United States
Environmental Protection
Agency
RobertS. Kerr Environmental
Research Laboratory
Ada OK 74820
Research and Development
EPA/600/S2-85/009 Mar. 1985'1
Project Summary
Land Treatment of an Oily
Waste—Degradation,
Immobilization, and
Bioaccumulation
R. C. Loehr, J. H. Martin, E. F. Neuhauser, R. A. Norton, and M. R. Malecki
Land treatment of an industrial oily
waste was investigated to determine
the loss and immobilization of waste
constituents and the impact of the
waste and the application process on
soil biota.
The waste was applied to field plots of
a moderately to slowly permeable heavy
silt loam in New York. The field plots
consisted of four replicates each of
natural controls, rototilled controls, and
low, medium, and high application rate
plots.''Wastes were applied in June
1982, October 1982. and June 1983.
In June 1983, the plots that had re-
ceived the low applications received a
high application and became the high
application plots. During the study, the
waste was applied to the test plots at
seven waste application rates that
ranged from 0.17 to 9.5 kg total oil and
grease/meter2 or from 0.09% to 5.26%
oil and grease in the zone of incorpora-
tion.
The application of the wastes in-
creased the pH and volatile matter of.
the soils. Over the period of the study,
the half life of the total oil and grease in
the field plots ranged from about 260 to
about 400 days. Not all of the applied
oil was lost from the plots. The refrac-
tory fraction ranged from 20% to an
apparent 50% of the applied oil and
grease. The refractory fraction did not
appear to adversely affect the soil biota.
Napthalenes, alkanes, and specific
aromatics were rapidly lost from the
soil, especially in the warmer months.
The half life of these compounds gen-
erally was less than 30 days.
The waste applications increased the
concentration of several metals in the
upper 15 cm of the soil. Except for
sodium, all of the metals were immobi-
lized in the upper 15 cm of the plots.
Earthworms bioaccumulated cadmi-
um, potassium, sodium, and zinc. The
accumulation could not be related to
waste application rates and occurred in
worms from the control plots as well as
in worms from the plots that received
the wastes. The land treatment of these
wastes did not cause any unexpected
bioaccumulation of metals in the earth-
worms. The earthworms did not ac-
cumulate napthalenes, alkanes, or spe-
cific aromatics that were in the applied
waste.
Rototilling and waste application re-
duced the numbers and biomass of
earthworms and the numbers and kinds
of microarthropods in the field plots.
Both types of soil biota were able to
recover from the rototilling and waste
application.
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 is a managed waste
treatment and ultimate disposal process
that involves the controlled application of
a waste to a soil. The wastes are applied
to the surface or mixed with the upper
-------
zone(0-1 ft. (0-0.3m)) of soil. The objective
of land treatment is the biological deg-
radation of organic waste constituents
and the immobilization of inorganic waste
constituents. In this way, the assimilative
capacity of the soil is utilized for waste
management. Municipal wastewaters
and sludges as well as industrial wastes
can be treated with this process.
The land treatment of industrial wastes
is receiving increasing attention as a cost
effective and environmentally sound meth-
od of waste management. Land treat-
ment has been used as a waste manage-
ment technology by petroleum refineries
in the United States for more than 25
years. The technology also has been used
by the exploration and production sector
of the petroleum industry and for the
cleanup of oil spills.
The major concerns when land treat-
ment is used for industrial wastes are the
transformations, transport, and fate of
potentially toxic metals and organics that
may be in the wastes. Feasible waste
application rates have been based on: (a)
physical and chemical characteristics of
the soil such as permeability, cation
exchange capacity (CEC), and pH; (b)
mobility and plant uptake of constituents
in the applied wastes; (c) the character-
istics of the waste; and (d) the degradation
and immobilization of constituents in the
wastes.
As identified in the Resource Conserva-
tion and Recovery Act (RCRA), land
disposal methods are to be protective of
human health and the environment. The
factors to be taken into account in as-
sessing such protection are the persist-
ence, toxicity, mobility, and propensity to
bioaccumulate hazardous wastes and
their constituents.
Except as part of organic degradation,
the soil biota rarely have been included in
any research or full scale land treatment
system or monitoring programs. However,
the top layer of soil contains myriad
microbes and invertebrates that degrade
and transform the applied organics and
that can affect the immobilization of the
applied inorganics. Earthworms are active
indigenous soil invertebrates that assist
the degradation of organic compounds. In
addition, in the terrestrial food chain,
earthworms represent one of the first
levels of bioaccumulation that can occur
when industrial wastes are applied to the
land. It is appropriate to consider earth-
worms as a test organism for determining
the impact of industrial waste on soil
biota when land treatment is used for
such wastes. Microarthropods, such as
mites and springtails, are also biota found
in abundance in most soils and are sec-
ondary decomposers a nd detritus feeders.
Studies have shown that they are affected
adversely by insecticides and other chem-
icals added to the soil.
The overall purpose of this project was
to determine: (a) the loss and immobil-
ization of constituents of an oily waste
when the waste was applied to the soil at
different application rates, (b) the impact
of the waste and the application process
on soil biota, and (c) the general assim-
ilative capacity of a soil when industrial
wastes are land applied.
Materials and Methods
This project was a cooperative agree-
ment between Cornell University and the
Robert S. Kerr Environmental Research
Laboratory (RSKERL) of the Environ-
mental Protection Agency (EPA). The
research was conducted in laboratories
of the Department of Agriculture Engi-
neering, College of Agriculture and Life
Sciences, Cornell University, and on land
adjacent to the Cornell campus. The
identification of the numbers and type of
microarthropods in soil samples was done
by Dr. Roy A. Norton of the Department of
Environmental and Forest Biology, Col-
lege of Environmental Science and For-
estry (CESF), State University of New
York, Syracuse, New York.
Wastes
The wastes were obtained on three
separate occasions from a site in Okla-
homa with the help of RSKERL personnel.
The wastes were of unknown origin but
were black, viscous, and collected from
the bottom of a lagoon used to store
wastes from oil refineries. Although the
wastes were collected from a large hold-
ing lagoon on three different occasions
and it was unlikely that the contents of
the lagoon were homogenous, the charac-
teristics of the wastes were reasonably
similar, expecially when expressed on a
moisture free basis (Table 1). The wastes
were applied to the field plots to obtain a
specific oil content in the soil of different
plots. Samples of the wastes were an-
alyzed before each application date, and
the oil data was used to determine the
'volumes of a waste to be added to a
specific plot.
These oily wastes had been contained
in the holding lagoon for several years
before the required quantities were re-
moved and transported to the field site for
application. Many volatile compounds
may have been lost while the wastes
were held in the lagoon.
Field Site (
The site used for application of the
waste was an old field in Tompkins
County, New York. It had not been used
for agricultural purposes and had not
received applications of lime, fertilizer,
pesticides, or herbicides for over 10 years
before its use in this project. The site had
been mowed annually to hinder growth of
woody plants. The soil at the site was a
Rhinebeck silt loam. It contained about
one foot of moderately to slowly perme-
able heavy silt loam over slowly perme-
able silty clay loam or silty clay. The soil
was somewhat poorly drained and existed
on nearly level to moderate slopes in
glacial lake areas.
The field site consisted of 20 plots, 4
meters by 4 meters, with 4 meters of
border area surrounding each plot. Four
waste application rates plus natural and
rototilled controls were used at the site.
Four replications were made for each
waste application rate and type of control.
All plots were mowed before each waste
application. All plots, except the natural
controls, were rototilled after each ap-
plication of the waste. The four rototilled
control plots had no waste applied but
were nevertheless rototilled. The four
natural control plots had no rototilling or
oily waste applied and were used to
separate the effect of the rototilling and
the waste applications. The applied
wastes were distributed over the plot
surface as uniformly as possible and
were rototilled into the soil to a depth of
about six inches (15 cm) such that the
zone of incorporation for these plots was
the top six inches.
Each test plot (16 m2) was marked with
corner stakes to permit placement of a
framed grid to define 400-0.04 m2 (20 cm
x 20 cm) sampling subplots. Three dif-
ferent subplots were sampled on each
sampling date to determine changes in
incorporation zone characteristics and in
earthworm and microarthropod popula-
tions. To eliminate edge effects, the edge
subplots were not sampled. The subplots
that were sampled from among the 324
possibilities were determined using a
random number table. Thus, different
sampling locations were used at each plot
each time samples were taken. No subplot
was sampled twice during the study. An
elevated plank platform was used to
obtain the samples so that the plots were
not disturbed or contaminated while the
samples were taken.
Natural vegetation such as grass was
allowed to become re-established on the
plots after the waste applications.
-------
nalytical Procedures
Soil samples were taken from each plot
at approximately monthly intervals except
during the winter. Hand sorting was used
to determine earthworm numbers and
biomass from each core. Before the
physical and chemical characteristics of
the soil were measured, the cores from
each plot were composited. Residual soil
was returned to the plots and used to fill
in the core holes. The microarthropod
samples were soil cores approximately 6
cm in diameter and 6 cm deep. The
microarthropods were separated from
the soil by inverting the soil core in a
heat-gradient extractor for one week.
Metals and certain organics in the
waste, soil, and earthworm samples were
malyzed by personnel at the EPA Robert
5. Kerr Environmental Research Labor-
itory (RSKERL). Cornell personnel ana-
yzed the waste and soil samples for more
outine parameters. Dr. Norton (CESF)
icunted and identified the microarthro-
>ods.
Special Studies
Two special studies were conducted to
etermine the variability in the character-
itics of the soil samples taken from
rious locations in the field plots, and
e precision and accuracy of the ana-
rtical method used for oil and grease
/hen used with soil samples. The spatial
ariability study identified the extent to
/hich the variability of the data was due
to the non-homogeneity of waste appli-
cation and rototilling. The results of the
oil and grease analytical method evalua-
tion established the extent to which this
method extracted the oil and grease in the
waste and soil samples.
Results and Discussion
The oily waste was applied to specific
test plots in June 1982, October 1982,
and June 1983. In October 1982, the
plots received larger application rates
than those of June 1982. In June 1983, a
very high waste application was made to
the plots that had received the initial low
application rates. The effect of seven
application rates, ranging from 0.17 to
9.5 kg oil per meter2 of surface area, was
evaluated. The rates covered those likely
to be used under actual field conditions.
Only the indigenous nutrients and
trace elements in the soil and the waste
were available to the micro- and macro-
organisms as the wastes were degraded.
No fertilizers or other amendments were
added to the plots. The plots were only
cultivated (rototilled) immediately before
and after the wastes were applied. No
subsequent cultivation occurred to aerate
the zone of incorporation. The plots were
undisturbed after the combined waste
applications and rototilling and only natu-
ral aeration occurred in the plots. This is
different from what would occur at most
industrial land treatment sites, which are
frequently tilled to promote mixing and
aeration and to increase degradation and
*Ue 1. A verage Characteristics of the Oily Wastes Applied to the Field Plots
Application Date
Parameter
June
1982
October
1982
June
1983
later. %WBm
sh.
if & Grease.
'/kg MFB
MalKjeldahl
litrogen, mg/kg MFB
ttal Phosphorus.
ng/kgMFB
iemical Oxygen
temand, g/kg MFB
59.0
26.9
660
2360
2620
1340
7.2
62.3
30.1
614
2320
NO"
1250
7.1
48.7
30.2
470
2080
1760
1460
6.7
VB = wet basis.
HFB = moisture free basis.
1 = not determined.
other losses. This approach was taken in
order to approximate the changes that
would occur under conservative and non-
optimum conditions such as when single
or highly intermittent waste applications
are administered or when a spill occurs.
The approach also caused one less var-
iable, the frequency and type of aeration
(tilling), to be included in the study.
The pH of the plots that received the
high applications of the oil waste in-
creased. The increase was pronounced
for the plots that received the very high
applications in June 1983. With the very
high application, the soil pH increased by
more than one pH unit. After the waste
applications, the pH stayed at above
background levels for the remainder of
the study.
The volatile matter in the soil was
increased by applying waste. Until the
waste applications in October 1982, the
volatile matter in the plots was about 9%
of the soil on a moisture free basis. After
the October 1982 application, the volatile
matter in the medium application plots
was about 10% and in the high applica-
tion plots, about 11%. After the applica-
tion in June 1983, the volatile matter in
the very high application plots was in the
range of 14 to 15%. There appeared to be
a slight decrease of the volatile matter in
the very high application plots with time.
With time, the concentration of oil and
grease in the soil decreased. However,
the applied oil and grease was not lost
completely. After each waste application,
a new apparent background concentra-
tion in the respective plots resulted.
It was impossible to correlate statis-
tically the oil and grease losses to the soil
temperatures in the field plots. Temper-
ature, however, should have an effect on
such losses, since it affects the rates of
biodegradation and volatilization, the
most likely mechanisms of loss in the
field plots. However, any effect due to
temperature could not be discerned and
separated from other parameters affect-
ing the oil losses. The effect of temper-
ature probably was masked by factors
such as the variability in the oil and
grease data, differences in soil moisture
as the soil temperature changed, and
differing oil and grease compounds in the
soil at different times during the study.
The immobilization of metals in the soil
was analyzed by comparing the metal
concentrations of subsoil samples from
the 15 to 30 cm depth taken in October
1983. The metal concentrations of sub-
soil samples from the plots to which the
wastes were applied were analyzed statis-
tically to determine if the deeper soils of
-------
the controls and the waste application
plots had differing metal concentrations.
As of the October 1983 sampling date,
the wastes had been applied to the
medium and high application plots for
about one year and had been applied to
the very high application plots for about
four months.
The statistical analysis indicated that
sodium was the only metal with a signif-
icantly different concentration in the 15
to 30 cm depth between the control plots
and any waste application plot. That
difference only occurred for sodium in the
soil of the very high plots.
Soil samples were extracted with meth-
ylene chloride and the extracts analyzed
for organics. Time and personnel con-
straints made it impossible to analyze for
the organic compounds in the oily waste.
Rather, a smaller number of organic
compounds were analyzed in selected
soil samples to determine the loss of
these compounds after application.
Soil samples from the very high applica-
tion plots were emphasized since the
concentration of organic compounds in
these plots was expected to be well above
detection limits and might remain so for a
reasonable period of time. Soil samples
from such plots were taken shortly after
the application in June 1983 and monthly
thereafter through October 1983. In
addition, soil samples from a very high
plot, a high plot, and a medium plot were
analyzed at longer time intervals eitherto
confirm the loss patterns from the very
high plots or to identify the losses in the
plots that had received lower waste
applications. The organic compounds
that were determined in the extracts
included C8 to C2e alkanes, napthalenes,
and several other aromatics such as
fluorene, anthracene, phenanthrene, and
pyrene.
The loss rate constants for the specific
organic compounds indicate that during
the warmer months (June through Octo-
ber), the losses were rapid, with half-lives
of generally less than 30 days. Because of
the limited data, it was impossible to
relate the loss rate constants to the soil
temperature or other factors that might
affect the loss of the organic compounds.
The fact that some of the alkanes were
detectable in the high application plot
after seven months of cold weather
suggests that the loss rates were lower
during the winter months.
Soil Biota
The application of the wastes had
definite effects on the earthworm num-
bers and biomass and on the microarthro-
pods in the field plots, due to both the
rototiU'mg and the immediate impact of
the waste. The soil biota were decreased
by the rototilling and even more so by the
wastes. However, with time, these soil
biota did repopulate the field plots. The
project results indicate that these soil
biota can recover from the modest addi-
tion of oily wastes.
The data indicated that the earthworms
accumulated cadmium, potassium, sod-
ium, and zinc. Potassium and sodium are
of physiological but not environmental
importance in terms of bioaccumulation.
The cadmium that accumulated in the
earthworm tissue probably came more
from the background cadmium in the soil
than from the cadmium in the applied
waste, especially since the cadmium had
bioaccumulated at comparably high levels
in the worms from the control plots. A
comparison of the data from this project
with data from the peer-reviewed liter-
ature indicates that the land application
of these oily wastes did not cause any
abnormal or unexpected bioaccumulation
of metals in earthworms.
Conclusions
The objectives of this study were at-
tained. The results indicated that the soil
has the capacity to treat wastes such as
those used in this study. Many of the
organics in the applied waste were re-
moved (lost) and the metals were im-
mobilized when the wastes were applied
to the soil intermittently and at varied
rates. The soil cultivation method (roto-
tilling) and the applied waste had an
immediate adverse impact on the soil
biota (earthworms and microarthropods),
but the soil biota recovered with time. A
fraction of the applied oil and grease was
not removed during the study. The re-
maining organics and the metals did not
appear to have any permanent adverse
effect on the soil biota.
In addition, the application of these oily
wastes to the field plots increased the pH
of the acid soils (as much as one pH unit
for the higher applications), increasedthe
temperature of the soil in the field plots
that received the higher applications by 1
to 5°C, and increased the organic matter
of the soil by 1 to 5%.
The half-life of organics applied to the
soil varied. The loss of specific organics
(napthalenes, alkanes, and certain aro-
matics) in the field plots was rapid,
especially in the warmer months. The
half-life of these compounds was general-
ly less than 30 days. In comparison, the
half-life of the total oil and grease in the
field plots ranged from about 260 to about
400 days. The oil and grease losses could
not be correlated to the soil temperature,
to other soil parameters, to the amounts
of waste that were applied, or to the
waste application rates.
All of the applied organics were not lost
from the soil during the study. The
separation and identification procedures
used were not able to identify the type or
structure of the residual organics that
remained in the soil at the end of the
study. However, based on laboratory
studies using soil from the field plots and
the fact that both earthworms and micro-
arthropods could repopulate the soil of
the plots receiving the wastes, the organ-
ics remaining in the soil did not appear to
result in a permanent adverse impact to
the soil biota.
As a result of the waste applications,
the concentration of many of the metals
in the waste increased in the top 15 cm of
the plots. This increase was especially
noticeable as a result of the high and very
high applications. However, analyses indi-
cated that, except for sodium in the very
high application plots, all metals were
immobilized in the top 15 cm of the soil.
The data indicated that soil biota such
as earthworms and microarthropods can
recover from intermittent applications of
an oily waste. With time, the numbers
and kinds of soil biota in the plots to which
the wastes are applied can again become
similar to those in the control plots,
although at a rate not presently predict-
able. The land application of these wastes
will not have an irreversible, adverse
impact on earthworms and microarthro-
pods.
The earthworms in the field plots did
bioaccumulate several metals that were.
in the applied waste: cadmium, potas-
sium, sodium, and zinc. However, when
the level of bioaccumulation was com-
pared to data from other studies and to
bioaccumulation in worms found in the
control plots, it was apparent that the
land treatment of these oily wastes did
not cause any unexpected bioaccumula-
tion of metals in the worms. The earth-
worms did not bioaccumulate naptha-
lenes, alkanes, or specific aromatics from
the applied waste. Thus, the land treat-
ment of these wastes did not lead to any
bioaccumulation of apparent Concern.
4
-------
-------
-------
R. C. Loehr, J. H. Martin, E. F. Neuhauser, R. A. Norton, andM. R. Maleckiare with
Cornell University, Ithaca, NY 14853.
John E. Matthews is the EPA Project Officer (see below).
The complete report, entitled "Land Treatment of an Oily Waste—Degradation,
Immobilization and Bioaccumulation," (Order No. PB 85-166 353/AS; Cost:
$14.50, 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
P.O. Box 1198
Ada. OK 74820
4 U.S. GOVERNMENT PRINTING OFFICE: 1985-559416/27051
United States
Environmental Protection
Agency
Center for Environmental Research
Information
Cincinnati OH 45268
Official Business
Penalty for Private Use $300
OCOC329 PS
U S ENVJR PROTECTION flGENCY
REGION 5 LIBRARY
230 S DEARBORN STREET
CHICAGO IL £0604
------- |