MIDWEST RESEARCH INSTITUTE
                           QUALITY ASSURANCE  MANUAL
            Inductively Coupled Plasma  Atomic Emission Spectrosnetry
                                       for
             Toxic Trace Metals in Vegetables, Soils, and Sludges
                     The National  Household Garden Survey
                                       by

                                Lloyd   M.  Petrie
                                 Senior Chemist
                          EPA  Contract No.  68-01-5915
                          MRI  Project No.  4901-A(42)
                                  May 26,  198;
MIDWEST RESEARCH INSTITUTE 425 VOLKER BOULEVARD, KANSAS CITY, MISSOURI 64110 •  816753-7600

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               QUALITY ASSURANCE MANUAL
Inductively Coupled Plasma Atomic Emission Spectrometry
                          for
 Toxic Trace Metals in Vegetables, Soils, and Sludges

                          in

         The National Household Garden Survey
                          by

                   Lloyd  M. Petrie
                    Senior Chemist
              EPA Contract No.  68-01-5915
              MRI Project No.  4901-A(42)
                     May 26,  1982

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                             TABLE OF CONTENTS

                                                                      Page

I.        Introduction 	     1

II.       Quality Assurance Objectives 	     2

III.      Personnel Responsibilities 	     2

IV.       Analytical Methods 	     4

               A.  Sample Container Cleaning 	     4
               B.  Plant Digestion 	     4
               C.  Soil and Sludge Leaching	     8
               D.  Inductively Coupled Plasma Atomic Emission
                     Spectrometry	     9

V.        Data Analysis, Storage and Retrieval	    21

               A.  General	    21
               B.  Significant Figures 	    22
               C.  Sample Concentration Calculations 	    22
               D.  Computer Operating Procedures 	    23
               E.  Analytical Data Documentation Control 	    24
               F.  Other Project Documentation Control 	    26

VI.       Sample Custody and Control 	    27

               A.  Field Samples	    27
               B.  Dried and Prepared Samples	    27
               C.  Computerized Sample Status Reporting	    27

VII.      Safety	    28

VIII.     References	    28

Appendix A - EPA Interim Method 200.7  	    29

Appendix B - Datatrieve File Structure for the 4901A42 Sample
               Status Data Base File	    63
                                     11

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 I.   Introduction

          The Field Studies Branch is conducting a nationwide survey of
 household gardens fortified with POTW (publicly owned treatment works)
 sewage sludge to assess level of pesticides, metals, and parasites in the
 soils and vegetables.  Approximately 240 garden sites will be sampled
 during the  1982 growing season.

          Toxic metals are relatively abundant in municipal sewage and tend
 to accumulate in high levels in the resulting sewage sludge in parts per
 million levels (Page and Chang, 1978; Swanson, 1981).  One means of disposal
 of the large quantities of sewage sludge is to use it as a fertilizer for
 cultivation of edible food crops.

          Nationally, a key concern regarding cropland fertilization with
 sewage sludge is the rate of uptake of toxic trace metals into the food crops
 This potential problem has been and is being studied to determine safe levels
 of sewage sludge application (Page and Chang, 1978; Page, 1978; Naylor and
 Loehr, 1981; Stoewsand, 1980; Garcia et al., 1981).  Page and Chang (1978)
 cite Cd, Cu, Mo, Ni, and Zn as the trace metals of greatest concern due to
 their abundance in sewage sludge and their mobility in soils.   Stoewsand
 (1980) cited As, Sb, Pb, Hg, and Pd of greatest human health concern with
 Pb and Cd being the most important toxic elements in sewage sludge cropland
 disposal due to their abundance and soil mobility.   Of these two, Cd is more
 readily taken up by plants.  The large survey by Garcia et al. was concerned
 with soil and plant concentration of Pb, Hg, Cd, and Zn.  Again, Cd was sig-
 nificantly accumulated in a wide range of edible crops.  Therefore, the MRI
 trace metal analysis of vegetables, soils, and sludges will include the fol-
 lowing key target trace elements Cd,  Pb, Cu, Mo, Ni, As, Sb, Hg, and Zn.
Also analyzed will be Sn, Tl, Co, Be, B, Mn, Cr, Ag, Y, Se, and Ba.

          Determination of trace metals in this study will be accomplished
 by first solubilizing the metals into an acidic medium from the solid samples.
Then, the ICP media will be quantitatively analyzed by inductively coupled
plasma-atomic emission spectrometry (ICP-AES).   ICP emission spectrometry
 is a rapid technique that is well-suited to multielemental analysis survey
work.

          The purpose of this document is to detail the quality assurance
program for ICP-AES to be followed during this  study.   It is designed to
assure ICP-AES analytical data with acceptable  accuracy and precision in  a
 cost-effective manner.   Likewise, the plan is designed to ensure proper
handling and control of samples and all written documentation.
                                                                 -v
          The analytical quality control aspects of this manual conform to
the USEPA Interim Method 200.7, "Inductively Coupled Plasma-Atomic Emission
Spectrometric Method for Trace Analysis of Water and Wastes,"  EPA-EMSL,
Cincinnati,  November 1980.   Appendix  A contains a  copy of this method.

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II.  Quality Assurance Objectives

          The objective for accuracy is percent recovery values for all
analyte metals in fortified samples between 80% and 120%.

          The objective for precision is percent relative standard deviation
values for all analyte metals in duplicated samples between 0% and 10%.


III.  Personnel Responsibilities

          John Hosenfeld will be the task leader for this program.  He will:

          *  Supervise the collection of all field samples and their transport
             to MRI.

          *  Oversee conformance to the policies and procedures stated in
             this Quality Assurance Plan.

          *  Review and accept each set of analytical data in view of the
             quality assurance objectives for ICP-AES metals screen.

          *  Monitor the technical progress of the program against financial
             expenditures.

          Lloyd Petrie will be the trace metal analysis leader.  He will:

          *  Direct conformance to the policies and procedures stated in
             this Quality Assurance Plan.

          *  Schedule the preparation and analysis of all field and quality
             control samples.

          *  Provide technical expertise for sample preparation and ICP
             emission spectrometric analysis.

          *  Prepare USEPA AQC standard for validation of instrument
             calibration standards.

          *  Maintain document control of laboratory data, field data,  notes,
             records, etc.

          *  Be responsible for sample log-in and chain of custody.

          *  Enforce instrument calibration and maintenance procedures  and
             schedule.

          *  Technically review all analytical data reported to the task
             leader.

          *  Provide technical expertise for operation of the Digital
             Equipment  Corporation (POP 11/23) computer.

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*   Immediately  report  in memo  form  any problems which  arise  during
    the  course of  the program to  the task  leader.

Gene Ray will be  the quality assurance coordinator.  He will:

*   Prepare blind  duplicate  samples  for sample preparation of both
    soils and vegetables.

*   Prepare blind  analytical quality control standards  for all
    ICP-AES analyses.

Carolyn Thornton  will  be the ICP-AES trace metal analyst.  She will:

*   Perform ICP-AES analysis of all  samples according to the  pro-
    cedures stated in this Quality Assurance Plan.

*   Prepare analysis quality control  standards and samples according
    to the Quality Assurance Plan procedures.

*   Prepare instrument  calibration standards according  to the Quality
    Assurance Plan procedures.

*   Generate, store and retrieve all analysis documentation according
    to the Quality Assurance Plan procedures.

*   Handle prepared digests and leachates according to  sample custody
    procedures stated in the Quality Assurance Plan.

*   Be responsible for  routine maintenance of the ICP emission spec-
    trometer.

Betty Jones will  be the sample preparation analyst.  She will:

*  Retrieve and handle all field samples according to  this Quality
   Assurance Plan sample custody procedures.

*  Clean and label all glassware or plasticware used in sample
   preparation according to procedures stated in this Quality
   Assurance Plan.

*  Prepare all field samples and related quality control samples
   according to the appropriate sample preparation procedures.

*  Generate, store and retrieve all sample preparation documenta-
   tion according to the Quality Assurance Plan procedures.

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IV.  Analytical Methods

     A.  Sample Container Cleaning

          1.  Objective:  To remove all trace metal contamination from the
surface of all plastic or glass containers used for sample handling.

          2.  Procedures

               a.  Wash only those glass centrifuge tubes containing organic
residues with freshly prepared soapy deionized water.  Do not wash plastic
bottles with soap.

               b.  Rinse the soap from the containers thoroughly with
deionized water.

               c.  Soak both glass and plastic containers in 8 N reagent
grade HN03 for 24 hr.  Prepare a fresh 8 N reagent grade HN03 bath every
2 weeks.

               d.  After 24 hr, remove and thoroughly rinse the containers
with deionized water.  At least six rinses will be necessary.

               e.  Dip the Teflon-lined centrifuge tube caps in the 8 N HN03
acid bath, remove immediately, and thoroughly rinse with deionized water.

               f.  Fill each container with 0.5 N double-distilled HN03 and
tightly cap the containers.  Let the container stand at least 12 hr.

               g.  Empty and rinse the containers six times with laboratory
deionized water.

               h.  Shake out remaining water, cap, and store the containers
in a clean drawer.

          3.  Time/material requirements:  Approximately 4 hr per batch of
preparation samples should be adequate for sample container cleaning.

          Copies of purchase requisitions or supply room orders should be
submitted to the metal analysis leader.

     B.  Plant Digestion

          1.  Objective:  To fully solubilize the entire plant tissue by a
wet acid digestion.

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          2.  Procedures

               a.  Sample preparation sheet:  A "SAMPLE PREPARATION SHEET"
 (Figure 1) will be completed in duplicate by the trace metal analysis leader.
The following conventions will be used:

          Digestion Code:  V (vegetable) nn j     incremented digestion number
                           S (soil)      nn >     (nn) of type preparation
                           L (sludge)    nn )     starting with 01

          Sample Names:

          Field samples (6-number code)

            Example:        01       107      2     = soil
                         Digestion  Sample    5     = sludge
                          Number    Number    7     = vegetable
                                            Sample
                                             Type

          Analytical quality control standards    AQC1,
            (6 alphanumeric code)                 N476E2

          Prepared reagent blank        VnnRBm - incremental number (m)
            (6 alphanumeric code)      '_7—"-.'~*
                                       Digestion
                                         Code

          Class Names:                  RB - prepared reagent blank
            (6 alphanumeric code)       SAMPLE - prepared field sample
                                        DUP - duplicate
                                        SP1 or SP2 - fortified sample at
                                          level "1" or "2"
                                        SRM1 or SRM2 - standard reference
                                          material "1" or "2"

               b.  Sample drying

                    (1)  Field vegetable samples should be dried within 1 week
of receipt at MRI.

                    (2)  Place a representative portion of each vegetable
in a clean porcelain dish or glass beaker.

                    (3)  Dry the samples for 4 hr at 90°C.

                    (4)  Remove the dried samples and let them cool to room
temperature.

                    (5)  Place the dried material in clean 30-ml plastic
bottles, each labeled with the field sample number,  sample type and date.

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                                  SAMPLE PREPARATION SHEET
Project No.:
Elements:	
Analyst:	
Date Begun:_
Prep Description:

     Sample Volume (ml or mass/g) :_
                    Digestion Code:
                    Date Completed:
     Fortification Levels (total g) :
     Digest Final Volume (ml):	
                 Class
Final Wt.
                                                                 Class
Final Wt.
1.
2.
3.
4.
5.
6.
7.
26.
27.
28.
29.
30.
31.
32.
8. 33.
9.
10.
11.
12.
13.
34.
35.
36.
37.
38.
U. 39.
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.
25.
40.
41.
42.
43.
44.
45.
46.
47.
48.
49.
50.
                                          Figure 1

                                               6

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               c.  Wet digestion

                    (1)  According to the "SAMPLE PREPARATION SHEET," label
the needed number of clean 10-ml centrifuge tubes and 30-ml plastic bottles
with the "Sample" and "Class" names.

                    (2)  Weigh the tubes and bottles and record the tare
weights.

                    (3)  Place approximately 0.1 g dried vegetable in each
preparation tube and weigh the actual amount added.

                    (4)  Add 4.0 ml 8 N Meek Suprapur® HN03 to the tubes.

                    (5)  Wrap the tube threads with Teflon® tape twice and
seal the tube with a clean Teflon®-lined cap.

                    (6)  Place the tube rack in a preheated oven at 90°C.

                    (7)  Check the tubes after 1 hr and gently agitate the
contents of each tube.

                    (8)  Remove tubes after 4 hr at 90°C.

                    (9)  Let the tubes air cool to room temperature.

                   (10)  Dilute the samples in the tubes to 10 g with
deionized water using the platform balance.

                   (11)  Label each tube with the "Sample" name, "Class"
name, "4901A42," and date.

                   (12)  Place a copy of the completed "SAMPLE PREPARATION
SHEET" in the appropriate MRI Technical Record Book and place the original
sheet with the completed samples on a tray.

          3.  Quality control:  Unless stated otherwise on the "SAMPLE
PREPARATION SHEET" to reflect unique conditions, the following percentages
of analytical quality control samples will be prepared with each batch of
field samples:

          10% duplicates of field samples
          10% fortified field samples
           5% reagent blanks
           5% quality control check standards or standard reference materials
           5% blind field duplicate samples selected by the quality
                assurance coordinator

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          4.  Time/materials requirements:  Sample drying should require
2 hr labor time per sample batch.

          Wet digestion of a 50-sample set should require 8 hr labor time
and should be fully completed during 1 day to minimize sample handling and
contamination.  Approximately 125 ml of Merck Suprapur® concentrated nitric
acid will be the major material usage.  The replacement frequency of the
Teflon®-lined centrifuge caps is not known.

     C.  Soil and Sludge Leaching

          1.  Objective;  To remove all trace metals from soil or sewage
sludge using a rigorous acid leaching without solubilizing all the Al, Fe,
Ca, Mg, Ti, and other nontoxic major elements in the samples.

          2.  Procedure

               a.  According to the "SAMPLE PREPARATION SHEET," label the
needed number of clean 10-ml centrifuge tubes and 30-ml plastic bottles
with the "Sample" and "Class" names.

               b.  Tare each centrifuge tube without the cap and record the
mass.

               c.  Place approximately 0.1 g soil in the appropriate tubes
and measure the net mass of sample added.   Record the masses on the "SAMPLE
PREPARATION SHEET."

               d.  Add 2 ml 8 N Merck Suprapur® HN03 to the appropriate tubes.

               e.  Wrap the tube threads with Teflon® tape.

               f.  Place the tube rack in a preheated oven at 130°C for 8 hr.

               g.  Set the timer on the oven electrical circuit for a time
8 hr hence.

               h.  Check the tubes every 2 hr and gently agitate the contents
of each tube.

               i.  Remove the tubes after 8 hr of heating.

               j.  Let the tubes air cool to room temperature.

               k.  Dilute the material in each tube to a final net mass of
10 g with deionized water.

               1.  Centrifuge each set of four tubes at the maximum setting
of the International Clinical centrifuge in Room 344W for 1 min.

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                m.  Remove  the  centrifuged  samples and  carefully pour  the
 liquid  leachate into  the appropriate plastic bottle.

                n.  Label each  plastic bottle with the  "Sample" name,  "Class"
 name, "4901A42" and date.

                o.  Place a copy of the completed "SAMPLE PREPARATION  SHEET"
 in  the  appropriate MRI Technical Record Book and place the original sheet
 with the completed samples on  a tray.

          3.  Quality control:  Unless stated otherwise, the following per-
 centages of analytical quality control samples will be prepared with  each
 batch of field  samples:

          10% duplicates of field samples
          10% fortified field  samples
           5% reagent blanks
           5% quality control  check standards or standard reference materials
           5% blind field duplicate samples selected by the quality assurance
                 coordinator

          4.  Time/materials requirements:  Acid leaching of each 50-sample
 set should require 8  hr labor  time.  Each preparation batch will consume
 approximately 75 ml of Merck Suprapur® concentrated nitric acid and Teflon®
 tape.   The replacement frequency of the Teflon®-lined centrifuge caps is
 not known.

     D.  Inductively  Coupled Plasma Atomic Emission Spectrometry

          1.  Objective;  To quantitatively determine the concentration of
 toxic trace metals in soil, sludge, and vegetable preparations by inductively
 coupled plasma  atomic emission spectrometry (ICP-AES).

          2.  General description of method;  ICP emission spectrometry is
 a relatively new method for rapid multielemental analysis using a new, stable
 excitation source (ICP) with the conventional direct reading or newer scanning
 spectrometers.

          Compared to other sources, spectral interferences for the ICP are
minimal.  It is hot enough to facilitate analyte emission,  yet the sustained
 argon plasma has fewer of the interferences associated with emission spec-
 troscopy.  The background in the region with most of the sensitive emission
 lines for many elements (190-300 nm) has relatively few interference emissions.

          However, there still are spectral interferences that are signifi-
 cant when attempting to measure parts-per-billion levels of trace metals in
the presence of parts-per-million levels of Al,  Ca,  Fe, Ti,  and other major
elements in plant and soil material.   The two major types of spectral inter-
ferences are (1) direct overlap by an interfering emission peak on the analy-
sis emission peak, and (2) baseline shifts due to stray light,  molecular
emission or broad band emission from an intense  nearby interfering peaks.

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To account for those cases where other elements may line interfere and are
commonly abundant in high concentrations  (Al and Fe, for example), correc-
tion factors are stored in a data file in the computer.  As part of the
final concentration calculations, a factor multiplied by the interfering
element intensities is subtracted from the gross analyte intensities.

          3.  Instrument description;  A 30-channel Jarrell-Ash Model 1155A
direct reading ICP emission spectrometer will be used in the study.  This
instrument has the following features to enhance sample analysis quality:

          *  Triple point background correction
          *  Automatic interelement spectral interference correction
          *  Spectrum scanning for sample matrix diagnostics
          *  200-Sample autosampler
          *  Peristaltic pump

          The emission spectrometer is fully controlled by a sophisticated
set of software performed at the Digital Equipment Corporation PDF 11/23
computer interfaced to the spectrometer.

          Based on prior method development studies, Table 1 lists typical
detection limits anticipated for this study for the 30 analytical emission
lines of the Model 1155A spectrometer.

          Two Analytical Control Tables will be used for this study:

               ACT Name                 Sample Matrix

                 VEG                    Vegetables
                 SOIL                   Soils and sludges

          4.  Daily instrument calibration procedure

               a.  Instrument calibration is based on Chapter 8 of the
Jarrell-Ash Mark III Atomcomp Interim Operator's Manual. M79, March 1979.
The analytical quality control aspects of calibration conform to USEPA
Interim Method 200.7.

               b.  Each of the 30 detector channels is calibrated by a
two-point curve method using a reagent blank and a 10-ppm standard, except
100 ppm for K.   The elements for the 10-ppm standard are actually grouped
into four mixed standards according to chemical stability and absence of
spectral interferences.   Table 2 shows the composition of the ICP-AES cali-
bration standards.

               c.  It is essential that the matrix of the calibration stan-
dards match the matrix of the samples.   In this study the following matrices
for calibration standards will be used.

               Vegetables          20% (v/v)  Merck Suprapur® HN03
               Soils and sludges   10% (v/v)  Merck Suprapur® HN03
                                   10

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                           TABLE 1
                AVAILABLE ANALYTICAL CHANNELS
Element

  Sn
  Tl
  As
  Hg
  Se
  Mo
  Sb
  Zn
  P
  Pb
  Co
  Cd
  Ni
  Be
  Al
  B
  Mn
  Fe
  Cr
  Fe
  Mg
  Al
  Cu
  Ag
  Ti
  Y
  Ca
  Ba
  Na
  K
Estimated Detection Limit
o
Wavelength (A)
1899
1908
1936
1942
1960
2020
2068
2138
2149
2203
2286
2288
2316
2348
2373
2496
2576
2599
2677
2714
2795
3082
3247
3280
3349
3710
3968
4934
5890
7665
(Mg/g
Soil
20
70
250
20
1,000
2.0
200
4.0
20
50
1.0
2.0
1.0
0.50
96
1.0
10
350
2.0
20
40
110
2.0
0.5
20
3.0
41
5.4
10
140
sample)
Vegetable
20
10
30
5.0
100
0.23
100
2.0
96
4.0
0.18
0.14
0.49
0.030
8.6
0.75
2.50
6.0
0.23
5.7
340
8.7
0.54
0.5
2.0
0.043
360
0.16
290
690
                            11

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                   TABLE 2

        ICP-AES CALIBRATION STANDARDS

      20% (v/v) HN03 (vegetables) or 10% (v/v) HN03 (soils)
Matrix:
Concentration:   10 ppm except 100 ppmK
Stability:      30 days
Standard ID

  STD 1

  STD 2

  STD 3

  STD 4

  AG
                                           Elements
                              Reagent blank

                              Ba, Ca, Cd, Co,  Cu,  K, Mg,  Mn,  Pb,  Zn

                              Al, Be, Fe, Mo,  Na,  Ni, Sb, Ti, Y

                              As, B, Cr, P, Se,  Sn,  Hg,  Tl

                              Ag
                    12

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               d.  The shelf life of the calibration standards is 30 days.

               e.  Each new batch of calibration standards that is prepared
must be verified weekly for accuracy by analyzing a standard reference material
and obtaining measured values within ± 5% of the certified values.  See the
section on "Analytical Quality Control."

               f.  The spectrometer is calibrated according to MRI Interim
Standard Operating Procedure "ICP Emission Spectrometer Calibration."

          5.  Daily sample analysis procedure:  After successful calibration,
a prepared sample set can be analyzed.  The Analytical Quality Control aspects
of this procedure conform to USEPA Interim Method 200.7.

               a.  Fill out an "ICP DATA REPORTING SHEET" (Figure 2) and
place it in the appropriate MRI Technical Record Book.  In this study, a
fixed crossflow nebulizer and peristaltic pump will always be used.

               b.  Aspirate each sample for 1 znin.

               c.  Analyze one representative sample for one 10-sec inte-
gration without dilution factors to determine if any detection channels are
beyond their linear response range (Table 3).  If necessary, dilute the sam-
ples and note that on the "SAMPLE PREPARATION SHEET."

               d.  Every 10th time, reanalyze STD1 and the ICS, after
thoroughly rinsing the nebulization system.

               e.  If the analytical results are still within ± 2 x standard
deviation control limits, continue.  If the results were out of control,
reanalyze STD1.  If the results are still out of control, recalibrate the
instrument.

               f.  If the measured values for the ICS are still within ± 5%
of the true values, continue.  If not, reanalyze the ICS.  If the results
are again out of control, recalibrate the instrument.

               g.  All prepared samples analyzed since the last successful
analysis of STD1 and the ICS must be reanalyzed if the instrument is recali-
brated.

               h.  Place data,  along with a copy of the "ICP DATA REPORTING
SHEET" into the "Sample Analysis" blue multi-ringed binder for computer paper
output.
                                   13

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                    ICP DATA REPORTING SHEET
Project No.:	
Sample Matrix:_
Elements:  	
           Analyst:^
           Date:	
           Digestion Code:_
Instrument Parameters

  Forward Power  (kw):_
  Reflected Power  (w) :
  Observation Height  (mm):	
  Nebulizer Type:	
  (FCF = Fixed crossflow)
  (HS  = High solids)

Sample Analysis
            Coolant  Gas Flow (i/min):
            Auxiliary Gas Flow (Z/min)
            Sample Gas Flow (i/min):	
            Solution Uptake (ml/min):_
            Peristaltic Pump Used?:	
  ACT Name:
   Test  Performed:
Spectrum Scan
  Integration Time (sec)
  Data Files:	
                       Disk Name:
                    _Quantitation and Log
                       Command String:	
                       Data File Name:	
                       Disk Name:	
                     Quantitation and Store
                       Command String:	
                       Data File Name:	
                       Disk Name:	
                           Figure 2

                               14

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                   TABLE 3




LINEAR RESPONSE RANGE OF THE ICP-AES CHANNELS
LCN
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
Channel
Ag
Al (3082 A)
Al (2373 A)
As
B
Ba
Be
Ca
Cd
Co
Cr
Cu
Fe (2714 A)
Fe (2599 A)
Hg
K
Mg
Mn
Mo
Na
Ni
P
Pb
Sb
Se
Sn
Ti
Tl
Y
An
Linear Maximum Concentration
(ppra)
100
200
150
500
100
50
50
50
200
100
50
150
500
30
500
500
20
50
50
200
200
200
500
500
200
500
50
200
50
30
                    15

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          6.  Analytical quality control

               a.  Spectral interferences

                    (1)  The occurrence of spectral interferences in ICP
source emission spectrometry is not as frequent as with other emission
sources but is common enough to require correction measures.  The "General
description of method" section described the common types of spectral inter-
ferences experienced in ICP-AES:  (a)  direct overlap by an interfering emis-
sion peak, and (b) baseline shifts due to stray light and molecular emission.
These interferences both result in falsely high analyte emission and, hence,
analyte concentration determinations.

                    (2)  The particular sample matrices to be analyzed in
this study do contain a large number of direct overlap spectral interferences
for ICP source emission spectrometry.  This is because plant tissues, soils,
and sewage sludge contain quite high levels of Al, Ca, Fe, K, Na, Mg and
other elements that introduce spectral interferences on As, Hg, Sb, Se, Sn,
Pb, Tl, and other minor elements.

                    (3)  Interferences are identified for a new sample matrix
by aspirating a representative sample and performing 63 2-sec emission inte-
gration counts in a scan 1 angstrom on either side of each analyte emission
peak centerline.  Figure 3 is an example of the plotted spectra for four
samples for the Se emission peak.  Note the significant Ca interference peak
overlap from the sample named "NEWSD2."

                    Such plots are prepared for all 30 detector channels.
The plots are interpreted by comparison to a library of spectrum scan plots
performed on known standards.  This interpretation information is summarized
on a "SPECTRUM SCAN" sheet (Figure 4).

                    (4)  The above procedure was used to identify 88 spec-
tral interferences requiring correction.  On-peak interelement correction
will be used to remove the effects of these interferences by subtracting a
concentration amount from the interfered element detection channel.  The
amount to be subtracted equals (concentration of interfering element) x cor-
rection factor.  The correction factors are determined by measuring the false
positive reading on the interfered channel when a sample containing 100 ppm
interfering element is measured.  The correction factor equals the false
positive concentration per 1 ppm interfering element.  Correction factors
are then placed in Group 4 of the appropriate Analytical Control Table (ACT).
Correction factors are specific for a given sample matrix and observation
position in the inductively coupled plasma.

                    (5)  All analysis data used to generate correction fac-
tors and copies of each Group 4 data will be placed in the program "Spectral
Interferences" MRI Technical Record Book.

                    (6)  Correction factors will be redetermined each time
the ICP torch has been cleaned and reassembled.
                                   16

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              WAVELENGTH  SCANS FOR SE AT 1960 ANGSTROMS

     B  NEWSD1        @   NEUSD2       X  NEUSD3        *   NEWSD4
INTENSITY
16000,
12SOO.
 9600,
 6400.
 3200,
                                      Ca Interference Peak
              PEAK IS AT POSITION   0   HALF-WIDTH IS  7

                                 Figure 3

                                   17

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                           SPECTRUM SCAN
Project No:	    Date:	
Integration Time (sec):	    Analyst:_
LCN    Element   Wavelength  (A)   	Comments

 1       LV           1001        	
 2       Ag           3280        	
 3       Al           3082        	
 4       Al           2373        	
 5       As           1937        	
 6       B            2496        	
 7       Ba           4934        	
 8       Be           2348        	
 9       Ca           3968        	
10       Cd           2288        	
11       Co           2286        	
12       Cr           2677        	
13       Cu           3247        	
14       Fe           2599        	
15       Fe           2714        	
16       Hg           1942        	
17       K            7664        	
18       Mg           2795        	
19       Mn           2576        	
20       Mo           2020        	
21       Na           5890        	
22       Ni           2316        	
23       P            2149        	
24       Pb           2203        	
25       Sb           2068        	
26       Se           1960        	
27       Sn           1899        	
28       Ti           3349        	
29       Tl           1908        	
30       Y            3710        	
31       Zn           2138
                              Figure 4
                                 18

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                     (7)  Correction factors will also be  redetermined each
time repeated analysis of the Interference Check Standard does not give  re-
sults within ±  1.5 o of the true values.  Table 4 shows the composition  of
the Interference Check Standard.
                                  TABLE 4

                        INTERFERENCE CHECK STANDARD3

             Analyte (mg/2)               Interferents  (mg/JE)

                                              Al    120
                                              Ca    600
                                              Fe    500
                                              Mg    300
                                              Na    100
Ag
As
B
Ba
Be
Cd
Co
Cr
Cu
Na
Ho
Ni
Pb
Sb
Se
Ti
Tl
V
Zn
K
0.3
1.0
0.5
0.3
0.1
0.3
0.3
0.3
0.3
0.38
0.36
0.3
1.0
1.0
0.5
1.0
1.0
0.3
10
20
                Interference QC Sample, EPA-EMSL, Cincinnati,
                  November 1980.
                    (8)  A representative sample from each sample prepara-
tion batch will be spectrum scanned, plotted, and evaluated to confirm that
all spectral interferences are being compensated by correction factors.
This procedure may be discontinued if repeated interference evaluations re-
veal a constancy of interferences.

               b.  Accuracy verification of instrument calibration standards

                    (1)  New calibration standards will be prepared every
30 days.   See Table 3 for the composition of the mixed calibration standards.
                                   19

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                    (2)  Each of the two types of sample matrices will have
a separate set of standards:

                    Soils and sludges   10% (v/v) HN03 (double-distilled)
                    Vegetables          20% (v/v) HN03 (double-distilled)

                    (3)  Each volumetric flask holding the calibration standards
will be labeled with the standard name, ACT name, and date.

                    (4)  The accuracy of each new batch of calibration standard
will be verified by analyzing a matrix-matched USEPA analytical quality control
(AQC) standard.  This is done by calibrating the ICP spectrometer with the
new standards and analyzing the AQC standard five times:  EAANANANANANTDTP.
Accuracy is acceptable if all measured values for the AQC standard are within
± 5% of the certified values.  If verification is not successful, recalibrate
the spectrometer and repeat the test.  If verification is still not successful,
prepare new standards.

                    (5)  All terminal output for the verification test will
be placed in the program "Instrument Calibration" Technical Record Book.

               c.  Verification of daily instrument calibration

                    (1)  Two quality control standards are to initially verify
the accuracy of the initial calibration of the ICP emission spectrometer
and to monitor instrument drift.  These standards are:

                    ISC  - Instrument Check Standard
                             Labeled Vnn or Son for the vegetable or soil
                             matrix, where on starts at 01 and is incre-
                             mented for each new standare prepared.
                    STD1 - Calibration reagent blank.

                    (2)  ICSs will be prepared monthly or as needed by the
trace metal analysis leader.

                    (3)  The true or accepted concentration values for a
new ICS will be determined by first successfully calibrating the ICP spectrom-
eter with existing quality control samples and performing 20 replicate analyses
of the new ICS.  The mean, standard deviation, and percent relative standard
deviation for the replicate analyses will be determined (TDTP).

                    (4)  The true or accepted values for STD1 will be deter-
mined the same way.

                    (5)  All computer terminal printouts will be placed in
the program "Instrument Calibration" Technical Record Book.
                                   20

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                    (6)  As described in Section 5, "Daily Instrument Cali-
bration Procedure," STD1 and the ICS are analyzed at the beginning and every
10th analysis for a sample set to assure continued acceptable instrument
calibration.  The control limits are:

                    STD1 ± 2 standard deviations for mean concentration
                      values
                    ICS  ± 5% from true or accepted concentration values.

                    (7)  Any samples analyzed after the last successful
verification of the daily instrument calibration will be reanalyzed after
calibration.

               d.  Verification of purify of double-distilled HN03

                    (1)  Each bottle of Merck Suprepur® HN03 will be checked
for metal contamination before it is used for sample preparation or instru-
mental analysis.

                    (2)  Each bottle will be dated and marked for "4901A42
Use" when opened.

                    (3)  Each bottle will be kept in a plastic bag when not
being used.

                    (4)  The ICP-AES elemental analysis of each bottle will
be kept in the program "Instrument Calibration" Technical Record Book.

          7.  Time/materials requirements:   Complete ICP-AES analysis of a
given 50-sample batch should require 8 hr labor time.   This includes docu-
mentation control.
V.  Data Analysis, Storage and Retrieval

     A.  General

          1.  All data entries will be in accordance with MRI procedure QA-7.

          2.  All records and data files will be kept in a centralized loca-
tion in Room 346.

          3.  All entries of original data or information will be made with
waterproof blank ink directly into the appropriate permanent record medium.

          4.  Entries will be both complete and timely.

          5.  Calculations and entries of all measured numbers will be accord-
ing to the following significant figure convention.
                                   21

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     B.  Significant Figures

          All data for this program will be reported with three significant
figures.

     C.  Sample Concentration Calculations

          1.  The final analyte concentrations will be expressed as micro-
grams analyte per gram dried sample.

          2.  The actual calculations to convert ICP emission intensity into
a microgram per gram (dry) final analyte concentration will be done immediately
upon completion of sample analysis by the computer.  The terminal output,
following ICP-AES analysis, will be the final concentrations for all channels.

          3.  The intensity of emission of each analyte element is measured
by the spectrometer as a series of emission counts.  At the end of the emis-
sion intensity measurement period, the count numbers are converted to a digi-
tal count and sent to the computer.  These counts are compared to linear
counts versus concentration relationships whose slope (AO) and intercept (Al)
are stored in the Analytical Control Table during instrument calibration:

               Concentration = AO x emission counts + Al

          4.  Then, any interelement spectral interference emission is sub-
tracted out:
                                                                 n
          Corrected Concentration = Uncorrected Concentration -  Z  K,.C.
                                                                i=l  U l

     where     K .  = interelement correction factor, ppm analyte/ppm interferent.

                C.  = interferent element concentration, ppm.

          5.  Lastly, the corrected analyte concentration in micrograms per
gram digest is converted to microgram per gram (dry) sample by multiplying
the preparation dilution factor:


               |Jg analyte  x     g digest     _    M8 analyte
                g digest      g (dry) sample     g (dry) sample)


          6.  These final concentrations are also stored on disk.
                                   22

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     D.  Computer Operating Procedures

          1.  General hardware/software description

               a.  The computer system used for this program is a Digital
Equipment Corporation PDF 11/23 model with 96K words of dynamic memory and
over 5 megabytes of disk storage space.  Two terminals are interfaced to
the computer:  (1)  an LA 120 180 character/sec printer terminal, and (2) a
VT100 video terminal.  The ICP spectrometer is remotely interfaced to the
computer by dual 40-port shielded cables.

               The LA 120 terminal located beside the ICP emission spectrom-
eter is the console terminal for the computer and is the terminal for opera-
tion of the spectrometer.  The VT100 terminal, located in Room 342W with
the computer, is a remote terminal despite its physical location.  One must
"log-on" a remote terminal with a proper User Identification Code (UIC) and
password.

               b.  The computer operation system is RSX-11M, which is a real-
time multitasking and multiprogramming software system.  What this means
for our system is that one person can operate the spectrometer at the LA 120
terminal while another person simultaneously runs other programs at the VT100
terminal.

               c.  The RSX-11M operating system is both powerful and complex.
Any questions or problems observed while operating the system should be com-
municated to the metals analysis task leader.

               d.  A good overview of RSX-11M is contained in the following
two Digital Equipment Coproration Manuals:

                    (1)  Introduction RSX-11M, AA-2555C-TC, Vol. 1A
                    (2)  RSX-11M Beginner's Guide, DEC-11-OMBGAA-D,  Vol.  1A

          2.  ICP-AES analytical quality control software:

               a.  Two programs have been written to permit immediate quality
control evaluation of a sample set analyzed by ICP-AES:

                    *  Generation and storage  of accuracy and precision con-
trol limits for standard reference mterials.

                    *  Generation and storage  of accuracy and precision con-
trol limits for the sample matrix.

                    *  Calculation and storage of detection limits.

                    *  Testing of all QC samples (SRM,  duplicates,  and spikes)
for accuracy and precision control.   All parameters  by  samples  that  are  out
of control are flagged.
                                   23

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                    *  Printout of data summary tables with the correct
number of  significant figures and flagged for < detection limit results.

                    *  Printout of QC accuracy % recovery summary tables.

                    *  Printout of QC precision relative percent standard
deviation  summary tables.

               b.  Table 5 summarizes the analytical quality control statis-
tics and limits used in the two programs.

     E.  Analytical Data Documentation Control

           Below are listed the primary types of data generated during sample
preparation and analysis followed by specific means by which it is to be
stored:

           1-  Initial sample preparation sheets:  These are to be completed
in duplicate by the trace metal analysis leader, who retains one copy.  One
copy is forwarded for action to the sample preparation analyst.

           2.  Completed sample preparation sheets:  The original SAMPLE
PREPARATION SHEET, completed by the sample preparation analyst is placed on
the tray with the prepared sample batch.  One copy if placed in the current
project "Sample Preparation" Technical Record Book (TRB).

           3.  Spectrum scan plots and summary sheets:  The original SPECTRUM
SCAN SUMMARY sheet is placed in the project "Spectral Interferences" TRB.
A copy of  the summary sheet plus the spectrum scan plots are placed in the
blue ringed binder marked "Spectral Interferences."

           4.  Spectral interelement interferences (Group 4):   Signed and
dated, the terminal output and a hard copy of new Group 4 for either VEG or
SOIL ALT is placed in the blue ringed binder marked "SPECTRAL INTERFERENCES."

           5.  Analyses of the interference check standards:   Signed and dated,
the terminal output for successful analysis of the Interference Check Standard
is placed  in the project "Spectral Interferences," TRB.

           6.  Preparation of interference check standards:   All information
concerning the preparation and true values of interference check standards
will also be placed in the project "Spectral Interferences"  TRB.

           7.  Analyses of USEPA AQC standards:   Terminal output for analyses
of USEPA Analytical Quality Control Standards for accuracy verification of
instrument calibration standards will be placed in the project  "Instrument
Calibration" TRB.

          8.  Preparation of USEPA AQC standards:   All information  concern-
ing preparation and true values  for USEPA AQC standards will  also be placed
in the project "Instrument Calibration"  TRB.
                                   24

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                                 TABLE 5


               ANALYTICAL QUALITY CONTROL STATISTICS AND LIMITS
 1.   PRECISION

     •   CONTROL STATISTIC - Si  - PERCENT RELATIVE STANDARD FOR 1th ELEMENT
                                 OF DUPLICATED SAMPLES   •

     •   CONTROL LIMITS

          WARNING  LIMIT =1.96  Si  (95S  CONFIDENCE LEVEL)

          CONTROL  LIMIT = 2.58  Si  (99%  CONFIDENCE LEVEL)


 2.   ACCURACY

     .   CONTROL STATISTIC »  PI  - PERCENT RECOVERY OF  1th  ELEMENT

                                100  x (MEASURED SPIKED  SAMPLE  CONCENTRATION  -
          SPIKED SAMPLES   Pf =   MEASURED UNSPIKED  SAMPLE CONCENTRATION)
                                        SPIKE  CONCENTRATION INCREASE


          REFERENCE SAMPLES   Pj = 100  x MEASURED  SAMPLE  CONCENTRATION
                                       KNOWN SAMPLE CONCENTRATION

     •   CONTROL LIMITS

         WARNING LIMITS  = MEAN  P, * 1.96 dP1  (952 CONFIDENCE  LEVEL)

         CONTROL LIMITS  - MEAN  Pj + 2.58 c5Pi  (99% CONFIDENCE  LEVEL)

         WHERE 5Pi = STANDARD DEVIATION OF MEAN PERCENT RECOVERY OF ith ELEMENT


3.  DETECTION LIMITS

    •  CONTROL STATISTIC = 3 x  STANDARD DEVIATION OF 10 OR MORE REPLICATE
                           DETERMINATIONS OF A REPRESENTATIVE SAMPLE
                                    25

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          9.  Analyses of blank (STD1) and instrument check standard (ICS):
The initial analyses terminal output of STD1 aad the ICS will be placed in
the project "Instrument Calibration" TRB.  Subsequent analyses will be part
of the analysis sample set data.

         10.  Preparation of calibration standards and ICS:  All information
concerning preparation and true values of calibration standards and ICS,
will also be placed in the project "Instrument Calibration" TRB.

         11.  Sample set analyses:  The original copy of the "ICP Data
Reporting Sheet," will be placed in the project "Sample Analysis" TRB.

          A copy of the "ICP Data Reporting Sheet" and all real-time terminal
output will be placed in the blue ringed binder marked "Sample Analysis."

          The results are also stored on disk under the file specification:
DL1:[1,54]digestion code.BRN;!.

         12.  VREPORT summary of sample set analyses:  The VREPORT terminal
report of recently completed analyses will be placed with the other terminal
output for that sample set in the ringed binder marked "Sample Analysis."

         13.  ICP-AES analytical quality control software results and reports:
The summary tables generated during execution of DOR21.TSK;! will be forwarded
with the appropriate "Sample Analysis" TRB and "Sample Analysis" blue ringed
binder for review by the trace metal analysis leader.

          Another copy of summary tables plus all terminal output from execu-
tion of DOR20.TSK;! and DOR21.TSK;! will be placed in the "Sample Analysis"
blue ringed binder.

         14.  Sample analysis data files stored on disk:   Each week all new
sample analysis data files stored on the current scratch disk in disk drive
1 will be copied onto the backup disk entitled "DA4901."

         15.  Data reports to the task leader:  The analytical summary tables
of analysis sample sets approved by the trace metal analysis leader will be
forwarded to the task leader with a cover memo.

     F.  Other Project Documentation Control

          1.  Purchase requisitions, shipping orders, and memos on stock
room purchases will be kept on file by the trace metal analysis leader.

          2.  Each week all personnel working on the project will submit to
the trace metal analysis leader a summary of hours worked.

          3.  Phone contact reports and other correspondence will be kept
on file by the trace metal analysis leader.
                                   26

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VI.  Sample Custody and Control

     A.  Field Samples

          1.  Samples arriving at MRI from the field will have an MRI "Chain
of Custody Record" sheet (Figure 5) with them.

          2.  The trace metal analysis leader or designee will receive the
samples by signing the custody sheet.

          3.  The sheet will be filed by the trace metal analysis leader in
the "Sample Custody" Technical Record Book.

          4.  Each sample will be logged in the bound "Sample Custody" TRB
by completing the following entries:

               •  Sample Code
               •  Arrival Date
               •  Arrival Time
               •  Signature of Receiver

          5.  The status of the samples wll be updated by completing the
following column entries:

               •  Date
                  Digest Code
               •  Analysis Date
               •  Report Date
                  Comments

          6.  Samples will be stored on the designated shelves in custody
refrigerated storage at all time when not being used for sample preparation.

     B.  Dried and Prepared Samples

          1.  Dried or digested sample sets will be stored in a metal cabinet
in the Inorganic Analysis Prep Laboratory (Room 344W) until those samples
have been analyzed and the data reported.

          2.  After data reporting, dried and digested samples will be
archived in the locked refrigerated sample custody storage.

     C.  Computerized Sample Status Reporting

          1.  In addition to the bound primary sample status tracking through
the bound MRI "Sample Custody" Technical Record Book, a computerized sample
tracking data base will be maintained.

          2.  This data base file will be an RMS indexed sequential file
amenable to DEC DATATRIEVE data base management software.
                                   27

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          3.  Each sample record will contain the following information:

               •  Sample Code                •  Analysis Date
               •  Arrival Date               •  Report Date
               •  Preparation Dae            •  Comments Section
               •  Digest Date

          4.  A weekly status table printout will be presented to the task
leader.

          5.  Appendix B contains a copy of the DATATRIEVE file information.


VII.  Safety

          All samples and extracts will be considered hazardous and will be
handled with utmost care.  Rigid sample and extract control will be exercised
to ensure sample integrity and minimize human exposure.

          All pertinent regulations of the MRI Safety and Health Manual and
the MRI General Safety Regulations for the Use of Carcinogenic Materials will
be followed.  In particular, all equipment and containers will be decontami-
nated as prescribed.


VIII.  References

      1.  Page, A. L., and A. C. Chang, "Trace Elements Impact on Plants
          During Cropland Disposal of Sewage Sludge," In:  National Confer-
          ence on Acceptable Sludge Disposal Technology [Proceedings, 5th],
          1978, pp. 91-6.

      2.  Page, A., "Sludge Treatment and Disposal," Vol. 2, USEPA Transfer
          Technology, EPA-625/14-78-012, October 1978.

      3.  Naylor, L., and R. Loehr, "Increase in Dietary Cadmium as a Result
          of Application of Sewage Sludge to Agricultural Land," Environ.
          Sci. and Technol.. 15, 881-6 (1981).

      4.  Stoewsand, G.,  "Trace Metal Problems with Industrial Waste Materials
          Applied to Vegetable Producing Soils," In:  The Safety of Foods,
          2nd Edition, H. D. Graham (ed.), Avi Publishing,  Westport, Connecticut,
          1980, pp. 423-43.

      5.  Garcia, W., et al., "Metal Accumulation and Crop  Yield for a Variety
          of Edible Crops Grown in Diverse Soil Media Amended with Sewage
          Sludge," Environ.  Sci. and Technol..  15, 793-804  (1981).

      6.  Swanson, S., "Summary of Analytical Methods,  Quality Assurance
          Procedures, and Analytical Results for Priority Pollutants,"
          Draft Final Report, POTW Sludge Analysis—Task 35, EPA Contract
          Nos. 68-03-2565 and 68-02-5915, Midwest Research  Institute,
          Kansas  City, Missour, 1981.

                                   28

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       APPENDIX A
EPA INTERIM METHOD 200.7
          29

-------
     U. S. ENVIRONMENTAL PROTECTION AGENCY
Environmental Monitoring and Support Laboratory
            Cincinnati, Ohio  45268
                       30

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                                   Foreword

    This method has been prepared by the staff of the Environmental
Monitoring and Support Laboratory - Cincinnati, with the cooperation of  the
EPA-ICP Users Group.  Their cooperation and support is gratefully acknowl-
edged.

    This method represents the current state-of-the-art, but as time pro-
gresses, improvements are anticipated.  Users are encouraged to identify
problems and assist in updating the method by contacting the Environmental
Monitoring and Support Laboratory, Cincinnati, Ohio, 45268.
                                       11
                                       31

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    INDUCTIVELY COUPLED PLASMA-ATOMIC EMISSION SPECTROMETRIC METHOD
            FOR TRACE ELEMENT ANALYSIS OF WATER AND WASTES
Scope and Application
1.1  This method may be used for the determination of dissolved, sus-
     pended, or total elements in drinking water, surface water,
     domestic and industrial wastewaters.
1.2  Dissolved elements are determined in filtered and acidified
     samples.  Appropriate steps must be taken in all analyses to ensure
     that potential interference are taken into account.  This is
     especially true when dissolved solids exceed 1500 mg/1.  (See 4.)
1.3  Total elements are determined after appropriate digestion pro-
     cedures are performed.  Since digestion techniques increase the
     dissolved solids content of the samples, appropriate steps must be
     taken to correct for potential interference effects.  (See 4.)
1.4  Table 1 lists elements for which this method applies along with
     recommended wavelengths and typical estimated instrumental detec-
     tion limits using conventional pneumatic nebulization.  Actual
     working detection limits are sample dependent and as the sample
     matrix varies, these concentrations may also vary.  In time, other
     elements may be added as more information becomes available and as
     required.
1.5  Because of the differences between various makes and models of
                                                                        *
     satisfactory instruments, no detailed instrumental operating
     instructions can be provided.   Instead,  the analyst is referred to
     the instructions provided by the manufacturer of the particular
     instrument.
                                   1
                                   32

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                    Table  1  -  Recommended  WavelengthsH)  and
                    Estimated Instrumental Detection Limits
Element
                Wavelength,  nm
Estimated detection
limit, ug/l(2)
Aluminum
Arsenic
Antimony
Barium
Beryllium

Boron
Cadmium
Calcium
Chromium
Cobalt

Copper
Iron
Lead
Magnesium
Manganese

Molybdenum
Nickel
Potassium
Selenium
Silica (S102)

Silver
Sodium
Thallium
Vanadium
Zinc
                    308.215
                    193.696
                    206.333
                    455.403
                    313.042

                    249.773
                    226.502
                    317.933
                    267.716
                    228.616

                    324.754
                    259.940
                    220.353
                    279.079
                    257.610

                    202.030
                    231.604
                    766.491
                    196.026
                    288.158

                    328.068
                    588.995
                    190.864
                    292.402
                    213.856
      45
      53
      32
       2
       0.

       5
       4
      10
       7
       7

       6
       7
      42
      30
       2
      75
      58

       7
      29
      40
       8
       2
(1)
(2)
(3)
The wavelengths listed are recommended because of their sensitivity
and overall acceptance.  Other wavelengths may be substituted  if
they can provide the needed sensitivity and are treated with the
same corrective techniques for spectral interference.  (See 4.1.1).

The estimated instrumental detection limits as shown are taken from
"Inductively Coupled Plasma-Atomic Emission Spectroscopy-Prominent
Lines," EPA-600/4-79-017.  They are given as a guide for an instru-
mental limit.  The actual method detection limits are sample
dependent and may vary as the sample matrix varies.

Highly dependent on operating conditions and plasma position.
                                       2

                                       33

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2.   Summary of Method
    2.1  The method describes »«&echf*»quete£cn|
                                    of trace elements in solution.  The
         basis of the method is the measurement of atomic emission by an
         optical spectroscopic technique.  Samples are nebulized and the
         aerosol that is produced is transported to the plasma torch where
         excitation occurs.  Characteristic atomic-line emission spectra are
         produced by a radio-frequency inductively coupled plasma (ICP).
         The spectra are dispersed by a grating spectrometer and the inten-
         sities of the lines are monitored by photomultiplier tubes.  The
         photocurrents from the photomultiplier tubes are processed and
         controlled by a computer system.  A background correction technique
         is  required to compensate for variable background contribution to
         the determination of trace elements.  Background must be measured
         adjacent to analyte lines on samples during analysis.  The position
         selected for the background intensity measurement, on either or
         both sides of the analytical line, will  be determined by the com-
         plexity of the spectrum adjacent to the analyte line.  The position
         used must be free of spectral interference and reflect the same
         change in background intensity as occurs at the analyte wavelength
         measured.  Background  correction is not  required in cases of line
         broadening where a background correction measurement would actually
         degrade the analytical  result.  The possibility of additional
         interferences named in  4.1  (and tests  for their presence as
         described in 4.2)  should also be recognized and appropriate
         corrections made.
                                       3
                                       34

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3.  Definitions
    3.1  Dissolved — Those elements which will pass through a 0.45 urn
         membrane filter.
    3.2  Suspended — Those elements which are retained by a 0.45 urn
         membrane filter.
    3.3  Total  — The concentration determined on an unfiltered sample
         following vigorous digestion (Section 8.3), or the sum of the
         dissolved plus  suspended concentrations.  (Section 8.1 plus 8.2).
    3-4  Total  recoverable —  The concentration determined on an unfiltered
         sample following treatment with hot,  dilute mineral  acid (Section
         8.4).
    3.5  Instrumental  detection  limit -- The concentration equivalent  to a
         signal,  due  to  the analyte,  which  is  equal  to  three  times the
         standard deviation of a series  of  ten replicate measurements  of a
         reagent  blank signal  at the  same wavelength.
    3.6   Sensitivity  --  The slope of  the analytical  curve,  i.e.  functional
         relationship  between  emission  intensity  and  concentration.
    3-7   Instrument check  standard  — A  multielement  standard of  known
         concentrations  prepared  by the  analyst to monitor  and  verify
         instrument performance  on  a daily  basis.  (See  6.6.1)
    3.8   Interference check  sample  - A solution containing  both  interfering
         and analyte elements  of  known concentration that can be  used  to
         verify background  and interelement correction factors.   (See  6.6.2.)
   3-9  Quality control  sample — A solution  obtained from an outside
         source having known, concentration values to be used to  verify the
        calibration standards.   (See 6.6.3)
                                       4
                                       35

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    3.10 Calibration standards —  a series of known  standard  solutions  used
         by the analyst for calibration of the  instrument  (i.e.,  preparation
         of the analytical curve).  (See 6.4)
    3.11 Linear dynamic range ~ The concentration range over which  the
         analytical curve remains  linear.
    3.12 Reagent blank — A volume of deionized, distilled water  containing
         the same acid matrix as the calibration standards carried through
         the entire analytical scheme.  (See 6.5.2)
    3.13 Calibration blank — A volume of deionized, distilled water acidi-
         fied with HN03 and HC1.   (See 6.5.1)
    3.14 Method of standard addition — The standard addition technique
         involves the use of the unknown and the unknown plus a known amount
         of standard.  (See 9.6.1.)
4.  Interferences
    4.1  Several types of interference effects may contribute to  inac-
         curacies in the determination of trace elements.  They can be
         summarized as follows:
         4.1.1   Spectral  interferences can be categorized as 1) overlap of a
                spectral  line from another element; 2) unresolved overlap of
                molecular band spectra;  3)  background contribution from
                continuous or recombination phenomena; and 4)  background
                contribution  from stray light from the line emission of high
                concentration elements.   The  first of these effects can be
                compensated  by utilizing a computer correction of the raw
                data,  requiring  the monitoring and measurement of the
                interfering  element.   The  second effect may require selec-
                                       5
                                       36

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               tion  of  an  alternate  wavelength.   The  third and fourth
               effects  can  usually be  compensated by  a  background correc-
               tion  adjacent  to the  analyte  line.   In addition,  users of
               simultaneous multi-element  instrumentation  must assume the
               responsibility of verifying the absence  of  spectral  inter-
               ference  from an element that  could occur in a  sample but  for
               which there  is no channel in  the  instrument array.   Listed
               in Table 2 are some interference  effects for the  recommended
               wavelengths given in  Table  1.  The data  in  Table  2  are
               intended for use only as a rudimentary guide for  the indica-
               tion of  potential spectral  interferences.   For this  purpose,
               linear relations between concentration and  intensity for  the
               analytes and the interferents can  be assumed.
               The interference information, which was  collected  at the
               Ames Laboratory , is  expressed as  analyte concentration
               eqivalents (i.e. false analyte concentrations)  arising from
               100 mg/1 of the interferent element.   The suggested  use of
               this information is as follows:  Assume  that arsenic (at
               193.696 nm) is to be  determined in  a sample  containing
               approximately  10 mg/1 of aluminum.  According  to Table 2,
Ames Laboratory, USDOE, Iowa State University, Ames Iowa  50011
                                    6
                                    37

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                                Table 2.   Analyte Concentration Equivalents (mg/1) Arising
                                         From Interferents at the 100 mg/1 Level
OJ
00
Analyte Wavelength,

Aluminum
Antimony
Arsenic
Barium
Beryllium
Boron
Cadmium
Calcium
Chromium
Cobalt
Copper
Iron
Lead
Magnesium
Manganese
Molybdenum
Nickel
Selenium
Silicon
Sodium
Thallium
Vanadium
Zinc

308.215
206.833
193.696
455.403
313.042
249.773
226.502
317.933
267.716
228.616
324.754
259.940
220.353
279.079
257.610
202.030
231.604
196.026
288.158
588.995
190.864
292.402
213.856
nm
Al Ca
• mm *m mm
0.47
1.3
— — _ w
—
0.04
— _ — _
— __
—
~ * • _
__ __
—
0.17
0.02
0.005 —
0.05
_ _ __
0.23
— _ — _
	
0.30
_- __
—

Cr Cu
„
2.9
0.44
mm •• • _
-_ __
__
mm mm -m mm
0.08
—
0.03
— - __
_-
._
0.11
0.01
mm « •• •_
— — •«
—
0.07
— - -._
-- __
0.05
0.14
Interferent
Fe Mg Mn
0.21
0.08
—
	
— — _ _ _..
0.32
0.03
0.01 0.01 0.04
0.003 — 0.04
0.005
0.003
0.12

0.13 — 0.25
0.002 0.002
0.03
••— — «• •. mm
0.09
^ i— •• •• ~ m~
— — — — .. _
	
0.005
__ __ __

N1 T1

.25


0.04

0.02
0.03
_-
0.03 0.15
0.05


0.07
—

mm _ — _
__
—
0.08

0.02
0.29

V
1.4
0.45
1.1

0.05


0.03
0.04

0.02


0.12
--

-m mm
--
0.01

--
__
_ m.

-------
        100 mg/1  of  aluminum  would  yield  a  false signal  for arsenic
        equivalent to  approximately 1.3 mg/1.   Therefore,  10 mg/1  of
        aluminum  would result in  a  false  signal  for  arsenic equiva-
        lent to approximately 0.13  mg/1.  The  reader is  cautioned
        that other analytical  systems may exhibit  somewhat  different
        levels of interference than  those shown  in Table 2, and that
        the interference effects  must be  evaluated for each indi-
        vidual system.
        Only those interferents listed were  investigated and the
        blank spaces in Table  2 indicate  that  measurable interfer-
        ences were not  observed for  the interferent  concentrations
        listed in Table 3.  Generally, interferences were discern-
        ible if they produced  peaks  or background  shifts corres-
        ponding to 2-5% of the peaks generated by  the analyte
       concentrations  also listed  in Table 3.
       At present,  information on the listed  silver and potassium
       wavelengths are not available but it has been reported  that
       second order energy from the magnesium 383.231 nm wavelength
        interferes with the listed potassium line  at 766.491 nm.
4.1.2  Physical   interferences are generally considered  to  be
       effects associated with the  sample nebulization  and
       transport processes.  Such properties as change  in  viscosity
       and surface  tension can cause significant  inaccuracies
       especially in samples which may contain high dissolved
       solids and/or acid concentrations.  The use of a peristaltic
       pump may lessen these interferences.  If these types of
                             8
                             39

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             interferences  are  operative,  they must be reduced by dilu-
             tion  of  the  sample and/or  utilization  of  standard addition
             techniques.  Another  problem  which can occur  from high
             dissolved  solids is salt buildup  at the tip of the nebuli-
             zer.  This affects aersol  flow  rate causing instrumental
             drift.   Wetting the argon  prior to nebulization,  the use  of
             a tip washer,  or sample dilution  have  been used to control
             this  problem.  Also,  it has been  reported that better
             control  of the argon  flow  rate  improves instrument perform-
             ance.  This  is accomplished with  the use  of mass  flow
             controllers.
     4.1.3   Chemical Interferences are characterized  by molecular
             compound formation, iom'zation  effects  and solute  vaporiza-
             tion effects.  Normally these effects  are not  pronounced
             with the ICP technique, however,  if observed they  can be
             minimized by careful  selection  of  operating conditions  (that
             is, incident power, observation position, and  so forth),  by
             buffering of the sample, by matrix  matching, and by  standard
             addition procedures.  These types  of interferences can  be
             highly dependent on matrix type and the specific analyte
             element.
4.2  It is recommended that whenever a new  or  unusual sample matrix is
     encountered, a series of  tests be performed prior to  reporting
     concentration data for analyte elements.   These  tests, as outlined
     in 4.2.1 through 4.2.4, will  ensure the analyst  that  neither
     positive nor negative interference effects are operative on  any of
                                   9
                                   40

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Table 3.  Interferent and Analyte Elemental Concentrations Used
           for  Interference Measurements  in  Table  2.
 Analytes   (rng/1)                           Interferents   (mo/1)

    Al         10                                  Al          1000
    As         10                                  Ca          1000
    B         10                                  Cr           200
    Ba          1                                  Cu           200
    Be          1                                  Fe          1000
    Ca          1                                  Mg          1000
    Cd         10                                  Mn           200
    Co          1                                  Ni           200
    Cr          1                                  Ti           200
    Cu          1                                  V            200
    Fe          1
    Mg          1
    Mn          1
    Mo         10
    Na         10
    Ni         10
    Pb         10
    Sb         10
    Se         10
    Si          1
    Tl         10
    V          1
    Zn         10
                               10
                               41

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 the  analyte  elements  thereby distorting the accuracy of the
 reported  values.
 4.2.1   Serial  dilution—If  the  analyte  concentration is sufficiently
        high  (minimally  a  factor of  10 above the  instrumental
        detection  limit  after dilution),  an  analysis  of  a dilution
        should  agree within  5 percent of  the original  determination
        (or within  some  acceptable control limit  (13.3)  that has
        been  established for  that matrix.).   If not,  a chemical or
        physical interference effect should  be suspected.
 4.2.2   Spike addition—The  recovery of a spike addition added at a
        minimum  level  of 10X  the instrumental detection  limit
        (maximum 100X) to  the original determination  should  be
        recovered to within 90 to 110 percent or within  the  estab-
        lished control limit  for that matrix.  If not, a matrix
        effect should  be suspected.  The  use of a standard addition
        analysis procedure can usually compensate for  this effect.
          Caution:  The standard addition technique does not detect
          coincident  spectral overlap.    If  suspected, use of
          computerized compensation, an  alternate wavelength, or
          comparison with an alternate method is recommended (See
          4.2.3).
                                  •
4.2.3  Comparison with alternate method of analysis—When investi-
       gating a new sample matrix, comparison tests may be
       performed with other  analytical  techniques such  as atomic
       absorption  spectrometry,  or other approved methodology.
                               11

                               42

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          4.2.4   Wavelength scanning of analyte line region—If the appro-
                 priate  equipment  is available, wavelength  scanning can be
                 performed  to  detect potential  spectral  interferences.
 5.   Apparatus
     5.1   Inductively Coupled  Plasma-Atomic  Emission Spectrometer.
          5.1.1   Computer controlled atomic  emission spectrometer with  back-
                 ground  correction.
          5.1.2   Radiofrequency  generator.
          5.1.3   Argon gas  supply, welding grade or  better.
     5.2   Operating conditions —  Because of the differences  between  various
          makes and models  of  satisfactory instruments,  no  detailed operating
          instructions can  be  provided.  Instead, the  analyst  should  follow
          the instructions  provided  by  the manufacturer  of  the particular
          instrument.  Sensitivity,  instrumental  detection  limit, precision,
          linear  dynamic range,  and  interference effects must  be investigated
          and established for  each individual analyte  line on  that  particular
          instrument.  It is the responsibility of the analyst  to verify that
          the instrument configuration  and operating conditions used  satisfy
          the analytical requirements and to maintain quality  control data
          confirming instrument performance  and  analytical results.
6.  Reagents and standards
    6.1  Acids used in the preparation of standards and for sample proces-
          sing must be ultra-high purity grade  or equivalent.  Redistilled
          acids are acceptable.
         6.1.1   Acetic acid, cone,  (sp gr 1.06).
         6.1.2  Hydrochloric acid, cone, (sp gr  1.19).
                                         12
                                         43

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     6-1.3  Hydrochloric  acid,  (1+1):   Add  500  ml  cone.  HC1  (sp gr 1.19)
            to 400 ml deionized,  distilled  water  and  dilute  to 1  liter.
     6.1.4  Nitric acid,  cone,  (sp  gr  1.41).
     6.1.5  Nitric acid.  (1+1):   Add 500 ml cone.  HN03  (sp.  gr 1.41)
            to 400 ml deionized,  distilled  water  and  dilute  to 1  liter.
6.2  Deionized, distilled water;  Prepare by  passing  distilled water
     through a mixed bed  of cation  and  anion  exchange resins.   Use
     deionized, distilled water for the preparation of  all reagents,
     calibration standards and as dilution  water.  The purity  of  this
     water must be equivalent to ASTM Type  II reagent water  of Specifi-
     cation D 1193 (13.6).
6.3  Standard stock solutions may be purchased or  prepared from ultra
     high purity grade chemicals or metals.  All salts must  be dried for
     1  h at 105°C unless otherwise specified.
     (CAUTION:   Many metal salts are extremely toxic  and may be fatal  if
     swallowed.   Wash hands thoroughly after handling.)
     Typical  stock solution preparation procedures follow:
     6.3.1  Aluminum solution, stock.  1 ml  = 100 ug Al:  Dissolve
            0.100 g of aluminum metal  in an acid mixture of 4 ml of
            (1+1)  HC1 and 1 ml of cone. HN03 in a beaker.  Warm gently
            to  effect solution.   When  solution is complete, transfer
            quantitatively to a liter  flask add an additional  10 ml of
            (1+1)  HC1 and dilute to  1,000 ml with deionized,  distilled
           water.
     6.3.2 Antimony solution stock, 1  ml = 100 ug Sb:  Dissolve
           0.2669  g  K(SbO)C4H4Og  in deionized distilled water,
                                   13
                                   44

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        add 10 ml  (1+1)  HC1  and dilute to 1000 ml  with deionized,
        distilled  water.
 6.3.3   Arsenic solution,  stock.  1  ml  = 100 ug As:   Dissolve
        0.1320 g of  As203  in 100  ml  of deionized,  distilled
        water  containing 0.4 g  NaOH.   Acidify the  solution with 2 ml
        cone.  HN03 and dilute to  1,000 ml  with deionized,  dis-
        tilled water.
 6.3.4   Barium solution, stock,  1 ml = 100 ug Ba:   Dissolve 0.1516 g
        BaCl2  (dried at 250°C for 2  hrs)  in 10 ml  deionized,
        distilled  water with 1  ml (1+1) HC1.   Add  10.0 ml  (1+1)  HC1
        and dilute to 1,000  ml  with  deionized,  distilled water.
 6.3.5   Beryllium  solution,  stock,  1 ml =  100 ug Be:   Do not  dry.
        Dissolve 1.966 g BeS04  ' 4H20,  in  deionized, distilled
        water,  add 10.0 ml cone. HN03  and  dilute to  1,000  ml  with
        deionized, distilled water.
 6.3.6   Boron  solution, stock,  1 ml =  100  ug  B:  Do  not dry.
        Dissolve 0.5716 g anhydrous H3B03  in  deionized, dis-
        tilled  water and dilute to  1,000  ml.   Use a reagent  meeting
        ACS specifications,  keep the bottle tightly  stoppered and
        store  in a desiccator to prevent the  entrance  of atmospheric
       moisture.
6.3.7  Cadmium solution, stock, 1 ml = 100 ug Cd:   Dissolve
       0.1142 g CdO in a minimum amount of (1+1) HN03.  Heat  to
        increase rate of dissolution.  Add  10.0 ml  cone. HN03  and
       dilute to  1,000 ml  with  deionized, distilled water.
6.3.8  Calcium solution,  stock, 1 ml = 100 ug Ca:   Suspend 0.2498 g
                               45

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        CaC03 dried at 180°C for 1  h before weighing in deion-
        ized, distilled water and dissolve cautiously with a minimum
        amount of (1+1) HNOj.  Add  10.0 ml cone.  HN03 and dilute
        to  1,000 ml  with deionized,  distilled water.
 6.3.9   Chromium solution,  stock. 1  ml  = 100 ug Cr:   Dissolve
        0.1923 g of Cr03 in deionized,  distilled  water.  When
        solution is  complete, acidify with 10 ml  cone.  HNO, and
        dilute to 1,000 ml  with deionized, distilled  water.
 5-3.10  Cobalt solution,  stock,  1 ml  =  100 ug Co:  Dissolve 0.1000 g
        of  cobalt metal  in  a minimum  amount of (1+1)  HNO,.   Add
                                                        0
        10.0  ml  (1+1)  HC1 and dilute  to 1,000 ml  with deionized,
        distilled water.
 6.3.11  Copper solution,  stock,  1 ml  =  100 ug Cu:  Dissolve  0.1252 g
        CuO in a minimum  amount  of (1+1) HN03.  Add 10.0  ml  cone.
        HN03  and dilute  to  1,000  ml with deionized, distilled
        water.
 6.3.12  Iron  solution,  stock,  1 ml =  100 ug  Fe:   Dissolve 0.1430 g
        Fe203  in 10 ml  deionized, distilled  water with  1  ml
        (1+1)  HC1.  Add  10.0  ml cone. HN03  and  dilute to  1,000  ml
        with  deionized, distilled water.
6.3.13  Lead  solution, stock,  1 ml =  100 ug  Pb:  Dissolve 0.1599 g
        Pb(N03)2  in a minimum  amount  of (1+1) HN03-  Add  10.0
       ml cone. HN03 and dilute to 1,000 ml with deionized, dis-
        tilled water.
6.3.14 Magnesium solution,  stock, 1  ml  =  100 ug Mg:   Dissolve
       0.1658 g MgO in a minimum amount of  (1+1)  HNO-,.  Add  10.0
                            15
                            46

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        ml  cone.  HN03 and dilute to 1,000 ml  with deionized,
        distilled water.
 6.3.15 Manganese solution,  stock.  1  ml  = 100 ug Mn:   Dissolve
        0.1000 g  of manganese metal in the acid mixture 10 ml  cone.
        HC1  and 1  ml  cone. HNOj,  and  dilute to 1,000  ml with
        deionized,  distilled water.
 6.3.16 Molybdenum solution,  stock. 1  ml  = 100 ug Mo:   Dissolve
        0.2043 g  (NH4)2Mo04  in deionized,  distilled water and
        dilute to  1,000 ml.
 6.3.17 Nickel  solution,  stock.  1 ml  = 100 ug Ni:   Dissolve 0.1000 g
        of nickel  metal in 10 ml  hot  cone.  HN03>  cool  and dilute
        to 1,000 ml with  deionized, distilled water.
 6.3.18 Potassium  solution,  stock.  1 ml =  100 ug  K:  Dissolve  0.1907
        g KC1,  dried  at 110°C,  in deionized,  distilled water
        dilute  to  1,000 ml.
 6.3.19  Selenium solution, stock. 1 ml =  100  ug Se:  Do not  dry.
        Dissolve 0.1727 g H2Se03  (actual  assay 94.6X)  in  deion-
        ized, distilled water  and dilute to 1,000  ml.
 6.3.20  Silica  solution, stock. 1 ml = 100 ug  SiO.:  Do not  dry.
        Dissolve 0.4730 g Na2Si03 .9H20 in deionized,  dis-
        tilled water.  Add 10.0 ml  cone. HN03  and  dilute-  to  1,000
       ml with deionized, distilled water.
6.3.21 Silver solution, stock. 1 ml = 100 ug Ag:  Dissolve 0.1575 g
       AgN03 in 100 ml of deionized, distilled water  and 10 ml
       cone. HN03.  Dilute to 1,000 ml with deionized, distilled
       water.
                             16
                             47

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      6.3.22  Sodium solution,  stock.  1  ml  = 100  ug Na:   Dissolve 0.2542 g
             Nad  in  deionized,  distilled  water.   Add  10.0 ml  cone.
             HN03  and dilute to  1,000 ml with  deionized,  distilled
             water.
      6.3.23  Thallium solution,  stock.  1 ml  =  100  ug Tl:   Dissolve
             0.1303 g T1N03 in deionized,  distilled water.   Add  10.0 ml
             cone.  HN03 and dilute to 1,000  ml with deionized, dis-
             tilled water.
      6-3.24  Vanadium solution,  stock.  1 ml  =  100  ug V:   Dissolve 0.2297
             NH4V03 in a minimum amount of cone. HN03.  Heat to
             increase rate of dissolution.   Add 10.0 ml cone. HN03 and
             dilute to 1,000 ml with deionized, distilled water.
      6.3.25  Zinc solution, stock. 1 ml =  100 ug Zn:  Dissolve 0.1245 g
             ZnO in a minimum amount of dilute HN03.  Add 10.0 ml cone.
             HN03 and dilute to 1,000 ml with deionized, distilled
            water.
6.4  Mixed calibration standard solutions—Prepare mixed calibration
     standard solutions by combining appropriate volumes of the stock
     solutions in volumetric flasks.  (See 6.4.1 thru 6.4.5)  Add 2 ml
     of (1+1) HN03 and 10 ml  of (1+1)  HC1  and dilute to 100 ml with
     deionized,  distilled water.  (See Notes 1 and 6.)   Prior to pre-
     paring the  mixed standards, each  stock solution  should be analyzed
     separately  to determine  possible  spectral interference or the
     presence of impurities.   Care should  be taken when preparing the
     mixed standards  that the  elements  are compatible  and stable.
     Transfer the mixed  standard solutions to  a  FEP fluorocarbon or
                                  17
                                  48

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 unused polyethylene bottle for storage.  Fresh mixed standards
 should be prepared as needed with the realization that concentra-
 tion can change on aging.   Calibration standards must be initially
 verified using a quality control  sample and monitored weekly for
 stability (See 6.6.3).   Although  not  specifically required,  some
 typical  calibration standard combinations  follow when using  those
 specific wavelengths  listed in  Table  1.
 6-4-1  Mixed  standard solution  I—Manganese,  beryllium,  cadmium,
       lead,  and  zinc.
 6'4*2  M1xed  standard solution  II—Barium,  copper, iron, vanadium,
       and cobalt.
 6.4.3  Mixed  standard solution  III-Molvbdenum.  silica, arsenic,
       and selenium.
6.4.4  Mixed  standard solution  IV—Calcium, sodium, postassium,
       aluminum, chromium and nickel.
6-4-5  Mixed standard solution V—Antimony, boron, magnesium,
       silver, and thallium.
          NOTE 1:  If the addition of  silver to the recommended
          acid combination  results in  an initial  precipitation, add
          15  ml of deionlzed distilled water and  warm the flask
          until the solution clears.   Cool  and dilute to  100  ml
          with deionlzed, distilled water.   For this  acid combina-
          tion the silver concentration  should be limited to  2
          mg/1.   Silver  under these conditions is stable  in a tap
          water matrix for  30 days.  Higher  concentrations of
          silver  require additional HC1.
                              18
                              49

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6.5  Two types of blanks  are required  for  the  analysis.   The  calibration
     blank  (3.13) is used  in establishing  the  analytical  curve  while the
     reagent blank  (3.12)  is used to correct for  possible contamination
     resulting from varying amounts of the  acids  used  in  the  sample
     processing.
     6.5.1  The calibration blank is prepared  by  diluting 2 ml  of  (1+1)
            HN03 and 10 ml of (1+1) HC1 to  100 ml with deionized,
            distilled water.  (See Note 6.)  Prepare a sufficient
            quantity to be used to flush the system between standards
            and samples.
     6.5.2  The reagent blank must contain  all the reagents and  in the
            same volumes as used in the processing of the samples.   The
            reagent blank must be carried through the complete  procedure
            and contain the same acid concentration in the final solu-
            tion as the sample solution used for  analysis.
6.6  In addition to the calibration standards, an instrument check
     standard (3.7), an interference check  sample (3.8) and a quality
     control sample (3.9) are also required for the analyses.
     6.6.1   The instrument check standard is prepared by  the analyst by
            combining compatible elements at a concentration equivalent
            to the midpoint of their respective calibration curves.
            (See 11.1.1.)
     6.6.2   The interference check sample is prepared by  the analyst in
            the following manner.   Select a representative sample which
            contains minimal  concentrations of the analytes of interest
            but known concentration of interfering elements that will
                                   19
                                   50

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                 provide  an  adequate  test  of  the  correction  factors.   Spike
                 the sample  with the  elements  of  interest  at the  approximate
                 concentration of either 100  ug/1  or  5  times the  estimated
                 detection limits given in Table  1.   (For  effluent  samples  of
                 expected high concentrations, spike  at an appropriate level.)
                 If the type of samples analyzed  are  varied,  a  synthetically
                 prepared sample may  be used  if the above  criteria  and intent
                 are met.  A limited  supply of a  synthetic interference  check
                 sample will be available from the Quality Assurance  Branch
                 of EMSL-Cincinnati.  (See 11.1.2).
         6.6.3   The quality control  sample should be prepared  in the same
                 acid matrix as the calibration standards  at  a concentration
                 near 1 mg/1 and in accordance with the  instructions  provided
                 by the supplier.  The Quality Assurance Branch of  EMSL-
                Cincinnati will either supply a quality control sample or
                 information where one of equal quality can  be procured.
                 (See 11.1.3.)
7.  Sample handling and preservation
    7.1  For the determination of trace elements, contamination and  loss are
         of prime concern.  Oust in the laboratory environment, impurities
         in reagents and impurities on laboratory apparatus which the sample
         contacts are all sources of potential contamination.  Sample
         containers can introduce either  positive or negative errors  in the
         measurement of trace  elements by (a) contributing contaminants
         through leaching or surface desorption and (b) by depleting concen-
                                        20
                                        51

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     trations through adsorption.  Thus the collection and treatment  of
     the sample prior to analysis requires particular attention.
     Laboratory glassware including the sample bottle (whether poly-
     ethylene, polyproplyene or FEP-fluorocarbon) should be thoroughly
     washed with detergent and tap water; rinsed with (1+1) nitric acid,
     tap water, (1+1) hydrochloric acid, tap and finally deionized,
     distilled water in that order (See Notes 2 and 3).
     NOTE 2:  Chromic acid may be useful to remove organic deposits from
     glassware; however, the analyst should be cautioned that the glass-
     ware must be thoroughly rinsed with water to remove the last traces
     of chromium.  This is especially important if chromium is to be
     included in the analytical scheme.  A commercial product, NOCHROMIX,
     available from Godax Laboratories, 6 Varick St., New York, NY
     10013, may be used in place of chromic acid.  Chromic acid should
     not be used with plastic bottles.
     NOTE 3:  If it can be documented through an active analytical
     quality control program using spiked samples and reagent blanks,
     that certain steps in the cleaning procedure are not required for
     routine samples, those steps may be eliminated from the procedure.
7.2  Before collection of the sample a decision must be made as to the
     type of data desired, that is dissolved, suspended or total, so
     that the appropriate preservation and pretreatment steps may be
     accomplished.  Filtration, acid preservation, etc., are to be
     performed at the time the sample is collected or as soon as
     possible thereafter.
                                   21
                                   52

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         7.2.1  For  the  determination  of  dissolved  elements  the sample must
                be filtered  through  a  0.45-um  membrane  filter as soon  as
                practical  after collection.   (Glass or  plastic filtering
                apparatus  are  recommended to avoid  possible  contamination.)
                Use  the  first  50-100 ml to rinse  the filter  flask.   Discard
                this portion and collect  the required volume of filtrate.
                Acidify  the  filtrate with (1+1) HNOj to a  pH of 2 or less.
                Normally,  3 ml of  (1+1) acid per  liter  should be sufficient
                to preserve the sample.
         7.2.2  For  the  determination  of  suspended  elements  a measured
                volume of  unpreserved  sample must be filtered through  a
                0.45-um  membrane filter as soon as  practical  after  collec-
                tion.  The filter  plus suspended material  should be trans-
                ferred to  a suitable container for  storage and/or shipment.
                No preservative is required.
         7.2.3  For the  determination  of  total or total recoverable elements,
                the  sample is  acidified with (1+1)  HN03 to pH  2  or  less as
                soon as  possible,  preferably at the  time of  collection.  The
                sample is  not  filtered before processing.
3.  Sample Preparation
    8.1  For the determinations of dissolved elements,  the filtered, pre-
         served sample may often be analyzed as received.  The  acid  matrix
         and concentration of  the  samples and calibration standards  must be
         the same.  (See Note 6.)  If a precipitate  formed upon  acidifica-
         tion of the sample or  during transit or storage, it must  be  re-
         dissolved before the analysis by adding additional  acid  and/or  by
                                       22
                                       53

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      heat as described in 8.3.
 8.2   For the determination of suspended elements, transfer the membrane
      filter containing the insoluble material to a 150-ml Griffin beaker
      and add 4 ml  cone.  HN03.  Cover the beaker with a watch glass and
      heat gently.   The warm acid will soon dissolve the membrane.
      Increase the  temperature of the hot plate and digest the material.
      When the acid has nearly evaporated,  cool the beaker and watch
      glass and add another 3 ml  of cone.  HNO-j.  Cover and continue
      heating until  the digestion is complete, generally indicated by a
      light colored digestate.  Evaporate to near dryness (2  ml),  cool,
      add 10 ml  HC1  (1+1)  and 15  ml  deionized, distilled water per 100 ml
      dilution and  warm the beaker gently for 15 min.  to dissolve  any
      precipitated  or residue material.   Allow to cool,  wash  down  the
      watch glass and beaker walls with  deionized distilled water  and
      filter the sample to  remove insoluble material  that could clog the
      nebulizer.  (See  Note 4.)   Adjust  the volume based on the expected
      concentrations of elements  present.   This volume will vary depend-
      ing  on  the elements to  be determined  (See Note  6).   The  sample is
      now  ready for analysis.  Concentrations  so  determined shall  be
      reported  as "suspended."
      NOTE  4:   In place of  filtering,  the sample  after diluting and  mix-
      ing may  be ceritrifuged  or allowed  to  settle  by  gravity overnight  to
      remove  insoluble  material.
8.3   For the determination of total elements,  choose  a measured,  volume
      of the well mixed acid  preserved sample  appropriate  for  the
     expected level of elements  and transfer  to  a Griffin beaker.   (See
                                23
                                54

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Note 5.)  Add 3 ml of cone. HNOj.  Place  the  beaker  on  a  hot
plate and evaporate to near dryness cautiously, making  certain  that
the sample does not boil and that no area of  the  bottom of  the
beaker is allowed to go dry.  Cool the beaker and add another 5  ml
portion of cone. HNOj.  Cover the beaker  with a watch glass and
return to the hot plate.   Increase the temperature of the hot plate
so that a gentle reflux action occurs.  Continue  heating, adding
additional acid as necessary, until the digestion is complete
(generally indicated when  the digestate is  light  in  color or does
not change in appearance with continued refluxing.)  Again, evapo-
rate to near dryness and cool the beaker.  Add 10 ml of 1+1 HC1  and
15 ml of deionized, distilled water per 100 ml  of final  solution
and warm the beaker gently for 15 min. to dissolve any  precipitate
or residue resulting from  evaporation.  Allow to  cool,  wash down
the beaker walls and watch glass with deionized distilled water  and
filter the sample to remove insoluble material that could clog the
nebulizer.  (See Note 4.)  Adjust the sample  to a predetermined
volume based on the expected concentrations of elements present.
The sample is now ready for analysis (See Note 6).  Concentrations
so determined shall be reported as "total."
NOTE 5:  If low determinations of boron are critical, quartz glass-
ware should be used.
NOTE 6:  If the sample analysis solution has  a different  acid con-
centration from that given in 8.4, but does not introduce a
physical  interference or affect the analytical result,  the  same
calibration standards may be used.
                             24
                             55

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    8.4  For the determination of total recoverable elements, choose  a
         measured volume of a well mixed, acid preserved sample  appropriate
         for the expected level of elements and transfer to  a Griffin
         beaker.  (See Note 5.)  Add 2 ml of (1+1) HN03 and  10 ml of  (1+1)
         HC1 to the sample and heat on a steam bath or hot plate until  the
         volume has been reduced to near 25 ml making certain the sample
         does not boil.  After this treatment, cool the sample and filter to
         remove insoluble material that could clog the nebulizer.  (See
         Note 4.)  Adjust the volume to 100 ml and mix.  The sample is  now
         ready for analysis.  Concentrations so determined shall be reported
         as "total."
9.  Procedure
    9.1  Set up instrument with proper operating parameters  established in
         Section 5.2.  The instrument must be allowed to become  thermally
         stable before beginning.  This usually requires at  least 30 min. of
         operation prior to calibration.
    9.2  Initiate appropriate operating configuration of computer.
    9.3  Profile and calibrate instrument according to instrument manufac-
         turer's recommended procedures, using the typical mixed calibration
         standard solutions described in Section 6.4.  Flush the system with
         the calibration blank (6.5.1) between each standard.  (See Note
         7.)  (The use of the average intensity of multiple exposures for
         both standardization and sample analysis has been found to reduce
         random error.)
         NOTE 7:  For boron concentrations greater than 500 ug/1 extended
         flush times of 1 to 2 minutes may be required.
                                    25
                                     56

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9.4  Before beginning the sample run, reanalyze the highest mixed  cali-
     bration standard as if it were a sample.  Concentration values
     obtained should not deviate from the actual values by more than ± 5
     percent (or the established control limits whichever is lower).   If
     they do, follow the recommendations of the instrument manufacturer
     to correct for this condition.
9.5  Begin the sample run flushing the system with the calibration blank
     solution (6.5.1) between each sample.  (See Note 7.)  Analyze the
     instrument check standard (6.6.1) and the calibration blank (6.5.1)
     each 10 samples.
9.6  If it has been found that methods of standard addition are required,
     the following procedure is recommended.
     9.6.1  The standard addition technique (13.2) involves preparing
            new standards in the sample matrix by adding known amounts
            of standard to one or more aliquots of the processed sample
            solution.  This technique compensates for a sample constitu-
            ent that enhances or depresses the analyte signal thus
            producing a different slope from that of the calibration
            standards.   It will not correct for additive interference
            which causes a baseline shift.   The simplest version of this
            technique is the single-addition method.   The procedure is
            as follows.  Two identical aliquots of the sample solution,
            each of volume V , are taken.  To the first (labeled A) is
                            A
            added a small volume Vg of a standard analyte solution of
            concentration GS.   To the second (labeled B)  is added the
            same volume V  of the solvent.   The analytical signals of
                               25
                                57

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                A  and  B  are measured  and  corrected  for  nonanalyte signals
                signals.  The unknown  sample  concentration  c   is  calcu-
                                                            A
                lated:
                                  SBVscs
                               l*A * V  Vx
                where Sft and Sg are the  analytical  signals  (corrected
                for the blank) of solutions A and B, respectively.   V   and
                GS should be chosen so that SA  is roughly twice S« on
                the average.   It is best if Vs  is made much  less  than
                V , and thus c  is much  greater than c , to  avoid
                 *             5                       X
                excess dilution of the sample matrix.  If a  separation  or
                concentration  step is used, the additions are best made
                first and carried through the entire procedure.
                For the results from this technique to be valid, the follow-
                ing limitations must be taken into consideration:
                1. The analytical curve must be linear.
                2. The chemical form of the analyte added must respond  the
                   same as the analyte in the sample.
                3. The interference effect must be constant over the working
                   range of concern.
                4. The signal must be corrected for any additive interfer-
                   ence.
10.  Calculation
    10.1  Reagent blanks (6.5.2) should be subtracted from all samples.   This
         is particularly important for digested samples requiring large
         quantities  of acids to complete the digestion.
                                    27
                                    58

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    10.2 If dilutions were performed, the appropriate factor must be applied
         to sample values.
    10.3 Data should be rounded to £he thousandth place and all results
         should be reported in mg/1 up to three significant figures.
11.  Quality Control (Instrumental)
    11.1 Check the instrument standardization by analyzing appropriate
         quality control check standards as follow:
         11.1.1 Analyze an appropriate instrument check standard (5.6.1)
                containing the elements of interest  at a frequency of 10%.
                This check standard is used to determine instrument drift.
                If agreement is not within * 5% of the expected values or
                within the established control limits, whichever is lower,
                the analysis is out of control.  The analysis  should be
                terminated,  the problem corrected,  and the instrument
                recalibrated.
                Analyze the  calibration blank (6.5.1)  at a frequency of
                10%.   The result should be within the  established  control
                limits of 2  standard deviations of the mean value.   If not,
                repeat the analysis two more times and average the  three
                results.   If the average is  not within the control  limit,
                terminate the  analysis,  correct the  problem and recalibrate
                the instrument.
         11.1.2 To  verify interelement and background  correction factors
                analyze the  interference check sample  (6.6.2)  at the begin-
                ning,  end, and  at  periodic intervals throughout the  sample
                run.   Results  should  fall  within  the established control
                                    28
                                    59

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                 limits  of  1.5  times  the  standard  deviation  of the mean
                 value.   If  not, terminate  the  analysis,  correct  the  problem
                 and recalibrate the  instrument.
          11.1.3  A quality control sample (6.6.3)  obtained from an outside
                 source must first be used  for  the initial verification of
                 the calibration standards.  A  fresh dilution  of  this  sample
                 shall be analyzed every week thereafter  to  monitor their
                 stability,  if the results are not within + 5% of the  true
                 value listed for the control sample, prepare  a new calibra-
                 tion standard and recalibrate the  instrument.  If this  does
                 not correct the problem, prepare  a new stock  standard  and a
                 new calibration standard and repeat the calibration.
12.  Precision and Accuracy
    12.1 In an EPA round robin phase 1 study, seven laboratories  applied the
         ICP technique to acid-distilled water matrices that had  been dosed
         with various metal concentrates.  Table 4 lists the true  value, the
         mean reported value and the mean % relative standard deviation.
13. References
    13.1 Winge,  R.K.,  V.J.  Peterson,  and V.A.  Fassel,  "Inductively Coupled
         Plasma-Atomic Emission Spectroscopy:   Prominent Lines, EPA-600/4-
         79-017.
    13.2 Winefordner,  J.D.,  "Trace Analysis:   Spectroscopic  Methods for
         Elements,"  Chemical Analysis.  Vol. 46, pp. 41-42.
    13.3 Handbook for  Analytical Quality Control  in Water and  Wastewater
         Laboratories,  EPA-600/4-79-019.
                                     29
                                     60

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                                       Table 4.   ICP Precision and Accuracy Data
                         Sample
Sample 12
Sample 03
CJ
o
Element
Be
Mn
V
As
Cr
Cu
Fe
Al
Cd
Co
N1
Pb
Zn
Se
True
Value
ng/i
750
350
750
200
150
250
600
700
50
500
250
250
200
40
Mean
Reported
Value
ng/l
733
345
749
208
149
235
594
696
48
512
245
236
201
32
Mean
Percent
RSD
6.2
2.7
1.8
7.5
3.8
5.1
3.0
5.6
12
10
5.8
16
5.6
21.9
True
Value
M9/1
20
15
70
22
10
11
20
60
2.5
20
30
24
16
6
Mean
Reported
Value
ug/1
20
15
69
19
10
11
19
62
2.9
20
28
30
19
8.5
Mean
Percent
RSD
9.8
6.7
2.9
23
18
40
15
33
16
4.1
11
32
45
42
True
Value
ug/1
180
100
170
60
50
70
180
160
14
120
60
80
80
10
Mean
Reported
Value
ug/1
176
99
169
63
50
67
178
161
13
108
55
80
82
8.5
Mean
Percent
RSO
5.2
3.3
1.1
17
3.3
7.9
6.0
13
16
21
14
14
9.4
8.3
       Not all elements were analyzed by all laboratories.

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13.4 Garbarino, J.R. and Taylor, H.E., "An Inductively-Coupled Plasma
     Atomic Emission Spectrometric Method for Routine Water Quality
     Testing," Applied Spectroscopy 33, No.  3(1979).
13.5 "Methods for Chemical Analysis of Water and Wastes,"
     EPA-600/4-79-020.
13.6 Annual Book of ASTM Standards, Part 31.
                                31
                                62

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               APPENDIX B
DATATRIEVE FILE STRUCTURE FOR THE 4901A42
      SAMPLE STATUS DATA BASE FILE
                  63

-------
     : REPORT 12
             STATUS REPORT OF MRI PROJECT 4901A-42 METALS ANALYSES
                                                                13-MAY-B2
                                                                PAGE 1
       ARRIVAL    PREP
SAMPLE  DATE      DATE
1012
1022
1032
1042
1052
1025
1017
1027
1062
1072
1032
1067
1077
1087
1037
1047
05-03-82
05-03-82
05-03-82
05-03-32
05-03-82
05-03-82
05-03-32
05-03-82
05-03-82
05-03-32
05-03-82
05-03-82
05-03-82
05-03-82
05-03-32
05-03-82
                  DIGEST ANALYSIS  REPORT
                   CODE    DATE     DATE
COMMENTS
DTK

-------
DTK  SHOW TASK425
DOMAIN TASK42
USING
FASK42-FILE ON DL1ICl»543TASK42.IDX51»
DTP:
DTK.  SHOW TASM2-FILE5
RECORD TA3K42-FILE
USING
01 TAS!\42.
 03 SAMPLE PIC X<6) .
 03 ARRIVAL-DATE PIC X(S).
 03 PREP-DATE PIC X(S) .
 03 DIGEST-CODE PIC X<4) .
 03 ANALYSIS-DATE PIC  X(8),
 03 REPORT-DATE PIC X,
 03 COMMENTS PIC X(30).
A
7
DTF:
BT:  SHOW REPORT--?2 ?
PROCEDURE REPORT42
REPORT TASN42 SORTED BY DESC ARRIVAL-DATE
SET F:EPORT-NAME='STATUS REPORT OF MRI PROJECT 4901A-42  METALS  ANALYSES-
SET CQLUMNS-PAGE=80
P'^INT SAMPLE*ARRIVAL-DATEiPREP-DATEFDIGEST-CODE*ANALYSl3-DATEiREPORT-DATEiCOMMEN
T3-
REPORT EMD;
END-PROCEDURE
DTR
                                      65

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