*************************************************************

DATA REQUIREMENTS

For all remedial investigation and cleanup sites, the vertical
and horizontal contaminant profiles should be defined as much as
possible.  Information on the overall range and diversity of
contamination across the site is critical to treatment technology
selection.  Obtaining this information generally requires taking
samples and determining their physical and chemical
characteristics.  If certain types of technologies are candidates
for use, the specific data needs for these technologies can be
met during the initial stages of the investigation.  The data
requirements are technology-specific and not risk-based.  The
following subsections present a partial list of the
characteristics and rationale for collection of treatment
technology preselection data for each of the three media.  A
matrix of characteristics affecting treatment cost or performance
versus technologies is provided in Appendix D, which is also an
effort by ETTC.

DATA REQUIREMENTS FOR SOIL, SEDIMENT, AND SLUDGE

Site soil conditions frequently limit the selection of a
treatment process.  Process-limiting characteristics such as pH
or moisture content may sometimes be adjusted.  In other cases, a
treatment technology may be eliminated based upon the soil
classification (e.g., particle-size distribution) or other soil
characteristics.

Soils are inherently variable in their physical and chemical
characteristics.  Usually the variability is much greater
vertically than horizontally, resulting from the variability in
the processes that originally formed the soils.  The soil
variability, in turn, will result in variability in the
distribution of water and contaminants and in the ease with which
they can be transported within, and removed from, the soil at a
particular site.

Many data elements are relatively easy to obtain, and in some
cases more than one test method exists.  Field procedures are
performed for recording data or for collecting samples to
determine the classification, moisture content, and permeability
of soils across a site.  Field reports describing soil
variability may lessen the need for large numbers of samples and
measurements to describe site characteristics.  Common field
information-gathering often includes descriptions of natural soil
exposures, weathering that may have taken place, cross-sections,
subsurface cores, and soil sampling.  Such an effort can
sometimes identify probable areas of past disposal through
observation of soil type differences, subsidence, and backfill.
> PARTICLE-SIZE DISTRIBUTION

Soil particle-size distribution is an important factor in many
soil treatment technologies.  In general, coarse, unconsolidated
materials, such as sands and fine gravels, are easiest to treat. 
Soil washing may not be effective where the soil is composed of
large percentages of silt and clay because of the difficulty of
separating the adsorbed contaminants from fine particles and from
wash fluids.  Fine particles also can result in high particulate
loading in flue gases from rotary kilns as a result of
turbulence.  Heterogeneities in soil and waste composition may
produce nonuniform feedstreams for many treatment processes that
result in inconsistent removal rates.  Fine particles may delay
setting and curing times and can surround larger particles,
causing weakened bonds in solidification/stabilization processes. 
Clays may cause poor performance of the thermal desorption
technology as a result of caking.  High silt and clay content can
cause soil malleability and low permeability during steam
extraction, thus lowering the efficiency of the process.

>  SOIL HOMOGENEITY AND ISOTROPY

Soil homogeneity and isotropy may impede in situ technologies
that are dependent on the subsurface flow of fluids, such as soil
flushing, steam extraction, vacuum extraction, and in situ
biodegradation.  Undesirable channeling may be created in
alternating layers of clay and sand, resulting in inconsistent
treatment.  Larger particles, such as coarse gravel or cobbles,
are undesirable for vitrification and chemical extraction
processes and also may not be suitable for the 
stabilization/solidification technology.

>  BULK DENSITY

The bulk density of soil is the weight of the soil per unit
volume, including water and voids.  It is used in converting
weight to volume in materials handling calculations, and can aid
in determining if proper mixing and heat transfer will occur.

>  PARTICLE DENSITY

Particle density is the specific gravity of a soil particle. 
Differences in particle density are important in heavy
mineral/metal 
separation processes (heavy media separation).  Particle
density is also important in soil washing and in determining the
settling velocity of suspended soil particles in flocculation and
sedimentation processes.

>  PERMEABILITY

Soil permeability is one of the controlling factors in the
effectiveness of in situ treatment technologies.  The ability of
soil-flushing fluids (e.g., water, steam, solvents, etc.) to
contact and remove contaminants can be reduced by low soil
permeability or by variations in the permeability of different
soil layers.  Low permeability also hinders the movement of air
and vapors through the soil matrix. This can lessen the
volatilization of VOCs in SVE processes.  Similarly, nutrient
solutions, used to accelerate in situ bioremediation, may not be
able to penetrate low-permeability soils in a reasonable time. 
Low permeability may also limit the effectiveness of in situ
vitrification by slowing vapor releases.

>  SOIL MOISTURE

High soil moisture may hinder the movement of air through the
soil in vacuum extraction systems and may cause excavation and
material transport problems.  High soil moisture also affects the
application of vitrification and other thermal treatments by
increasing energy requirements, thereby increasing costs.  On the
other hand, increased soil moisture favors in situ biological
treatment.

>  PH

The pH of the waste being treated may affect many treatment
technologies.  The solubility of inorganic contaminants is
affected by pH; high pH in soil normally lowers the mobility of
inorganics in soil.  The effectiveness of ion exchange and
flocculation processes may be negatively influenced by extreme pH
ranges.  Microbial diversity and activity in bioremediation
processes also can be affected by extreme pH ranges.

>  REDOX POTENTIAL

Eh is the oxidation-reduction (redox) potential of the material
being considered when oxidation-reduction types of chemical
reactions are involved.  Examples of these types of reactions
include alkaline chlorination of cyanides, reduction of
hexavalent chromium with sulfite under acidic conditions, aerobic
oxidation of organic compounds into CO2 and H2O, or anaerobic
decomposition of organic compounds into CO2 and CH4.  Maintaining
a low Eh in the liquid phase enhances anaerobic biologic
decomposition of certain halogenated organic compounds.

>  OCTANOL/WATER PARTITION COEFFICIENT (Kow)

Kow (the octanol/water partition coefficient) is defined as the
ratio of a chemical"s concentration in the octanol phase to its
concentration in the aqueous phase of a two-phase octanol/water
system.  Kow is a key parameter in describing the fate of an
organic chemicals in environmental systems.  It has been found to
be related to the water solubility, soil/sediment adsorption
coefficient, and the bioconcentration factors for aquatic
species.  The physical meaning of Kow is the tendency of a
chemical to partition itself between an organic phase [e.g.,
polycyclic aromatic hydrocarbons (PAHs) in a solvent] and an
aqueous phase.  Chemicals that have a low Kow value (<10) may be
considered relatively hydrophilic; they tend to have a high water
solubility, small soil/sediment adsorption coefficients, and
small bioconcentration factors for aquatic life.  Conversely, a
chemical with a large Kow (>104) is considered hydrophobic and
tends to accumulate at organic surfaces, such as on humic soil
and aquatic species.

>  HUMIC CONTENT (ORGANIC FRACTION)

Humic content (organic fraction) is the decomposing part of the
naturally occurring organic content of the soil.  High humic
content will act to bind the soil, decreasing the mobility of
organics and decreasing the threat to groundwater; however, high
humic content can inhibit soil vapor extraction (SVE), steam
extraction, soil washing, and soil flushing as a result of strong
adsorption of the contaminant by the organic material.  Reaction
times for chemical dehalogenation processes can be increased by
the presence of large amounts of humic materials.  High organic
content may also exert an excessive oxygen demand, adversely
affecting bioremediation and chemical oxidation.

>  TOTAL ORGANIC CARBON

Total organic carbon (TOC) provides an indication of the total
organic material present.  It is often used as an indicator (but
not a measure) of the amount of waste available for
biodegradation.  TOC includes the carbon both from naturally-
occurring organic material and organic chemical contaminants;
however, all of it competes in reduction/oxidation reactions
leading to the need for larger amounts of chemical reagents than
would be required by the contaminants alone.

>  VOLATILE HYDROCARBONS, OXYGEN, CARBON DIOXIDE

Measurement of volatile hydrocarbons, oxygen (O2), and carbon
dioxide (CO2) at sites containing biodegradable contaminants like
petroleum hydrocarbons or sites with high TOC is useful in
further delineating and confirming areas contaminated as well as
identifying the strong potential for bioremediation by
bioventing.  In addition, if the use of thermal combustion or
certain oxidation systems is planned for off-gas treatment of
extracted vapors, then adequate supply of air or oxygen will have
to be provided to efficiently operate these systems.

>  BIOCHEMICAL OXYGEN DEMAND (BOD, COD)

Biochemical oxygen demand (BOD) provides an estimate of the
aerobic biological decomposition of the soil organics by
measuring the oxygen consumption of the organic material that can
be readily or eventually biodegraded.  Chemical oxygen demand
(COD) is a measure of the oxygen equivalent of the organic
content in a sample that can be oxidized by a strong chemical
oxidant such as dichromate or permanganate.  Sometimes COD and
BOD can be correlated, and the COD/BOD ratio can give another
indication of biological treatability or treatability by chemical
oxidation.  COD is also useful in assessing the applicability of
wet air oxidation.

>  ELECTRON ACCEPTORS

One of the major determining factors in the fate of biodegradable
contaminants is the availability of sufficient electron acceptors
(i.e., oxygen, nitrate, iron, manganese, sulfate, etc.) to
support biodegradation.  Internal tracers, such as trimethyl and
tetramethylbenzenes, are normal constituents of fuels that are
significantly less biodegradable than benzene, toluene,
ethylbenzene, and xylenes (BTEX), yet have very similar transport
characteristics.  Thus, these "internal tracers" can be detected
downgradient of the remediation area, thereby demonstrating that
monitoring wells are properly placed and the absence of BTEX is a
result of biodegradation.  The concentrations of these tracers
can also provide a basis to correct for the contribution of
dilution to contaminant attenuation.

>  OIL AND GREASE

Oil and grease, when present in a soil, will coat the soil
particles.  The coating tends to weaken the bond between soil and
cement in cement-based solidification.  Similarly, oil and grease
can also interfere with reactant-to-waste contact in chemical
reduction/oxidation reactions, thus reducing the efficiency of
those reactions.

>  DATA REQUIREMENTS FOR GROUNDWATER, SURFACE WATER AND LEACHATE

It is common for groundwater to be contaminated with the water
soluble substances found in overlying soils.  Many of the
required data elements are similar, e.g., pH, TOC, BOD, COD, oil
and grease, contaminant identification and quantification, and
soil and aquifer characterization.  Additional water quality
monitoring data elements include hardness, ammonia, total
dissolved solids, and metals content (e.g., iron, manganese). 
Knowledge of the site conditions and history may contribute to
selecting a list of contaminants and cost-effective analytical
methods.

>  PH

As with soils, the pH of groundwater is important in determining
the applicability of many treatment processes.  Often, the pH
must be adjusted before or during a treatment process.  Low pH
can interfere with chemical reduction/oxidation processes. 
Extreme pH levels can limit microbial diversity and  hamper the
application of both in situ and aboveground applications of
biological treatment.  Contaminant solubility and toxicity may be
affected by changes in pH.  The species of metals and inorganics
present are influenced by the pH of the water, as are the type of
phenolic and nitrogen-containing compounds present.  Processes
such as carbon adsorption, ion exchange, and flocculation may be
affected by pH.

>  Eh

Eh helps to define, with pH, the state of oxidation-reduction
equilibria in aqueous wastestreams.  As noted earlier in the
soils section, maintaining anaerobiosis (low Eh) enhances
decomposition of certain halogenated compounds.

>  BOD, COD, and TOC

BOD, COD, and TOC measurements in contaminated water, as in
soils, provide indications of the biodegradable, chemically
oxidizable, or combustible fractions of the organic
contamination, respectively.  These measurements are not
interchangeable, although correlations may sometimes be made in
order to convert the more precise TOC and/or COD measurements to
estimates of BOD.

> OIL AND GREASE

Oil and grease, even in low concentrations, may require
pretreatment to prevent clogging of primary treatment systems
(i.e., ion exchange resins, activated carbon systems, or other
treatment system components).  Oil and grease may be present in a
separate phase in groundwater.

> SUSPENDED SOLIDS

Suspended solids can cause clogging of primary treatment systems
and may require pretreatment of the wastestream through
coagulation/sedimentation and/or filtration.  MAJOR ANIONS
(chloride, sulfate, phosphate, and nitrate) and CATIONS (calcium,
magnesium, sodium, and potassium) are important for evaluating in
situ geochemical interactions, contaminant speciation, and water-
bearing zone migration.  IRON CONCENTRATIONS should be measured
to determine the potential for precipitation upon aeration. 
ALKALINITY should also be measured when analyzing for major
anions and cations.

> GEOLOGY AND HYDROGEOLOGY

In addition to chemical parameters, geologic and hydrologic
information is usually needed to plan and monitor a groundwater
remediation.  A detailed geologic characterization is usually
needed to assess the uniformity (homogeneity and isotropy) of the
subsurface hydrostratigraphy.  The average rate of groundwater
flow can be estimated from the hydraulic conductivity, hydraulic
gradient, and effective porosity.  Hydraulic gradient is
calculated from groundwater elevations measured in monitor wells. 
Effective porosity is usually assumed based on ranges of values
cited in scientific literature or estimated from pumping tests. 
Hydraulic conductivity is usually estimated from slug tests or
pumping tests.  If an active groundwater extraction system is
being planned, safe aquifer yields and boundary conditions must
be established.  These parameters require that pumping tests be
conducted.

DATA REQUIREMENTS FOR AIR EMISSIONS / OFF-GASES

Predictive modeling may be useful in estimating emissions from a
site or treatment system.  An appropriate theoretical model is
selected to represent the system (e.g., SVE treatment,
incinerator, etc.), and site and contaminant information is used
to estimate gross emissions.  Because many variables affect
emission rates, this approach is limited by the
representativeness of the model and by the input used.  This
approach is usually used as a screening-level or pre-design
evaluation.  Site-specific data to support planning or technology
selection activities (e.g., health risk assessments, pilot-scale
studies) should be performed prior to actual implementation.

Emissions of VOCs and particulate matter during site
disturbances, such as excavation, may be several orders of
magnitude greater than the emission levels of an undisturbed
site.  The potential air emissions from the undisturbed and
disturbed site must be understood before developing a site
mitigation strategy.  EPA has developed a systematic approach,
called an Air Pathway Analysis (APA), for determining what air
contaminants are present and at what level these compounds may be
released into the atmosphere.  The APA method is outlined in a
four-volume series (Air Superfund National Technical Guidance
Study Series, EPA, 1989).

Emissions from treatment systems (e.g., SVE or incinerators,
etc.) may be approximated by using soil contaminant
concentrations and flow or throughput rate.

If the use of thermal combustion or certain oxidation systems is
planned for off-gas treatment of extracted vapors, then an
adequate supply of air/oxygen will have to be provided for in
order to operate these efficiently.

Information regarding the concentration and permeability/percent
flow at discrete vertical intervals is extremely useful in
optimized recovery from the regions of highest contaminant
mass/removal potential.  In other words, if 90% of the
contaminant mass is being extracted from only 5% of the vertical
interval, then off-gas treatment is biased by the large
contribution of uncontaminated soil gas.  Thus, changes in
screened intervals, flow rates, mass transfer rates, and residual
contaminant composition over time can dramatically affect off-gas
treatment and should be evaluated.


Source: 

Marks, Peter J., Walter J. Wujcik and Amy F. Loncar, October
1994. REMEDIATION TECHNOLOGIES SCREENING MATRIX AND REFERENCE
GUIDE, SECOND EDITION.  DOD Environmental Technology Transfer
Committee. NTIS No. PB95-104782.  Reproduced for the Bloomington,
Indiana PCB Superfund Sites Bulletin Board with the permission of
USAEC, SFIM-AEC-ETD, APG, MD.

*************************************************************