First International Symposium
FIELD SCREENING METHODS FOR
HAZARDOUS WASTE SITE
INVESTIGATIONS
October 11-13, 1988
Symposium Proceedings

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THE APPLICATION OF X-RAY FLUORESCENCE TECHNOLOGY IN THE CREATION
OF SITE COMPARISON SAMPLES AND IN THE DESIGN OF
HAZARDOUS WASTE TREATABILITY STUDIES
John J. Barich, III
Environmental Engineer
USEPA, Seattle, Washington
Gregory A. Raab
Lockheed Engineering Management Services Company
Las Vegas, Nevada
ABSTRACT
Site Comparison Samples (SCS) and treatability studies
are contemporary tools used in the investigation and
remediation of hazardous waste sites. Each depends on
the development of large volume samples which are
characteristic of the most difficult conditions at a site
to treat. The use of X-ray fluorescence spectrometers
(XRF) to identify sample locations at a major Superfund
site is described. The subsequent processing of samples
into SCS materials and treatment samples is presented.
INTRODUCTION
As byproducts of a growing technological society
continue to find their way into the environment, the
Environmental Protection Agency (EPA) must face an
ever-expanding problem of how to handle and measure
the harmful byproducts. Before contaminants can be
removed or neutralized, they must be characterized for
type and quantity. Field-Portable X-ray Fluorescence
(FPXRF) instrumentation has been shown to be useful
as a screening tool for heavy metals in soils at
hazardous waste sites (1,2). Instruments are smaller
than their laboratory counterparts, transportable by a
single individual, hermetically sealed, and provide
immediate data from analyses completed with little or
no sample preparation. Analyses are either conducted
in a field laboratory or in situ.
The Bunker Hill Superfund Site is located in the Coeur
d'Alene mining district of northern Idaho. The site is 7
miles by 3 miles. Primary site contaminants are lead
and zinc associated with the mining, beneficiation,
smelting and refining of lead-zinc-silver ores. Lead
smelting commenced in 1917 and zinc refining
operations began in 1927. Operations ceased in 1981.
Over the period of operation of these facilities, metals
were emitted to the atmosphere from both point and
fugitive sources. Tailings from the beneficiation
operations were discharged to the Coeur d'Alene River
prior to the construction and use of tailings
impoundments. These emissions and discharges resulted
in widespread contamination of area with metals (3).
The management of large, complex Superfund sites
requires years of effort by many parties, and is
composed of a series of individual projects and
concurrent tasks. Each task requires development of
its own quality assurance plan. Quality control within
and between projects relating to the same site is an
Roy R. Jones
Quality Assurance Management Office
USEPA, Seattle, Washington
James R. Pasmore
Columbia Scientific Industries Corporation
Austin, Texas
important element of an overall quality assurance
program. Due to the size of the site (21 square miles),
the number of parties involved, and the length of time
until remediation is complete, the use of Site
Comparison Samples (SCS) as tools for applied quality
control allow quality assurance of data between
projects on the same site.
As a result, two requirements presented themselves
simultaneously:
(1)	The need to develop large, homogenous
volumes of heavily contaminated soils for
treatability studies , and
(2)	The need to develop large homogenous
samples of soils which should be processed as Site
Comparison Samples ("SCS project").
Field screening using FPXRF technology was selected
as the analytical tool to ensure that appropriate soils
were developed for both of these purposes.
FIELD ACTIVITIES
Over 500 kilograms of soil was required for the site
studies and the SCS project. The soils needed to be
heavily contaminated and as dry as possible.
Authorization to proceed was received in October
1987. Then current weather conditions in northern
Idaho were unusually dry for that time of year; hence,
any field effort had to be mobilized quickly or
postponed until the following summer. Postponement
was not acceptable. The high cost of the treatability
studies and the critical nature of the SCS project to the
long term quality control program at the site demanded
that soils of known concentrations with known data
quality be obtained; sample collection without
concurrent analysis was not acceptable. Field
activities needed to be supported, therefore, with
instrumentation that could be mobilized quickly, be
portable enough to be moved throughout a large site
and be capable of providing analytical responses to field
personnel on a "real-time" basis.
Equipment
The FPXRF used at Bunker Hill is the X-Met 840
manufactured by Columbia Scientific Industries
Corporation. A technical description highlighting its
applicability for use at hazardous waste sites is
provided by Piorek and Rhodes (4). The X-Met 840 is a
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self-contained, battery powered, microprocessor-based,
multichannel X-ray fluorescence analyzer weighing 8.5
kg. The surface analysis probe is specially designed for
field use. The X-Met 840 is hermetically sealed and
can be decontaminated with soap and water. The probe
includes a radioisotope source of Curium-244, a
proportional counter and the associated electronics.
The source is protected by an NRC-approved safety
shutter.
The electronic unit has eight calibration memories
called "models". Each model can be independently
calibrated for as many as six elements each. These can
be used to measure elements from aluminum up to
uranium assuming two probes with the associated
isotope sources are available. The unknown sample
intensities are regressed against the calibration curves
to yield concentrations. For the Bunker Hill site only
lead and zinc were investigated and only two models
were calibrated. Model 1 was calibrated from
background up to 4980 mg/kg Pb and 9791 mg/kg Zn.
Reference Soil Standards for Quality Control and
Standardization
The commercially available FPXRF systems use
standards to establish calibration curves for
comparison. Heretofore there has not been a demand
for FPXRF systems in hazardous waste screening.
Because of this low demand, there were no standards
commercially available until recently. Columbia
Scientific Industries Inc. (CSI) has produced the first set
of commercially available standards designed
specifically for hazardous wastes in soils. The primary
calibration curves are based on these standards, which
are listed in Table I as CSI. A description of a
calibration technique for X-Ray Analyzers used in
hazardous waste site screening is presented by Piorek
and Rhodes (5).
Sampling
Sampling was completed in two days. Formerly
acquired metals data was reviewed to identify several
potential areas for field screening. These were visited
in an attempt to limit the number of areas actually
screened with the FPXRF. Three areas ranging in size
from less than one to greater than 10 acres appeared to
be appropriate, i.e., existing data suggested heavy
contamination at those locations, the soil matrix was
typical of the area, the areas were accessible and dry,
and samples processing could be accomplished without
disrupting other activities.
FPXRF screening was accomplished in two steps. First,
a series of stations were staked and located on site
maps. A two-person crew was used, one to set stakes
and one to map the sample locations using a Brunton
compass and a 300 foot tape. Second, a two-person
FPXRF crew completed on site screening at each
station. One person operated the instrument and one
served as data recorder.
FPXRF data was acquired at each of the three target
areas at a rate which exceeded one data point per two
minutes. The rate limiting factor at each target area
was the time required to survey the sampling grid, not
to operate the FPXRF instrument. It might have been
possible to eliminate the second person on the FPXRF
crew without compromising the data acquisition rate.
More time was required to move between target areas
than to sample once the team was in an area. Typical
FPXRF measurement times were 20 seconds per data
point.
The levels of contamination as measured by the FPXRF
for stations within the three areas ranged from 2300 to
70,000 mg/kg for lead, and 750 to 27,000 mg/kg for
zinc. These values cannot be compared directly to
contaminant values as obtained by standard SW 846
methods or CLP methods because they use partial
digestions or extracts for analysis and FPXRF provides
total elemental (or bulk) analyses.
Based on a review of these data, bulk soils were
collected at two target areas between stations
exhibiting the highest contamination levels. Sixteen
samples, each with a field weight of at least 60 pounds
was collected. Prior to shipping , each of these was
analyzed in duplicate for lead and zinc by the FPXRF.
Lead contamination in the samples ranged from 15,000
to 67,000 mg/kg. Zinc ranged from 1900 to 28,000
mg/kg. Samples with this level of contamination were
adequate for both the SCS project and the treatability
studies.
SCS DEVELOPMENT
As analytical instrumentation has moved into the field
to complement laboratory instrumentation, so have the
inherent problems of quaLity assurance and the
application of field quality control to compare to data
produced by established "conventional" methods of
sample analysis. Given the problems of variability in
results caused by selection of sampling points on a site,
or by variability in relative large volume samples later
analyzed by small aliquot "high sensitivity"
methodologies, project officers and sample plan
designers have turned to two recognized QC procedures
to establish comparability; splitting samples between
analytical facilities and increased use of Standard
Reference Materials. With the increased use of
contract laboratory facilities, the problems have
increased disproportionately with each added analytical
facility introduced in the larger multiple party
sites.Cost and resource expenditure in time and
logistics increase.
Definition
"A Site Comparison Sample (SCS) is a site specific
reference material which is representative of the type
of problems encountered when analyzing or treating
materials from the site." SCS's:
•	Contain key contaminants in the matrix of
the site;
•	Are available in sufficient numbers to
satisfy numerous site management and
QA/QC purposes;
•	Exhibit the lowest possible coefficient of
variation (cv);
•	Are managed by an organization capable of
being a depository of analytical results,
providing a common management point for
quality assurance, inter- and
intra-laboratory studies.
SCS differ from Standard Reference Materials (SRM) by
virtue of being site specific, and not produced under a
protocol requiring the pre-release rigorous analytical
method specific, statistically validated
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characterization applied to SRMs. They also differ
from Performance Evaluation (PE) samples used in
studies to directly compare inter-laboratory results
under a defined methodology. A SCS stock could
conceivably provide the material for a SRM or PE, but
would require those protocols to be applied before so
identifying.
Quality assurance of data developed from multiple
sources presents a complex situation. One major
problem is the question of sample variability and
comparability caused by distribution of compounds of
interest on a site. A second is the variability inherent
in, and between, analytical methods, particularly due to
matrix interference effects. Two common techniques
for dealing with these problems are the use of "split"
samples and analyses of Standard Reference Materials.
Splitting increases the risk of magnifying the problem
due to distribution; standard reference materials
seldom reflect the matrix effects present in "natural"
site samples.
Late in 1984 and early in 1985, the concept of
manufacturing a homogenized bulk sample was
developed to provide vendors of propietary soil
stabilization services uniform materials for evaluation.
The use of screening techniques to define areas of
concern on a site was directly applied to statistically
choosing sources of material to provide a sample
representative of the more highly contaminated
material distributed in the matrix of the site. Mixing
methods were investigated from the viewpoints of cost,
available resources, and practicality. Separate
elements of the methodology were tested on available
materials at various sites. Protocols and standard
operating procedures regarding from where to select
the material, how to homogenize it, and how to fill the
bulk sample containers in a manner that would reduce
bias in the distribution of the material to the large bulk
containers were developed.
The question of how to mix bulk samples of site matrix
materials to achieve a relatively homogenized material
had to be answered empirically. Because of the wide
variety of particle sizes, moisture content, cohesive
characteristics and distribution of contaminants, it was
decided to thoroughly mix the material for the first
1400 pound sample by manually quarter piling through
several cycles; and then do a multiple random fill of
enough buckets (sixty-nine) to meet all projected
needs. It was labor intensive, and took 4 people most
of one day.
The sequence of events discussed in the creation of the
bulk reference materials led logically to the concept of
further treatment of the bulk material to provide a
"Site Comparison Sample (SCS)" for each major site.
Initially, approximately two dozen 8 oz. sample
containers were "broken out" of a bucket, and used for
comparative analyses to determine the degree of
mixing achieved. Some pressure was felt to supply
some of these for comparison analyses instead of
splitting samples. At that time, resources were not
available to so use the material; no statistically sound
evaluation of the material existed to back up any
results.
It cannot be emphasized too heavily that the SCS is not
be to considered a sample that represents the actual
concentration of a contaminant at any given point on a
site. Also, it cannot initially be considered as a true
SRM, although it may be possible to up-grade it's status
if a large number of SCS are generated, and enough
analytical resources are available to utilize a portion of
the banked samples for a statistically sound
standardization analyses. The concept of the SCS is to
produce a material that can be used in lieu of split
samples, and provide a data bank for both continuing
and retroactive analysis of variation due to differing
methods of sample acquisition, handling, and analyses.
As the discrete SCS will be archived in controlled
storage, the effects of holding time can be
demonstrated for each set by continuing
characterization analyses. The more SCS analyzed, the
stronger the statistical evaluation of all data generated
by analyses becomes; not only of the SCS bank itself,
but of the sample of record data and the laboratories
producing the data.
In Statistics there is the "The Central Limit
Theorom": It states:
"From an unknown distribution a random sample
size n is obtained. If n is allowed to become
larger, the sample mean will behave as if it came
from a Normal distribution, regardless of what
the parent distribution looked like."
John Webber, Statistician for EPA Office of Policy and
Planning, had provided a table illustrating how
Normality affects a sample population (Table II) taken
from a universe, and reverse logic suggests that very
low variances could be expected from discrete samples
of n|1( especially if the discrete samples were
produced by actually filling the randomly selected
sample containers with a series of multiple portions
selected at random from the bulk n^ material. (The
"double random" referred to hereafter.)
Reasoning from this point, if n is sufficiently large, and
then thoroughly mixed or homogenized, multiple
random creation of n^ should result in a low variance
that approaches the "true" value of the concentration
of the mean of n. As the number of random selections
used to create np, increases, the coefficient of
variation should decrease.
Through the balance of 1985 and into 1986, the
analytical results from the stabilization tests made on
the bulk materials were reviewed Protocols were
developed through experimentation to mix sludges of
water, sediment and hydrocarbon products. A protocol
for groundwater SCSs was developed
Finally, in late 1986 an opportunity presented itself to
produce an actual SCS for a large, established
Superfund site. This dovetailed with the trial of the
X-Met FPXRF equipment, and made it possible to more
soundly screen the bulk "raw material" for both
stabilization studies and two SCSs; one "high" range and
one "low" range. A fairly ambitious design was
proposed to produce between 300 and 500 8 oz. samples
in each range.
Experience with the homogenization of the original
stability samples suggested that it would be desirable to
utilize more efficient methods of mixing the hulk
sample material. Accordingly, a "drum roller" was
obtained, and 55 gal O.T. steel drums were modified
with two interior deflection vanes similar to those used
in industrial dry mixing of materials. The bulk sample
material was batched through this drum and then spread
out in a distribution box for the double random
selection of the SCS samples. The available quantity of
material dictated that only a single SCS be produced, so
the "high" and "low" bulk retains were incorporated into
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a single batch for processing.
REFERENCES
The 600 aliquots have been "banked", and a master
random distribution list prepared. From the bank, an
initial set of 10 SCS (the first block on the list) were
supplied to the USEPA Environmental Monitoring
Services Laboratory, Las Vegas, NV. for preliminary
characterization analyses. At the same time, a
principle contractor was issued the next 30 samples for
release to their contract laboratories for the same
purpose. All analytical data results are to be reported
to Region 10, and a running control chart of results
developed.
As the number of samples analyzed increases, the data
will become progressively more refined, and amenable
to other statistical analyses to more closely define the
sources of variability, from laboratory, to method, and
to a certain extent, the effects of holding time. Data
currently available are presented in Figures 1 and 2.
Although the number of data points are limited, there is
a suggestion that inter-laboratory differences may be
important (Figure 1), and that overall cv's are low (less
than 30%).
As related, this is an ongoing developmental effort.
Preliminary data indicate the approach is sound. For
middle to large site hazardous waste operations, and for
long term ambient monitoring projects, the economies
of scale would apply. For improved data quality and
scientific credibility the concept is entirely appropriate
and defensible. The practical application awaits
resources and initiatives on the part of the user
programs.
(1)	Chappell, R. W., Davis, A. O., Olsen, R. L.,
"Portable X-Ray Fluorescence as a Screening
Tool for Analysis of Hazardous Materials in Soils
and Mine Wastes," the 7the National Conference
of Management of Uncontrolled Hazardous Waste
Sites, Hazardous Materials Control Research
Institute, Silver Spring, Maryland, 1986.
(2)	Raab, G. A., D. Cardenas, and S. J. Simon,
"Evaluation of a Prototype Field-Portable X-Ray
Fluorescence System for Hazardous Waste
Screening," EPA/600/4-87/021, U.S.
Environmental Protection Agency, Las Vegas,
Nevada, 1987.
(3)	.Gulf Resources and Chemical Corporation,
"Bunker Hill Site Remedial
Investigation/Feasibility Study for Unpopulated
Areas," April 24, 1987.
(4)	Piorek, S., Rhodes, J. R., "Hazardous Waste
Screening Using a Portable X-ray Analyzer,"
Symposium on Waste Minimization and
Environmental Programs within DOD, American
Defense Preparedness Association, Long Beach,
California, April 1987.
(5)	Piorek, S., Rhodes, J. R., "A New Calibration
Technique for X-Ray Analyzers Used in
Hazardous Waste Screening"
Standard Elements:
Name
Table I
Concentrations of Standards
Pb	Zn	Cu	As
(All values are in mg/kg)
1 CSI IB
0
4790
4790
6970
2 CSI 2B
0
0
0
11,340
3 CSI 3B
4980
0
0
0
4 CSI 5B
240
240
8160
7740
5 CSI 6B
484
482
6300
5590
6 CSI 7B
4760
4900
3810
11,070
7 CSI 8B
1474
983
2950
4530
8 CSI 9B
1990
2970
982
3390
9 CSI 10B
2930
3910
I960
2250
10 CSI 11B
2440
6360
490
1140
11 CSI 12B
3405
8270
243
565
12 CSI13B
4126
9791
96
224
13 CSU4B
0
0
4950
0
14 CSI15B
0
4950
0
0
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Table II
Illustration of How Normality Affects Samples
Let us phrase the question "How many samples do I need to be within Q
sigma "s" (Standard Deviations) of the true value?":
Confidence	Confidence	Confidence
90%	95%	99%
Q Sigma Normal Worst	Normal Worst	Normal Worst
"s" Case	Case	Case
2s
1
3
1
5
2
25
Is
3
10
4
20
6
100
0.75s
5
18
7
36
10
178
0.5s
11
40
16
80
22
400
0.4s
17
63
25
125
34
625
0.3s
31
112
43
223
61
1112
0.2s
68
250
97
500
136
2500
0.1s
271
1000
385
2000
543
10000
from: "Statistical Considerations in Sampling Hazardous Waste Sites", John Warren
E.P.A./O.P.R.M.
Figure 1
BETWEEN LABORATORY COMPARISON
Laboratory A
Target Chemical
(///A Laboratory B
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Figure 2
SCS COEFFICIENT OF VARIATION
All Laboratories by Chemical
DISCUSSION
HAROLD VINCENT: How were you going to apply the zeolites to the
problem?
JOHN BARICH: Our first step was to determine whether or not the zeolites
would be a useful soil amendment. If the answer to thai was a strong yes, then
the application technique would have been the next thing we would have looked
at.
HAROLD VINCENT: That's in place of removaP
JOHN BARICH : In place of removal, yes. We had literally many square miles
of land whose condition needed to be improved. There was just not enough
secure landfill capacity, to do anything other than in situ
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