
9.2 0.4
7.0 0.4
Selenium
<0.95
<0.90
<0.90
<0.90
<0.90
<0.90
0.42 0.06
0.52 0.06
n.a.†
Thallium
<0.38
n.a.
n.a.
n.a.
n.a.
n.a.
* The soils analyzed were a Charlton silty sand (the clean soil), the Palmerton site soil (contaminated), and the DCR-treated Palmerton site soil.
† Not analyzed.
water extractions for the DCR-treated soil is prob-
ment immobilizes heavy metals but does not phys-
ably between a calcium acetate extraction and a
ically remove them from the soil. The average total
water extraction, which apparently extract similar
Zn, Pb, and Cd concentrations in the Palmerton
soil of 29,000 1900, and 160 g g1 are somewhat
quantities of heavy metals.
Because Zn is the dominant heavy metal in
lower than those cited by Sopper (1989) of 31,000,
5200, and 1250 g g1, respectively. Distance from
these soils (Table 10), the following discussion will
focus on Zn chemistry. In another report, we also
the smelter and specific location on Blue Mountain
discuss Cu, Pb, and Cd chemistry in leachates and
are both critical factors with respect to soil contam-
plants (Marion et al., in prep.).
ination at Palmerton (Buchauer 1973, Sopper
The DCR-treatment leachates were alkaline
1989).
from the beginning of the experiments, and be-
For the TCLP extracts, the Palmerton soil had
came progressively more alkaline with time,
higher concentrations of Zn, Pb, Cu, Cd, Ni, and Se
reaching pHs in the 1112 range by the conclusion
than either the clean soil or the DCR-treated
of the experiments (Fig. 4). The compacted core
Palmerton soil. The Palmerton soil exceeded TCLP
regulatory limits for Pb (5.0 g mL1), Cd (1.0 g
was slower in reaching high pH, indicating some
mL1), and Se (5.0 g mL1); this soil passed regu-
vertical movement of water around the core. The
latory limits for Ag (5.0 g mL1), As (5.0 g mL1),
clean soil and the Palmerton soil had similar pHs,
Cr (5.0 g mL1), and Hg (0.2 g mL1); regulatory
in the range 6.27.4, until day 61 when the Palmer-
ton soil became more acidic (pH < 6.0).
levels have not been established for Zn, Cu, Be, Ni,
Zinc concentrations also showed a sharp in-
Sb, and Tl (Federal Register, 29 March 1990). The
crease for all treatments on day 61 (Fig. 5). This
DCR treatment lowered TCLP concentrations of
was most striking for the Palmerton soil, which
Zn, Pb, Cu, Cd, and Se; in all cases, the DCR-treat-
reached 200 mg L1. In contrast, the levels in the
ed soil passed TCLP standard for regulated heavy
other treatments were always less than 1 mg L1.
metals (Pb, Cd, Ag, As, Cr, Hg, and Se).
The Palmerton soil had higher levels of water
The DCR treatments were effective in immobiliz-
soluble Zn and Cd than the DCR-treated Palmer-
ing Zn in the Palmerton soil.
ton soil (Table 10). On the other hand, water-solu-
There were no apparent differences between
ble Pb and Cu concentrations were higher in the
plant species with respect to pH (Fig. 4) or Zn (Fig.
DCR-treated Palmerton soil than in the contami-
5). The responses of perennial ryegrass and tall
nated Palmerton soil. The DCR extracts had com-
fescue were quite similar. Plant roots reached the
parable levels of heavy metals in the TCLP and
experimental soil level by day 50 in all treatments,
water extracts (Table 10). This suggests that the al-
approximately 30 days after planting. Shortly
kalinity of the DCR treatment neutralized the ace-
thereafter, there was a sharp drop in pH in the
tic acid used in the TCLP test. During laboratory
Palmerton soil (Fig. 4) and a sharp increase in Zn
TCLP tests, it was clear that the aromatic bite of
leaching in all the treatments (Fig. 5). The plant
acetic acid was missing from the DCR-treatments.
roots probably acidified the soil increasing the mo-
The real comparison between the TCLP and the
bility of Zn, especially in the contaminated
14
Previous Page
