United States
                    Environmental Protection
                    Agency
 Environmental Monitoring
 Systems Laboratory
 Las Vegas NV 89114
                    Research and Development
 EPA-600/S4-84-028 May 1984
&ER&          Project  Summary
                    Multielemental  Analytical
                    Techniques for  Hazardous
                    Waste Analysis:  The  State-of-
                    the-Art

                    T.A. Hinners, J.A. Oppenheimer, A.D. Eaton, and L.Y.C. Leong
                      Based on a comprehensive review of
                    the literature, the multielemental tech-
                    niques of inductively coupled plasma
                    optical emission spectroscopy (ICP), x-
                    ray fluorescence spectroscopy (XRF)
                    and instrumental neutron  activation
                    analysis (INAA) have been compared
                    for the determination  of  antimony,
                    arsenic, barium, beryllium, cadmium,
                    chromium, copper, lead, mercury,
                    nickel, selenium, silver, thallium and
                    zinc in hazardous  waste  matrices.
                    These particular elements were chosen
                    because they are on the list for classifying
                    a waste as hazardous and/or on the
                    U.S. Environmental Protection Agency's
                    (EPA's) Priority Pollutant  list.  Each
                    technique is discussed with respect to
                    theory, anticipated  interferences and
                    correction techniques, observed pre-
                    cision  and accuracy for simple and
                    complex matrices, detection limits, and
                    cost.
                     The literature review revealed that
                    there has not been sufficient analytical
                    work on complex matrices to fully
                    compare these three techniques for
                    many of the priority pollutant elements.
                    For those elements  with a sufficient
                    database to  compare precision  and
                    accuracy  by the three techniques
                    (arsenic, barium, chromium, lead,
                    nickel and zinc) ICP offers an advantage
                    in detection limits and  precision,
                    whereas XRF may be very useful as a
                    preliminary screening technique due to
                    its ability to provide rapid, semi-quanti-
                    tative data even at trace levels. XR F and
                    ICP have significant cost advantages
over INAA, requiring much less capital
expenditure and lower labor costs.
  This Project Summary was developed
by EPA's Environmental Monitoring
Systems Laboratory, Las Vegas, NV, to
announce 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
  Information on the pollutant content of
wastes is required to properly assess the
hazard and the need for waste manage-
ment or for remedial action. Multielemental
analytical techniques are attractive as the
means to  obtain inorganic  content
information on wastes rapidly and/or
economically. Although  multielemental
techniques are  widely used,  complex
wastes and contaminated soil present the
potential for interferences not  normally
encountered. The elements antimony
(Sb), arsenic (As), barium (Ba), beryllium
(Be), cadmium  (Cd), chromium  (Cr),
copper  (Cu), lead (Pb), mercury  (Hg),
nickel (Ni), selenium (Se), silver  (Ag),
thallium (Tl) and zinc (Zn) are identified in
federal  publications as  pollutants  of
special concern.
  The present  work  is a literature
evaluation of currently available multi-
elemental techniques in order to compare
the advantages and  limitations for the
analysis of the  specified elements  in
hazardous wastes or in  contaminated
soils. The currently  available multiele-
mental  techniques  for trace  element

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determinations are isotope dilution mass
spectrometry, spark source mass spectro-
metry, multielemental atomic absorption
spectroscopy, voltammetry, inductively
coupled plasma optical emission spectro-
scopy, instrumental  neutron  activation
analysis, and x-ray fluorescence spectro-
scopy. Each technique was evaluated in
terms of accuracy,  precision, detection
limits, severity of matrix interferences
and economic factors.

Procedure
  A preliminary evaluation was conducted
to select the most promising techniques
for an extensive literature search and a
survey of users.  A thorough  literature
search  was accomplished  with  the
assistance of the Lockheed  computer
system DIALOG which enables the user
to search selected abstract files. The files
searched included Chemical  Abstracts,
National Technical  Information Service
(NTIS), Compendex (collection of engineer-
ing journals), Agricola (collection of
agricultural journals). Foundation Grants
Index, Dissertation Abstracts,  Enviroline
(collection  of  environmentally oriented
journals), Scisearch,  Pollution Abstracts,
SSIE  Current Research, and Conference
Papers  Index. More  than  50 different
journals  and abstracts  were searched.
Any publication which provided informa-
tion  on  detection limits, precision or
accuracy for any of the selected elements
was included in the data set.  This was
accomplished with the aid of the computer
system  Datatrieve on the VAX 11/780
computer.  In addition,  a questionnaire
was sent out to users of the various
techniques to  solicit the most recent
information.
   Finally, an assessment and comparison
of the  most promising techniques for
analyzing hazardous  wastes  was con-
ducted with respect to analytical capabili-
ties  and limitations, detection limits,
precision, accuracy, complexity of sample
preparation, availability of commercial
services and cost.

Results and Discussion
   Table  1  summarizes the advantages
and disadvantages of each of the potential
analytical techniques.  Isotope dilution
mass spectrometry and spark  source
mass spectrometry possess unacceptable
economic factors of  large capital cost,
expensive  labor costs,  and  lengthy
analysis time. Multielemental  atomic
absorption spectroscopy is  not currently
available commercially, and has not been
fully  investigated. Voltammetry lacks
sufficient selectively to be developed as a
Table 1 .    Comparison Summary of Multielemental Techniques (+ = advantage, - = disadvantage!
                                                  Technique
            Property
MAAS  AAS  ICP  XRF   INAA  IDMS  SSMS VM
Minima/ Operator Skill Required
Cost
Detection Limits
Freedom from Interferences
Precision
Availability
Working Range
Large Number of Elements
Analysis Time
MAAS = Multielemental Atomic Absorption Spectroscopy.
AAS  =Atomic Absorption Spectroscopy.
ICP   =lnductively Coupled Plasma Optical Emission Spectroscopy.
XRF  =X-Ray Fluorescence Spectroscopy.
INAA  -Instrumental Neutron Activation Analysis.
IDMS  = Isotope Dilution Mass Spectrometry.
SSMS = Spark Source Mass Spectrometry.
VM   = Voltammetry.
method for routine multielemental analy-
ses of complicated  matrices. ICP, INAA
and  XRF  were judged to be the most
promising multielemental methods for
the determination of the specified ele-
ments in hazardous wastes.
  The numerical results of the literature
search are summarized by element and
technique in Table 2. A minimal amount
of data was found for x-ray fluorescence
determination of Ag, Cd, Sb, Hg, Se and
Tl. XRF has traditionally  been used for
determining  major elements and this
explains  the  paucity  of data for these
elements, which typically occur at fairly
low  concentrations in environmental
samples. For neutron activation there is a
minimal amount of data available on Be,
Pb and Tl because these elements do not
possess isotopes with adequate reaction
cross-sections to form sufficient gamma-
emitting radio-nuclides. For ICP, little data
are available for Hg or Tl because these
elements  can be determined to lower
Table 2.    Number of Records in the Litera-
          ture by Element and Technique

                 Technique
Element
Ag
As
Ba
Be
Cd
Cr
Cu
Hg
Ni
Pb
Sb
Se
Tl
Zn
ICP
34
50
87
55
110
137
198
9
149
166
27
27
7
164
INAA
10
18
53
1
15
54
12
18
34
6
31
18
0
35
XRF
1
11
82
0
7
96
66
4
116
56
1
3
0
78
Total
45
79
222
56
132
287
276
31
299
228
59
48
7
277
          concentrations using cold-vapor AAS and
          furnace AAS, respectively; and few
          standard reference materials have these
          elements  present  at concentrations
          measurable by ICP.  Information entries
          on the specified elements number 1220
          for ICP, 521 for XRF and 305 for INAA.


          Inductively Coupled Plasma
          Optical Emission Spectroscopy
          (ICP)
            Inductively coupled plasma is a form of
          optical emission spectroscopy that utilizes
          an argon plasma as the excitation source.
          Optical  emission spectroscopy is a
          technique that involves heating a sample
          in  a flame, electric arc, electric spark or
          plasma to produce a population of excited
          atoms and ions that return to the ground
          state by emitting radiation. Each element
          emits light of a characteristic wavelength,
          and signal  response is  proportional  to
          concentration level.
            Accuracy is affected by a number of
          potential sources  of  error. Analytical
          errors in ICP are caused by direct spectral
          and  background interferences due  to
          matrix elements,  sample interaction
          with  the  plasma,  variable physical
          characteristics of different matrices and
          instrumental drift. Accuracy is assessed
          by examining percent  recoveries  for
          analytes added to samples or by agree-
          ment with certified values for reference
          materials,  such as Standard  Reference
          Materials (SRMs)  from the National
          Bureau of Standards.  For 12 of  the  14
          elements there are sufficient data
          available to make some assessments for
          determinations  by ICP.  For Hg  and Tl
          there are no available data on precision
          and accuracy. This is principally because

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 Hg and Tl are usually determined with far
 greater sensitivity using cold-vapor AAS
 and furnace AAS, respectively. In addition,
 there are no SRMs with certified values
 for Hg or Tl at levels measurable by ICP.
   The ICP instrumental analysis  rate is
 typically 30-100 samples  per day. The
 rate-limiting step for analysis of solid
 samples is the required preliminary
 digestion to provide  a liquid for introduc-
 tion  into the instrument. Although the
 digestion can be set  up for batches of 50-
 100  samples, the overall digestion time
 for these samples is  several hours. Many
 laboratories  offer ICP analysis at rates
 ranging from $20-$100/sample, depend-
 ing on the  number of elements  being
 analyzed  and  the  complexity  of the
 sample preparation.

 Capital Investment  (ICP)
 $50K (Basic ICP) Add $10K for sampler
       and printer
S100K (ICP/AAS full system - Monochro-
       mator or 20 channel Simultaneous
       ICP)
$175K (Top-of-the-Line Simultaneous
       ICP with scanning capacity and 40
       channels).


 Instrumental Neutron
 Activation Analysis (INAA)
   Instrumental neutron activation analy-
 sis is a nuclear technique in which the
 sample is exposed to a neutron flux and
 the induced radioactivity  is determined
 using gamma ray spectrometry. Charac-
 terization and  measurement  of the
 energy of the emitted gamma rays yields
 qualitative and quantitative analysis of the
 sample. The advantages of this technique
 are its nondestructive nature, minimum
 sample manipulation requirements and
 low detection limits. The main limitations
 are matrix interferences, required access
 to a neutron source (with associated high
 capital costs),  the  fact that not all
 elements are amenable to this type of
 analysis, and the possibility that the small
 solid specimen which is analyzed may not
 be homogeneous  and representative of
 the bulk sample.
   In  multielemental  analysis by  INAA,
 detection limits must be sacrificed some-
 times in order to avoid serious interferen-
 ces with the other elements being deter-
 mined and the major  matrix constituents.
 Beryllium cannot  be analyzed by INAA
 because it  forms no gamma-emitting
 radionuclide. Only one gamma-emitting
 nuclide exists for Pb and for Tl, and the
 very low reaction cross-section for these
 nuclides implies poor detection limits for
 Pb and Tl by INAA.
  Analytical errors in INAA occur when
factors affecting  the formation of the
radioactive isotope or detection of the
emitted radiation differ significantly
between the sample and the standard.
Formation of the radioactive  isotope  is
dependent on the neutron flux density,
the number  of target  nuclei, and the
reaction cross-section.  The number  of
target  nuclei and the  reaction cross-
section are intrinsic properties of the
sample, and variations in the flux density
hitting samples and standards are trivial
due to constant rotation of the specimens
within the reactor. The detection of the
emitted  gamma-rays is  primarily a
potential source of error. The accuracy of
the total  photopeak count must be
corrected  for  systematic errors arising
from spectral interferences, peak-broaden-
ing errors, absorption errors, and instru-
ment dead-time  losses.  Random errors
result  from counting  statistics  and
procedural uncertainties.
  Using several irradiations for different
periods and counting after different decay
periods eliminate many potential sources
of error. Different irradiation times allow
the analyst to obtain data for short-lived
isotopes without generating high specific
activity from  longer lived isotopes (with
a potential for large dead-time correc-
tions). Alternate  decay periods make it
easy to resolve peaks of similar energy
but different  half-lives. Sophisticated
computer software is essential for
performing these corrections.
  Precision improves with increasing
concentration for INAA while the accuracy
is excellent for the high levels but poor for
some of the elements at low levels (<10
fjg/g). No INAA data were reported for Ag,
possibly because its INAA detection limit
near 1  A/g/g  is comparable to, or larger
than, the level in most terrestrial materials
used as SRMs.  The precision exceeds
20% for As at 10/jg/g, for Ba at 10Ofjg/g,
for Cr at 10 fjg/g, for Ni at 10Ofjg/g, and
for Sb at <1 /ug/g. The poor Ni precision
probably  reflects measurements with
reactors having few fast neutrons, while
Ba  suffers from  Fe interference.  The
accuracy exceeds the arbitrary acceptance
criterion of 100 ± 20% recovery at, and
below, a level of 10/ug/g for Cd, 10^/g/g
forCr, <1 /ug/g for Hg, 10/ug/gforNi, and
10/ug/g for Sb.
  INAA involves  no elaborate  sample
preparation procedures. Solids are
ground, and a representative aliquot is
mixed with cellulose and pressed into a
standard size pill. Dissolved material  in
liquids can be analyzed after freeze drying
and pelletizing the resulting powder.
Chromium contamination at the level of
0.5//g/g sometimes results from the tool-
steel dies used to prepare the pellets.
  The  rate limiting step  is the time
required before interfering radiation  has
decayed sufficiently to allow long-lived
isotopes to be counted. This can be as
long as 30 days for the analysis  of long
half-life isotopes such as Cr51. Throughput
can also depend on the cross-sections of
matrix interferents as well as the half-life
of the  element of interest. If  matrix
elements  become  highly radioactive,  it
may be difficult  to detect  the small
amount of radiation emitted by  a trace
element.  In this  case, provided  the
interferents have shorter half-lives than
the elements of interest, it is necessary to
wait until  the interfering  radiation  has
decayed  away before counting  the
sample.
  Typical cost for single-sample multiele-
mental analysis is $400  with delivery
times  of  5-6 weeks  after  receipt of
sample. Availability of commercial  ser-
vices is quite  limited because  of  the
difficulties in acquiring  access to a
nuclear reactor.  Services which  use
university reactors are  available,  but
typically only on a research  basis  and not
for routine analyses.  It  is possible to
perform INAA using a radioactive element
as a neutron source (such  as Cf264), but
the flux obtained from such a source is
typically not adequate for trace level
work.

Capital Investment (INAA)
  $500K
  (requires permit)

  $135K and up
  depending on
  required length
  of irradiation,
  sample size,
  and neutron flux
  $30K and up
Nuclear Reactor (or
access to irradiation
source)
Commercial Irradia-
tion Cost (for short-
lived  isotopes, the
detector must be at
the irradiation site)

Gamma-Ray Spec-
trometer and Detec-
tor
X-ray Fluorescence
  X-ray fluorescence is a form of spectro-
scopy in  which a sample is bombarded
with x-rays and inner-orbital electrons
are  ejected from  atoms  within the
sample.  The resulting  excited  atoms
dissipate  energy by filling these vacancies
with electrons from  higher energy levels
and emitting characteristic x-ray photons.
This secondary  emission of x-rays is
referred to as fluorescence and, because
only certain emissions occur, the x-ray
spectral  lines are indicative of the
elements present. Element concentra-
tions are deduced from  the x-ray count

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rate of a characteristic line. The advan-
tages of this technique are basically the
same as  those of neutron activation
analysis. XRF  is nondestructive, allows
for direct analysis of solid samples, and
exhibits useful detection limits. Disad-
vantages of this technique are the
severity of matrix effects,  difficulty in
analyzing liquid samples directly, and the
fact that elements with atomic numbers
less than  10 cannot be determined with
conventional instrumentation.
  In  XRF  a significant portion of  the
secondary and primary x-rays is absorbed
by the major constituents comprising the
sample matrix. The  key to obtaining
reliable x-ray fluorescence data is proper
sample preparation. The sample must be
prepared in a manner which will minimize
matrix absorption  problems and also
ensure homogeneity (which is important
because incident x-rays do not penetrate
far into the sample). Conversion of x-ray
count rate to element concentration will
not be accurate unless the sample mass
absorption effects can be compensated
for  or eliminated. Interferences  which
can occur in addition to matrix absorption
are direct spectral  interferences,  back-
ground radiation interferences, and self-
absorption of fluorescent radiation.
  XRF precision does not  often drop
below the arbitrary acceptance value of
20% for the  relative standard deviation
until the concentration is greater than 10
fjg/g and, in some cases (Ba, Cr, Ni), not
until  the  concentration  is greater than
100 /jg/g. Barium and chromium, along
with Pb, are also the elements that exhibit
poor accuracy at lower concentrations.
  Commercial analysis costs range $5-
$100 per sample depending  upon  the
quantity of samples and the complexity of
the  analyses. No commercial services
offer analysis for the 13 listed elements
(excluding Be) that are measurable; by
conventional XRF  instruments. The
availability of commercial XRF services is
much more limited than for ICP.

Capital Investment (XRF)
  $75-85K (Energy Dispersive) add $15 -
  20K for sampler
  $95K (Wavelength Dispersive, sequen-
  tial)
  $125K (Wavelength Dispersive  - more
  intensity)
  $350K (Wavelength Dispersive, Simul-
  taneous, Deluxe)

Comparison of ICP, INAA
and XRF Techniques
  ICP is the only technique, among the
three, capable of analyzing all of  the 14
specified pollutant elements. Beryllium
cannot be determined by INAA (because
its radionuclide emits no gammas) nor by
conventional  XRF  (because the  long
wavelengths of the emitted x-rays cannot
be dispersed). Pb and Tl are too  weakly
activated to be successfully determined
by INAA, except  at very high concentra-
tions. The lack of a substantial database
for XRF analysis of  trace  elements
reflects the trend for it to be  used most
frequently as a major element technique.
Table 3 ranks these three techniques for
eight characteristics. Table 4  shows the
median detection limit for each element
as a function  of instrumental technique.
  A comparison of the accuracy and
precision for  the three techniques was
obtained by using data for rock, sediment,
soil, sludge, coal, oil, steel, and pottery.
The comparison was made by calculating
the percentage  of sample  data where
recovery (accuracy) exceeded an arbitrary
criterion of 100  ± 20% and where the
relative standard deviation (precision)
exceeded  an  arbitrary criterion of 20%.
The results of these  calculations are
shown in Tables 5 and 6.
  For some of the elements, insufficient
data were available for all three tech-
niques, and a valid comparison could not be
made. This is the case for the precision
data on Ag, Be, Cd, Hg, Pb, Sb, Se, andTI.
I n terms of precision, ICP appears to yield
the  best results for almost all the
remaining elements. ForZn the precision
differences among the three techniques
are insignificant. Cu has insufficient data
by INAA to allow a comparison. For XRF
and INAA, there are only sufficient data
for comparison of As,  Ba, Cr, Ni, and Zn.
Table 6 shows that these two techniques
give approximately the same criterion
percentages for As, Ba, Cr and Zn while Ni
results are better by XRF than by INAA.
  Inspection of the accuracy data indicates
insufficient information for Ag, Be, Hg,
Sb, Se, and Tl.  Of the eight remaining
elements, ICP gives the best  results  for
Cd, Cr, Cu and Ni. For XRF and INAA there
are insufficient data for comparison of As.
INAA gives better results for Ba, and XRF
Table 4.    Comparison of Median Detection
          Limits (ug/g) for the Selected Ele-
          ments as a Function of Instru-
          mental Technique
                     Technique
   Element
                ICP*
    XRF    INAA
Ag
As
Ba
Be
Cd
Cr
Cu
Hg
Ni
Pb
Sb
Se
Tl
Zn
0.3
3
0.05
005
0.2
03
0.2
3
0.8
2
3
2
2
2
—
09
10
—
5
1
1
2
1
2
—
13
—
3
1
0.2
53
—
15
2
6
0.3
160*"
—
0.08
0.3
—
5
 'Assuming digestion of WO mg of solid
  sample with 10 ml of acid.
**Ftesult for Ni is probably biased by unoptimized
  procedure.
Table 5.
 Element
          Percentage of Sample Data Where
          Accuracy (Recovery) Exceeds
          Arbitrary 100 ± 20% Criterion

                   Technique
            ICP
XRF
INAA
Ag
As
Ba
Be
Cd
Cr
Cu
Hg
Ni
Pb
Sb
Se
Tl
Zn
si%(i6r
15%(13)
1 1%(36)
47%(15)
39%(26)
33%(54)
5%(76)
NA
J9%(47)
44%(63)
NA
NA
NA
19%(43)
NA}
O%(2)
20%f71J
NA
75%(4)
35%(79)
41%(39j
NA
21%(90)
29%(34)
NA
0%(1}
NA
2%(49)
NA
0%(2)
0%(16l
NA
50%(4)
44%(18J
10O%(1)
20%(5)
62%(13J
25%(4!
86%(7)
0%(1 )
NA
12%(17)
* Numbers in parentheses indicate the quantity
 of data records for a technique.
Y'NA" indicates information Not Available.

gives better results for Zn. The case of Pb
is somewhat misleading for it appears
that INAA gives comparable results to
XRF. This observation would be disturbing
since INAA is known to be a poor trace
 Table3.   Comparison of ICP. INAA and XRF Characteristics
    Characteristic
                       Relative Ranking
                        (Best to Worst)
 1 Rapid Analysis
2 Detection Limits
3 Precision and Accuracy
4 Ease of Error Corrections
5 Low Cost
6 Flexibility
 7 Availability
8 Ease of Sample Preparation
                       XRF>ICP>INAA
                       ICP, INAA>XRF
                       INAA>ICP. XRF
                       INAA, ICP>XRF
                       ICP>XRF»INAA
                       ICP, INAA>XRF
                       ICP>XRF>INAA
                       INAA>XRF>ICP

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Table 6.    Percentage of Sample Data Where
          the Relative Standard Deviation
          Exceeds Arbitrary 20% Criterion

                  Technique
Element
Ag
As
Ba
Be
Cd
Cr
Cu
Hg
Ni
Pb
Sb
Se
Tl
In
ICP
20%(5i*
1 4%(7)
O%(12)
0%(7)
4%(27)
0%(28)
12%(49)
NA
16%(43)
3%(30)
0%(2)
NA
NA
2%(40)
XFtF
AMt
40%(5)
8(12)
NA
10O%(1)
21%(34)
29%(17)
NA
18%(38)
18%(1 1)
NA
0%(1)
NA
0%(20)
INAA
NA
45%(1 1)
6%(35)
NA
NA
19%(26)
0%(1)
NA
53%(15)
NA
46%(13)
0%(2)
NA
8%(12)
^Numbers in parentheses indicate the quantity
 of data records for a technique
Y'NA" indicates information Not Available.

technique for  Pb. Closer  inspection
revealed that the  INAA Pb  results  are
based on only four samples with extremely
high levels of Pb.
  The relative importance of the various
sources of analytical error for the three
techniques is shown in Table 7. For both
INAA and XRF, the counting errors  are
the  least significant error  and never
amount  to  more  than 1%. For XRF,
sample preparation is the most important
source  of error because it is directly
related to the..nonspectral errors which
are  a  major problem  in  XRF. Unless
sample preparation is adequate, satisfac-
tory data will  never  be generated no
matter  how  elaborate the  nonspectral
correction procedures. Nonspectral errors
rank second  in importance followed by
spectral interference  errors and then
instrumental  errors. The different types
of spectral interferences are well docu-
mented and can usually be anticipated
and corrected.  Adequate correction for
spectral and  nonspectral errors is com-
pletely dependent on the operator's skill
and experience.  Instrumental  error
results  in a small residual background.
This error can be corrected by plotting the
spectral background as a function of the
Compton scattered radiation and discern-
ing the value of the y-intercept. For INAA,
both instrument and sample preparation
errors are minimal. The major source of
INAA error is spectral interference, and
the  major requirement  for  adequate
correction  is an experienced  operator
skilled  in making  confirmative isotope
measurements for an element. The major
source of error for ICP is sample prepara-
tion  because of the potential for contam-
ination  or  loss of analyte during this
step. Spectral interference is  the  next
most important source of error  in ICP
because correction is dependent on the
skill  and experience  of the operator  in
recognizing these errors. Instrumental
drift  is  usually not a serious ICP problem,
if re-calibration is performed periodically.
  XRF  is far superior to ICP and INAA in
its ability  to  generate  a rapid semi-
quantitative analysis scan of a sample in
less than 5 minutes. The sample prepara-
tion  time for ICP takes well over an hour
while  INAA  requires  weeks  to allow
sample activity decay for certain elements.
XRF could, therefore,  have  utility as a
preliminary  screening  technique for
hazardous waste samples of  totally
unknown composition.
   ICP  is the least costly of the three
methods in terms of both capital invest-
ment and  operating  costs. In  addition,
commercial services  for  ICP are low in
cost compared to XRF or INAA. The cost of
operating an XRF system is comparable
to ICP although more extensive computer
facilities are required. The expense  of
operating an INAA system is on the order
of 5 to 10 times that of ICP or XRF, and
even commercial service fees are 5 to  10
times higher.
Conclusions
  After considering detection limits,
precision, accuracy, errors and correction
procedures, expense, flexibility, availabil-
ity and sample preparation, ICP appears
to be the multielemental technique most
amenable  to analysis of  hazardous
waste samples; XRF may be most useful
as a preliminary  of hazardous waste
samples; and XRF may be most useful as
a preliminary screening technique. Any
literature review suffers from:
 a. A lack of comparable databases for
    individual techniques with respect to
    sample types, definition of detection
    limits, and elements.
 b. An inherent bias that published data
    are typically the best available and
    not  indicative of  what  may be
    observed in routine applications.
  A  laboratory  comparison of identical
samples  by all three  techniques  is
necessary before a more comprehensive
comparison can be made for determining
these  elements in wastes that are
potentially hazardous.
Table 7.   Ranking the Importance of Error Sources for ICP, INAA and XRF

                                       Error Categories
Technique
ICP
INAA
XRF
Sample
Prep
1
3
1
Instrumental
3
4
4-5
Counting
5
5
Non-
Spectral
4
2
2
Spectral
2
J
3
1 = High (very important).
5 - Low (Trivial).

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       The EPA author Thomas A. Hinners (also the EPA Project Officer, see below) is
         with the Environmental Monitoring Systems Laboratory, Las Vegas, NV89114;
         J. A. Oppenheimer, A.  D.  Eaton, and L.  Y. C.  Leong are  with James M.
         Montgomery, Consulting Engineers, Pasadena, CA 91101.
       The complete  report, entitled  "Multielemental  Analytical  Techniques for
         Hazardous Waste Analysis:  The State-of-the-Art," (Order No.  PB 84-178 425;
         Cost: $13.00, subject to change) will be available only from:
              National Technical Information Service
              5285 Port Royal Road
              Springfield, VA 22161
              Telephone: 703-487-4650
       The EPA Project Officer can be contacted at:
              Environmental Monitoring Systems Laboratory
              U.S. Environmental Protection Agency
              P.O. Box 15027
              Las Vegas, NV 89114
United States
Environmental Protection
Agency
                          Center for Environmental Research
                          Information
                          Cincinnati OH 45268
Official Business
Penalty for Private Use $300
f,Ss
                                          AGENCY
                                                                                 U.S. GOVERNMENT PRINTING OFFICE: 1984-759-102/0977

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