compaction on pesticide sequestering and leach-
alkalinity of the DCR-treated soils. The water sol-
ability. This compacted cylinder sample was
uble tests were identical to the TCLP tests except
shipped via Federal Express under chain of cus-
that water was used as the extraction fluid.
tody to the Environmental Lab. The same suite of
The CRREL greenhouse column experiments
analyses used for the raw untreated soil sample
were designed to assess the efficacy of the DCR
and loose (uncompacted) 64.7% DCR-treated
process to stabilize heavy metals against leaching
material was requested, with the proviso that the
losses and plant uptake. The clear acrylic col-
cylinder be crushed to the minimum extent nec-
umns were 60 cm in length and 5 cm in inside
essary to pass through the 9.5-mm sieve (speci-
diameter. These columns were split longitudinally
fied in the TCLP test) before leaching.
to facilitate root sampling at the conclusion of the
study. The tubes were placed in a dark box with
each tube inclined 15 from the vertical to facili-
Palmerton zinc smelter study
Palmerton is in Carbon County, Pennsylvania,
tate root growth observations. Each tube was di-
just north of the Lehigh Water Gap. Current vege-
vided into three sections. On the bottom was a 14-
tation on the Blue Mountain site is depauperate
cm sand zone; on top of this layer was a 20-cm
with many areas completely barren; common
experimental soil zone; and the surface 25-cm
species on these sites include Sassafras albidum,
zone consisted of a clean (i.e., uncontaminated)
Nyssa sylvatica, and Arenaria patula (Buchauer
soil.
1973). The soils on top of Blue Mountain are De-
The four experimental soils were 1) a Charlton
kalb very stony loams, formed on periglacially
silty sand (clean soil), 2) a Palmerton silt (contam-
worked, acid, gray sandstone (Fisher et al. 1962).
inated soil), 3) a DCR-treated Palmerton soil, and
The soil is classified as a loamy-skeletal, mixed,
4) a compacted DCR-treated Palmerton soil. The
mesic Typic Dystrochrept. These soils are strong-
compacted treatment was designed to assess
ly acidic, well drained, and contain many stones.
whether plant roots would grow around the
The contaminated soil was collected in plastic
DCR-treated soil if given an opportunity. The
bags at the Palmerton site about midslope on the
compacted samples were 4.0 cm in diameter and
north aspect of Blue Mountain and shipped in
20 cm in length and were prepared by dropping a
metal drums to CRREL. The "clean" soil was a
weight 10 times on the soil encased in a plastic
Charlton silty sand and was collected locally.
tube. The final density of these cores was 2.02
0.05 g cm3. The core was then placed in the cen-
These soil samples were air-dried on large tarps
ter of the column and clean soil was filled in
and sieved to pass a 2-mm screen.
around the core.
The air-dried and sieved soils were DCR-treat-
The two plant species were Pennfine perennial
ed at the SOUND/epic laboratory in Carlsbad,
ryegrass (Lolium perenne) and Pixie tall fescue
California, in August 1995. Contaminated soil
(Festuca arundinacea). These two grasses were
and CaO (10% w/w) were mixed in an Eirich
chosen because tall fescue shows promise for
mixer with sufficient water to assure proper hy-
heavy metal tolerance, while perennial ryegrass
dration (eq 1). The resultant product was a dry,
has little tolerance for heavy metals (Chaney
dusty, soil-like material.
1993). There were four replicates of each treat-
Total, TCLP extractable, and water soluble
ment for a total of 32 columns (4 soils 2 plant
heavy metals were measured by the Environmen-
species 4 replicates).
tal Lab. Total soil analyses for Ag, Be, Cd, Cr, Cu,
The experimental columns were prepared on 7
Ni, Sb, and Zn were done using EPA Methods
December 1995. Unfortunately the greenhouse
3051 (digestion) and 6010 (ICP); for As, Methods
3051 and 7060 (AA) were used; for Pb, Methods
which caused the columns to freeze. Problems
3051 and 7421 (AA) were used; for Se and Tl,
with the heating system and other factors de-
Methods 3051 and 7740 were used; and for Hg,
layed planting with tall fescue and perennial
Method 7471 (AA) was used (USEPA 1992). TCLP
ryegrass until 19 January 1996. Seeds were germi-
extractions and analyses for Ag, Be, Cd, Cr, Co,
nated on filter paper, planted 1.0 cm deep in the
Ni, Sb, Zn, As, Pb, and Se were done using EPA
tubes, and after emergence and early growth,
Methods 1311 (extraction) and 6010 (ICP); TCLP
thinned to four plants/tube. Plants were watered
extractions and analyses for Hg were done using
as needed with half-strength, pH-neutral Hoag-
EPA Methods 1311 and 7470 (AA) (USEPA 1992).
land's nutrient solution (minus Zn) (Johnson et
The TCLP tests used acetic acid extraction fluid
al. 1957). Every third watering was with distilled
no. 2 (USEPA 1992) for all samples because of the
7
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