United States
Environmental Protection
Agency
Robert S. Kerr Environmental
Research Laboratory
Ada OK 74820
Research and Development
EPA/600/S2-88/055 Jan. 1989
Project Summary
Characterization and
Laboratory Soil Treatability
Studies for Creosote and
Pentachlorophenol Sludges and
Contaminated Soil
Gary D. McGinnis, Hamid Borazjani, Linda K. McFarland, Daniel F. Pope, and
David A. Strobel
The full report presents information
from the first two phases of a three-
phase study pertaining to on-site
treatability potential of soils con-
taining hazardous constituents from
wood-treatment waste (EPA-K001).
Phase I studies involved: (1)
developing a soil treatability data-
base from the literature for creosote
and pentachlorophenol wood-
treating chemicals, and (2) obtaining
baseline data on qualitative and
quantitative distribution of wood-
treating chemicals contained in
samples of contaminated soils and
sludges collected at eight wood
treating sites located in the
southeastern United States. Phase II
studies involved developing soil
transformation, soil transport, and
toxicity information for selected
wood treating solution constituents
identified in these samples. Phase III
studies currently under way involve
comprehensive field evaluation of
soil treatability of creosote and
pentachlorophenol waste constitu-
ents at one of the eight sites studied
in Phases I and II.
The full report contains:
1. A literature assessment of soil
treatability potential for wood
treating chemicals;
2. Sludge and soil characterization
data for eight wood treating sites;
and
3. Treatability information pertaining
to degradation and toxicity of
wood-treating chemicals in soils
from four of the sites.
The literati- -e assessment indi-
cated that creosote and pentachlo-
rophenol waste constituents may be
treatable in soil. Each of the eight
K001 sludges characterized con-
tained the PAH class of semivolatile
constituents; however, relative con-
centrations of individual PAH
compounds varied among different
sludges. PCP sludges contained
pentachlorophenol, octachlorodi-
benzo-p-dioxin, and traces of hepta
and hexa dioxins and the corre-
sponding furans.
PAH's with two rings generally
exhibited half lives less than ten
days. Three ring PAH's generally
exhibited longer half lives in most
cases, but less than one hundred
days. Four or five ring PAH's
exhibited half lives of one hundred
days or more; however, in specific
cases, particular four or five ring
PAH's exhibited half lives less than
ten days. PCP half lives varied from
twenty days to over a thousand days
in different soils. PCP was
transformed very slowly in soils with
no prior long term exposure to PCP.
Low concentrations of OCDD
apparently were transformed slowly
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in three of the four soils tested. In
the soil that had previous long-term
exposure to POP, OCDD exhibited a
half life less than one hundred days
even at the highest concentration
tested. However, results were
variable, and more information must
be obtained before a definite con-
clusion can be made on OCDD
transformation rates in soils.
Microorganism population counts
of the type used in this study did not
appear to be closely related to
transformation rates.
This Project Summary was devel-
oped by EPA's Robert S. Kerr Envi-
ronmental Research Laboratory, Ada,
OK, to announce key findings of the
research project that is fully docu-
mented in a separate report of the
same title (see Project Report
ordering information at back).
Introduction
Treatment of waste containing
undesirable organic constituents in a
carefully designed and managed soil
system is a potentially cost-effective,
environmentally safe, low energy
technology that has been used suc-
cessfully for a wide variety of domestic
and industrial wastes. Examples of
industrial wastes for which soil systems
have been used as a waste management
alternative include those from the food
processing, petroleum refining, organic
chemical manufacturing, coke, textiles,
and pulp and paper industries. However,
there currently are few definitive data in
the literature that quantify treatment rates
in full-scale soil treatment systems.
This research project is directed
toward collecting hazardous waste and
soil samples from eight wood-
preserving locations in the southeastern
United States for use in evaluating and
quantifying treatment potential for those
types of waste in various soil types. A
comprehensive assessment of literature
available for two types of wood-
preserving wastes, pentachlorophenol
and creosote, was conducted to aid in
making these evaluations
This project involves three phases:
Phase I - site selection and
characterization studies for defining
selected soil and sludge characteristics
at eight wood-treating sites; Phase II -
laboratory treatability studies for
determining rates of microbiological
degradation or other transformation
processes, soil transport properties of
creosote and pentachlorophenol waste
contaminants, and toxicity of the water-
soluble fraction of waste-soil mixtures;
and Phase III - a field evaluation study at
one of the eight wood-treating sites.
This report presents and discusses
results from the characterization phase
for each of the eight sites and from the
laboratory treatability phase for four of
the eight sites.
Wood-Preserving Industry
Wood preserving in the United States
is a hundred-year-old industry. Wood
is treated under pressure in cylinders
with one of four types of preservatives:
(1) creosote, (2) pentachlorophenol in
petroleum, (3) water solutions of copper,
chromium, and arsenic (CCA), and (4)
fire retardants.
The organic preservative most used is
coal tar creosote, a by-product from the
production of coke from coal. Creosote is
a blend of the various coal tar distillates
having specific physical characteristics
that meet standards of the American
Wood-Preservers' Association (AWPA).
Both yield and chemical and physical
properties of the various distillate
fractions are influenced by: (1) the
characteristics of the coal from which the
tar originates, (2) the type of equipment
used in the distillation process, and (3)
the particular distillation process used.
Creosote consists mostly of aromatic
single to multiple ring compounds. Over
200 different components have been
identified in creosote; however, it is
generally agreed that creosote contains
several thousand different compounds
which could be identified with GC/MS.
Most of these are present in very small
amounts. Pentachlorophenol (PCP) dis-
solved in No. 2 fuel oil carrier is the
second most common organic wood
preservative. Technical grade PCP is
about 85% to 90% pure PCP. The
remaining materials in technical grade
PCP are 2,3,4,6-tetrachlorophenol (4 to
8%), "other chlorophenols" (2 to 6%),
and dioxins and furans (0.1%). Analyses
of samples of technical grade PCP have
revealed that the principal chloro-
dibenzodioxin and chlorodibenzofuran
contaminants are those containing 6 to 8
chlorines. The highly toxic 2,3,7,8-
tetrachlorodibenzo-p-dioxin (TCDD)
has not been identified in any sample of
PCP produced in the United States that
has been analyzed to date.
Pure PCP is considered to be rather
inert chemically. The chlorinated ring
structure tends to increase stability, but
the polar hydroxyl group tends to
facilitate biological degradation. All
monovalent alkali metal salts of PCP are
very soluble in water, but the proton,
(phenolic) form is virtually insolu
Hence, transport of PCP in wate
related to the pH of the environm
Pentachlorophenol is moderately vole
therefore, PCP can be lost from soils
volatilization.
Wood-Preserving Wastes
There are several sources of c
lamination at wood-treating sites. Du
the treatment cycle, wastewater \
traces of preservative in water
produced from several sources, inc
ing: live steaming of the wood, va
drying or oil seasoning, vacu
condensate, steam and oil leaks aro
the system, cleanup, and contamim
rain water. Treatment of this plant ws
water produces sludges that
classified by EPA as K001, Hazard
Waste.
Prior to current environmental re
lations pertaining to wastewa
discharge, treated wastewater efflu
generally went directly to surf.
drainage or a stream. Most woi
treating plants also had sumps or pot
to trap heavy oil residuals prior
wastewater treatment before discharg
to a publicly-owned treating works.
Normal wood-treatment operatic
create additional waste for dispo;
Treating tanks and cylinders have to
cleaned periodically to maintain qua
standards. In the past these preserval
sludges often were used as fuel, for r(
paving or were buried at the facility.
Soil contaminated with wood-treat
chemicals is another source of envir
mental concern. Treated wood is w
drawn from the cylinder and moved
rails to storage areas. During trai
portation, the preservative may drip fr
the treated wood onto the soil along
track. Contaminated areas are comrr
around storage, treating, and unload
tanks where minor preservative spillc
from broken pipes, bleeding of treat
wood, etc., has occurred. These are
can be rather large, especially in 1
older railroad and pole plants.
Decomposition/Immobilization
of Creosote and PCP in Soil
Creosote
Major components of creosote <
polycyclic aromatic hydrocarbo
(PAH's) with trace amounts of phen
and azaarenes. A wide range of s
organisms, including bacteria, fun
cyanobacteria (blue-green algae), a
eukaryotic algae, have been shown
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have the enzymatic capacity to oxidize
PAH's. Generally, rates of degradation
for PAH compounds have been found to
decrease as the molecular weight
increases; rates of degradation have
been found to be faster in soil than in
water; and, overall rates of degradation
have been reported as faster where there
is an acclimated bacteria population.
Compounds, such as naphthalene,
phenanthrene, and anthracene, that are
relatively water soluble have been found
to readily metabolize while compounds,
such as chrysene and benzo(a)pyrene,
that have a lower water solubility have
been found to be more persistent. Some
researchers have found that pyrene and
fluoranthene, although more soluble than
anthracene, are less appreciably
metabolized by soil microorganisms.
Other factors that may affect the
persistence of PAH compounds are
insufficient bacterial membrane perme-
ability to the compounds, lack of enzyme
specificity and lack of aerobic conditions.
Some PAH's with more than four rings
are not known to be utilized as a sole
carbon source but have been reported to
be co-metabolized with other organic
compounds. The co-metabolism pro-
cess involves concurrent metabolism of a
compound that a microorganism is
unable to use as a sole source of energy
along with metabolism of a carbon
source capable of sustaining growth.
Pentach/orophenof
A large number of studies on
biodegradation of PCP in soil have been
conducted. The route of decomposition
involves dechlorination leading to a
series of partial dechlorinated products,
such as 2,3,5,6-tetrachlorophenol. The
second step in the decomposition
reaction involves an oxidation step to
form substituted hydroquinones or
catechols, such as 2,3,4,5-tetrachlo-
rocatechol. The oxidation product then
undergoes ring cleavage, ultimately
forming COa and an inorganic chloride
ion.
Mobility, persistence, and fate of PCP
in soils depend on physical and chemical
characteristics of the soil as well as the
prevailing microbial population. Adsorp-
tion of PCP depends primarily on the pH
of the system. The more acid the soil,
the more complete is the "apparent
adsorption" of PCP. Organic matter
content of soils is important to adsorption
of PCP at all pH values. Soil containing
humus always adsorbs more PCP than
soil in which organic matter has been
removed by treatment with hydrogen
peroxide. Adsorption of PCP by humus is
more important when the concentration is
low, but the inorganic fraction increases
in importance at higher concentrations.
Persistence of PCP in soil depends on
a number of environmental factors. For
example, the sodium salt of PCP has
been found to be relatively stable in air-
dried soils, to persist for 2 months in soil
of medium moisture content, and to
persist for 1 month 'in water-saturated
soil. Although the rates of degradation in
soil may be maximized at the higher
moisture values, these high moisture
conditions may not be environmentally
acceptable because of the increased
potential for migration.
PCP also has been found to break
down more slowly in heavy clay than in
sandy or sandy clay soils. The rate of
degradation of PCP has been found to
correlate with clay mineral composition,
free iron content, phosphate adsorption
coefficients and cation exchange capa-
city of the soil, although the greatest
effect was found to correlate with organic
matter. Little or no correlation has been
found with soil texture, clay content,
degree of base saturation, soil pH, and
available phosphorus.
The preponderance of information
indicates that microbial activity plays an
important part in degradation of PCP in
soil. Many types of bacteria and fungi are
capable of degrading pentachlorophenol,
including Pseudomonas, Aspergillus,
Trichoderma, and Flavobacterium.
However, the number of species and
their population may be limited. In most
cases where rapid soil degradation of
PCP by microorganisms has been
demonstrated, the source of the soil
and/or inoculum was from areas where
PCP had been used for a long time.
Bioaccumulation/Toxicity of
Creosote and PCP
Plant/Animal Uptake of
Creosote
Little information was found on
bioaccumulation/toxicity of creosote;
however, considerably more information
was found on the bioaccumulation/
toxicity of individual PAH's contained in
creosote. Higher plants can take up
PAH's and translocate them throughout
the plant, although the PAH's may
concentrate in certain plant parts. Some
PAH's can be catabolized by plants.
Toxic Effects of Creosote
Many of the components of creosote,
especially the higher weight PAH's, are
considered to be mutagenic, carcino-
genic, fetotoxic, or teratogenic. The
heterocyclic oxygen and sulfur com-
pounds, paraffins, and naphthenes are
not known to be toxic.
Plant!Animal Uptake of PCP
Limited information was found on the
uptake and translocation of PCP by
plants, and no information was found on
the metabolism of PCP by plants. Uptake
of PCP by animals can occur by
inhalation, oral ingestion (including
consumption of PCP-contaminated food
and licking or chewing treated wood) and
dermal absorption by direct contact with
treated wood. There is some evidence
that PCP may be a metabolic product of
other environmental contaminants, but
the significance of this source is not
known.
Many phenols undergo conjugation
reactions in animals. These reactions
include the formation of glucuronides,
ethereal sulphates, and monoesters of
sulfuric acid. Some PCP is excreted
unchanged, and the amount that is
metabolized or conjugated depends on
the species. The short half-lives of PCP
suggest that there will be no buildup of
residues to a toxic level with continuing
intake of PCP.
Toxic Effects of PCP
Available data suggest that PCP has
moderately acute oral toxicity, but that
the LDso value may vary with the quality
and quantity of contaminants. Man
appears to be more susceptible than the
rodent and the female to be more
susceptible than the male. Commercial
samples have produced chloracne in the
rabbit ear bioassay, but the purified
material has not. Positive reactions have
been produced by topical or oral
application, but allergic contact dermatitis
has not been a problem in handling PCP.
Workers have reported that the dust is
irritating to the mucous membrane of the
nose and throat.
Study Sites
Site Selection Criteria
The eight wood-treating sites selected
were located in the southeastern United
States, each having a different soil type.
The wood-treating sites were selected
using the following criteria:
1. Site had to have a source of sludges,
preferably a separate source for PCP
and creosote sludges.
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2. Site demonstration area soil should
have had low level exposure to PCP
and creosote so that an acclimated
bacteria population would be
available; however, high levels of
contamination should not be contained
within or below the proposed
treatment zone (1 meter).
3. Site had to have an available method
for collecting and disposing of run-
off water.
Site, Soil, and Sludge
Characterization
An initial visit was made to each plant
site to select one or more potential field
demonstration areas. Composite soil
samples were collected for analyses of
creosote and pentachlorophenol and for
determination of soil microbial popu-
lations. Based on results from the
chemical analyses, microbial populations
found, and initial observations, one
potential demonstration area approxi-
mately 1/2 to 1 acre in size was selected
at each plant location. A second visit to
each site was made in order to do a
thorough site assessment including a
more complete chemical and microbio-
logical characterization of the field
demonstration area soil.
A third visit was made to each site to
conduct soil evaluation tests. Soil profiles
were examined at each site in freshly
excavated pits, and they were described
and sampled using standard soil survey
methods. Soil morphological descriptions
included horizonation, Munsell color,
texture, horizon boundaries, consistency,
coarse fragments, root distribution,
concretions and pedological features.
Each horizon was sampled for laboratory
analyses.
Laboratory Treatability Studies
Transformation/Degradation
Using a Standard Creosote/PCP
Mixture: Experiment I
Laboratory treatability studies were
conducted for each soil to determine
rates of degradation/transformation, soil
transport properties of creosote and
PCP, and toxicity of the water-soluble
fraction of waste-soil mixtures. An initial
set of degradation/transformation
experiments for each site was conducted
by applying, at 1% of the soil dry weight,
a standard mixture containing 200 ppm
technical-grade PCP and 2000 ppm
technical-grade creosote to a sample of
the site soil. Sample aliquots from test
units set up for each soil-waste mixture
prepared were taken at 0, 30, 60, and 90
day time intervals. These aliquots were
subjected to chemical and microbio-
logical analyses.
Transformation/Degradation of
Site Specific Sludges:
Experiment II
The second part of the laboratory
degradation studies involved studying
the kinetic rates of degradation using
samples of the soil and sludge collected
from each site. The objective was to
assess the potential for treatment of the
sludge present at a site in the soil at that
site. Three sludge loading rates were
tested for each site, and each set of
experiments was replicated three times.
Sample aliquots were taken at 0, 30, 60
and 90 day time intervals. These aliquots
were subjected to chemical and
microbiological analyses.
Results and Discussion
Site and Soil Characterization
The eight sites investigated repre-
sented diverse soil, geologic, climatic,
and environmental conditions. These
sites ranged from near sea level in
Gulfport, Mississippi, and Wilmington,
North Carolina to elevations above 1000
feet at Atlanta, Georgia. The study areas
were located in six Major Land Resource
Areas (MLRA) of the United States. The
sites encompassed several geomorphic
landforms ranging from fluvial terraces to
upland ridges. Soil parent materials
varied from sandy Coastal Plain
sediments to silty Peoria loess to granite
gneiss residuum.
Sludge Characterization
Each plant site had different types and
sources of waste. Six of the plants had
open lagoons of creosote and/or PCP;
one site had three lagoons which were
segregated into PCP, PCP in a heavy oil,
and creosote; two other plants had no
lagoons but had areas of dried sludge
and contaminated soil.
Transformation/Degradation
with the Standard Mixture:
Experiment I
All PAH compounds selected for
analyses were transformed in the
Gulfport soil; however, pyrene and
benzo(a)pyrene exhibited relatively slow
breakdown rates. All PAH's but
anthracene were transformed in the
Columbus soil, though at somewhat
slower rates than the Gulfport soil for
most compounds. Gulfport and Colurr
soils developed higher levels
acclimated organisms than the o
sites, possibly accounting for the b<
transformation. Soil from the other
sites transformed more of the lo
molecular weight PAH's readily; howe
many of the higher molecular weight f
(fluoranthene, pyrene, 1,2-benzant
cene, chrysene, and benzo(a)pyre
tended to transform slowly, if at
Pyrene and fluoranthene appeared tc
most recalcitrant at all locations.
Technical grade PCP transforma
occurred in Gulfport, Grenada, Cl
tanooga, Wilmington, and Meridian si
The PCP half life was 64 days in Gulf]
soil, but well over 100 days for the o
soils. Columbus, Atlanta, and Wigc
soils exhibited no transformation
technical grade PCP.
The results of this prelimin
experiment indicated that all of
compounds studied potentially could
transformed in soils under
appropriate conditions. Microorgan
counts of the type used in t
experiment were not found to
extremely accurate indicators of poter
breakdown rates for particular cc
pounds; however, there appeared to
some tendency for soils with hig
populations of acclimated mic
organisms to transform more of
different PAH's found in creosote anc
somewhat faster rates. This may hi
been due to larger numbers of partici
microorganisms or to a more dive
array of microbial species.
Transformation/Degradation o
Site Specific Sludges:
Experiment II
Breakdown of total PAH's for sim
waste loading concentrations was sim
in soils from each of the four sites. Ba;
on breakdown rates, individual PAH's c
be divided into three groups: those v
half lives of 10 days or less, those v
half lives of 100 days or less, and th(
with half lives of more than 100 da
Naphthalene, 2-methy(naphthalene,
methylnaphthalene, biphenyl, acenai
thalene, acenaphthene, dibenzofuran, i
fluorene exhibited half lives of ten d<
or less in most cases. Phenanthre
anthracene, carbazole, and fluorantht
exhibited half lives between 10 and 1
days in most cases. Pyrene, 1
benzanthracene, chrysene, benzo
pyrene, and benzo-(g,h,i)-peryle
exhibited half lives greater than 100 d<
in some cases. In several cases, he
ever, essentially no breakdown w
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ibserved for these last five compounds
vithin the time frame of the experiment.
Breakdown rates of individual PAH's
ipparently were related to molecular size
md structure, as noted in previous
tudies. The 0 to 10 day half life group
:ontained compounds with two aromatic
ings; the 10 to 100 day half life group
:ontained compounds with three
iromatic rings; and, the 100 plus day half
ife group contained compounds with four
>r more aromatic rings. However, some
)f the larger, most recalcitrant com-
Dounds apparently were broken down
eadily in some situations. This indicates
hat even the most persistent PAH
compounds may yield to biological
•emediation techniques under the right
;et of management conditions.
The microbial populations found in the
Dlate counts were not closely related to
DAH breakdown; PAH breakdown was
similar at similar concentrations over the
our sites, while microbe counts were
lighly variable.
PCP transformation occurred in all the
soils, but was slow in Columbus soil, a
site not previously exposed to PCP type
wastes. Grenada soil transformed PCP
with half lives ranging from one to two
months, a range which should be
practical for soil treatment system
operations. Meridian soil also exhibited
rapid transformation rates of PCP except
at the highest loading rate. Wiggins soil
transformed PCP with half lives of three
to four months, a range which still should
be appropriate for soil treatment system
operations especially considering its
deep south location where soil temper-
atures are high enough for good
microbiological activity most of the year.
Although the Columbus soil did exhibit
some transformation of PCP, the low
rates would bring into question the
practicality of treating PCP in a soil
system at that location without additional
studies. It is not known what length of
time would be required to build up a
population of microorganisms suitable for
rapid degradation of PCP in hitherto
unexposed soil. Evidently, the relatively
short time frame of these experiments
was insufficient for the Columbus soil. It
is likely in most soils with chronic
exposure to PCP (which is where PCP
treatment in soil systems would be used)
that suitable microbial populations exist
and that these populations could be
enhanced relatively quickly with proper
management.
Transformation of OCDD occurred to
some degree in soils from all sites, but
only in the Grenada soil was consistent
OCDD transformation indicated at all
loadings. Since PCP also was consis-
tently transformed in the Grenada soil,
the potential for transformation of these
two compounds in a soil may be
interrelated. Dioxins are widely regarded
as being highly recalcitrant to biological
transformation in soils, but these data,
while variable, indicate that this may not
be the case for all soils. Further study is
needed to investigate this possibility.
General Discussion
Results from these experiments
indicated that PCP and PAH compounds
in wood-preserving wastes potentially
can be transformed at practically useful
rates in soil. Although the variability of
the data is relatively large in some cases,
the general trend is apparent. Treatment
of creosote and PCP wood-treating
wastes in soil systems appears to
provide one viable management
alternative at some locations. The data
variability, however, supports the need
for conducting site-specific treatability
studies for a given site to discern the
appropriate operation and management
scenario.
Further study of treatability of PCP and
higher molecular weight PAH compounds
in soils is needed to determine the mos*
advantageous environmental conditions
and management techniques for more
rapid transformation of these compounds
at a given site. Further study may reveal
reliable techniques for enhancing soil
systems for treatment of even the more
recalcitrant wood-preserving com-
pounds. Since the environmental prob-
lems that the wood-treating industry has
to deal with are almost unlimited, and the
resources available to solve these prob-
lems are quite limited, reliable, safe,
economical bioremediation techniques
using soil systems are very attractive anc
warrant thorough study and evaluation.
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Gary 0. McGinnis, Hamid Borazjani, Linda K. McFarland, Daniel F. Pope, and
David A. Strobel are with Mississippi State University, Mississippi State, MS
39762.
John E. Matthews, is the EPA Project Officer (see below).
The complete report, entitled "Characterization and Laboratory Soil Treatability
Studies for Creosote and Pentachlorophenol Sludges and Contaminated Soil,"
(Order No. PB 89-109 920,'AS; Cost: $28.95, 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
Adat OK 74820
United States
'Environmental Protection
•Agency
Center for Environmental Research
Information
Cincinnati OH 45268
Official Business
Penalty for Private Use $300
EPA/600/S2-88/055
0000329 PS
U S ENVIR PROTECTION AGENCT
REGION 5 LIBRARY
230 S OEAR8GRN STREET
CHICAGO IL 6060*
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