United States
Environmental Protection
Agency
Robert S. Kerr Environmental
Research Laboratory
Ada OK 74820
Research and Development
EPA-600/S2-84-162 Dec. 1984
&EPA Project Summary
Closure Evaluation for
Petroleum Residue Land
Treatment
Leale E. Streebin, James M. Robertson, Alistair B. Callender, Lynne Doty, and
K. Bagawandoss
Three oily residue land treatment
sites to which no waste applications
had been made for six months, nine
months, and six years, respectively,
were sampled to define existing condi-
tions. Runoff, zone of incorporation (0-
25 cm), and unsaturated zone (26-152
cm) samples were collected at each site
during the 15-month study period.
A considerable variation in residual oil
content existed at the three sites. Site
2, a well-managed operating site which
had received no waste for six years, had
a residual oil concentration of 2-3 wt.%
in the zone of incorporation. Sites 1 and
3, which had received waste applica-
tions within the 12 months previous to
this study, contained 5-6 and 8-9 wt.%
residual oil, respectively-, Oil concentra-
tions greater than background were
detected as deep as 45-50 cm at all
sites with the highest concentrations
being found at site 3. Average concen-
trations of oil in soil remained relatively
constant at each site during the study
period; however, large variations in oil
content of individual core samples were
found within each site. Possible con-
tributing factors to this apparent lack of
degradation were extended periods of
extremely wet or dry soil, low available
soil nitrogen levels giving extremely
high carbon-to-nitrogen ratios, and the
presence of persistent hydrocarbons.
Thirteen or more organic priority pollut-
ants were identified in samples collected
at each site; however, only trace quan-
tities were found below the zone of
incorporation. Several of these priority
pollutants also were identified in ad-
jacent soil backqround samples.
Metals were immobilized in the top
25 cm of soil at all sites. Soil and soil
pore water at each site contained high
chloride levels.
Site 2 supported a lush growth of
vegetation while sites 1 and 3 supported
little or no vegetative growth.
Vegetation studies revealed that grass-
es were more tolerant than tree seed-
lings when planted in areas having an oil
content of 5-6 wt.%. Root development
was inhibited at levels of 4-5 wt.%. In
areas having an oil content of 9-13
wt.%, survival rates for both were very
low.
This Project Summary was developed
by EPA's Robert S. Kerr Environmental
Research Laboratory, Ada, OK, to an-
nounce key findings of the research
project that is fully documented in a
separate report of the same title (see
Project Report ordering information at
back).
Introduction
Land treatment as a disposal method
for petroleum residues from oil refinery
operations has become popular in recent
years, although the technique has been
in use for 15 to 20 years. Several studies
have been performed to determine the
fate of the oil and metals at active land
treatment sites. However, few studies
have been carried out at closed sites to
see if a long-term threat to ground water
exists. The purpose of this study was to
identify the potential long-term environ-
mental impacts of immobilized metals
and persistent organics at closed land
treatment sites to which previous appli-
-------
cations of petroleum residues had been
made.
Both the zone of incorporation (0-25
cm) and the unsaturated zone (to a depth
of 152 centimeters) were monitored for
contaminants at each site selected for
study. Soil and runoff samples from each
site were analyzed for oil content, metals,
and selected organic pollutants. Other
parameters monitored included: pH, cat-
ion exchange capacity, soil texture, soil
permeability, soil structure, nitrate and
phosphate levels, and chloride ion con-
centrations.
A revegetation study was carried out at
one of the sites to identify grasses or trees
which would grow at land treatment sites
and possibly aid in site recovery.
Experimental Procedures
Approach
Three oil refinery land treatment sites
in Oklahoma were selected for this study.
Inactive land treatment areas to which no
waste had been applied for six months
(site 3), nine months (site 1), and sixyears
(site 2) were studied. Soil samples from
depths from 0-25 cm and 25-51 cm were
analyzed for oil content, metals, TOC,
COD, pH, nutrients, chlorides, cation
exchange capacity, and selected organic
compounds. Soil core samples from the
unsaturated zone at depths from 51 -152
cm were analyzed for oil content, metals,
and selected organic compounds. Soil
pore water samples from a depth of 1.2 m
were analyzed for oil content, metals,
TOC, COD, and selected organics.
The 0-25 cm depths were sampled
because the till zone usually extends to a
depth of about 25 cm at most operating
land treatment facilities. The 25-51 cm
depth was sampled because analyses of
preliminary samples at these sites showed
the presence of oil in some areas.
Soil samples from the deeper unsatu-
rated zone were analyzed to determine if
any migration of pollutants had occurred.
Samples of soil pore water were analyzed
as a part of the unsaturated zone monitor-
ing program to identify any pollutants
which might pass through the unsaturat-
ed zone.
Oil content of the 0-25 cm and 25-51
cm zone samples was determined at
selected intervals during the 15-month
sampling period in an attempt to deter-
mine rates of degradation of residual oil
following site closure. In addition, a part
of each site was tilled to see if tilling
Table 1. Organic Compounds Identified in Soil at Land Treatment Sites
Site 1
Site 2
Site 3
Anthracene
Phenanthrene
Fluoranthene
Pyrene
Naphthalene
Chrysene
Benzo(b)fluoranltiene
Benzo(a)anthracene
Benzo(a)pyrene
Dibenzofa. hjanthracene
Benzofg, h, ilperylene
Isophorone
Bis(2 -ethylhexyl)phthalate
Butylbenzylphthalate
1,2- diphen ylhydrazine
Phenol
Pentachlorophenol
4-Nitrophenol
2-Nitrophenol
2. 6-dinitrotoluene
Benzene
Toluene
Ethylbenzene
Bromoform
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
"x" denotes compound which was present.
enhanced the rate of degradation. No
nutrients were added to the site soils
during the study, except in those areas
used for the revegetation study.
The revegetation study was conducted
to identify trees or grasses that would
grow in oily soil to aid in the recovery of
land treatment sites. The revegetation
study was conducted only at research site
3. The growth characteristics of five tree
species and four grass species were
observed for one growth season.
Site Characteristics
The site soils were tested for selected
priority pollutants. The compounds ident-
ified at each site are listed in Table 1. The
priority pollutants present were primarily
polynuclear aromatics and phenolics.
The soil at each site was sampled
periodically over a 15-month period. A
subarea at each site was tilled so that the
rate of residual oil degradation in the
tilled and the unfilled sections could be
compared and evaluated. Oil concentra-
tions present in different core samples at
each site indicated that a considerable
variation in the oil content occurred
across the site. The mean oil content
concentration in the top (0-25 cm) and
bottom (25-51 cm) layers of soil at the
three sites is shown in Table 2.
The residual oil content at site 2 (2-3
wt.%) was significantly less than that at
site 1 (5-6 wt.%) which was significantly
less than site 3 (8-9 wt.%). Waste had not
been applied at site 2 for approximately
six years while sites 1 and 3 had received
waste applications within the previous 12
months. No apparent degradation of
residual oil occurred at any of the sites
during the 15-month study period, which
might be attributable to several noticeable
factors: (1) the large variation in oil
content for sajnples collected within any
one site indicate poor application, mixing
and/or sampling techniques; (2) during
the project period, no nitrogen fertilizer
was added to produce a carbon-to-nitro-
gen ratio more favorable for sustained
microbial activity; (3) adverse weather
during the project produced long periods
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Table 2. Oil Content Data— Means
Site 1
Date
*Background Top
* Background Bottom
4/8/82
Top
Bottom
12/1/82
Top
Bottom
Site 2
'Background Top
'Background Bottom
4/6/82
Top, tilled
Bottom, tilled
Top, unfilled
Bottom, unfilled
7/8/82
Top, tilled
Bottom, tilled
Top. unfilled
Bottom, unfilled
11/19/82
Top, tilled
Bottom, tilled
Top, unfilled
Bottom, unfilled
2/16/83
Top, tilled
Site 3
"Background Top
"Background Bottom
3/26/82
Top
Bottom
6/7/83
Top
Bottom
"Mean of all background concentrations.
of saturated or dry soil conditions either
of which might have inhibited microbial
activity; and (4) the residual oil at each
site contained a relatively high content of
high-molecular-weight organic corn-
Mean Std Dev.
%
0.56
0.13
4.90
0.64
5.62
1.85
0.43
0.40
2.63
0.78
2.95
"
2.58
1.08
2-60
1.17
2.93
1.46
2.65
1.08
2.97
0.57
0.10
8.7
2.7
9.03
5.1?
0.30
0.06
1.52
0.35
2.33
1.40
.152
0.10
0.96
0.37
0.52
"
0.95
.33
1.72
0.58
1.46
1.31
1.67
1.14
1.70
0.50
0.0
2.90
4.57
4.85
4.62
pounds which are more
Variance
0.090
0.003
2.30
0.12
5.45
1.96
.023
0.01
0.92
.14
0.28
"
0.902
0.11
2.97
0.34
2.14
1.72
2.79
1.29
2.89
0.25
0.00
8.42
20.85
23.56
21.42
resistant to
biotransformation.
The effect of
degradation was
tilling on
evaluated
the rate of
at site 2. A
statistically significant change in the oil
content of the tilled vs. unfilled sections
could not be detected over a 14-month
period. Potential degradation might have
been inhibited by low nitrogen levels.
Waste had not been applied to this site for
over six years. Oil was still present in
some locations at concentrations above
background; however, the site soil sup-
ported a dense growth of lush vegetation.
The concentration of selected heavy
metals in the soil at the sites was
compared to background concentrations.
At all sites, metals were present at levels
above background. There was consider-
able variability in the metal concentration
across the sites, as with the oil content
concentrations. The actual concentra-
tions of metals were low. The metals
were concentrated in the top 25 cm of
soil, with little or no vertical migration.
Soil acidity at the top (0-25 cm) and the
bottom (25-51 cm) of site soil was deter-
mined to indicate the potential for solubil-
ization of metals. The range of pH was
from 7.1 to 7.5 at all sites.
The chloride ion concentrations of the
site soils were higher than background at
all three sites (Table 3). Only one set of
determinations were made, so variation
over time could not be observed. However,
since the chloride ion concentration of
the soil pore water decreased with time.
the same trend could be expected for soil
chloride ion concentration.
Total Organic Carbon (TOC) values for
the sites are given in Table 4. The TOC
values in the top (0-25 cm) of soil at all the
sites were greater than background. The
bottom (25-51 cm) sample at site 3 had
greater TOC values than background. At
site 2 the top sample had a higher TOC
than background. Sites with the higher oil
contents had correspondingly higher TOC
values. The oil at site 3 extended well
below the zone of incorporation. This
correlated with the high TOC values of
the bottom sample at site 3.
The unsaturated zone at each of the
three sites was monitored for pollutants
by core sampling below the zone of
incorporation at depths between 51 cm
and 1 52 cm, and by collecting pore water
passing through the unsaturated zone.
Water passing through the unsaturated
zone contained amounts of chloride (from
1 2 mg/l to 5,000 mg/l), and extractable
oil and grease. Some metals appeared to
be solubilized under the existing condi-
tions at these sites. Even though the pH of
the soil pore water and the soil in the top
51 cm was usually above 7.0, barium.
zinc, iron, and manganese were all at
fairly high concentrations in the soil pore
water.
3
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Table 3. Soil Chloride Concentration
Date Top
Mean CT Concentration (mg/kg)
Bottom Bkg T Bkg B
Site 1
6/30/82
Site 2
7/8/82
Site 3
11/4/82
119.6
28.0
72.6
103.3
33.1
101.5*
17.6
137
19.8
*Mean of 2 determinations
Table 4. Soil TOC
Date
Top
Mean TOC %
Bottom Bkg T
Site 1
11/10/81
Site 2
7/21/81
11/12/81
Site 3
11/17/81
10.4
3.6
5.2
11.2
1.5'
2.6
0.9
6.7
2.0
1 1
0.8
1.4
*Mean of 2 values.
Table 5. Organics Present in Unsaturated Zone Cores
Compound
Site 1
Site 2
Acenaphthene
1,2-Diphenylhydrazine
2,4 Dinitrotoluene
Anthracene
Bis(2-ethylhexyl)phthalate
Isophorone
A cenaphthylene
Fluorene
Diethylphthalate
Butylbenzylphthalate
2-Nitrophenol
4-Nitrophenol
2.4-Dichlorophenol
Phenol
Phenanthrene
Pyrene
Chrysene
Benzo(a)anthracene
Benzo(b)fluoranthene
Benzo(k)fluoranthene
Benzofa)pyrene
2.6-Dinitrotoluene
Di-n-butylphthalate
15.4
2.9
7.3
BkgB
1.3
0.5
0.3
0.3
Site 3
x
x
x
x
x
x
x
x
x
The soil pore water also contained high
levels of TOC and COD. The average
COD/TOC ratio ranged from 3.2 to 3.5. At
site 1 the COD values ranged from 400 to
2420 mg/l initially, then decreased with
time. The COD at site 2 ranged from 335
to 990 mg/l initially and also decreased
with time. An exception which did not
follow the typical trend occurred at site 3,
where the COD values first decreased
and increased again toward the end of the
research period.
Evidence for significant migration of oil
or metals into the soil of the unsaturated
zone (below 50 cm) was not found.
Indications are that there was movement
of trace quantities of organic priority
pollutants into the unsaturated zone. The
soil cores samples from the unsaturated
zone contained some priority pollutants
at concentrations in the low ppb range.
More priority pollutants were present in
the soil cores than in the soil pore water
at sites 2 and 3, but not at site 1. The
compounds identified in deeper soil cores
and the soil pore water were generally
different compounds and are listed in
Tables 5 and 6. Several of these same
compounds also were identified in back-
ground samples.
The site soils were characterized for
texture, permeability, X-ray diffraction,
and cation exchange capacity. Composite
samples from each site and from areas
adjacent to the sites were analyzed.
Grain size distribution for the soils
were determined in accordance with
ASTM designation 0422-63(72) or
AASHTO designationT-88-78. Site 1 was
a silty loam, site 2 a sandy loam, and site 3
a clay. Standard laboratory permeability
tests were performed on samples of the
top 25 cm of soil. No significant difference
between the permeability of the back-
ground soil and site soil was observed at
any of the sites.
The X-ray diffraction analysis showed
some changes in the soil structure. There
was a masking of the montmorillonite
and chlorite peaks. One explanation is
that the oily residues penetrated the
interplanar structures of the clays. There
were changes in the intensities of the
calcite, feldspar, dolomite, and quartz
peaks. Generally, the major peaks either
remained the same or diminished in
intensity with increasing oil content. The
exception to this trend was the calcite
peaks which generally increased in in-
tensity with increasing oil content.
The cation exchange capacity of both
site and background soils was determined
using the ammonium saturation method.
At sites 1 and 2, there was an increase in
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Table 6. Organics Present in Soil Pore Water
Compound Site 1
Site 2
Site 3
Phenol
4-Nitrophenol
Pentachlorophenol
Chrysene
Bisl2-ethylhexyl)phthalate
Di-n-butylphthalate
Table 7. Characteristics of Site Runoff
Site No.
1
2
3
COD
(mg/l as Ot)
120
5
540
roc
(mg/l as C)
18
<5
495
Oil and Grease
(mg/l)
8.4
10.8
35.8
Site 1 - unfilled, no grass cover.
Site 2 - unfilled, grass cover.
Site3 - tilled.
CEC where oil was applied to the soil.
However, at site 3, the CgC of site soil
was lower than the background soil.
Runoff
Runoff samples were collected to de-
termine if runoff from closed land treat-
ment sites contained hazardous constit-
uents. A 25-year, 24-hour storm for the
region was simulated.
The COD, oil, and grease data (Table 7)
show that the runoff from tilled areas
contained more organic material than
unfilled areas. Runoff from the tilled
areas was in contact with the oily soil for
a longer period because the tilled area
was more porous.
Aluminum and iron were in runoff from
all three sites at higher concentrations
than that of applied water.
Revegetation
The revegetation study involved both
field and laboratory (environmental cham-
ber) testing. Trees and grasses were
planted at site 3 and monitored for growth
and development characteristics for one
season. The trees planted were black
locust (Robinia pseudoacacia), hackberry
(Celtis occidentalis), osage orange (Mac-
lura pomifera), red cedar (Juniperus
virgin/ana), Russian olive (Elaeagnus
angustifolia). The grasses planted in the
field were: bermuda grass (Cynadon
dactylon), colonial bentgrass (Agrostis
tenuis). crabgrass (Digitaria sanguinalis),
weeping lovegrass (Eragrpstis curvula).
The field site was divided into two oil
level sections. One contained moderate
amounts of oil (5-6%) and the other heavy
amounts (9-13%). A control site which
contained no oil was also established.
Tree seedlings were placed in holes with
a mixture of peatmoss and soil from the
control area. Th is was to buffer the young
roots from adverse effects of the waste
until they were better established. The
grasses were planted by broadcasting
seed onto beds of processed cow manure
and wheat straw. Bermuda grass was
sprigged.
Crabgrass seed and bermudagrass sod
were used for both environmental cham-
ber and field studies.
With the exception of one red cedar, all
trees in the heavily oiled area failed to
survive. The survival rate was greater in
the moderately oiled soil; however, the
trees that lived were stunted. Red cedar
trees showed best tolerance. Their ability
to tolerate heat and drought was reflected
by a higher survival rate.
Crabgrass and bermudagrass grew
best in the field. There was a germination
delay and, biomass production when
compared to the control soil. Oil and
volatile waste products in the site soil are
suspected to be responsible for the growth
abnormalities.
Heavy amounts of oil had adverse
effects on the vegetation. Drought resist-
ant species fared best in the dry, hot
climate. In addition to the species planted,
a few native plants were observed grow-
ing in lightly oiled (1 -5%) sections of the
land treatment site.
Conclusions
1. Sampling procedures at land treat-
ment sites must be carefully de-
signed, since there can be consid-
erable variability in oil concentra-
tions across a site.
2. Management of closed land treat-
ment sites, i.e., nutrient addition,
etc., should continue following the
last waste application until biotrans-
formation of all organic hazardous
constituents has occurred.
3. Some vertical migration of oil may
occur at the land treatment sites,
but this migration probably will not
extend below 50 cm of the surface.
In this study, no oil was present in
the soil between 50 and 150 cm at
any of the three sites.
4. Persistent organic priority pollut-
ants in oily residue land treatment
site soils consist primarily of high-
weight polynuclear aromatic com-
pounds. If management of closed
sites is not maintained, movement
of these pollutants into the unsatu-
rated zone may occur.
5. Reduction of the oil content at land
treatment sites to background lev-
els may not be possible. One site in
this study had been well managed,
had no residues applied for six
years, and supported profuse vege-
tative growth; yet this site still had
an average oil content level be-
tween 2.5 and 3 percent. Thus, it
may be more practical to reduce
pollutant levels to the point where
inhibition of vegetative growth and
leaching, air emissions, or surface
runoff of hazardous constituents
are no longer problems.
6. If proper pH management is main-
tained, metals in land treatment
site soils should be immobilized in
the top 25 cm of the soil.
7. Volatile hydrocarbons may be emit-
ted during the tilling process for an
extended period of time after waste
application has ceased.
8. Vegetative cover reduces the po-
tential for contamination of runoff
with site pollutants. Grasses pro-
vide the best vegetative cover. A
ground cover using grasses can be
established at oil concentrations of
4 to 5 wt.%; however, root develop-
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ment and crop yield may be signifi-
cantly inhibited.
9. Closed oily residue land treatment
sites should be tilled at frequent
intervals and nutrients applied until
the oil concentration has decreased
to a maximum of 3 percent prior to
attempting to establish a ground
cover using forage crops (grasses).
This report was submitted in fulfillment
of Cooperative Agreement No. CR 807-
936010 by the School of Civil Engineering
and Environmental Science, University of
Oklahoma under the sponsorship of the
U.S. Environmental Protection Agency.
This report covers a period from November
1980 to July 1983 and work was com-
pleted as of June 1983.
LealeE. Streebin, JamesM. Robertson. A list air B. Cat'lender, LynneDoty, andK.
Bagawandoss are with the University of Oklahoma, Norman, OK 73019.
Don H. Kampboll is the EPA Project Officer (see below).
The complete report, entitled "Closure Evaluation for Petroleum Residue Land
Treatment." (Order No. PB 85-115 822; Cost: $ 19.00. subject to change) will be
available only from:
National Technical Information Service
5285 Port Royal Road
Springfield, VA 22161
Telephone: 703-487-4650
The EPA Project Officer can be contacted at:
Robert S. Kerr Environmental Research Laboratory
U.S. Environmental Protection Agency
Ada, OK 74820
• U S GOVERNMENT PRINTING OFFICE 1985- 559-111/10748
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