16020 - 07/71
        /tXEAKh,
METHODS FOR CHEMICAL ANALYSIS
              OF
      WATER AND  WASTES
             1971
       ENVIRONMENTAL PROTECTION AGENCY

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METHODS FOR CHEMICAL ANALYSIS
                 OF
        WATER AND WASTES
                 1971
      ENVIRONMENTAL PROTECTION AGENCY
    National Environmental Research Center
     Analytical Quality Control Laboratory
          Cincinnati, Ohio  45268

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               DISCLAIMER

  Mention  of trade names  or commercial
  products  does  not constitute  endorse-
  ment by  the Water Quality Office or
  the Environmental Protection  Agency.
For sale by the Superintendent of Documents, U.S. Government Printing Office
             Washington, D.C. 20402- Price $3
                Stock Number 5501-0067

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                             PREFACE
     This manual describes the analytical procedures selected for use in

Water Quality Office laboratories for the chemical analysis of water and

waste samples.  The methods were chosen by a committee of senior chemists

from within the Office, using Standard Methods for the Examination of

Water and Wastewater, 13th Edition (1971) and ASTM Standards, Part 23,

Water; Atmospheric Analysis (1970), and current water pollution control

literature as basic references.  When necessary, methods derived from

these sources have been modified or replaced to more adequately meet the

needs of the Office.

     In order to provide reliable water quality and waste constituent

data for use by the Office, these procedures will be used in all Office

laboratories except under very unusual circumstances.  Other agencies and

individuals are encouraged to use these methods, in the interest of uni-

formity throughout the water pollution control effort.
                                         David D. Dominick
                                         Acting Commissioner
                                         Water Quality

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                                TABLE OF CONTENTS
                                                                       Page
 Introduction  	   ix
 Sample Preservation  	    1
 Acidity  (Electrometric Titration, pH 8.3)  	    5
 Alkalinity
   Manual (Electrometric Titration, pH 4.5) 	    g
   Automated  (Methyl Orange)  	    g
 Arsenic  (Silver Diethyldithiocarbamate) 	   13
 Biochemical Oxygen Demand  (Winkler-Azide or DO Probe) 	   15
 Chemical Oxygen Demand
   Routine Levels (Dichromate Reflux-0.25N) 	   17
   Low Level  (Dichromate Reflux-0.025N) 	   19
   Saline Waters  (Chloride Correction) 	   24
 Chloride
   Manual (Mercuric Nitrate Titration) 	   29
   Automated  (Ferricyanide) 	   31
 Chlorine Requirement 	.	   36
 Color (Platinum-Cob alt Visual)  	   38
 Cyanide  (Silver Nitrate Titration or Pyridine-Pyrazalone) 	   41
 Dissolved Oxygen
   Manual (Winkler-Azide)  	   53
   Probe (Ion Selective Electrode) 	   60
 Fluoride
   Manual (SPADNS, with Distillation) 	   64
   Automated  (Complexone)  	   66
   Probe (Ion Selective Electrode) 	   72
Hardness
   Manual (EDTA Titration) 	   76
   Automated  (Calmagite) 	   78
   Calculation (Ca + Mg by Atomic Absorption) 	   83

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                         TABLE OF CONTENTS (Contd.)

                                                                          Page
 Metals  (Atomic Absorption Methods)
    Aluminum [[[    gg
    Arseni c [[[    99
    Cadmium [[[   JQI
    Calcium [[[   102
    Chromium
   c°PPer  [[[   106
   Iron  [[[   108
   Lead  [[[   110
   Magnesium [[[   , •, 2
   Manganese [[[   •, -, »
   Potassium [[[
   Silver  [[[
   Sodium  [[[
   zinc  [[[   120
Mercury  (Flameless AA) ^ ..............................................
Methylene  Blue Active Substances  (Methylene Blue) .....................
Nitrogen

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                        TABLE OF  CONTENTS  (Contd.)
                                                                        Page
Nitrilotriacetic Acid  (NTA)
   Manual  (Zinc-Zincon) 	 205
   Automated  (Zinc-Zincon) 	 209
Oil and Grease  (Hexane Soxhlet Extraction)  	 217
Organic Carbon  (Instrumental) 	 221
pH (Electrometric)  	 230
Phenolics  (4-Aminoantipyrine) 	 232
Phosphorus, All Forms
   Manual  (Single Reagent) 	 235
   Automated  (Single Reagent) 	 246
   Automated  (Stannous Chloride)  	 259
Selenium (Diaminobenzidine)	 271
Silica (Molybdate)  	 273
Solids
   Filterable (Glass Fiber, 180°C)  	 275
   Non-Filterable (Glass Fiber, 103-105°C)  	 278
   Total (Gravimetric, 105°C) 	 280
   Volatile (Gravimetric, 550°C)  	 282
Specific Conductance (Wheatstone  Bridge) 	 284
Sulfate
   Manual  (Turbidimetric)	 286
   Automated  (Barium Chloranilate)  	 288
Sulfide (lodometric)	 294
Temperature (Mercury, Dial, or Thermistor)  	 296
Threshold Odor (Consistent Series)  	 297
Turbidity  (Instrumental) 	 308
                                     Vll

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                               INTRODUCTION


This  1971 edition of "Methods for Chemical Analysis of Water and Wastes"


describes chemical analytical procedures to be used in Water Quality Office


(WQO) laboratories.  The methods were chosen through the combined efforts of


the Regional Analytical Quality Control CAQC) Coordinators, Laboratory Quality


Control Officers, and other senior chemists in both federal and state labora-


tories.  Method selection was based on the following criteria:


(1)  The method should measure the desired constituent with precision and


     accuracy sufficient to meet the data needs of WQO in the presence of

                         i
     the interferences normally encountered in polluted waters.


(2)  The procedures should utilize the equipment and skills normally avail-


     able in the typical water pollution control laboratory.


C3)  The selected methods are in use in many laboratories or have been suf-


     ficiently tested to establish their validity.


[4)  The methods should be sufficiently rapid to permit routine use for the


     examination of a large number of samples.


Except where noted under "Scope and Application" for each constituent, the


methods can be used for the measurement of the indicated constituent in both


water and wastewaters and in both saline and fresh water samples.


Instrumental methods have been selected in preference to manual procedures


because of the improved speed, precision,  and accuracy.  Procedures for the


Technicon AutoAnalyzer have been included for laboratories having this equip-


ment available.


Precision and accuracy statements have been derived from inter-laboratory


studies conducted by the Methods and Performance Activity, Analytical Qual-


ity Control Laboratory, WQO; the American Society for Testing Materials; or


the Analytical Reference Service of the Public Health Service, DHEW.
                                     ix

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 Specific instructions for the handling and preservation of samples  cannot be




 given because of the wide variability in types of samples  and  local sampling




 situations.  However, certain general principles  should be followed.  Wherever




 possible, the sampling program should be designed to provide for the shortest




 possible interval between sample collection and analysis.   Positive steps




 should be taken to maintain both the concentration and  the physical state of




 the constituents to be measured.   Where  both total and  dissolved concentrations




 are to be determined, the dissolved concentration is the amount present after




 filtration through a 0.45 membrane filter.   When  the dissolved concentration




 is  to be determined,  filtration should be  carried out as soon as possible after




 collection of the sample,  preferably in  the  field.  Where  field filtration is




 not practical,  the sample should be filtered as soon as  it  is received in the




 laboratory.





 In  situations where  the interval between sample collection  and analysis is long




 enough  to produce  significant changes  in either the concentration or the physical




 state of the  constituent  to be measured, the preservatives  listed in Table II




 are  recommended.





 Although every effort has been made  to select methods which are applicable to




 the widest range of sample types, significant interferences may be encountered in




 certain isolated samples.  In these  situations, the analyst should define the




nature of the interference with the method herein and bring this information to




the attention of the Analytical Quality Control Laboratory through the  appropriate




Regional AQC Coordinator.  Recommendations for alternative procedures will be made




and modification of the method will be developed to overcome the interferences.
                                    x

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                  Regional Analytical Quality Control Coordinators
Warren H. Oldaker, AQC Coordinator
Environmental Protection Agency, Region I
John F. Kennedy Building, Room 2303
Boston, Massachusetts  02203

Francis T. Brezenski, AQC Coordinator
Environmental Protection Agency, Region II
Edison Water Quality Laboratory
Edison, New Jersey  08817
                              i
Charles Jones, Jr., AQC Coordinator
Environmental Protection Agency, Region III
Custom House, Room 1004
Second § Chestnut Streets
Philadelphia, Pennsylvania  19106

James H. Finger, AQC Coordinator
Environmental Protection Agency, Region IV
Southeast Water Laboratory
College Station Road
Athens, Georgia  30601

LeRoy E. Scarce, AQC Coordinator
Environmental Protection Agency, Region V
Illinois District Office
1819 West Pershing Road
Chicago, Illinois  60609
Bobby G. Benefield, AQC Coordinator
Environmental Protection Agency, Region VI
Kerr Water Research Center
P.O. Box 1198
Ada, Oklahoma  74820

Dr. Harold G. Brown, AQC Coordinator
Environmental Protection Agency, Region VII
911 Walnut Street, Room 702
Kansas City, Missouri  64106

John R. Tilstra, AQC Coordinator
Environmental Protection Agency, Region VIII
Suite 900, Lincoln Tower Building
1860 Lincoln Street
Denver, Colorado  80203

Donald B. Mausshardt, AQC Coordinator
Environmental Protection Agency, Region IX
Phelan Building, 760 Market Street
San Francisco, California  94102

Daniel F. Krawczyk, AQC Coordinator
Environmental Protection Agency, Region X
Pacific Northwest Water Laboratory
200 South 35th Street
Corvallis, Oregon  97330
                                           XI

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                              SAMPLE PRESERVATION






Complete and unequivocal preservation of samples, either domestic sewage,




industrial wastes or natural waters, is a practical impossibility.  Regard-



less of the nature of the sample, complete stability for every constituent



can never be achieved.  At best, preservation techniques can only retard the



chemical and biological changes that inevitably continue after the sample is



removed from the parent source.





The changes that take place in a sample are either chemical or biological.  In



the former case, certain changes occur in the chemical structure of the con-



stituents that are a function of physical conditions.  Metal cations may



precipitate as hydroxides or form complexes with other constituents; cations



or anions may change valence states under certain reducing or oxidizing con-



ditions; other constituents may dissolve or volatilize with the passage of



time.  Metal cations may also adsorb onto surfaces (glass, plastic, quartz,



etc.), such as, iron and lead.  Biological changes taking place in a sample may



change the state of an element or a radical to a different state.  Soluble con-



stituents may be converted to organically bound material in cell structures, or



cell lysis may result in release of cellular materials into solution.  The



well known nitrogen and phosphorus cycles are examples of biological influence



on sample composition.





Methods of preservation are relatively limited and are intended generally to



(1) retard biological action, (2) retard hydrolysis of chemical compounds and



complexes and (3) reduce volatility of constituents.

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Preservation methods are generally limited to pH control, chemical addi-

tion, refrigeration, and freezing.  Table 1 shows the various preservatives

that may be used to retard changes in samples.



                                 Table 1
Preservative
HgCl,
Acid (HN03)
Acid (H2S04)
Alkali (NaOH)
Refrigeration or
freezing
       Action
Bacterial Inhibitor
Metals solvent, prevents
precipitation

Bacterial Inhibitor
Salt formation with
organic bases

Salt formation with
volatile compounds

Bacterial Inhibitor
  Applicable to:

Nitrogen forms,
Phosphorus forms

Metals
Organic samples (COD,
oil § grease, organic
carbon, etc.)

Ammonia, amines
Cyanides, organic
acids

Acidity - alkalinity,
organic materials,
BOD, color, odor,
organic P, organic N,
carbon, etc., biological
organisms (coliform, etc.)
In summary, refrigeration at temperatures near freezing or below is the best

preservation technique available, but is not applicable to all types of

samples.
The recommended choice of preservatives for various constituents is given in

Table 2.  These choices are based on the accompanying references and oh infor-

mation supplied by various Regional Analytical Quality Control Coordinators.

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                          Table 2 - Sample Preservation
    Parameter

Acidity-Alkalinity

Biochemical Oxygen Demand

Calcium

Chemical Oxygen Demand

Chloride

Color

Cyanide

Dissolved Oxygen

Fluoride

Hardness

Metals, Total

Metals, Dissolved

Nitrogen, Ammonia

Nitrogen, Kjeldahl
               \
Nitrogen, Nitrate-Nitrite

Oil and Grease

Organic Carbon

pH

Phenolics



Phosphorus
    Preservative

Refrigeration at 4°C

Refrigeration at 4°C

None required

2 ml H2S04 per liter

None required

Refrigeration at 4°C

NaOH to pH 10

Determine on site

None required

None required

5 ml HNO_ per liter
        O
   Maximum
Holding Period

  24 hours

   6 hours

   7 days

   7 days

   7 days

  24 hours

  24 hours

  No holding

   7 days

   7 days

   6 months
Filtrate: 3 ml 1:1 HNO  per liter   6 months
                      J
40 mg HgCl * per liter - 4°C

40 mg HgCl * per liter - 4°C

40 mg HgCl2* per liter - 4°C

2 ml H2S04 per liter - 4°C

2 ml H2SO. per liter (pH 2)

Determine on site

1.0 g CuS04/l + H3P04 to

  pH 4.0 - 4°C

40 mg HgCl * per liter - 4°C
   7 days

  Unstable

   7 days

  24 hours

   7 days

  No holding

  24 hours



   7 days
*Disposal of mercury-containing samples is a recognized problem; research
 investigations are under way to replace it as a preservative.

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                         Table 2 - Sample Preservation
                                  (Continued)


                                                                  Maximum
    Parameter                     Preservative                 Holding Period

Solids                        None available                      7 days

Specific Conductance          None required                       7 days

Sulfate                       Refrigeration at 4°C                7 days

Sulfide                       2 ml Zn acetate per liter           7 days

Threshold Odor                Refrigeration at 4°C               24 hours

Turbidity                     None available                      7 days
References:

    Jenkins, David, "A Study of Methods Suitable for the Analysis and Pre-
      servation of Phosphorus Forms in an Estuarine Environment."  Report
      for the Central Pacific River Basins Project, Southwest Region,
      FWPCA (1965).

    Jenkins, David, "A Study of Method for the Analysis and Preservation
      of Nitrogen Forms in an Estuarine Environment."  Report for the
      Central Pacific River Basins Project, Southwest Region, FWPCA (1965).

    Howe, L. H.  and Holley, C.  W.   "Comparisons of Mercury (II)  Chloride
      and Sulfuric Acid as Preservatives for Nitrogen Forms in Water
      Samples."   Env. Sci. § Tech. 3:478 (1969).

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                                  ACIDITY



                                                               STORE! NO.  00455



1.  Scope and Application



    1.1  The method recommended is identical to the procedure described in



         ASTM Standards, Part 23, pp 155-158, except that the sample is



         titrated to a final pH of 8.3 and results reported as mg/1  CaCO .



    1.2  This method is not applicable to analysis of acid samples  from mine



         drainage.  It is the decision of the AQC staff to delay the method



         selection for measurement of acidity in acid mine drainage  samples



         until such time that a more comprehensive review of the problem can



         be made.



    1.3  Methods for analysis of mine drainage samples for all constituents



         contributing to acidity of such samples may be selected at  the option



         of the respective laboratory directors.



2.  Calculation



    2.1  Acidity is reported as calcium carbonate (CaCO,) according  to the



         following formula:


                   A -j-*       /i r ™    A X N X 50,000
                   Acidity as mg/1 CaC03 =   ml sampi;




         where:



                   A = ml of base used for titration



                   N = normality of base



3.  Precision and Accuracy



    3.1  Forty analysts in seventeen laboratories analyzed synthetic water



         samples containing increments of bicarbonate with the following results:
Increment as
Acidity
mg/1, CaC03
20
21
Precision as
Standard Deviation
mg/ liter, CaCO,
1.79
1.73
Accuracy as
Bias,
+2.77
+0.52
Bias,
mg/liter,
+ .55
+ .11
CaCO

    (FWPCA Method Study 1, Mineral and Physical Analyses)



                                    5

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                             ALKALINITY




                                                STORET Number:  00410



 1.  Scope  and Application




    1.1  This method  is applicable to drinking waters and surface waters,




         domestic and industrial wastes, and saline waters.




    1.2  The method is suitable for all concentration ranges of alkalinity;




         however, appropriate aliquots should be used to avoid a titration




         volume greater than 50 ml.




    1.3  Automated titrimetric analysis is equivalent.




 2.  Summary of Method




    2.1  An unaltered sample is titrated to an electrometrically determined




         end point of pH 4.5.  The sample must not be filtered, diluted,




         concentrated, or altered in any way.




 3.  Comments




    3.1  The sample must be analyzed as soon as practical; preferably,




         within a few hours.  Do not open sample bottle before analyses.




    3.2  Substances,  such as salts of weak organic and inorganic acids




         present in large amounts, may cause interference in the electro-




         metric pH measurements.




    3.3  Oil and greases, by coating the pH electrode, may also interfere,




         causing sluggish response.




4.  Precision and Accuracy




    4.1  Forty analysts in seventeen laboratories analyzed synthetic




         water samples containing increments of bicarbonate, with the




         following results:

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                                                         (Alkalinity)
Increment as
Alkalinity
rag/ liter, CaCO
8
9
113
119
Precision as
Standard Deviation
mg/liter, CaCO_
J
1.27
1.14
5.28
5.36
Accuracy
Bias,
%
+10.61
+22.29
- 8.19
- 7.42
as
Bias,
mg/liter, CaCO
+0.85
+2.0
-9.3
-8.8
(FWPCA Method Study 1, Mineral and Physical Analyses)





    4.2  In a single laboratory (AQC),  using surface water samples at an




         average concentration of 122 mg CaCO,/l, the standard deviation




         was ± 3.




5.  Reference




    5.1  The procedure to be used for this determination is found in:




         Standard Methods for the Examination of Water and Wastewater,




         13th Edition, p. 52, Method 102 (1971).




         ASTM Standards, Part 23, Water; Atmospheric Analysis, p. 154,




         Method D-1067 (1970).

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                                  TOTAL ALKALINITY

                         (Automated Methyl Orange Method)
                                                                STORET NO.  00410

 1.   Scope and Application

     1.1   This automated method  is applicable to surface and saline waters.  The

          applicable  range  is  10 to 200 mg/1 as CaCO,.

 2.   Summary of Method

     2.1   Methyl  orange is  used  as the indicator in this method because its pH

          range is  in the same range as the equivalence point for total alka-

          linity, and it has a distinct color change that can be easily measured.

          The methyl  orange is dissolved in a weak buffer at a pH of 3.1, just

          below the equivalence  point, so that any addition of alkalinity causes

          a  loss of color directly proportional to the amount of alkalinity.

 3.  Sample  Handling  and Preservation

    3.1   Sample should be refrigerated at 4°C and run as soon as practical.

 4.  Interferences

    4.1   No  significant interferences.

 5.  Apparatus

    5.1   Technicon AutoAnalyzer consisting of:

          5.1.1  Sampler I.

          5.1.2  Manifold.

          5.1.3  Proportioning pump.

          5.1.4  Colorimeter equipped with 15 mm tubular flow cell and 550 ™n

                filters.

         5.1.5  Recorder equipped with range expander.

6.  Reagents

    6.1  Methyl Orange:  Dissolve 0.125 g of methyl orange in 1 liter of

         distilled  water.

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                                                        (Total Alkalinity)


    6.2  pH 3.1 Buffer:  Dissolve 5.1047 g of potassium acid phthalate  in

         distilled water and add 87.6 ml 0.1 N HC1 and dilute to 1 liter.

         Stable for one week.

    6.3  Methyl Orange-Buffered Indicator:  Add 1.0 liter of pH 3.1 buffer  to

         200 ml methyl orange solution and mix well.   Stable for 24 hours.

    :6.4  Stock Solution:  Dissolve 1.060 g of anhydrous sodium carbonate

         (oven-dried at 140°C for 1 hour) in distilled water and dilute to

         1.0 liter.  1.0 ml = 1.00 mg CaCO .
                                          J

         6.4.1  Prepare a series of standards by diluting suitable volumes  of

                stock solution to 100.0 ml with distilled water.   The following

                dilutions are suggested:

                        ml of Stock           „       /n     _, „_.
                         Solution             Conc.,mg/l  as CaC05

                           1.0                        10
                           2.0                        20
                           4.0                        40
                           6.0                        60
                           8.0                        80
                          10.0                       100
                          18.0                       180
                          20.0                       200

7.   Procedure

    7.1  No advance sample preparation is required.   Set  up manifold as shown

         in Figure 1.

    7.2  Allow both colorimeter and recorder to warm  up for 30 minutes.  Run

         a baseline with all reagents, feeding distilled  water through  the

         sample line.  Adjust dark current and operative  opening on colorimeter

         to obtain stable baseline.

    7.3  Place distilled water wash tubes in alternate openings on sampler  and

         set sample timing at 2.0 minutes.

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                                                         (Total Alkalinity)




    7.4  Place working standards in sampler in order of decreasing concentration.



         Complete filling of sampler tray with unknown samples.



    7.5  Switch sample line from distilled water to sampler and begin analysis.



8.  Calculation



    8.1  Prepare standard curve by plotting peak heights of processed standards



         against known concentrations.  Compute concentration of samples by



         comparing sample peak heights with standard curve.



9.  Precision and Accuracy



    9.1  In a single laboratory (AQC), using surface water samples at concen-



         trations of 15, 57, 154, and 193 mg/1 as CaCO,, the standard deviation
                                                      «J


         was ±0.5.



    9.2  In a single laboratory (AQC), using surface water samples at concen-



         trations of 31 and 149 mg/1 as CaCO_, recoveries were 100% and 99%,



         respectively.








                                    References
1.  Technicon AutoAnalyzer Methodology, Bulletin 1261, Technicon Controls,  Inc.,



    Chauncey, N.Y.  (1961).



2.  Standard Methods for the Examination of Water and Wastewater, 13th Edition,



    p.  52, Method 102  (1971).
                                        10

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ml / min ^5od^



LARGE MIXING COILS /
00000000 00000000 . /
f
s==s 1/2 DELAY COIL

>
\


PRO
PURPLE

GREEN

RED
BLUE

P B
PORTIONING 1

SAMPLER 1
2.00 SAMPLE

0.80 AIR

>
01 Mi—

CONTINU

I.60 BUFFER + INDICATOR

2.90 WASTE
PUMP
k



             if
   COLORIMETER    RECORDER
15mm TUBULAR  f/c
  550 nm  FILTERS
SAMPLING TIME: 2.0 MINUTES
WASH TUBES: ONE
  FIGURE 1. ALKALINITY MANIFOLD

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                                                       STORE! No:        Total  01002
                                ARSENIC                    Inorganic, Dissolved  00995
                                                              Inorganic, Total  00997
1.  Scope and Application

    1.1  The silver diethyldithiocarbamate method determines  inorganic  arsenic

         when present in concentrations at or above 10 yg/1.   The method  is

         applicable to most fresh and saline waters in the absence  of high con-

         centrations of chromium, cobalt,  copper, mercury, molybdenum,  nickel,

         and silver.

    1.2  Difficulties may be encountered with certain industrial waste  materials

         containing volatile substances.  High sulfur content of wastes may

         exceed removal capacity of the lead acetate scrubber.

2.  Summary of Method

    2.1  Arsenic in the sample is reduced  to arsine, AsH,, in acid  solution  in

         a hydrogen generator.  The arsine is passed through  a scrubber to remove

         sulfide and is absorbed in a solution of silver diethyldithiocarbamate

         dissolved in pyridine.  The red complex thus formed  is measured  in  a

         spectrophotometer at 535 nm.

3.  Comments

    3.1  In analyzing most surface and ground waters, interferences are rarely

         encountered.  Industrial waste samples should be spiked with  a known

         amount of arsenic to establish adequate recovery.

    3.2  It is essential that the system be air-tight during  evolution of the

         arsine, to avoid losses.

    3.3  If concentration of sample and oxidation of any organic matter is

         desired to measure organically-bound arsenic, refer  to Standard  Methods,

         13th Ed., Method 104B, p 65, Procedure 4.a (1971).
                                     13

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                                                           (Arsenic)






4.  Precision and Accuracy
                           »



    4.1  A synthetic unknown sample containing 40 ug/1, as As, with other




         metals was analyzed in 46 laboratories.  Relative standard deviation




         was 13.8% and relative error was 0%.




5.  Reference




    5.1  The procedure to be used for this determination is found in:




             Standard Methods for the Examination of Water and Wastewater,




             13th Edition, p 62, Method 104A (1971).
                                      14

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                          BIOCHEMICAL OXYGEN DEMAND






                                                            STORET No:   00310
1.  Scope and Application



    1.1  The biochemical oxygen demand test (BOD)  is used for determining the



         relative oxygen requirements of municipal and industrial wastewaters.



         Application of the test to organic waste  discharges allows  calculation



         of the effect of the discharges on the oxygen  resources of the receiving



         water.  Data from BOD tests are used for  the development of engineering



         criteria for the design of wastewater treatment plants.



    1.2  The BOD test is an empirical bioassay-type procedure which  measures  the



         dissolved oxygen consumed by microbial life while assimilating and



         oxidizing the organic matter present.  The standard test conditions



         include dark incubation at 20°C for a specified time period (often 5



         days).  The actual environmental conditions of temperature, biological



         population, water movement, sunlight, and oxygen concentration cannot



         be accurately reproduced in the laboratory.  Results obtained must take



         into account the above factors when relating BOD results to stream



         oxygen demands.



2.  Summary of Method



         The sample of waste, or an appropriate dilution, is incubated for 5  days




         at 20°C in the dark.  The reduction in dissolved oxygen concentration



         during the incubation period yields a measure of the biochemical oxygen



         demand.



3.  Comments




    3.1  Because of the effect of local conditions, types of samples to be tested,




         and the variabilities in bioassay procedures, no specific standard test



         for BOD has been selected by the Water Quality Office.




                                        15

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                                                                    (BOD)


    3.2  Determination of dissolved oxygen in the BOD test may be made by use

         of either the Modified Winkler with Full-Bottle Technique (Pg. 53  )

         or the Probe Method  (Pg. 60  ) in this manual.

    3.3  Additional information relating to oxygen demanding characteristics

         of wastewaters can be gained by applying the Total Organic Carbon and

         Chemical Oxygen Demand tests (see pp 221-229 and 17-28, respectively).

4.  Precision and Accuracy

    4.1  Seventy-seven analysts in fifty-three laboratories analyzed natural

         water samples plus an exact increment of biodegradable organic compounds.

         At a mean value of 194 mg/1 BOD, the standard deviation was ±40 mg/1.

    4.2  There is no acceptable procedure for determining the accuracy of the

         BOD test.

5.  References

    The procedure to be used for this determination is found in:

         Standard Methods for the Examination of Water and Wastewater, 13th
         Edition,  P.  489, Method 219 (1971).

         ASTM Standards,  Part 23, Water; Atmospheric Analysis,  P. 712,
         Method D 2329-68 (1970).
                                       16

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                           CHEMICAL OXYGEN DEMAND






                                                            STORE! No:    00540




1.  Scope and Application




    1.1  This method determines the quantity of oxygen required to oxidize




         the organic matter in a waste sample, under specific conditions  of




         oxidizing agent, temperature, and time.




    1.2  Since the test utilizes a rigorous chemical oxidation rather than  a




         biological process, the result has no defineable relationship to the




         BOD of the waste.  The test result should be considered as an inde-




         pendent measurement of organic matter in the sample, rather than as




         a substitute for the BOD test.




    1.3  The method can be applied to domestic and industrial waste samples




         having an organic carbon concentration greater than 15 mg/1.   For




         lower concentrations of carbon such as in surface water samples, the




         Low Level Modification, Pg. 19, should be used.   When the chloride




         concentration of the sample exceeds 2000 mg/1>the modification for




         saline waters, pg.  24, is required.




2.  Summary of Method




    2.1  Organic substances  in the sample are oxidized by potassium dichromate




         in 50% sulfuric acid solution at reflux temperature.  Silver sulfate




         is used as a catalyst and mercuric sulfate is added to remove chloride




         interference.  The  excess dichromate is titrated with standard ferrous




         ammonium sulfate, using orthophenanthroline ferrous complex as an




         indicator.
                                        17

-------
                                                                (COD)

3.  Comments

    3.1  To reduce loss of volatile organics, the flask should be cooled during

         addition of the sulfuric acid solution.

4.  Precision and Accuracy

    4.1  Eighty-nine analysts in fifty-eight laboratories analyzed a distilled

         water solution containing oxidizable organic material equivalent to

         270 mg/1 COD.  The standard deviation was ±27.5 mg/1 COD and the mean

         recovery was 96% of the true value.

5.   References

    The procedure to be used for this determination is found in:

         Standard Methods for the Examination of Water and Wastewater, 13th
         Edition, P.  495 Method 220 (1971).

         ASTM Standards, Part 23, Water;  Atmospheric Analysis, P.  246
         Method D 1252-67  (1970).
                                       18

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                              CHEMICAL OXYGEN DEMAND



                                  (Low Level)

                                                              STORE! NO. 00555


1.  Scope and Application




    1.1  The scope of this modification of the Chemical Oxygen Demand (COD)




         test is the same as for the high level test.  It is applicable to




         the analysis of surface waters, domestic and industrial wastes with




         low demand characteristics.




    1.2  This method (low level) is applicable for samples having a COD in  the




         range of 5-50 mg/1 COD.


                           I :

2.  Summary of Method      i
                           i •
                           i i

    2.1  Organic and oxidizable inorganic substances in an aqueous sample are




         oxidized by potassium dichromate solution in 50 percent (by volume)




         sulfuric acid solution.  The excess dichromate is titrated with standard




         ferrous ammonium sulfate using orthophenanthroline ferrous complex




         (ferroin) as an indicator.




5.  Sampling and Preservation




    5.1  Collect the samples in glass bottles, if possible.  Use of plastic




         containers is permissible if it is known that no organic contaminants




         are present in the containers.




    5.2  Biologically active samples should be tested as soon as possible.




         Samples containing settleable material should be well mixed, pre-




         ferably homogenized, to permit removal of representative aliquots.




    5.5  Samples may be preserved with sulfuric acid at a rate of 2 ml of




         cone. H2SO. per liter of sample.




4.  Interferences




    4.1  Traces of organic material either from the glassware or atmosphere may




         cause a gross, positive error.
                                        19

-------
                                                       (Chemical Oxygen Demand)
                                                              (Low Level)

          4.1.1   Extreme  care  should be exercised to avoid inclusion of

                 organic  materials in  the distilled water used for reagent

                 preparation or sample dilution.

          4.1.2   Glassware used in the test should be conditioned by running

                 blank procedures to eliminate traces of organic material.

    4.2   Volatile materials may be lost when the sample temperature rises during

          the sulfuric acid addition step.

    4.3   Chlorides are quantitatively oxidized by dichromate and represent a

          positive interference.  Mercuric sulfate is added to the digestion flask

          to complex the  chlorides, thereby effectively eliminating the inter-

          ference on all but brine and estuarine samples.

5.  Apparatus

    5.1   Reflux  apparatus - Glassware should consist of a 500 ml Erlenmeyer

          flask or a 300 ml round bottom flask made of heat-resistant glass

          connected to a 12 inch Allihn condenser by means of a ground glass

          joint.  Any equivalent reflux apparatus may be substituted provided that

          a ground-glass connection is used between the flask and the condenser.

6.   Reagents

    6.1  Distilled water.  Special precautions should be taken to insure that

         distilled water used in this test be low in organic matter.

    6.2  Standard potassium dichromate solution (0.025 N) - Dissolve 12.259 g

         K Cr?0_, primary standard grade,  previously dried at 103°C for two

         hours,  in distilled water and dilute to 1.0 1.  Mix this solution

         thoroughly then dilute 100 ml to  1.0 1 with distilled water.

    6.3  Sulfuric acid reagent - Cone. H_S04 containing 23.5 g silver sulfate,

         Ag-SO.,  per 9 Ib. bottle (one to  two days  required for dissolution).
                                     20

-------
                                                  (Chemical  Oxygen Demand)
                                                        (Low Level)


    6.4  Standard ferrous ammonium sulfate (0.025  N)  -  Dissolve  98  g o£

         Fe(NH4)2(S04)2.6H20 in distilled water.   Add 20 ml  of cone. H_SO  ,

         cool and dilute to 1.0 1.  Dilute 100  ml  of  this solution to 1.0  1

         with distilled water.   This solution must be standardized daily

         against K_Cr20_ solution.

         6.4.1  Standardization - To 15 ml of distilled water add 10 ml of

                0.025 N Kr2Cr207 solution.  Add 20 ml of H2S04 and cool.

                Titrate with ferrous ammonium sulfate using  1 drop of ferroin

                indicator.   The color change is sharp,  going from blue-green

                to reddish-brown.
                                       (ml K2Cr20?)(0.025)
                           Normality =  ml Fe(NH4)2(S04)2


    6.5  Mercuric sulfate - Powdered HgSO..

    6.6  Phenanthroline ferrous sulfate (ferroin)  indicator  solution - Dissolve

         1.48 g of l-10-(ortho)-phenanthroline  monohydrate,  together with

         0.70 g of FeS04-7H 0 in 100 ml of water.  This indicator may be pur-

         chased already prepared.

    6.7  Silver sulfate - Powdered Ag2S04<

    6.8  Sulfuric acid (sp. gr. 1.84) - Concentrated  H2SO  .

7.   Procedure

    7.1  Place several boiling stones in the reflux flask,  followed by 1 g of

         HgS04.  Add 5.0 ml cone. JUSCK (6.8);  swirl  until mercuric sulfate

         has dissolved.  Place reflux flask in  an ice bath  and slowly add, with

         swirling, 25.0 ml of 0.025 N K^^Cy   Now  add 70.0 ml  of sulfuric

         acid-silver sulfate solution (6.3) to  the cooled  reflux flask, again

         using slow addition with swirling motion.
                                     21

-------
                                                      (Chemical  Oxygen  Demand)

                                                            CLow Level)





     7.2  With the reflux flask still in the  ice bath, place  50.0 ml of sample




          or a sample aliquot diluted to 50.0 ml into the  reflux flask.




          Caution:  Care must be taken to assure that the  contents of the flask




          are well mixed.   If not,  superheating may  result, and  the mixture may




          be blown out of the open  end of the condenser.   Attach the flask to




          the condenser and start the cooling water.




     7.3  Apply heat to the flask and reflux  for 2 hours.  For some waste waters,




          the 2-hour reflux period  is not necessary.  The  time required to give




          the maximum oxidation for a waste water of constant or known  com-




          position may be  determined and a shorter period  of refluxing may be




          permissible.




     7.4   Allow the  flask  to  cool and wash down the  condenser with about 25 ml




          of water.   If a  round bottom flask has been used, transfer the mixture




          to  a 500-ml  Erlenmeyer  flask, washing out  the reflux flask 3 or 4




          times with water.   Dilute  the  acid solution to about 300 ml with water




          and  allow  the solution  to  cool  to about room temperature.  Add 8 to 10




          drops of ferroin  indicator  to  the solution and titrate the excess




          dichromate with 0.025 N ferrous ammonium sulfate solution to the




          end point.  The color change will be sharp, changing from a blue-




          green to a reddish hue.




    7.5  Blank - Simultaneously run a blank determination following the details




         given in 7.1 and  7.2, but using low COD water in place of the sample.




8.  Calculation




    8.1  Calculate the COD in the sample in mg/1 as follows:




                 rrm    /T+     (A - B) N X 8000
                 COD, mg/liter =	'—•=	





    where:
                                       22

-------
                                                      CChemical Oxygen Demand)
                                                            (low Level)


                A = mi Hi liters of Fe (NH.) _ (SO.) _ solution required for

                    titration of the blank,

                B = milliliters of Fe (NH.) „ (SO.) 2 solution required for

                    titration of the sample,

                N = normality of the Fe(NH.)2(SO )  solution,  and

                S = milliliters of sample used for the test.

9.  Precision               ji

    9.1  The precision of the low level test described in the  foregoing

         material has not been determined by collaborative testing.
                                        23

-------
                             CHEMICAL OXYGEN DEMAND

                        (High Level for Saline  Waters)
                                                               STORE! NO.  00540
 1.   Scope and Application

     1.1  When the chloride level  exceeds  1000  mg/1 the minimum accepted value

          for the COD will be 250  mg/1.  COD levels which fall below this value

          are highly  questionable  because  of the high chloride correction which

          must be made.

 2.   Summary  of Method

     2.1  Organic and oxidizable inorganic substances in an aqueous sample are

          oxidized by potassium dichromate solution in 50 percent (by volume)

          sulfuric acid solution.   The excess dichromate is titrated with

          standard ferrous  ammonium sulfate using orthophenanthroline ferrous

          complex (ferroin)  as an  indicator.

 3.   Sample Handling  and Preservation

     3.1  Collect  the samples in glass bottles, if possible.  Use of plastic

          containers  is permissible if it  is known  that no organic contaminants

          are present in the  containers.

     3.2  Biologically active samples should be tested as soon as possible.

          Samples  containing  settleable material should be well mixed, pre-

          ferably homogenized, to permit removal of representative aliquots.

     3.3 Samples are preserved by the addition of 2 ml of cone. H2S04 per liter

          of sample.

4.  Interferences

    4.1  Traces of organic material either from the glassware or atmosphere

         may cause a gross, positive error.

         4.1.1  Extreme care should be exercised to avoid inclusion of organic

                materials in the distilled water used for reagent preparation
                                       24

-------
                                                 (COD - High Level  for
                                                        Saline Waters)


                or sample dilution.


         4.1.2  Glassware used in the test should be conditioned by running


                blank procedures to eliminate traces of organic material.


    4.2  Volatile materials may be lost when the sample temperature rises


         during the sulfuric acid addition step.


    4.3  Chlorides are quantitatively oxidized by dichromate and represent


         a positive interference.  Mercuric sulfate is added to the digestion
                            i

         flask to complex the chlorides, thereby effectively eliminating the


         interference on all but brine samples.


5.  Apparatus


    5.1  Reflux apparatus - Glassware should consist of a 500 ml Erlenmeyer


         flask or a 300 ml round bottom flask made of heat-resistant glass


         connected to a 12 inch Allihn condenser by means of a ground glass


         joint.  Any equivalent reflux apparatus may be substituted provided


         that a ground-glass connection is used between the flask  and the con-


         denser.


6.  Reagents


    6.1  Standard potassium dichromate solution, (0.25 N) :   Dissolve 12.2588 g


         of K-Cr-0 , primary standard grade, previously dried for  2 hours at


         103°C in water and dilute to 1.0 liter.


    6.2  Sulfuric acid reagent:  Cone. H2S04 containing 23.5 g silver sulfate,


         Ag?SO., per 9 Ib. bottle (1 to 2 days required for dissolution).


    6.3  Standard ferrous ammonium sulfate,  0.250 N:  Dissolve 98  g of


         Fe(NH4)2(S04)2.6H20 in distilled water.  Add 20 ml of cone.  H2S04,


         cool and dilute to 1.0.1.   This solution must be standardized


         against the standard potassium dichromate solution daily.
                                      25

-------
                                                          (COD - High Level for
                                                                 Saline Wa
          6.3.1  Standardization:  Dilute 25.0 ml of standard dichromate

                 solution to about 250 ml with distilled water.   Add 75 ml  cone.

                 sulfuric acid.  Cool, then titrate with ferrous ammonium sulfate

                 titrant, using 10 drops of ferroin indicator.

                                       (ml K Cr20 ) (0.25)
                                        ml Fe(NH4)2(S04)2

    6.4  Mercuric sulfate - Powdered HgSO..

    6.5  Phenanthroline ferrous sulfate (ferroin) indicator solution -  Dissolve

         1.48 g of l-10-(ortho)-phenanthroline monohydrate, together with 0.70 g

         of FeS0..7H20 in 100 ml of water.  This indicator  may be purchased

         already prepared.

    6.6  Silver sulfate - Powdered Ag-SO..

    6.7  Sulfuric acid (sp.  gr. 1.84) - Concentrated H-SO..

7.   Procedure

    7.1  Pipet a 50 ml aliquot of sample not to exceed 800  mg/1  of COD  into a

         500 ml, flat bottom, Erlenmeyer flask.  Add 25 ml  of 0.25 N Kr2Cr207,

         then 5.0 ml of cone. H^SO. (containing no silver sulfate).   Add HgSO.

         in the ratio of 10 mg to 1 mg chloride, based upon the  mg of chloride

         in the sample aliquot.  Swirl until all the mercuric sulfate has dissolved.

         Carefully add 70 ml of sulfuric acid-silver sulfate solution and gently

         swirl until the solution is thoroughly mixed.  Glass beads should  be added

         to the reflux mixture to prevent bumping, which can be  severe  and

         dangerous.   (CAUTION:  The reflux mixture must be  thoroughly mixed before

         heat is applied.  If this is not done, local heating occurs in the bottom

         of the flask, and the mixture may be blown out of  the condenser).
                                          26

-------
                                                         (COD - High Level for
                                                               Saline Waters)

         7.1.1  If volatile organics are present in the sample,  use an Allihn

                condenser and add the sulfuric acid-silver sulfate solution

                through the condenser, while cooling the flask,  to reduce

                loss by volatilization.

    7.2  Attach the flask to the condenser and reflux the mixture for two hours,

    7.3  Cool, and wash down the interior of the condenser with  25 ml of

         distilled water.  Disconnect the condenser and wash the flask and

         condenser joint with 25 ml of distilled water.  Remove  the condenser

         and carefully add to the flask 175 ml of distilled water so that the

         total volume is 350 ml.  Cool to room temperature.

    7.4  Titrate with standard ferrous ammonium sulfate using 10 drops of

         ferroin indicator.  (This amount must not vary from blank, sample and

         standardization).  The color change is sharp, going from blue-green

         to reddish-brown and should be taken as the end point although the

         blue-green color may reappear within minutes.

    7.5  Run a blank, using 50 ml of distilled water in place of the sample

         together with all reagents and subsequent treatment.

    7.6  For COD values greater than 800 mg/1, a sjnaller aliquot of sample

         should be taken; however, the volume should be readjusted to 50 ml

         with distilled water having a chloride concentration equal to the

         sample.

    7.7  Chloride correction* - Prepare a standard curve of COD  versus mg/1
*Bums, E. R., Marshall, C., Journal WPCF, Vol. 37, pp 1716-1721 (1965)
                                         27

-------
                                                           (COD - High. Level for
                                                                 Saline Waters)


          of chloride,  using  sodium  chloride solutions of varying concen-

          trations  following  exactly the  procedure outlined.  The chloride

          interval,  as  a minimum  should be 4000 mg/1 up to  20,000 mg/1

          chloride.   Lesser intervals of  greater concentrations must be run

          as  per the requirements of the  data, but  in no case must extra-

          polation be used.

8.  Calculation

    8.1                  mg/1 COD =CCA - B) C X 8000-500]   ^2Q
                          &             ml sample

         where:

          COD = chemical oxygen demand from dichromate

           A = ml Fe(NH4)2(S04)2 for blank;

           B = ml Fe(NH4)2(S04)2 for sample;

           C = normality of Fe(NH4)2(S04)2;

           D = chloride correction  from curve (step 7.7).

        1..20 = compensation factor  to account for the extent of chloride

               oxidation which is dissimilar in systems containing organic

               and nonorganic material.

9.  Precision and Accuracy

    9.1  Precision and accuracy data are not available at this time.
                                       28

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                              CHLORIDE




                                                STORET Number:   00940




1.  Scope and Application




    1.1  This method is applicable to drinking waters  and surface waters,




         domestic and industrial wastes,  and saline waters.




    1.2  The method is suitable for all concentration  ranges  of chloride




         content; however,  in order to avoid large titration  volumes, use




         a sample aliquot containing not  more than 10  to  20 mg  Cl per 50 ml.




    1.3  Automated titration may be used.




2.  Summary of Method




    2.1  Dilute mercuric nitrate solution is added to  an  acidified  sample




         in the presence of mixed diphenylcarbazone -  bromophenol blue




         indicator.  The end point of the titration is the formation of




         the blue - violet mercury diphenylcarbazone complex.




3.  Comments




    3.1  Anions and cations at concentrations normally found  in surface




         waters do not interfere.




    3.2  Sulfites interfere.  If presence is suspected, oxidize by  treating




         50 ml of sample with 0.5 to 1 ml of H,,CL.




4.  Precision and Accuracy




    4.1  Forty-two analysts in eighteen laboratories analyzed synthetic




         water samples containing exact increments of  chloride, with the




         following results:
                                      29

-------
                                                                (Chloride)
Increment as
Chloride
rag/liter
17
18
91
97
382
398
Precision as
Standard Deviation
mg/liter
1.54
1.32
2.92
3.16
11.7
11.8
Accuracy as
Bias, Bias,
% mg/liter
+2.16 +0.4
+3.50 +0.6
+0.11 +0.1
-0.51 -0.5
-0.61 -2.3
-1.19 -4.7
(FWPCA Method Study 1, Mineral and Physical Analyses)




    4.2  In a single laboratory (AQC), using surface water samples at an




         average concentration of 34 mg Cl/1, the standard deviation was




         ±1.0.




5.   Reference




    5.1  The procedure to be used for this determination is found in:




         Standard Methods for the Examination of Water and Wastewater,




         13th Edition, p. 97, Method 112B (1971).




         ASTM Standards,  Part 23,  Water;  Atmospheric Analysis,  p.  24,




         Method 512-67 (1970).
                                     30

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                                 CHLORIDE
                    (Automated Ferricyanide Method)
                                                              STORE! NO.  00940

1.  Scope and Application
    1.1  This automated method is applicable on surface water, domestic and
         industrial wastes, and saline waters.   The  applicable range is 1 to
         250 mg Cl/1.   Approximately 15 samples per  hour can be analyzed.
2.  Summary of Method
    2.1  Thiocyanate ion (SCN) is liberated from mercuric thiocyanate,  through
         sequestration of mercury by chloride ion to form un-ionized mercuric
         chloride.  In the presence of ferric ion, the liberated SCN forms
         highly colored ferric thiocyanate, in concentration proportional to
         the original chloride concentration.
3.  Sample Handling and Preservation
    3.1  No special requirements.
4.  Interferences
    4.1  No significant interferences.
5.  Apparatus
    5.1  Technicon AutoAnalyzer consisting of:
         5.1.1  Sampler I.
         5.1.2  Continuous filter.
         5.1.3  Manifold.
         5.1.4  Proportioning pump.
         5.1.5  Colorimeter equipped with 15 mm tubular flow cell and
                480 nm filters.
         5.1.6  Recorder.
6.  Reagents
    6.1  Ferric Ammonium Sulfate:  Dissolve 60 g of FeNH CSO.) .12 HO in
         approximately 500 ml distilled water.   Add 355 ml of cone. HNO  and

                                        31

-------
                                                                 (Chloride)


          dilute  to  1  liter with distilled water.  Filter.

     6.2   Saturated  Mercuric Thiocyanate:  Dissolve 5 g of Hg(SCN)- in 1 liter

          of distilled water.  Decant and filter a portion of the saturated

          supernatant  liquid to use as the reagent and refill the bottle with

          distilled  water.

     6.3   Stock Solution  (0.0141 N NaCl):  Dissolve 0.8241 g of pre-dried  (140°C) NaCl

          in distilled water.  Dilute to 1 liter-  1 ml = 0.5 mg Cl~.



          6.3.1  Prepare a series of standards by diluting suitable volumes of

                stock solution to 100.0 ml with distilled water.   The following

                dilutions are suggested:

                       ml of Stock Solution       Cone., mg/1

                              0.2                    1.0
                              1.0                    5.0
                              2.0                    10
                              4.0                    20
                              8.0                    40
                             15.0                    75
                             20.0                   100
                             30.0                   150
                             40.0                   200
                             50.0                   250
7.  Procedure

    7.1  No advance sample preparation is required.   Set up manifold as  shown

         in Figure 1.   For water samples known to be  consistently  low in

         chloride content, it is advisable to use only one distilled water in-

         take line.

    7.2  Allow both colorimeter  and  recorder to warm  up for 30 minutes.  Run a

         baseline with all reagents,  feeding distilled water  through the sample

         line.  Adjust dark current  and operative opening on  colorimeter to

         obtain stable baseline.
                                       32

-------
                                                           (Chloride)


    7.3  Place distilled water wash tubes in alternate openings in sampler

         and set sample timing at 2.0 minutes.

    7.4  Place working standards in sampler in order of decreasing concentrations.

         Complete filling of sampler tray with unknown samples.

    7.5  Switch sample line from distilled water to sampler and begin  analysis.

8.  Calculation

    8.1  Prepare standard curve by plotting peak heights of processed  standards

         against known concentrations.  Compute concentration of samples  by
                              i
         comparing sample peak!heights with standard curve.
                              i
9.  Precision and Accuracy

    9.1  In a single laboratory, (AQC), using surface water samples at con-

         centrations of 1, 100,  and 250 mg Cl /I, the standard deviation  was  ±0.3.

    9.2  In a single laboratory (AQC), using surface water samples at  concen-

         trations of 10 and 100 mg Cl/1, recoveries were 97% and 104%,

         respectively.



                                  Reference


1.  J. E. O'Brien, "Automatic Analysis of Chlorides in Sewage," Waste  Engr.,

    33, 670-672 (Dec. 1962).
                                      33

-------
SMALL
MIXING
COILS
                       WASTE
          COLORIMETER
     15mm TUBULAR f/c
       480 nm  FILTERS
                                     IX
                                                           ml/min
                                                            2.00
                                              BLUE
           BLUE
                                              W
              W
                                               PROPORTIONING
                                                  PUMP
                                                             1.20  SAMPLE
                 1.20
      DISTILLED
      WATER

      AIR
                                CONTINUOUS FILTER
1.60 Fe NH4(S04J2
0.60
                                                                 Hg (SCN)
                                                            2.50
                                                              WASTE
RECORDER
      SAMPLING TIME:  2.0  MINUTES
      WASH TUBES: ONE
                           FIGURE 1. CHLORIDE  MANIFOLD

-------
                             CHLORINE REQUIREMENT




                                                            STORE! NO.
1.  Scope and Application



    1.1  This method is applicable to drinking water,  surface waters,



         domestic and industrial wastes and saline waters.   Limitations of


         the method are implied in paragraph 1.2, below.



    1.2  Chlorine requirement is defined as the amount of chlorine which



         must be added per unit volume of sample to  produce  a desired result



         under stated conditions.  It is therefore applicable to  control  of
                              i
                              j
         coliform densities,  destruction of certain  chemical compounds and


         odorous materials, and establishment of specified chlorine  residuals.



    1.3  Chlorine requirement is not an absolute value and cannot be used



         to compare results from time to time or place to place.



2.  Summary of Method



    2.1  A solution of known  chlorine content is added incrementally to a


         series of sample aliquots.  At the end of the stipulated contact



         time or when the desired result has been achieved the  residual


         chlorine is measured by the appropriate method.



3.  Comments


    3.1  In cases where the desired result is a specified residual chlorine



         concentration, it is important that the same  method for  chlorine



         measurement be used  for both laboratory testing  and operational



         control.


    3.2  In reporting results all of the pertinent information  must  be in-



         cluded:  the conditions of chlorination, such as pH, temperature and



         contact time; the method used for determining the result and the



         chlorine required to produce the desired result  (i.e., the  chlorine



         requirement).




                                        36

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                                                          (Chlorine)


4.  Precision and Accuracy

    4.1  The nature of this test precludes the use of accuracy and

         precision statement.

5.  Reference

         The procedure to be used for this determination is found in:
                  Standard Methods for the Examination of Water and
                  Wastewaters, 13th Edition, pp 388-391, Method No.
                  205A and 205B (1971).
                                    37

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                                    COLOR
                                                              STORE! NO.  00080
1.  Scope and Application

    1.1  The Platinum-Cobalt method is useful  for measuring  color of water

         derived from naturally occurring materials,  I.e., vegetable residues

         such as leaves, barks, roots, humus  and peat materials.   The method

         is not applicable to color measurement on waters containing highly

         colored industrial wastes.

         Note - The Spectrophotometric and Tristimulus methods  are useful

         for detecting specific color problems.  The  use of  these methods,

         however, is laborious and unless determination of the  hue,  purity,

         and luminance is desired, they are of limited value.

2.  Summary of Method

    2.1  Color is measured by visual comparison of the sample with platinum-

         cobalt standards.  One unit of color is that produced  by 1  mg/1

         platinum in the form of the chloroplatinate  ion.

3.  Interferences

    3.1  Since very slight amounts of turbidity interfere with  the determination,

         samples showing visible turbidity should be  clarified  by centrifugation.

4.  Sample Handling and Preservation

    4.1  Representative samples shall be taken in scrupulously  clean glassware.

    4.2  Since biological activity may change the color characteristics  of a

         sample, the determination should be made as  soon as possible.   Refri-

         geration at 4°C is recommended.

5.  Apparatus

    5.1  Nessler tubes - Matched, tall form,  50 ml capacity.
                                        38

-------
                                                                     (Color)


 6.   Reagents

     6.1  Standard chloroplatinate solution.   Dissolve  1.246 g potassium chloro-

          platinate,  K2PtCl,,  (equivalent to  0.500 g metallic Pt) and 1 g

          crystalline cobaltous chloride, CoCl2.6H20, in distilled water con-

          taining 100 ml  of cone.  HC1.   Dilute to 1 liter with distilled water.

          This  standard solution is  equivalent to 500 color units.

 7.   Preparation  of Standards

     7.1  Prepare standards  in  increments from 5 to 70  units.

          The following series  is  suggested:

          ml  of Standard  Solution
          Diluted to  50.0 ml                          Color in
          with  Distilled  Water                    Chloroplatinate Units

                 0.0                                      0
                 0.5                                      5
                 1.0                                     10
                 1.5                                     15
                 2.0                                     20
                 2.5                                     25
                 3.0                                     30
                 3.5                                     35
                 4.0                                     40
                 4.5                                     45
                 5.0                                     50
                 6.0                                     60
                 7.0                                     70

    7.2  Protect these standards against evaporation and contamination by use

         of clean, inert stoppers.

         Note - The standards also must be protected aganst the absorption

                of ammonia since an increase in color will result.

8.   Procedure

    8.1  Apparent color - Observe the color of the sample by filling a matched

         Nessler tube to  the 50 ml mark with the water and compare  with standards.

         This comparison  is made by looking vertically downward through the
                                        39

-------
                                                                     CColor)

          tubes toward a white or specular surface placed at such an angle

          that light is reflected upward through the columns of liquid.   If

          turbidity has not been removed by the procedure given in 8.2,  report

          the color as "apparent color."  If the color exceeds 70 units,

          dilute the sample with distilled water in known proportions until

          the color is within the range of the standards.

     8.2  True color - Remove turbidity by centrifuging the sample until  the

          supernatant is clear..  The time required will depend upon the nature

          of the sample, the speed of the motor, and the radius of the centri-

          fuge, but rarely will more than one hour be necessary.  Compare the

          centrifuged sample with distilled water to insure that turbidity has

          been removed.  If the sample is clear, then compare with standards as

          given in 8.1.

 9.  Calculation

     9.1  Calculate the color units by means of the following equation:


                                 „ ,     ....    A x 50
                                 Color units =
                                                 V

          Where:   A = estimated color of diluted sample.

                   V = ml sample taken for dilution.

     9.2  Report the results in whole numbers as follows:

                    Color Units                  Record to Nearest

                      1-50                              1
                     51-100                             5
                    101-250                            10
                    251-500                            20

10.   Precision and Accuracy

    10.1  Precision and accuracy data are not available at this time.


          Reference - Standard Methods for the Examination of Water and Waste-

                      water, 13th. Edition, p. 160, Method 118   (1971) •
                                         40

-------
                                     CYANIDE





 1.   Scope  and  Application



     1.1  This  method is  applicable to the determination of cyanide in surface



         waters, domestic  and industrial wastes, and saline waters.



     1.2  The titration procedure using silver nitrate with p-dimethylamino-



         benzalrhodanine indicator is used for measuring concentrations of



         cyanide exceeding 1 mg/1 (0.2 mg/200 ml of absorbing liquid).



     1.3  The colorimetric  procedure  is used for concentrations below 1 mg/1 of



         cyanide and is  sensitive to about 5 yg/1.



 2.   Summary of Method



     2.1  The cyanide as  hydrocyanic  acid (HCN) is released from metallic cyanide



         complex ions by means of a  reflux-distillation operation and absorbed



         in a  scrubber containing sodium hydroxide solution.  The cyanide ion



         in the absorbing  solution is then determined by volumetric titration




         or colorimetrically.



     2.2  The colorimetric measurement employs the pyridine-pyrazolone reaction



         in which the cyanide is coupled with free chlorine to form cyanogen



         chloride and then with pyridine to a glutaconic aldehyde.  The aldehyde



         then reacts with  l-phenyl-3-methyl-5-pyrazolone to form a highly colored



         blue dye.



     2.3  The titrimetric measurement uses a standard solution of silver nitrate



         to titrate cyanide in the presence of a silver sensitive indicator.




3.   Definitions



    3.1  Cyanide is defined as cyanide ion and complex cyanides converted to



         hydrocyanic acid  (HCN)  by reaction in a reflux system of a mineral acid




         in the presence of magnesium and mercuric ions.
                                         41

-------
                                                              (Cyanide)

4.  Sampling Handling and Preservation
    4.1  The sample should be collected in plastic bottles of 1  liter or larger
         size.  All bottles must be thoroughly cleansed and thoroughly rinsed
         to remove soluble material from containers.
    4.2  Samples must be preserved with 2 ml of 10 N  sodium hydroxide per liter
         of sample (pH of 11) at the time of collection.
    4.3  Samples should be analyzed as rapidly as  possible after collection.
         If storage is required, the samples should be stored in a refrigerator
         or in an ice chest filled with water and  ice  to maintain temperature at
          4O/-i
           C.
5.  Interferences
    5.1  Interferences are eliminated or reduced by using the distillate obtained
         with the preliminary screening procedure.
    5.2  Sulfides are an interference that should  be removed prior to distillation.
         Remove sulfides with pH adjustment to >11, addition of  lead carbonate and
         mixing.  Filter sample to remove lead sulfide.  Repeat  until no more lead
         sulfide is formed as evidenced by whiteness of the lead carbonate.
    5.3  Oxidizing substances interfere and should be  treated with ascorbic acid.
6.  Apparatus
    6.1  Reflux distillation apparatus such as shown in Figure 1 or Figure 2.
         The boiling flask should be of 1 liter size with inlet  tube and pro-
         vision for condenser.   The gas absorber may be a Fisher-Milligan scrubber.
    6.2  Microburet,  5.0 ml (for titration).
    6.3  Spectrophotometer suitable for measurements at 620 nm with a 1.0 cm cell
         or larger.
                                        42

-------
ALLIHN CONDENSER —

AIR INLET TUBE
— CONNECTING TUBING
ONE LITER
BOILING FLASK
                                    SUCTION
                   GAS ABSORBER
                 FIGURE 1
   CYANIDE DISTILLATION  APPARATUS

-------
   COOLING WATER
   INLET
SCREW CLAMP
     I
        HEATER -*
                                  TO LOW VACUUM
                                     SOURCE
                               -*• ABSORBER
                           DISTILLING FLASK
                  O
             FIGURE 2
CYANIDE DISTILLATION  APPARATUS
                 45

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                                                               (Cyanide)






7.   Reagents




    7.1  Sodium hydroxide solution,  1 N.   Dissolve 40 g of NaOH in distilled




         water, and dilute to a liter with distilled water.




    7.2  Lead carbonate.




    7.3  Ascorbic acid.




    7.4  Mercuric chloride solution.  Dissolve  34 g HgC^ in 500 ml distilled




         water.




    7.5  Magnesium chloride solution.  Dissolve 51 g MgCl~.6H20 in 100 ml




         distilled water.  '




    7.6  Sulfuric acid, concentrated.




    7.7  Sodium dihydrogenphosphate, 1 M.   Dissolve 138 g of Na^PC^.l^O in one




         liter of distilled water.   Refrigerate this solution.




    7.8  Stock cyanide solution.  Dissolve 2.51 g of KCN and 2  g KOH  in one liter




         of distilled water.   Standardize  with  0.0192 N AgNOj.  Dilute to




         appropriate concentration so that 1 ml = 1 mg CN~.




    7.9  Standard cyanide  solution,  intermediate.  Dilute 10 ml of stock




         (1 ml = 1 mg CN)  to a liter of distilled water (1 ml = 10 yg).




   7.10  Standard cyanide  solution.  Prepare fresh daily by diluting  100 ml of




         intermediate cyanide solution to  a liter of distilled  water  and store in




         a  glass stoppered bottle.   One ml = 1.0 yg CN  (1.0 mg/1).




   7.11  Standard silver nitrate  solution,  0.0192 N.  Prepare by crushing




         approximately 5 g AgNOg  crystals  and drying to constant weight at 40°C.




         Weigh  out 3.2647 g of dried AgNO,, dissolve in water, and dilute to 1.0




         liter (1 ml = 1 mg CN).
                                        47

-------
                                                                 (Cyanide)






     7.12   Rhodanine  indicator.   Dissolve  20 mg  of p-dimethylamino-benzal-




           rhodanine  in  100 ml of acetone.




     7.13   Chloramine T  solution.  Dissolve 1.0  g of white water soluble Chloramine




           T  in  100  ml  of distilled water and refrigerate until ready to use.



           Prepare fresh weekly.




     7.14   Pyridine-pyrazolone solution.




           7.14.1  One-phenyl-S-methyl-S-pyrazolone reagent.  Weigh 0.25 g of




                   3-methyl-l-phenyl-2-pyrazolone-5-one and dissolve in 50 ml of




                   distilled water by heating to 60°C.  Cool after reagent is




                   in solution.




           7.14.2  Three, 3'Dimethyl-l,l'-diphenyl-4,4f-bi-2 pyrazolone - 5,5'




                   dione (bispyrazolone).  Dissolve 0.01 g of bispyrazolone in




                   10 ml of pyridine.




           7.14.3  Pour solution  7.14.1 through nonacid-washed filter paper.




                   Collect the filtrate.  Through the same filter paper pour




                   solution 7.14.2 collecting the filtrate in the same container




                   as filtrate from 7.14.1.   Mix until the filtrates are homo-




                   geneous.   The mixed reagent develops a pink color but this




                   does not affect the color production with cyanide if used with-




                   in 24 hours of preparation.




8.   Procedure




    8.1   Place 500 ml  of sample, or an aliquot diluted to 500 ml in the 1-liter




          boiling flask.  Add 50 ml of 1 N sodium hydroxide (7.1) to the absorbing




          tube and dilute if necessary with distilled water to obtain an adequate




          depth of liquid in the absorber.  Connect the boiling flask,  condenser,




          absorber and  trap  in the train.
                                           48

-------
                                                         (Cyanide)






8.2  Start a slow stream of air entering the boiling flask by adjusting




     the vacuum source.  Adjust the vacuum so that approximately 1 bubble




     of air per second enters the boiling flask through the air inlet tube.




     (Caution:  The bubble rate will not remain constant after the reagents




     have been added and while heat is being applied to the flask.  It will




     be necessary to readjust the air rate occasionally to prevent the




     solution in the boiling flask from backing up into the air inlet tube).




8.3  Add 10 ml of mercuric chloride solution (7.4) and 40 ml of magnesium




     chloride solutions (7.5) through the air inlet tube.  Rinse the air inlet




     tube with a few ml of distilled water and allow the air flow to mix the




     contents of the flask for at least 3 minutes.




8.4  Slowly add 25 ml of concentrated sulfuric acid (7.6) through the air




     inlet tube and rinse with distilled water.




8.5  Heat the solution to boiling, taking care to prevent the solution from




     backing up into and overflowing from the air inlet tube.  Reflux for




     one hour.  Turn off heat and continue the airflow for at least 15 minutes




     After cooling of the boiling flask disconnect absorber and close off the




     vacuum source.




8.6  Drain the solution from the absorber into a 250 ml volumetric flask




     and bring up to volume with distilled water washings from the absorber




     tube.




8.7  Withdraw 50 ml  of the solution from the volumetric flask and transfer




     to a 100-ml volumetric flask.  Add 10 ml of sodium phosphate solution




     (7.7)  and 0.2 ml of Chloramine T solution (7.13) and mix.  Add an




     additional 5 ml of the sodium phosphate (7.7), followed by 5 ml of
                                 49

-------
                                                       (Cyanide)


     mixed pyridine-pyrazolone solution,  (7.14.3),  bring to mark  with

     distilled water and mix.   Allow 40 minutes for color development.

8.8  Read absorbance at 620 nm using at least a 1.0 cm cell.

8.9  Prepare a series of standards by diluting suitable volumes of standard

     solution to 500.0 ml with distilled  water as follows:

     ml of Standard Solution         Cone.,  When Diluted to
       (1.0 ml = 1 yg CN)              500  ml, mg/1 CN

             0 (Blank)                        0
             5.0                              0.01
            10.0                              0.02
            20.0                              0.04
            50.0                              0.10
           100.0                              0.20
           150.0                              0.30
           200.0                              0.40

     8.9.1  Standards must be  treated in  the same manner as the samples,

            as outlined in 8.1 through 8.8 above.

     8.9.2  Prepare a standard curve by plotting absorbance of standards

            vs.  cyanide concentrations.

     8.9.3  Subsequently, at least two standards (a high and  a low)  should

            be treated as in 8.9.1 to verify standard curve.   If  results

            are  not comparable (±20%),  a  complete new standard curve must

            be prepared.

     8.9.4  To check the  efficiency of the sample distillation, add an

            increment of  cyanide  from either the intermediate standard

            (7.9)  or the  working  standard (7.10)  to insure  a  level  of 10

            pg/1 or a significant increase in absorbance value.   Proceed

            with the analysis  as  in Procedure (8.)  using the  same flask

            and  system from which the  previous sample was just distilled.
                                  50

-------
                                                             (Cyanide)



    8.10  Alternatively, if the sample contains  more than 1 mg  of CN  transfer


          the distillate, or a suitable aliquot  diluted  to 250  ml,  to a 500-ml


          Erlenmeyer flask.  Add 10-12 drops  of  the benzalrhodanine indicator.


    8.11  Titrate with standard silver nitrate to the first change  in color


          from yellow to brownish-pink.  Titrate a distilled water  blank using


          the amount of sodium hydroxide and  indicator as the sample.


    8.12  The analyst should familiarize himself with the end point of the


          titration and the amount of indicator  to be used before actually


          titrating the samples.   A 5 or 10 ml microburet may be  conveniently

                         |
          used to obtain a more precise titration.


9.  Calculation


    9.1   Using the colorimetric procedure, calculate concentration of CN, mg/1,


          directly from prepared standard curve.


    9.2   Using the titrimetric  procedure, calculate concentration of CN as


          follows:


          w    fl ^      (A-B) x 1000        	250	
            '  °     Vol. of original sample   Vol.  of aliquot  titrated


          where:


          A = volume of AgNO, for titration of sample.


          B = volume of AgNO_ for titration of blank.


0.  Precision and Accuracy


    10.1  A synthetic sample prepared by the  Analytical  Reference Service  (PHS)


          at a known concentration of 0.02 mg/1  CN was analyzed by 47 analysts;


          the data showed a standard deviation of 0.035  mg/1 for  the titrimetric


          procedure and 0.020 mg/1 for the colorimetric  procedure.  Similarly, at


          a concentration of 1.10 mg/1 of CN,  the data showed a standard deviation
                                         51

-------
                                                                (Cyanide)





          of 0.333 mg/1 for the titrimetric procedure and 0.306 mg/1 for the




          colorimetric procedure.








                                    References




1.  Bark, L. S., and Higson, H. G.  Investigation of reagents for the colorimetric




    determination of small amounts of cyanide.  Talanta, 2:471-479 (1964).




2.  Elly, C. T.  Recovery of cyanides by modified Serfass distillution.   Journal




    Water Pollution Control Federation, 40:848-856 (1968).
                                        52

-------
                                DISSOLVED OXYGEN
                  (Modified Winkler With Full-Bottle Technique)
1.   Scope and Application                                   ' STORE! NO.  00500
    1.1  This method is  applicable  for use with most wastewaters and streams
         that contain nitrate nitrogen and not more than  1 mg/1 of ferrous
         iron.  Other reducing or oxidizing materials should be absent.  If
         1 ml fluoride solution is  added before acidifying the sample and
         there is  no delay in titration, the method is also applicable  in the
         presence  of 100-200 mg/1 ferric iron.
    1.2  The Dissolved Oxygen Probe technique (see p 60)  gives comparable
         results on all  sample types.
    1.3  The azide modification is  not applicable under the following condi-
         tions:  (a)  samples containing sulfite, thiosulfate, polythionate,
         appreciable quantities of  free chlorine or hypochlorite; (b) samples
         high in suspended solids;  (c) samples containing organic substances
         which are readily oxidized in a highly alkaline  solution, or which are
         oxidized  by free iodine in an acid solution; (d) domestic sewage; (e)
         biological floes;  and (f)  where sample color interferes with endpoint
         detection.  In  instances where the azide modification is not appli-
         cable, the DO probe should be used.
2.   Summary of Method
    2.1  The sample is treated with manganous sulfate, potassium hydroxide, and
         potassium iodide (the latter  two reagents combined in one solution)
         and finally sulfuric acid.  The initial precipitate of manganous hydrox-
         ide, Mn(OH)_, combines with the dissolved oxygen in the sample to form
         a brown precipitate,  manganic hydroxide, Mn 0(OH)_.  Upon acidification,
         the manganic hydroxide forms  manganic sulfate which acts as an oxidizing
         agent to  release free iodine  from the potassium  iodine.  The iodine,
         which is  stoichiometrically equivalent to the dissolved oxygen in the
         sample is then  titrated with  sodium thiosulfate.
                                       53

-------
                                                      (Dissolved Oxygen)





3.  Interferences




    3.1  There are a number of interferences to the dissolved oxygen test,




         including oxidizing and reducing agents, nitrate ion, ferrous iron,



         and organic'matter.



    3.2  Various modifications of the original Winkler procedure for dissolved



         oxygen have been developed to compensate or eliminate interferences.



         The Alsterberg modification is commonly used to successfully eliminate



         the nitrite interference, the Rideal-Stewart modification is designed



         to eliminate ferrous iron interference, and the Theriault procedure is



         used to compensate for high concentration of organic materials.



    3.3  Most of the common interferences in the Winkler procedure may be over-



         come by use of the dissolved oxygen probe.



4.  Sample Handling and Preservation



    4.1  Where possible, collect the sample in a 300 ml  BOD incubation bottle.



         Special  precautions are required to avoid entrainment or solution of



         atmospheric oxygen or dissolution of dissolved  oxygen.



    4.2  Where samples  are collected from shallow depths (less than 5 feet),



         use of an APHA-type sampler is recommended.  Use of a Kemmerer type



         sampler  is recommended for samples collected from depths of greater



         than 5 feet.



    4.3  When a Kemmerer sampler is used,  the BOD sample bottle should be filled



         to overflowing.  (Overflow for approximately 10 seconds).   Outlet tube



         of Kemmerer should be  inserted to bottom of BOD bottle.   Care must be



         taken to prevent turbulence and the formation of bubbles when filling




         bottle.




    4.4  The sample temperature  should be  recorded at time of sampling as pre-




         cisely as  required.
                                   54

-------
                                                       (Dissolved Oxygen)





    4.5  Do not delay the determination of dissolved oxygen in samples  having




         an appreciable iodine demand or containing ferrous.iron.   If samples




         must be preserved either method 4.5.1 or 4.5.2,  below, may be  employed.




         4.5.1  Add 2 ml of manganous sulfate reagent and then 2 ml of  alkali




                azide reagent to the sample contained in  the'BOD bottle.   Both




                reagents must be added well below the surface  of the liquid.




                Stopper the bottle immediately and mix the contents thoroughly.




                The sample should be stored at the temperature of the collection




                water, or water sealed and kept at a temperature of 10  to  20°C,




                in the dark.




         4.5.2  Add 0.7 ml of concentrated H SO, and 1 ml sodium azide  solution




                (2 g NaN, in 100 ml distilled water) to the sample in the  DO




                bottle.  Store sample as in 4.5.1.   Complete the procedure using




                2 ml of manganous sulfate solution, 3 ml  alkali iodide  solution,




                and 2 ml of concentrated HJ5Q..




    4.6  If either preservation technique is employed, complete the analysis




         within 4-8 hours after sampling.




5.   Apparatus




    5.1  Sample bottles - 300 ml ±3 ml capacity BOD incubation bottles  with




         tapered ground glass pointed stoppers and flared mouths.




    5.2  Pipets - with elongated tips capable of delivering 2.0 ml ±0.1 ml of




         reagent.




6.   Reagents




    6.1  Manganous sulfate solution:  Dissolve 480 g manganous sulfate




         (MnS0..4H 0) in distilled water and dilute to 1  liter.
                                       55

-------
                                                    (Dissolved Oxygen)




      6.1.1  Alternately, use 400 g of MnS04-2H20 or 364 g of MnS04.H_0



            per liter.  When uncertainty exists regarding the water of



            crystallization, a solution of equivalent strength may be



            obtained by adjusting the specific gravity of the solution to



            1.270 at 20°C.



6.2   Alkaline iodide solution:  Dissolve 500 g of sodium hydroxide (NaOH)



      or 700 g of potassium hydroxide (KOH) and 135 g of sodium iodide (Nal)



      or 150 g of potassium iodide (KI) in distilled water and dilute to 1



      liter.  To this solution add 10 g of sodium azide (NaN_) dissolved in



      40 ml of distilled water.



6.3   Sulfuric acid, concentrated.



6.4   Starch solution:  Prepare an emulsion of 10 g soluble starch in a mortar



      or beaker with a small quantity of distilled watejr.   Pour this emulsion


      into 1 liter of boiling water, allow to boil a few minutes,  and let



      settle overnight.  Use the clear supernate.  This solution may be pre-



      served by the addition of 5 ml per liter of chloroform and storage in



      a 10°C refrigerator.



      6.4.1  Dry, powdered starch indicators such as "thyodene" may be used



            in place of starch solution.



6.5  Potassium fluoride solution:  Dissolve 40 g KF.2H20 in distilled water



     and dilute to 100 ml.



6.6  Sodium thiosulfate, stock solution,  0.75 N:  Dissolve 186.15 g



     Na^S-O .5H_0 in boiled and cooled distilled water and dilute to liter.
       £t £ O   £•


     Preserve by adding 5  ml chloroform.



6.7  Sodium thiosulfate standard titrant, 0.0375 N:  Prepare by diluting



     50.0 ml of stock solution to 1 liter.   Preserve by adding 5  ml of
                                    56

-------
                                                     (Dissolved Oxygen)

         chloroform.  Standard sodium thiosulfate,  exactly 0.0375  N is

         equivalent to 0.300 mg of DO per 1.00 ml.   Standardize with

         0.0375 N potassium biiodate.

    6.8  Potassium biiodate standard, 0.0375 N:  Dissolve 4.873 g  potassium

         biiodate, previously dried 2 hours at 103°C,  in 1.0  liter of dis-

         tilled water.  Dilute 250 ml to 1.0 liter  for 0.0375 N biiodate

         solution.

    6.9  Standardization of 0.0375 N sodium thiosulfate:  Dissolve

         approximately 2 g (±1.0 g) KI in 100 to 150 ml distilled  water;

         add 10 ml of 10% H-SO. followed by 20 ml standard potassium biiodate.

         Place in dark for 5 minutes, dilute to 300 ml, and titrate with

         the standard sodium thiosulfate to a pale  straw color.  Add 1-2 ml

         starch solution and continue the titration drop by drop until the

         blue color disappears.  Run in duplicate.   Duplicate determinations

         should agree within ±0.05 ml.

7.  Procedure

    7.1  To the sample collected in the BOD incubation bottle, add 2 ml of

         the manganous sulfate solution followed by 2  ml of the alkali-

         iodide-azide reagent, well below the surface  of the  liquid; stopper

         with care to exclude air bubbles, and mix  well by inverting the

         bottle several times.  When the precipitate settles, leaving a

         clear supernatant above the manganese hydroxide floe, shake again.

         When settling has produced at least 100 ml of clear  supernate,

         carefully remove the stopper and immediately  add 2.0 ml of cone.

         H_SO. (sulfamic acid packets, 3 g may be substituted for  H9SO.)^
(1)   Kroner, R. C., Longbottom, J. E., Gorman, R.,  A Comparison of Various
     Reagents Proposed for Use in the Winkler Procedure for Dissolved Oxygen,
     PHS Water Pollution Surveillance System Applications and Development
     Report #12, Water Quality Section, Basic Data  Branch,  July 1964.


                                    57

-------
                                                         (Dissolved Oxygen)





         by allowing the acid to run down the neck of the bottle, re-stopper,



         and mix by gentle inversion until the iodine is uniformly dis-



         tributed throughout the bottle.  Complete the analysis within 45



         minutes.



    7.2  Transfer the entire bottle contents by inversion into a 500-ml



         wide mouth Erlenmeyer flask and titrate with 0.0375 N thiosulfate



         solution (where problems of stability arise, 0.0375 N phenylarsine



         oxide (PAO)may be substituted as titrant) *• ' to a pale straw color.




         Add 1-2 ml of starch solution or 0.1 g of powdered indicator and



         continue to titrate to the first disappearance of the blue color.



    7.3  If ferric iron is present (100 to 200 ppm), add 1.0 ml of KF



         solution before acidification.



    7.4  Occasionally, a dark brown or black precipitate persists in the



         bottle after acidification.  This precipitate will dissolve if the



         solution is kept for a few minutes longer than usual or, if parti-



         cularly persistent,  a few more drops of H..SO. will effect disso-



         lution .




8.  Calculation



    8.1  Each ml of 0.0375 sodium thiosulfate titrant is equivalent to 1 mg




         DO when the entire bottle contents are titrated.



    8.2  If the results are desired in milliliters of oxygen gas per liter



         at 0°C and 760 mm pressure, multiply mg/1 DO by 0.698.




    8.3  To express the results as percent saturation at 760 mm atmospheric



         pressure,  the solubility data in Table 218 (Whipple § Whipple



         Table, p.  480,  Standard Methods, 13th Edition)  may be used.



         Equations  for correcting the solubilities to barometric pressures




         other than mean sea  level are given below the table.
                                     58

-------
                                                         (Dissolved Oxygen)

    8.4  The solubility of DO in distilled water at any barometric pressure,
         p (mm Hg), temperature, T°C,  and saturated vapor pressure, y  (mm Hg) ,
         for the given T, may be calculated between the temperature of 0° and
         30 °C by:
         and between 30° and 50°C by:
                           .1/1 DO . c - a ; ?-827
9.  Precision and Accuracy
    9.1  Exact data are unavailable on the precision and accuracy of this
         technique; however, reproducibility is approximately 0.2 ppm of DO
         at the 7.5 ppm level due to equipment tolerances and uncompensated
         displacement errors.
                                     59

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                               DISSOLVED OXYGEN

                                 (Probe Method)

                                                              STORE! NO.  00300
 1.  Scope  and Application

    1.1  The probe method for dissolved oxygen is recommended for those samples

         containing materials which interfere with the modified Winkler procedure

         such as sulfite, thiosulfate, polythionate, mercaptans, free chlorine

         or hypochlorite, organic substances readily hydrolyzed in alkaline

         solutions, free iodine, intense color or turbidity, biological floes, etc.

    1.2  The probe method is recommended as a substitute for the modified Winkler

         procedure in monitoring of streams, lakes, outfalls, etc., where it is

         desired to obtain a continuous record of the dissolved oxygen content of

         the water under observation.

    1.3  The probe method may be used as a substitute for the modified Winkler

         procedure in BOD determinations where it is desired to perform non-

         destructive DO measurements on a sample.

    1.4  The probe method may be used under any circumstances as a substitute for

         the modified Winkler procedure provided that the probe itself is

         standardized  against the Winkler method on samples free of interfering

         materials.

    1.5  The electronic readout meter for the output from dissolved oxygen probes

         is normally calibrated in convenient scale (0 to 10, 0 to 15, 0 to 20 mg/1

         for example)  with a sensitivity of approximately 0.05 mg/liter.

2.  Summary of Method

    2.1  The most common instrumental probes for determination of dissolved oxygen

         in water are dependent upon electrochemical reactions.  Under steady-

         state conditions,  the current or potential can be correlated with DO
                                        60

-------
                                                           (DO  -  Probe Method)






         concentrations.   Interfacial  dynamics  at  the probe-sample  interface




         are a factor in probe response and a significant  degree  of inter-




         facial turbulence is necessary.   For precision performance, turbulence




         should be constant.




3.  Sample Handling and Preservation




    3.1  See 4.1,  4.2,  4.3,  4.4 under  Modified  Winkler Method.




4.  Interferences




    4.1  Dissolved organic materials are not known to interfere in  the output




         from dissolved oxygen probes.




    4.2  Dissolved inorganic salts are a factor in the performance  of dissolved




         oxygen probe.




         4.2.1  Probes  with membranes  respond to partial pressure of oxygen which




                in turn is a function  of dissolved inorganic  salts.  Conversion




                factors for seawater and brackish  waters may  be calculated from




                dissolved oxygen saturation versus salinity data.   Converson




                factors for specific inorganic  salts may be developed experimentally.




                Broad variations in the kinds and  concentrations  of salts in




                samples can make the use of a membrane probe  difficult.




         4.2,2  The thallium probe requires the presence of salts in concentrations




                which provide a minimum conductivity of approximately 200 micromhos.








    4.3  Reactive  compounds can interfere with  the output  or  the  performance  of




         dissolved oxygen probes.




         4.3.1  Reactive gases which pass through  the membrane  of membrane probes




                may interfere.  For example, chlorine will depolarize the cathode




                and cause a high probe-output.   Long-term  exposures to  chlorine
                                        61

-------
                                                         (DO _ probe Method)





                will coat the anode with the chloride of the anode metal and




                eventually desensitize the probe.  Alkaline samples in which




                free chlorine does not exist will not interfere.  Hydrogen




                sulfide will interfere with membrane probes if the applied




                potential is greater than the half-wave potential of the




                sulfide ion.  If the applied potential is less than the half-




                wave potential, an interfering reaction will not occur, but




                coating of the anode with the sulfide of the anode metal can • '




                take place.




         4.3.2  Sulfur compounds (hydrogen sulfide, sulfur dioxide and mer-




                captans, for example) cause interfering outputs from the




                thallium probe.  Halogens do not interfere with the thallium




                probe.




    4.4  At low dissolved oxygen concentrations, pH variation below pH 5 and




         above pH 9 interfere with the performance of the thallium probe




         (approximately ±0.05 mg/1 DO per pH unit).  The performance of membrane




         probes is not affected by pH changes.




    4.5  Dissolved oxygen probes are temperature sensitive, and temperature




         compensation is normally provided by the manufacturer.   The thallium




         probe has a temperature coefficient of 1.9 m/°C.   Membrane probes have




         a temperature coefficient of 4 to 6 percent/°C dependent upon the




         membrane employed.




5.   Apparatus




    5.1  No specific probe or accessory is especially recommended as superior.




         However,  probes which have been evaluated or are  in use and found to be




         reliable are the Weston § Stack DO Analyzer Model  30 and the Yellow




         Springs Instrument  (YSI)  Model 54.
                                       62

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                                                       (DO - Probe Method)





6.  Calibration



    Follow manufacturer instructions.



7.  Procedure



    Follow manufacturer instructions.



8.  Calculation



    Follow manufacturer instructions.



9.  Precision and Accuracy



    Manufacturer's specification claim 0.1 rag/1 repeatability with ±1% accuracy.
                                        63

-------
                                 FLUORIDE
                (SPADNS Method with  Bellack  Distillation)
                                                            STORE! NO. 00950
 1.   Scope and Application
     1.1   This method is  applicable  to the measurement of fluoride in
          drinking waters, surface waters, domestic wastes and industrial
          wastes  and  saline waters.  It is the method to be used when the
          accessories for  the probe  method are not available.
     1.2   The  method  covers the range from 0.1 to about 2.5 mg/1 F.
 2.   Summary of Method
     2.1   Following distillation to  remove interferences the sample is
          treated with the SPADNS reagent.  The loss of color resulting
          from the reaction of fluoride with the zirconyl-SPADNS dye is
          a function  of the fluoride concentration.
 3.   Comments
     3.1  The  SPADNS  reagent is more tolerant of interfering materials
         than other  accepted fluoride reagents.  Reference to Table 121, (1)
         page  169, Standard Method  for the Examination of Waters and Waste-
         waters, 13th Edition, will help the analyst decide if distillation
         is required.  The addition of the highly colored SPADNS reagent
         must be done with utmost accuracy because the fluoride concen-
         tration is measured as a difference of absorbance in the blank
         and the sample.  A small error in reagent addition is the most
         prominent source of error in this test.
4.  Precision and Accuracy
    4.1  On a sample containing 0.83 mg/1 F with no interferences, 53
         analysts using the Bellack distillation and the SPADNS reagent
         obtained a mean of 0.81 mg/1 F with a standard deviation of
         0.089 mg/1.
                                    64

-------
                                                           (Fluoride)


    4.2  On a sample containing 0.57 mg/1 F (with 200 mg/1 SO. and

         10 mg/1 Al as interferences) 53 analysts using the Bellack

         distillation obtained a mean of 0.60 mg F/l with a standard

         deviation of 0.103 mg/1.

    4.3  On a sample containing 0.68 mg/1 F (with 200 mg/1 SO., 2 mg/1 Al

         and 2.5 mg/1 [NaPO_]6 as interferences^ 53 analysts using the

         Bellack distillation obtained a mean of 0.72 mg/1 F with a standard

         deviation of 0.092 mg/1.

    4.4  Analytical Reference Service, Sample 111-B water, Fluoride,

         August, 1961.

5.   Reference           j

         The procedure to be used for this determination is found in:

             Standard Methods for the Examination of Water and Waste-
             waters, pp 171-172 (Method No. 121A, Preliminary Distil-
             lation Step) and pp 174-176 (Method 121C, SPADNS) 13th
             Edition, (1971).

             American Society for Testing and Materials, Part 23, pp
             213-218, Method No. D1179-68, (1970).
                                  65

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                                FLUORIDE


                       (Automated Complexone Method)

                                                            ;STORET NO.   00950

 1.  Scope and Application


    1.1  This method is applicable to surface waters, domestic and industrial


         wastes, and saline waters.  The applicable range of the method is


         0.05 to 1.5 mg F/l.  Twelve samples per hour can be analyzed.


 2.  Summary of Method


    2.1  Fluoride ion reacts with the red cerous chelate of alizarin com~


         plexone.  It is unlike other fluoride procedures in that a positive


         color is developed as contrasted to a bleaching action in previous


         methods.


 3.  Sample Handling and Preservation


    3.1  No special requirements.


4.  Interferences


    4.1  Method is free from most anionic and cationic interferences, except

                                                                        _3
         aluminum, which forms an extremely stable fluoro compound, AlFfi


         This is overcome by treatment with 8-hydroxyquinoline to complex


         the aluminum and by subsequent extraction with chloroform.


5.  Apparatus


    5.1  Technicon AutoAnalyzer Unit consisting of:


         5.1.1  Sampler I.


         5.1.2  Manifold.


         5.1.3  Proportioning pump.


         5.1.4  Continuous  filter.


         5.1.5  Colorimeter equipped with 15 mm tabular flow cell and


                650 nm filters.


         5.1.6  Recorder equipped with range expander.
                                     66

-------
                                                                 (Fluoride)





6.   Reagents




    6.1  Sodium acetate solution:   Dissolve  272 g  (2 moles) of sodium acetate




         in distilled water and dilute to  1  liter.




    6.2  Acetic acid-8-hydroxyquinoline  solution:  Dissolve 6 g of 8-hydroxy-




         quinoline in 34 ml of cone,  acetic  acid,  and dilute to 1 liter.




    6.3  Chloroform:   Analytical reagent grade.




    6.4  Ammonium acetate solution (6.7%):   Dissolve 67 g of ammonium acetate




         in distilled water and dilute to  1  liter.




    6.5  Hydrochloric acid (2 N):   Dilute  172 ml of cone. HC1 to  1 liter.




    6.6  Lanthanum alizarin fluoride  blue  solution*:  Dissolve 0.18 g of




         alizarin fluoride blue in a  solution containing 0.5 ml of cone.




         ammonium hydroxide and 15 ml of 6.7% ammonium acetate.   Add a solution




         that contains 41 g of anhydrous sodium carbonate and 70 ml of glacial




         acetic acid  in 300 ml of  distilled  water.  Add 250 ml of acetone.




         Dissolve 0.2 g of lanthanum  oxide in 12.5 ml of 2 N hydrochloric acid




         and mix with above solution.  Dilute to 1 liter.




    6.7  Stock Solution:  Dissolve 2.210 g of sodium fluoride in  100 ml of




         distilled water and dilute to 1 liter.  1 ml = 1.0 mg F.




    6.8  Standard Solution:  Dilute 10.0 ml  of stock solution to  1 liter.




         1  ml = 0.01  mg F.




         6.8.1  Using standard solution, prepare the following standards




                in 100-ml volumetric  flasks:
M.  T.  Baker Laboratory Chemical  No. J112  or equivalent,
                                       67

-------
                                                               (Fluoride)


                mg  F/l              ml Standard Solution/100 ml

                  0.05                           0.5
                  0.10                           1.0
                  0.20                           2.0
                  0.40                           4.0
                  0.60                           6.0
                  0.80                           8.0
                  1.00                          10.0
                  1.20                          12.0
                  1.50                          15.0

7.  Procedure

    7.1  Set up manifold as shown in Figure 1.

    7.2  Allow both colorimeter and recorder to warm up for 30 minutes.  Run

         a baseline with all reagents, feeding distilled water through the

         sample line.  Adjust dark current and operative opening on colorimeter

         to obtain stable baseline.

    7.3  Place distilled water wash tubes in alternate openings in Sampler and

         set sample timing at 2.5 minutes.

    7.4  Arrange fluoride standards in Sampler in order of decreasing concen-

         tration.  Complete loading of Sampler tray with unknown samples.

    7.5  Switch sample line from distilled water to Sampler and begin analysis.

8.  Calculation

    8.1  Prepare standard curve by plotting peak heights of processed fluoride

         standards against concentration values.   Compute concentration of

         samples by comparing sample peak heights with standard curve.

9.  Precision and Accuracy

    9.1  In a single laboratory, using surface water samples at concentrations

         of 0.06, 0.15, 0.55, and 1.08 mg F/l, the standard deviation was

         ±0.018 (AQC Laboratory).
                                       68

-------
                                                              (Fluoride)





    9.2  In a single laboratory,  using surface water samples  at concentrations



         of 0.14 and 1.25 mg F/l  recoveries were 89% and 102%,  respectively



         (AQC Laboratory)I








                               References





1.  R.  Greenhaigh and J. P. Riley, "The Determination of Fluorides in Natural



    Waters, with Particular Reference to Sea Water."  Anal.  Chim.  Acta,  25,



    179 (1961).



2.  K.  M.  Chan and J. P. Riley, "The Automatic Determination of Fluoride in



    Sea Water and Other Natural Waters."  Anal. Chim. Acta,  35, 365 (1966).
                                      69

-------
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-------
                                    FLUORIDE
                         (Specific Ion Electrode Method)     STORET No:      Total  00951
                                                                       Dissolved  00950
1.  Scope and Application
    1.1  This method is applicable to the measurement of fluoride in finished
         waters, natural waters, brines, and industrial waste waters and  the
         need for distillation of the sample is eliminated.
    1.2  Concentrations of fluoride from 0.1 up to 1000 mg/liter may be measured.
2.  Summary of Method
    2.1  The fluoride is determined potentiometrically using a specific ion
         fluroide electrode in conjunction with a standard single junction sleeve-
         type reference electrode and a pH meter having an expanded  millivolt
         scale or a specific ion meter having a direct concentration scale for
                            j
         fluoride.
    2.2  The fluoride electrode consists of a lanthanum fluoride crystal  across
         which a potential is developed by fluoride ions.  The cell  may be re-
         presented by Ag/Ag Cl, Cl~ (0.3), F~ (0.001) LaF_/ test solution/SCE/.
                                                         o
3.  Interferences
    3.1  Extremes of pH interfere; sample pH should be between 5 and 9.  Poly-
         valent cations of Si  , Fe   and Al   interfere by forming  complexes
         with fluoride.  The degree of interference depends upon the concentration
         of the complexing cations, the concentration of fluoride and the pH of
         the sample.  The addition of a pH 5.0 buffer (described below) contain-
         ing a strong, chelating agent preferentially complexes aluminum  (the
         most common interference), silicon, and iron, and eliminates the pH
         problem.
4,  Sampling Handling and Preservation
    4.1  No special requirements.
                                       72

-------
                                                                (Fluoride)


 5.   Apparatus

     5.1   Electrometer,  (pH meter) with expanded mv scale or a specific ion

          meter  such  as  the Orion 400 Series.

     5.2   Fluoride  Ion Activity Electrode, such as Orion No. 94-09*- ' .

     5.3   Reference electrode, single junction, sleeve-type, such as Orion

          No. 90-01,  Beckman No. 40454, or Corning No. 476010.

     5.4   Magnetic  Mixer, Teflon-coated stirring bar.

 6.   Reagents

     6.1   Buffer solution, pH 5.0-5.5.  To approximately 500 ml of distilled

          water in  a  one-liter beaker add 57 ml of glacial acetic acid, 58 g

          of sodium chloride and 2 g of CDTA   .  Stir to dissolve and cool

          to room temperature.  Adjust pH of solution to between 5.0 and 5.5

         with 5 N  sodium hydroxide (about 150 ml will be required).  Transfer

          solution  to a one-liter volumetric flask and dilute to the mark with

         distilled water.  For work with brines, additional NaCl should be

         added to raise the chloride level to twice the highest expected

          level of chloride in the sample.

         Note - CDTA replaces citric acid used in the original buffer for-

         mula.   It is a strong chelating agent and more effectively ties up

         aluminum than the original citric acid.

    6.2  Sodium fluoride, stock solution (1.0 mg = 0.01 mg F).  Dissolve

         0.2210 g of sodium fluoride in water and dilute to 1.0 liter.

         Dilute 100 ml of this solution to 1.0 liter with water.  Store

         in chemical-resistant glass or polyethylene.
(1)  Patent No.  3,431,182 (March 4, 1969).

(2)  CDTA is the abbreviated designation of 1,2-cyclohexylene dinitrilo
    tetraacetic acid,  (Mathieson,  Coleman  § Bell,  Cat. No.  P8661)  or
    cyclohexane diamine tetraacetic acid (Merck-Titriplex IV or Baker
    Cat.  No.  G083).
                                     73

-------
                                                               (Fluoride)


7.  Calibration

    7.1  Prepare a series of standards using the fluoride stock  solution

         (1 ml = 0.01 mg F) in the range of 0 to 2.00  mg/liter by  diluting

         appropriate volumes to 50 ml.  The following  series may be  used:

              Milliliters of Stock      Concentration  when Diluted
              (1.0 ml = 0.01 mg/F)         to 50 ml, mg F/liter

                      0.00                         0.00
                      1.00                         0.20
                      2.00                         0.40
                      3.00                         0.60
                      4.00                         0.80
                      5.00                         1.00
                      6.00                         1.20
                      8.00                         1.60
                     10.00                         2.00

    7.2  Calibration of Electrometer:   Immerse the electrodes  in each  stock

         solution starting with the lowest concentration and measure the

         developed potential while mixing.  The electrodes must  remain in

         the solution for at least three minutes or until the  reading  has

         stabilized.  Using semilogarithmic graph paper, plot  the  concen-

         tration of fluoride in mg/liter on the log axis vs. the electrode

         potential developed in the standard on the linear axis, starting

         with the lowest concentration at the bottom of the scale.

    7.3  Calibration of a specific ion meter:  Follow  the directions of the

         manufacturer for the operation of the instrument.

8.  Procedure

    8.1  Place 50.0 ml of sample and 50.0 ml of buffer in a 150-ml beaker.

         Place on a magnetic stirrer and mix at medium speed.   Immerse the

         electrodes in the solution and observe the meter reading  while mixing.

         The electrodes must remain in the solution for at least three minutes
                                    74

-------
                                                                 (Fluoride)





         or until the reading has stabilized.  At concentrations under 0.5 mg/




         liter F, it may require as long as five minutes to reach a stable meter




         reading; higher concentrations stabilize more quickly.  If a pH meter




         is used, record the potential measurement for each unknown sample and




         convert the potential reading to the fluoride ion concentration of the




         unknown using the standard curve.  If a specific ion meter is used,




         read the fluoride level in the unknown sample directly in mg/1 on the




         fluoride scale.




9.  Precision and Accuracy




    9.1  A synthetic sample prepared by the Analytical Reference Service, PHS,




         containing 0.85 mg/1 fluoride and no interferences was analyzed by  111




         different analysts; a mean of 0.84 mg/1 with a standard deviation of




         ±0.030 was obtained.




    9.2  On the same study, a synthetic sample containing 0.75 mg/1 fluoride,




         2.5 mg/1 polyphosphate and 300 mg/1 alkalinity, was analyzed by the




         same 111 analysts; a mean of 0.75 mg/1 fluoride with a standard deviation




         of ±0.036 was obtained.
                                       75

-------
                              HARDNESS



                                                STORET Number:   00900



1.   Scope and Application



    1.1  This method is applicable to drinking waters  and surface  waters,



         domestic and industrial wastes.



    1.2  The method is suitable for all concentration  ranges of hardness;



         however, in order to avoid large titration volumes, use a sample



         aliquot containing not more than 25 mg CaCO_  per 50 ml sample.
                                                    «J         .           •


    1.3  Automated titration may be used.



2.   Summary of Method



    2.1  Calcium and magnesium ions in the sample are  sequestered  upon the



         addition of disodium dihydrogen ethylenediamine tetraacetate



         (Na2EDTA).  The end point of the reaction is  detected  by  means of



         Chrome Black T or Calmagite/- ' which has a red color in the



         presence of calcium and magnesium and a blue  color when the cations



         are sequestered.



3.   Comments



    3.1  Excessive amounts of heavy metals can interfere.  This is usually



         overcome by complexing the metals with cyanide.



         3.1.1  Routine addition of sodium cyanide solution (CAUTION:  Deadly



                poison) to prevent potential metallic  interference is



                recommended.



4.   Precision and Accuracy



    4.1  Forty-three analysts in nineteen laboratories analyzed six



         synthetic water samples containing exact increments of calcium



         and magnesium salts, with the following results:
^ %ach Cat. No. 825 or equivalent.
                                    76

-------
                                                          (Hardness)
Increment as
Total Hardness
mg/liter as CaCO,
31
33
182
194
417
444
Precision as
Standard Deviation
mg/liter as CaCO,
2.87
2.52
4.87
2.98
9.65
8.73
Accuracy as
Bias,
-0.87
-0.73
-0.19
-1.04
-3.35
-3.23
Bias ,
mg/liter, CaC03
-0.003
-0.24
0.4
-2.0
-13.0
-14.3
(FWPCA Method Study 1, Mineral and Physical Analyses)



    4.2  In a single laboratory (AQC), using surface water samples at an


         average concentration of 194 mg CaCO /I, the standard deviation was
                                             O

         ± 3.


5.   Reference


    5.1  The procedure to be used for this determination is found in:


         Standard Methods for the Examination of Water and Wastewater,


         13th Edition, p. 179, Method 122B (1971).


         ASTM Standards, Part 23, Water; Atmospheric Analysis, p. 187,


         Method D1126-67 (1970).
                                     77

-------
                            HARDNESS, TOTAL

                           (Automated Method)
                                                           STORET NO.  00900

1.  Scope and Application


    1.1  This automated method is applicable to surface and saline waters.


         The applicable range is 10 to 400 mg/1 as CaCO_.   Approximately 12


         samples per hour can be analyzed.


2.  Summary of Method


    2.1  The disodium magnesium EDTA exchanges magnesium on an equivalent


         basis for any calcium and/or other cations to form a more stable


         EDTA chelate than magnesium.  The free magnesium reacts with cal-


         magite at a pH of 10 to give a red-violet complex.  Thus, by

                            I
         measuring only magnesium concentration in the final reaction stream,


         an accurate measurement of total hardness is possible.


3.  Sample Handling and Preservation


    3.1  No special requirements.


4.  Interferences


    4.1  No significant interferences.


5.  Apparatus


    5.1  Technicon AutoAnalyzer consisting of:


         5.1.1  Sampler I.


         5.1.2  Continuous Filter.


         5.1.3  Manifold.


         5.1.4  Proportioning Pump.


         5.1.5  Colorimeter equipped with 15 mm tubular flow cell and 520


                nm filters.


         5.1.6  Recorder equipped with range expander.
                                     78

-------
                                                        (Hardness, Total)


6.  Reagents

    6.1  Buffer:  Dissolve 67.6 g NH.C1 in 572 ml of NH.OH and dilute to 1 liter.

    6.2  Calmagite^•':  Dissolve 0.25 g in 500 ml of distilled water by stirring

         approximately 30 minutes on a magnetic stirrer.  Filter.

    6.3  Magnesium EDTA:  Dissolve 0.2 g of MgEDTA in 1 liter of distilled water.

    6.4  Stock Solution:  Weigh 1.0 g of calcium carbonate (pre-dried at 105°C)

         into 500 ml Erlenmeyer flask; add 1:1 HC1 until all CaCO_ has dissolved.
                                                                 o
         Add 200 ml of distilled water and boil for a few minutes.  Cool, add a

         few drops of methyl red indicator, and adjust to the orange color with

         3N NH.OH and dilute to 1 liter.  1.0 ml = 1.0 mg CaCO,.
              ^                                               o

         6.4.1  Dilute each of the following volumes of stock solutions to 250 ml

                for appropriate standards:

                       Stock Solution, ml          CaCO,, mg/1


                              2.5                      10.0
                              5.0                      20.0
                             10.0                      40.0
                             15.0                      60.0
                             25.0                     100
                             35.0                     140
                             50.0                     200
                             75.0                     300
                            100.0                     400

7.  Procedure

    7.1  Set up manifold as shown in Figure 1.

    7.2  Allow both colorimeter and recorder to warm up for 30 minutes.   Run a

         baseline with all reagents,  feeding distilled water through the sample

         line.   Adjust dark current and operative opening on colorimeter to

         obtain stable baseline.
        Cat.  No.  825 or equivalent.


                                        79

-------
                                                          (Hardness,  Total)




    7.3  Place distilled water wash tubes in alternate openings in Sampler



         and set sample timing at 2.5 minutes.



    7.4  Arrange working standards in Sampler in order of decreasing  con-



         centration.  Complete loading of Sampler tray with unknown samples.



    7.5  Switch sample line from distilled water to Sampler and begin analysis,



8.  Calculation



    8.1  Prepare standard curve by plotting peak heights of processed stan-



         dards against concentration values.  Compute concentration of



         samples by comparing sample peak heights with standard curve.



9.  Precision and Accuracy



    9.1  In a single laboratory (AQC), using surface water samples at con-



         centrations of 19, 120, 385, and 366 mg/1 as CaCO_, the standard



         deviations were ±1.5, ±1.5, ±4.5, and ±5.0, respectively.



    9.2  In a single laboratory (AQC), using surface water samples at



         concentrations of 39 and 296 mg/1 as CaCO,, recoveries were  89%
                                                  O


         and 93%, respectively.







                                  References



1.  Technicon AutoAnalyzer Methodology, Bulletin No. 2, Technicon Controls,



    Inc., Chauncey, New York (July 1960).



2.  Standard Methods for the Examination of Water and Wastewater, 13th



    Edition, p. 179, Method 122B (1971).
                                      80

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                              FIGURE 1. HARDNESS MANIFOLD

-------
                               METALS
                       (Atomic Absorption Methods)

1.   Scope and Application
    1.1  Metals in solution may be readily determined by  atomic absorption
         spectroscopy.   The method is simple,  rapid, and  applicable to a
         large number of metals in surface waters, domestic and industrial
         wastes, and saline waters.
    1.2  Detection limits,  sensitivity and optimum ranges  of the metals
         will vary with the various  makes and  models of satisfactory  atomic
         absorption spectrophotometers.   The data shown in Table 1, however,
         provide some indication of the  concentration ranges measurable.  In
         the majority of instances the concentration range shown in the table
         may be extended much  lower  with scale expansion  and conversely ex-
         tended upwards by  using a less  sensitive wavelength.  Detection
         limits may also be extended through concentration of the sample or
         through solvent extraction  techniques.  Table 1  lists detection
         limits, sensitivities,  and  the  optimum concentration ranges  achieved
         directly on the sample using the Instrumentation Laboratories,
         Model IL-153 without  scale  expansion  (Pos 2.5).   The boat tech-
         nique developed at Perkin-Elmer for use with the  PE303 or 403 may
         also be used to extend absolute detection limits.  ^
                                     83

-------
                                                               (Metals)
                                   TABLE  1

                            Concentration Ranges
                                                                  Optimum
                                                               Concentration
Metal
Aluminum
Arsenic
Cadmium
Calcium
Chromium
Copper
Iron
Lead
Magnesium
Manganese
Potassium
Silver
Sodium
Zinc
Detection Limit
mg/1
0.1
0.05
0.001
0.003
0.01
0.005
0.004
0.01
0.0005
0.005
0.005
0.01
0.001
0.005
Sensitivity
mg/1
0.4
1.0
0.004
0.07
0.02
0.04
0.006
0.06
0.005
0.04
0.01
0.05
0.003
0.02
Range
mg/1
10
10
0.1
1
1
0.1
0.1
1
0.01
0.1
0.01
0.1
1
0.1

1000
100
2
200
200
10
20
10
2
20
2
20
200
2
2.   Summary of Method


    2.1  Atomic absorption spectroscopy is similar to flame emission photometry


         in that a sample is atomized and aspirated into a flame.   Flame


         photometry,  however,  measures the amount of light emitted,  whereas,


         in atomic absorption  spectrophotometry a light  beam is  directed


         through the  flame into a monochromator,  and onto a detector that


         measures  the amount of light absorbed.  In many  instances absorption


         is  more sensitive because it depends upon the presence  of  free un-


         excited atoms  and generally  the  ratio  of unexcited to excited atoms


         at  a  given moment is  very high.   Since  the wavelength of the light beam


         is  characteristic of  only the metal being determined, the  light energy


         absorbed  by  the  flame is  a measure of the concentration of that metal in


         the sample.  This  principle  is the basis  of atomic absorption spectroscopy.


   2.2   Although  methods have been reported for the analysis of solids by

                                       r 2")
         atomic  absorption  spectroscopy    the technique  generally is limited
                                      84

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                                                                (Metals)






         to metals in solution or solubilized through some form of sample



         processing.  Thus, it is a relatively simple matter to determine



         metals in the dissolved fraction by aspirating a filtered portion




         of the water sample.



         2.2.1  In those instances where complete characterization of a



                sample is desired, the suspended material must also be



                analyzed.  This may be accomplished by filtration and acid



                digestion of the suspended material.  Metallic constituents



                in this acid digest are subsequently determined and the sum



                of the dissolved plus suspended concentrations will then



                provide the total concentrations present.



         2.2.2  The sample may also be treated with acid before filtration



                to measure what may be termed "extractable" concentrations.



3.  Definition of Terms



    3.1  Sensitivity:  is the concentration in milligrams of metal per liter




         that produces an absorption of 1%.



    3.2  Detection Limit:  is defined as the concentration that produces



         absorption equivalent to twice the magnitude of the fluctuation in




         the background (zero absorption).



    3.3  Dissolved Metals:  those constituents (metals) which will pass



         through a 0.45 n membrane filter.




    3.4  Suspended Metals:  those constituents (metals) which are retained



         by a 0.45 y membrane filter.



    3.5  Total Metals:  the concentration of metals determined on an unfiltered



         sample following vigorous digestion (Section 4.1.3), or the sum of



         the concentrations of metals in both the dissolved and suspended




         fractions.




                                      85

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                                                               (Metals)
    3.6  Extractable Metals:  the concentration of metals in an unfiltered
         sample following digestion with hot dilute mineral acid (Section
         4.1.4).
4.  Sample Handling and Preservation
    4.1  For the determination of trace metals, contamination and loss are
         of prime concern.  Dust in the laboratory environment, impurities
         in reagents and impurities on laboratory apparatus which the sample
         contacts are all sources of potential contamination.   For liquid
         samples, containers can introduce either positive or negative errors
         in the measurement of trace metals by (a) contributing contaminants
         through leaching or surface desorption and (b)  by depleting concen-
         trations through adsorption.   Thus the collection and treatment of
         the sample prior to analysis  requires particular attention.   The
         sample bottle should be thoroughly washed with  detergent and tap
         water; rinsed with chromic acid,  tap water,  1:1 nitric acid, tap
         water and finally distilled water in that order.   Before collection
         of the sample a decision must be  made as  to  the type  of data desired,
         i.e.,  dissolved,  suspended, total or extractable.
         4.1.1   For the determination  of dissolved constituents  the sample should
                be filtered through a  0.45 \i membrane filter as  soon  as
                practicable after collection.   Use the first 50-100 ml  to rinse
                the filter flask.   Discard this portion  and collect the  re-
                quired volume of filtrate.   Acidify the  filtrate  with 1:1  re-
                distilled  HNO, (3 ml per liter).   Normally  this  amount  of acid
                will  lower the pH to 2 or  3 and should be sufficient  to
                preserve the  sample  indefinitely.   (See  Note 1).  Analyses
                performed  on  a sample  so treated shall be reported as "dissolved"
                                     86

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                                                    (Metals)




       concentrations.



       NOTE 1:  It has been suggested (International Biological




       Program, Symposium on Analytical Methods, Amsterdam, Oct.



       1966) that additional acid, as much as 25 ml of concentrated



       HCl/liter may be required to stabilize certain types of



       highly buffered samples if .they are to be stored for any



       length of time.  Therefore, special precautions should be



       observed for preservation and storage of unusual samples in-



       tended for trace metal analysis.



4.1.2  For the determination of suspended metals a representative



       volume of sample should be filtered through a 0.45 u membrane



       filter.  When considerable sediment is present, as little as



       100 ml of a well shaken sample is filtered.



       Record the volume filtered and transfer the membrane filter



       containing the sediment to a 250 ml Griffin beaker and add



       3 ml distilled HNO_.   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 evaporated,  cool the beaker and



       watch glass and add another 3 ml  of distilled HNO_.



       Cover and continue heating until  the digestion is complete,



       generally indicated by a light colored residue.  Add distilled



       1:1 HC1 (2 ml)  to the dry residue and again warm the beaker



       gently to dissolve the material.   Wash down the watch glass



       and beaker walls with distilled water and filter the sample



       to remove silicates and other insoluble material that could




       clog the atomizer.   Adjust the volume to  some predetermined



       value based on the expected concentrations of trace metals






                            87

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                                                (Metals)





       present.  This volume will vary depending on the metal  to




       be determined.  The sample is now ready for analysis.   Con-




       centrations so determined shall be reported as "suspended".




       STORET parameter numbers for reporting this type of data are




       currently being assigned.




4.1.3  For the determination of total metals  the sample is not




       filtered before processing.   Choose a  volume of sample




       appropriate for the expected level of  metals.   If  much  sus-




       pended material is present,  as little  as  50-100 ml of well




       mixed sample will most probably be sufficient.   (The sample




       volume required may also vary proportionally with  the




       number of metals to be determined).




       Transfer a representative aliquot of the  well  mixed sample to




       a Griffin beaker and add 3 ml of concentrated  distilled HNO_.




       Place the beaker on a hot plate and evaporate  to dryness making




       certain that the sample does  not boil.  Cool the beaker and




       add another 3 ml portion of  distilled  concentrated HNO_.  Cover
                                                            •3



       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 by a light  colored  residue.  Add  sufficient




       distilled 1:1  HC1 and  again warm the beaker to  dissolve  the




       residue.   Wash  down  the beaker walls and  watch  glass with




       distilled water and  filter the sample  to  remove  silicates and




       other  insoluble material  that could  clog  the atomizer.   Adjust
                                88

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                                                          (Metals)





                the volume to some predetermined value based on the expected




                metal concentrations.  The sample is now ready for analysis.




                Concentrations so determined shall be reported as "total".




                STORET parameter numbers for reporting this type of data have




                been assigned and are given for each metal.




         4.1.4  To determine metals soluble in diluted hot HC1 - HNO_,




                acidify the entire sample at the time of collection with re-




                distilled HNO_, 5 ml/1.  At the time of analysis the sample




                is mixed and a 100-ml aliquot transferred to a beaker or flask.




                Five ml of redistilled hydrochloric acid is added and the




                sample heated for 15 minutes on a steam bath or hot plate.




                After this digestion period the sample is filtered and the




                volume adjusted to 100 ml.  The sample is then ready for




                analysis.




                The data so obtained are significant in terms of "total" metals




                in the sample, with the reservation that something less than




                "total" is actually measured.  Concentrations of metal found,




                especially in heavily silted samples, will be substantially




                higher than data obtained on only the soluble fraction.  STORET




                parameter numbers for the storage of this type data are not




                available at this time.




5.   Interferences




    5.1  The most troublesome type of interference in atomic absorption spectro-




         photometry is usually termed "chemical" and is caused by lack of




         absorption of atoms bound in molecular combination in the flame.  This




         phenomenon can occur when the flame is not sufficiently hot to
                                       89

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                                                               (Metals)





         dissociate the molecule, as in the case of phosphate interference




         with magnesium, or because the dissociated atom is immediately




         oxidized to a compound that will not dissociate further at the




         temperature of the flame.  The addition of lanthanum will overcome




         the phosphate interference in the magnesium determination.  Similarly,




         silica interference in the determination of manganese can be




         eliminated by the addition of calcium.




         5.1.1  Chemical interferences may also be eliminated by separating




                the metal from the interfering material.  While complexing




                agents are usually employed to increase the sensitivity of




                the analysis they may also be used to eliminate or reduce




                interferences.




6.  Apparatus




    6.1  Atomic absorption spectrophotometer:  Any commercial atomic absorption




         instrument having an energy source, an atomizer burner system, a mono-




         chromater, and a detector is suitable.




    6.2  Burner:  A Doling burner is recommended for most aqueous solutions.




         A premix burner is used for organic solvents.   For certain elements




         the nitrous oxide burner is required.




    6.3  Volumetric flasks; 200 ml,  for extraction with organic solvents.




    6.4  Glassware:  All glassware,  including sample bottles, should be washed




         with detergent, rinsed with tap water, chromic acid, tap water, 1:1




         nitric acid,  tap water and  distilled water in  that order.




    6.5  Borosilicate  glass distillation apparatus.
                                       90

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                                                              (Metals)
 7.   Reagents


     7.1   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.


     7.2   Nitric acid (cone):  Distill reagent grade nitric acid in a boro-


          silicate glass distillation apparatus.  Prepare a 1:1 dilution


          with deionized distilled water.  Caution:  Distillation should be


          performed in hood with  protective sash in place.


     7.3   Hydrochloric acid (1:1):  Prepare a 1:1 solution of reagent grade


          hydrochloric acid and distilled water.  Distill this mixture from
                            i
                            j
          a borosilicate glas£ distillation apparatus.


     7.4   Stock metal solutions:  Prepare as directed in 8.1 and under the


          individual metal procedures.


     7.5   Standard metal solutions:  Prepare a series of standards of the metal


         by dilution of the appropriate stock metal solution to cover the con-


          centration range desired.


     7.6   Fuel and oxidant:  Commercial grade acetylene is generally acceptable.


          Air may be supplied from a compressed air line, a laboratory com-


         pressor, or from a cylinder of compressed air.  Reagent grade nitrous


          oxide is also required  for certain determinations.


     7.7  Special reagents for the extraction procedure.


          7.7.1  Ammonium pyrrolidine dithiocarbamate solution (APDC):  Dissolve


                1 g APDC in 100 ml of deionized distilled water.  Prepare fresh


                before use.


         7.7.2  Hydrochloric acid, 0.3N:  Mix 25 ml cone. HC1 with deionized


                distilled water  and dilute to 1 liter.
Ammonium pyrrolidine dithiocarbamate (APDC) may be obtained commercially
from Fisher Scientific Company (Cat. No. A-182), K and K Labs., Inc., or
Eastman Kodak.

                                     91

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                                                              (Metals)








         7.7.3  Methyl isobutyl ketone (MIBK):  (see Note 2)



                NOTE 2:  One objection to MIBK is the increased solubility



                in a highly acid medium.  By using a 3:1 mixture of MIBK -



                cyclohexane the solubility in the aqueous phase is decreased



                without any significant change in the extraction of the



                various chelates or burning characteristics of the ketone.



                Ethyl propionate has also been found to be a suitable



                solvent.  Benzene and kerosene are inferior to MIBK because



                they produce a large luminous and smoke flame.  Carbon



                tetrachloride or chloroform may also be used;  however, the



                enhancement is considerable less than with MIBK.



         7.7.4  Sodium hydroxide, 2.5N:  Dissolve 10 g NaOH in deionized



                distilled water and dilute to 100 ml.



8.   Preparation of Standards and Calibration



    8.1  Stock solutions are prepared from high purity metals, oxides or



         nonhygroscopic reagent grade salts using redistilled  nitric or



         hydrochloric acids.  Sulfuric or phosphoric acids should be avoided



         as they produce an adverse effect on many elements.  The stock




         solutions are prepared at concentrations  of 1000 mg of the metal



         per liter.



    8.2  Standard solutions are prepared  by diluting the stock metal solutions



         at the time  of analysis.   For best results,  calibration standards



         should be prepared fresh each time an analysis is to  be made and
                                       92

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                                                            (Metals)




         discarded after use.  Prepare a blank and calibration standards



         in graduated amounts in the appropriate range.  As the filtered



         samples are preserved with redistilled nitric acid (3 ml 1:1 per



         liter) the acid strength of the calibration standards should be



         similarly adjusted.  Beginning with the blank and working toward the



         highest standard, aspirate the solutions and record the readings.



         Repeat the operation with both the calibration standards and the



         samples a sufficient number of times to secure a reliable average



         reading for each solution.



    8.3  For those instruments which do not read out directly in concentration



         a calibration curve is prepared to cover the appropriate concentration



         range.  Usually, this means the preparation of standards which produce



         an absorption of 0 to 80 percent.  The correct method for plotting



         data derived from an atomic absorption instrument equipped with a



         linear readout system is to convert percent absorption to absorbance



         and plot the absorbance against concentration.  The following relation-



         ship is used to convert absorption values to absorbance:



                       absorbance  =  log (100/% T)  =  2 - log % T



                       where % T  =  100 - % absorption



         As the curves are frequently nonlinear, especially at high absorption



         values, the number of standards should be increased in that portion



         of the curve.



9.  General Procedure for Analysis by Atomic Absorption



    9.1  Differences between the models of satisfactory atomic absorption



         spectrophotometers prevent the formulation of detailed instructions



         applicable to every instrument.  The analyst should follow the
                                     93

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                                                             (Metals)






     manufacturer's operating instructions for his particular instrument.



     In general, after  choosing the correct hollow cathode lamp for the



     analysis, the lamp should be allowed to warm up for a minimum of



     15 minutes.  During this period, align the instrument, position the



     monochromator at the correct wavelength, select the proper mono-



     chromator slit width, adjust the hollow cathode current according to



     the manufacturer's recommendation, light the flame and regulate the



     flow of fuel and oxidant, adjust the burner for maximum percent



     absorption and stability and balance the photometer.  Run a series of



     standards of the element under analysis and construct working curves



     by plotting the concentrations of the standards against the absor-



     bance.  For those instruments which read directly in concentration



     set the curve corrector to read out the proper concentration.



     Aspirate the samples and determine the concentrations either



     directly or from the calibration curve.   For best results run



     standards each time a sample or series of samples are run.



9.2  Special Extraction Procedure:  When the concentration of the metal



     is not sufficiently high to determine directly,  or when considerable



     dissolved solids are present in the sample, certain of the metals may



     be chelated and extracted with organic solvents.  Ammonium pyrrolidine



     dithiocarbamate (APDC)  is widely used for this purpose and is parti-



     cularly useful for zinc, cadmium, iron,  manganese, copper,  silver,



     lead and chromium"1"^.   Tri-valent chromium does not react with APDC



     unless it has  first been converted to the hexavalent form .   Aluminum,



     beryllium,  barium and strontium also do not react with APDC.
                                 94

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                                                       (Metals)






The most frequently used organic solvent for APDC is methyl iso-



butyl ketone (MIBK).  Apart from the fact that the solvent should



extract the chelate, it should burn and provide a stable flame.



In addition, the physical properties of the solvent such as vis-



cosity, surface tension, boiling point, and mutual solubility in



an aqueous medium must be taken into account.  It should not



produce toxic products during combustion or give a high background



in the flame (see Note 3).



NOTE 3:  The methods described herein have been found to be satis-



factory for natural and fresh water types of samples when used by



a qualified analyst.  Occasions have been reported when other types



of samples (sea water, brine, etc.) have presented some problems



with the extraction procedure.  Therefore, users are cautioned to



confirm their suitability through application on spiked samples.



9.2.1  Extraction Procedure with APDC:  The following extraction



       procedure is a general one which may be used for the majority



       of metals.  Manganese, however, will not be extracted unless




       the pH is adjusted to between 4.5 and 5.0.  In addition,  the



       manganese complex is extremely  unstable and must be analyzed




       without delay.



       a.  Transfer a volume of sample (100 ml maximum) into a 250



           ml Griffin beaker and adjust the volume to 100 ml with



           deionized distilled water.



       b.  Prepare a blank and sufficient standards in the same



           manner and adjust the volume of each to approximately




           100 ml with deionized distilled water.
                             95

-------
                                                                  (Metals)


                  c.   Adjust  the pH of the  samples and standards to a pH of

                      2.5 using a pH meter.

                  d.   Transfer the samples  and standards to a 200 ml volumetric

                      flask and add 2.5 ml  fresh APDC solution and mix.

                  e.   Add 10.0 ml MIBK and  shake vigorously for one minute.

                  f.   Allow the layers  to separate and add deionized distilled

                      water until the  ketone  layer is completely in the neck

                      of the  flask.  Centrifuge if separation is not complete.

                  g.   Aspirate the ketone layer and record the scale readings

                      for each standard and sample against the prepared blank.

                      Repeat  and average the  duplicate results.  Plot a cali-

                      bration curve in yg metal vs. absorbance (see Note 4).

                      NOTE 4:  When aspirating organic solvents the fuel-to-

                      air ratio should be reduced as the burning of the organic

                      solvent contributes to  the fuel supply.  When adjusting

                      the fuel-to-air ratio of the gas mixture at the burner,

                     begin with the settings recommended by the manufacturer.

                     Gradually reduce the fuel flow while the organic solvent

                      is being aspirated until the flame is as blue as possible.

                     Care should be taken that the flame does not lift off

                     the burner producing an undesirable luminescent flame.

10.   Calculation

     10.1  Direct determination:   Read the jnetal value in mg/1 from the cali-

           bration curve or directly from the readout system of the instrument.

              mg/1 metal in sample = (mg/1 of metal in the aliquot) x D

              where D = m*  °f aliquot + ml of deionized distilled water
                                        ml of aliquot
                                      96

-------
                                                                (Metals)





     10.2  Extracted samples:  Read the metal value in yg from the extracted



           calibration curve or from the readout system of the instrument.



                  mg/1 metal in sample = Vg metal in aliquot

                                            ml of aliquot



11.  Precision and Accuracy



     11.1  Three synthetic unknown samples containing varying concentrations



           of cadmium, chromium, copper, iron, lead, magnesium, manganese,



           silver, and zinc were analyzed in 59 laboratories with the results



           indicated in Table 2.  (Analytical Reference Service PHS).





                           !       Table 2
                           I


         Precision and Accuracy Data for Atomic Absorption Methods


Metal
Direct determination
Cadmium
Chromium
Copper
Iron
Magnesium
Manganese
Silver
Zinc
Extracted samples
Cadmium
Lead

Metal
Concentration ,
Vg/1
50
50
1000
300
200
50
50
500
10
50

Relative
Error,
percent
8.15
2.29
3.42
0.64
6.30
6.00
10.57
0.41
3.03
19.00
Relative
Standard
Deviation,
percent
21.62
26.44
11.23
16.53
10.49
13.50
17.47
8.15
72.77
23.46
References:
(1) Atomic Absorption Newsletter, 7_, 35 (1968).

(2) Spectrochim Acta, 24B, 53  (1969).

(3) Atomic Absorption Newsletter, 6_, 128 (1967).
                                    97

-------
                                   AUMHHI
                            (Standard Conditions)             DISSOLVED:   01105
                                                             TOTAL     :   01106
 Optimum Concentration Range   10-1000 rag/1 using  the  3092 A  line
 Sensitivity  0.4  mg/1
 Detection  Limit   0.1  mg/1
 Preparation of Standard Solution
      1.  'Stock Solution:   Carefully  weigh  1.000 gram  of aluminum metal
          (analytical  reagent grade).  Add  15 ml of concentrated HC1 to the
         metal in a covered beaker and warm gently.   When solution is complete,
         transfer quantitatively  to  1 liter volumetric flask and make up to
         volume with  distilled water.  One ml equals  1 mg Al.
      2.  Prepare  dilutions  of the stock solution  to be used as calibration
         standards at the  time of analysis.  Maintain an acid strength of
         0.15% nitric acid  in all calibration standards.
 Instrumental  Parameters (General)
      1.  Aluminum hollow cathode  lamp
      2.  Wavelength:   3092  A
      3.  Type of burner:  Nitrous  oxide
      4.  Fuel:  Acetylene
      5.  Oxidant:  Nitrous  oxide
      6.  Type of  flame;  Fuel rich
      7.  Photomultiplier tube:  IP-28


Notes
      1.  The following lines may also be used:
         3082 A Relative Sensitivity 1
         3962 A Relative Sensitivity 2
         3944 A Relative Sensitivity 2.5
                                      98

-------
                                   ARSENIC
                             ,„.,,_,..   .         STORE! NO:
                             (Standard Conditions)            DISSOLVED:  01000
                                                             TOTAL    :   01QQ2
Optimum Concentration Range   10-100 mg/1 using the 1937 A line

Sensitivity  1.0 mg/1

Detection Limit  0.5 mg/1

Preparation of Standard Solution

     1.  Stock Solution:  Dissolve 1.320 grams of arsenic trioxide (As^O ,

         analytical reagent grade) in a small quantity of distilled water

         in which a pellet of NaOH has previously been dissolved.  When solution

         is complete acidify  with HC1 and make up to 1 liter with distilled

         water.  One ml equals 1 mg As (1000 mg/1).
                             I
     2.  Prepare dilutions of the stock solution to be used as calibration

         standards at the time of analysis.

Instrumental Parameters (General)

     1.  Arsenic hollow cathode lamp

     2.  Wavelength:  1937 A

     3.  Type of burner:  Nitrous oxide

     4.  Fuel:  Acetylene

     5.  Oxidant:  Nitrous oxide

     6.  Type of flame:  Fuel rich

     7.  Photomultiplier tube:  R-106

Notes

     1.  The R-106 photomultiplier tube is more sensitive to UV light and

         therefore is suggested in place of the IP-28 phototube.

     2.  Arsenic may also be  determined using an air-acetylene system; however,

         the detection limit  is 3-5 mg/1.  Using an argon-hydrogen system this

         limit may be lowered to 0.25 mg/1; however, both chloride a'nd nitrate

         ions interfere.
                                      99

-------
                                                     (Metals)





3.  Samples high in total salt content (above 1%) will produce an



    apparent absorption at the 1937 A arsenic line even when the



     element is absent using the air-acetylene system.



4.  The high-solids burner is reported to give lower detection limits



     with both the argon-hydrogen and air-acetylene systems.



5.  The silver diethyldithiocarbamate colorimetric method is suggested




     for low levels of arsenic.
                               100

-------
                                 CADMIUM
                                                         STORE! NO:
                             (Standard Conditions)          DISSOLVED:  01025
                                                            TOTAL     :  01027
Optimum Concentration Range  0.1-1 mg/1 using the 2288 A line

Sensitivity  0.004 mg/1

Detection Limit  0.001 mg/1

Preparation of Standard Solution

     1.  Stock Solution:  Carefully weigh 1.142 grams of cadmium oxide

         (CdO, analytical reagent' grade) and dissolve in 5 ml redistilled

         HNO_.  Dilute to 1 liter with distilled water.   One ml equals

         1 mg Cd.

     2.  Prepare dilutions of the stock solution to be used as calibration

         standards at the time of analysis.   Maintain an acid strength of

         0.15% nitric acid in all calibration standards.

Instrumental Parameters (General)

     1.  Cadmium hollow cathode lamp

     2.  Wavelength:  2288 A

     3.  Type of burner:  Boling

     4.  Fuel:  Acetylene

     5.  Oxidant:  Air

     6.  Type of flame:  Oxidizing

     7.  Photomultiplier tube:  IP-28
                                     101

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                                  CALCIUM                  STORE! NO:     Total 00916

                            (Standard Conditions)                     Dissolved 00915




 Optimum Concentration  Range   1.0-200 mg/1 using the 4227 A line



 Sensitivity   0.07 mg/1



 Detection  Limit  0.003 mg/1



 Preparation of Standard Solution



     1.  Stock Solution:  Suspend  1.250  grams of CaCO_ (analytical reagent
                                                     O


         grade), dried at 180°C for 1 hour before weighing, in distilled



         water and dissolve cautiously with a minimum of dilute HC1.  Dilute



         to 1000 ml with distilled water.  One ml equals 0.5 mg of Ca



         (500 mg/1).



     2.  Lanthanum chloride solution:  Dissolve 29 g of La 0_, slowly and in
                                                          2 5


         small portions, in 250 ml concentrated HC1.  (Caution!  Reaction is



         violent) and dilute to 500 ml with distilled water.



     3.  Prepare dilutions of the stock calcium solutions to be used as cali-



         bration standards at the time of analysis.  To each calibration



         standard solution,  add 1.0 ml of LaCl_ solution for each 10 ml of



         volume of working standard, ie., 20 ml working standard + 2 ml



         LaCl_ = 22 ml.



Instrumental Parameters (General)



     1.  Calcium hollow cathode lamp



     2.  Wavelength:   4227 A



     3.  Type of burner:   Boling



     4.  Fuel:  Acetylene



     5.  Oxidant:  Air



     6.  Type of flame:  Reducing



     7.  Photomultiplier tube:  IP-28
                                       102

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                                                               (Metals)


Notes


     1.  Phosphate, sulfate and aluminum interfere but are masked by the


         addition of lanthanum.  Since low calcium values result if the  pH


         of the sample is above 7, both standards and samples are prepared


         in dilute hydrochloric acid solution.   Concentrations of magnesium


         greater than 1000 mg/1 also cause low calcium values.  Concentrations


         of up to 500 mg/1 each of sodium, potassium and nitrate cause no inter-


         ference .


     2.  Anionic chemical interferences can be expected if lanthanum is  not


         used in samples and standards.


     3.  The nitrous oxide-acetylene flame will provide two to five times

                            |.
         greater sensitivity and freedom from chemical interferences.  lonization


         interferences should be controlled by adding a large amount of alkali


         to the samples and standards.  The analysis appears to be free  from


         chemical supressions in the nitrous oxide - acetylene flame.


     4.  The 2399 A line may also be used.  This line has a sensitivity  of


         20 mg/1.
                                        103

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                                     CHROMIUM

                                                            STORET NO:

                              (Standard Conditions)            DISSOLVED:   01030

                                                              TOTAL    :   01054


 Optimum  Concentration  Range   1.0-200 mg/1 using the 3579 A line



 Sensitivity   0.02 mg/1



 Detection  Limit  0.01  mg/1



 Preparation  of Standard Solution



      1.  Stock Solution:  Dissolve  1.923 gram of chromium trioxide (CrO_,
                                                                       O


         reagent grade) in distilled water.  When solution is complete,



         acidify with  redistilled HNO_ and dilute to 1 liter with distilled



         water.  One ml equals 1 mg chromium.



      2.  Prepare dilutions of the stock solution to be used as calibration



         standards at  the time of analysis.  Maintain an acid strength of



         0.15% nitric  acid in all calibration standards.



 Instrumental Parameters (General)



      1.  Chromium hollow cathode lamp



      2.  Wavelength:   3579 A



      3.  Type of burner:  Boling



      4.  Fuel:  Acetylene



      5.  Oxidant:  Air



      6.  Type of flame:  Slightly fuel rich



      7.  Photomultiplier tube:  IP-28
Notes
     1.  The following wavelengths may also be used:



         3605 A Relative Sensitivity 1.2



         3593 A Relative Sensitivity 1.4



         4254 A Relative Sensitivity 2



         4274 A Relative Sensitivity 3



         4289 A Relative Sensitivity 4
                                       104

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                                                            (Metals)





2.  The determination of chromium requires a rich acetylene flame.



    The absorption is very sensitive to the fuel-to-air ratio.



3.  The absorption of chromium is suppressed by iron and nickel.  If



    the analysis is performed in a lean flame the interference can



    be lessened but the sensitivity will also be reduced.  The inter-



    ference does not exist in a nitrous oxide - acetylene flame.



4.  For low levels of chromium the extraction procedure (MIBK-APDC) is



    recommended.  Only hexavalent chromium will react with APDC, thus,



    to measure trivalent chromium an oxidation step must be included.



    (See ref. 3).
                                  105

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                                    COPPER                  STORET NO:
                             CStandard  Conditions)             DISSOLVED:   01040
                                                              TOTAL    :   01042

 Optimum Concentration Range   0.1-10 mg/1  using  the  3247 A  line

 Sensitivity   0.04  mg/1

 Detection  Limit  0.005 mg/1

 Preparation  of Standard Solution

      1.  Stock Solution:  Carefully weigh 1.00  gram of electrolytic copper

         (analytical  reagent  grade).   Dissolve  in 5 ml redistilled HNO, and

         make  up to 1  liter with distilled water.   Final concentration is 1

         mg  Cu per ml  (1000 mg/1).

      2.  Prepare dilutions of the stock solution to be used as calibration

         standards at  the time of analysis.  Maintain an acid strength of

         0.15% nitric  acid in all calibration standards.

 Instrumental Parameters (General)

      1.  Copper hollow  cathode lamp

      2.  Wavelength:   3247 A

      3.  Type of burner:  Boling

     4.  Fuel:  Acetylene

     5.  Oxidant:  Air

     6.  Type of flame:  Oxidizing

     7.  Photomultiplier tube:  IP-28


Notes

     1.  For copper concentrations below 0.05 mg/1, the extraction procedure

         is suggested.

     2.  Copper atoms  are distributed over a wider area in laminar flow-flames

         than that  normally found.   Consequently, the burner parameters are not

         as critical as for most other elemental determinations.
                                       106

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                                                           (Metals)


3.  Because of the spectral intensity of the 3247 A line, the P.M.  tube


    may become saturated.  If this situation occurs the current should


    be decreased.


4.  Numerous absorption lines are available for the determination of


    copper.  By selecting a suitable absorption wavelength,  copper samples


    may be analyzed over a very wide range of concentration.  The following


    lines may be used:


    3264 A Relative Sensitivity 2


    2178 A Relative Sensitivity 4


    2165 A Relative Sensitivity 7

    2181 A Relative Sensitivity 9
                        i,
    2225 A Relative Sensitivity 20


    2024 A Relative Sensitivity 20


    2492 A Relative Sensitivity 90
                                  107

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                                                           STORET NO:
                             (Standard Conditions)            DISSOLVED:    01046
                                                             TOTAL    :    01045

 Optimum  Concentration  Range  0.1-20 mg/1 using the 2483 A  line

 Sensitivity   0.006 mg/1

 Detection  Limit   0.004 mg/1

 Preparation of Standard Solution

     1.  Stock Solution:  Carefully weigh 1.000 gram of pure iron wire

         (analytical reagent grade) and dissolve in 5 ml redistilled

         HNO_, warming if necessary.  When solution is complete make up

         to 1 liter with distilled water.  One ml equals 1 mg Fe  (1000 mg/1).

     2.  Prepare  dilutions of the stock solutions to be used as calibration

         standards at  the time of analysis.  Maintain an acid strength of

         0.15% nitric  acid in all calibration standards.

 Instrumental Parameters (General)

     1.  Iron hollow cathode lamp

     2.  Wavelength:   2483 A

     3.  Type of burner:  Boling

     4.  Fuel:  Acetylene

     5.  Oxidant:  Air

     6.  Type of flame:  Oxidizing

     7.  Photomultiplier tube:   IP-28


Notes

     1.  The following lines may also be used:

         2488 A Relative Sensitivity 2

         2522 A Relative Sensitivity 2

         2719 A Relative Sensitivity 4

         3021  A Relative Sensitivity 5
                                       108

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                                                         (Metals)




    2527 A Relative Sensitivity 6



    2721 A Relative Sensitivity 9



    3720 A Relative Sensitivity 10



    2967 A Relative Sensitivity 12



    3860 A Relative Sensitivity 20



    3441 A Relative Sensitivity 30



2.   Absorption is strongly dependent upon the lamp current.



3.   Better signal-to-noise can be obtained from a neon-filled hollow



    cathode lamp than from an argon-filled lamp.
                                  109

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                                     LEAD

                             (Standard Conditions)           S™?ED:  01049
                                                              TOTAL    :  01051
 Optimum Concentration Range  1-10 mg/1 using the  2170 A  line

 Sensitivity   0.06  mg/1

 Detection Limit  0.01 mg/1

 Preparation  of Standard Solution

      1.   Stock Solution:  Carefully weigh  1.599 gram of  analytical reagent

          grade lead nitrate [Pb(NO_)2,;} and  dissolve in  redistilled water.

          When  solution is complete acidify with 10 ml redistilled HNO_ and

          dilute to 1  liter  with distilled  water.  One ml equals 1 mg Pb

          (1000 mg/1).

      2.   Prepare dilutions  of the stock solution  to be used as calibration

          standards at  the time of analysis.  Maintain an acid strength of

          0.15% nitric  acid  in all  calibration standards.

 Instrumental Parameters (General)

      1.   Lead  hollow  cathode lamp

      2.  Wavelength:   2170

      3.  Type  of burner:  Boling

      4.  Fuel:  Acetylene

      5.  Oxidant:  Air

      6.  Type  of flame:  Slightly oxidizing

      7.  Photomultiplier tube:  IP-28
Notes
     1.  The analysis of this metal is exceptionally sensitive to turbulence

         and absorption bands in the flame.  Therefore, some care should be

         taken to position the light beam in the most stable, center portion of
                                      110

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                                                      (Metals)


    the flame.  To do this, first adjust the burner to maximize the

    absorbance reading with a lead standard.  Then, aspirate a  water

    blank and make minute adjustments in the burner alignment to

    minimize the signal.

2.  Better analytical results with the 2170 A line may be obtained by

    using a R-106 photomultiplier tube which is more sensitive  to UV

    light.

3.  For lead concentrations below 0.2 mg/1, the extraction procedure

    is suggested.  The optimum pH for the extraction is  2.8.

4.  The following lines may also be used:

    2833 A Relative Sensitivity   2
                        |
    2614 A Relative Sensitivity 500

    3683 A Relative Sensitivity 900
                                111

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                                 MAGNESIUM                  STQRET NQ.
                           (Standard Conditions)               DISSOLVED:  00925
                                                              TOTAL    :  00927
 Optimum Concentration Range  0.01-2 mg/1  using the  2852  A line
 Sensitivity  0.005 mg/1
 Detection Limit  0.0005  mg/1
 Preparation of Standard  Solution
       1.   Stock Solution:   Dissolve 0.829 g of magnesium oxide, MgO
           (analytical reagent  grade)  in  10 ml of redistilled HNO, and
           dilute to 1 liter with distilled water.   One ml  equals 0.50 mg.
       2.   Lanthanum chloride  solution:  Dissolve 29 g of La?0_, slowly
                                                            f» O
           and in small portions  in  250 ml concentrated HC1,  (Caution!
           Reaction is violent)  and  dilute to 500 ml with distilled water.
       3.   Prepare dilutions of  the  stock  magnesium  solution to be used as
           calibration standards  at  the time of analysis.   To each calibration
           standard solution,  add 1.0 ml of LaCl, solution  for each 10 ml
                                                O
           of volume of working  standard,  ie.,  20 ml  working standard + 2 ml
           LaCl3  =  22  ml.
 Instrumental  Parameters  (General)
       1.   Magnesium hollow cathode  lamp
       2.   Wavelength:  2852 A
       3.   Type of burner:  Boling
      4.   Fuel:  Acetylene
      5.   Oxidant:  Air
      6.  Type of flame:  Reducing
      7.  Photomultiplier tube:  IP-28

Notes
      1.  Analytical sensitivity decreases with increased lamp current.
      2.  The interference caused by aluminum at concentrations greater than
                                       112

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                                                   (Metals)





    2 mg/1 is masked by addition of lanthanum.  Since low magnesium




    values result if the pH of the samples is above 7, both standards




    and samples are prepared in dilute hydrochloric acid.  Sodium,




    potassium and calcium cause no interference at concentrations less




    than 400 mg/1.




3.  Because of the spectral intensity of the 2852 line, the P.M.  tube




    may become saturated.  If this situation occurs,  the current  should




    be decreased.




4.  The f&llowing lines may also be used:




    2025 A Relative Sensitivity  250




    7025 A Relative Sensitivity  250




    2796 A Relative Sensitivity 1000




5.  To cover the range of magnesium values normally observed in surface




    waters (0.1-20 mg/1), it is suggested that the burner be rotated 55s
                                113

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                                 MANGANESE

                                                           STORET NO:
                            (Standard Conditions)             DISSOLVED;   01056
                                                             TOTAL    :   01055

 Optimum  Concentration  Range  0.1-20 mg/1 using the 2795 A line

 Sensitivity   0.04 mg/1

 Detection  Limit  0.005 mg/1

 Preparation of Standard Solution

     1.  Stock Solution:  Carefully weigh 1.583 gram of analytical reagent

         grade manganese dioxide, MnO  and dissolve in 10 ml of HC1.  When

         solution is complete dilute to 1 liter with distilled water.  One

         ml equals 1 mg Mn  (1000 mg/1).

     2.  Prepare dilutions  of the stock solution to be used as calibration

         standards at  the time of analysis.  Maintain an acid strength of

         0.15% nitric  acid  in all calibration standards.

 Instrumental  Parameters (General)

     1.  Manganese hollow cathode lamp

     2.  Wavelength:   2795  A

     3.  Type of burner:  Boling

     4.  Fuel:  Acetylene

     5.  Oxidant:  Air

     6.  Type of flame:  Oxidizing

     7.  Photomultiplier tube:  IP-28

Notes^

     1.  For manganese concentrations below 0.01 mg/1, the extraction

         procedure is  suggested.  The extraction is carried out at pH 4.5-5.

         The manganese chelate is very unstable and the analysis must be

         made without delay to prevent its re-solution in the aqueous phase.

     2.  Analytical sensitivity is somewhat dependent on lamp current.
                                        114

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                                 POTASSIUM

                            (Stanza Coitions,            S™™D:
                                                             TOTAL     :  00957
Optimum Concentration Range  0.01-2 mg/1 using the 7665 A line


Sensitivity  0.01 mg/1


Detection Limit  0.005 mg/1


Preparation of Standard Solutions


      1.  Stock Solution:  Dissolve 0.1907 grains of KC1 (analytical reagent


          grade), dried at 110°C, in distilled water and make up to 1 liter.


          One ml equals 0.10 mg of potassium (100 mg/1).


      2.  Prepare dilutions of the stock solution to be used as calibration


          standards at the time of analysis.


Instrumental Parameters (General)

                            j :
      1.  Potassium hollow cathode lamp


      2.  Wavelength:  7665 A


      3.  Type of burner:  Boling


      4.  Fuel:  Acetylene


      5.  Oxidant:  Air


      6.  Type of flame:  Slightly oxidizing


      7.  Photomultiplier tube:  IP-21



Notes


      1.  If an IP-21 photodetector tube is not available, the IP-28 may be


          used.  This will result in some loss of sensitivity.


      2.  The Osram potassium vapor-discharge lamp may also be used in the


          Perkin-Elmer 303." In this case the lamp current should be 350 ma or


          the optimum operating current.


      3.  Sodium may interfere if present at much higher levels than the


          potassium.  This effect can be avoided by approximately matching the
                                       115

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                                                          (Metals)





    sodium content of the potassium standards with that of the sample.




4.  Potassium absorption is enhanced in the presence of Na, Li and Cs,




    especially in a high-temperature flame.  This enhancement effect of




    sodium can be eliminated by changing the burner height and the type




    of flame used.  The burner assembly is set approximately 0.05 cm below




    the optical light path so that the optical light path is sliced at the




    bottom by the burner head.  A fuel-rich flame is used (303-burner,




    airflow 7.5, acetylene flow 9.0).




5.  The 4044 A line may also be used.  This line has a sensitivity of




    5 mg/1 for 1% absorption.




6.  To cover the range of potassium values normally observed in surface




    waters (0.1-20 mg/1), it is suggested that the burner be rotated 75°.
                                 116

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                                  SILVER

                             (Standard Conditions)           ^DISSOLVED: 01075
                                                              TOTAL    :  01077
Optimum Concentration Range  0.1-20 mg/1 using the 3281 A line

Sensitivity  0.05 mg/1

Detection Limit  0.01 mg/1

Preparation of Standard Solution

      1.  Stock Solution:  Dissolve 1.575 g of AgNO_ (analytical reagent  grade)

          in distilled water, add 10 ml HNO, and make up to 1 liter.  One ml

          equals 1 mg of silver  (1000  mg/1).

      2.  Prepare dilutions of the stock solution to be used as calibration

          standards at the time of analysis.  Maintain an acid strength of

          0.15% HNO_ in all calibration standards.

Instrumental Parameter (General)
                            1
      1.  Silver hollow cathode lamp

      2.  Wavelength:  3281 A

      3.  Type of burner:  Doling

      4.  Fuel:  Acetylene

      5.  Oxidant:  Air

      6.  Type of flame:  Oxidizing

      7.  Photomultiplier tube:  IP-28


Notes

      1.  The 3382 A line may also be used.  This line has a relative

          sensitivity of 3.

      2.  Silver nitrate standards are light sensitive.  Dilutions of the

          stock should be discarded after use as concentrations below 10 mg/1

          are not stable over long periods of storage.
                                       117

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                                  SODIUM


                                                            S™:   00930
                                                              TOTAL    :   00929
 Optimum Concentration Range  1.0-200 mg/1 using the 3302 A line

 Sensitivity  0.003 mg/1

 Detection  Limit  0.001 mg/1

 Preparation of Standard Solutions

      1.   Stock Solution:  Dissolve 2.542 g of NaCl (analytical reagent grade),

           dried at 140°C, in distilled water and make up to 1 liter.  One ml

           equals 1 mg of sodium  (1000 mg/1) .

      2.   Prepare dilutions of the stock solution to be used as calibration

           standards at the time of analysis.

 Instrumental Parameters (General)

      1.   Sodium hollow cathode lamp

      2.   Wavelength:  3302 A

      3.   Type of burner:  Boling

      4.   Fuel:  Acetylene

      5 .  Oxidant :  Air

      6.  Type of flame:  Oxidizing

      7.  Photomultiplier tube:   IP- 28
Notes
      1.  For the Perkin-Elmer instrument the "290" burner is used to

          increase the concentration range of sodium using the most sensitive

          line 5890.  The burner is installed perpendicular (rotated 90°)

          to the light path.   The upper concentration limit is 60 mg/1  without

          sample dilution.

      2.  The 3302 A resonance line of sodium yields a sensitivity of about

          5 mg/1 sodium for 1% absorption and provides a convenient way to
                                      118

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    avoid the need to dilute more concentrated solutions of sodium.




3.  Low-temperature flames increase sensitivity by reducing the extent




    of ionization of this easily ionized metal.




4.  For more sensitivity the IP-21 photomultiplier tube and the 5890 A




    line may be used to extend the range to 0.005-0.2 mg/1.
                                 119

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                                   ZINC
                             ,_.   .  ,  ,,  ,._    .           STORE! NO:
                             (Standard  Conditions)             DISSOLVED:  01090
                                                              TOTAL    :   01092
 Optimum Concentration Range  0.1-2 mg/1  using the  2139  A line

 Sensitivity  0.02 mg/1

 Detection Limit  0.005 mg/1

 Preparation of Standard Solution

       1.   Stock Solution:   Carefully weigh  1.00  gram of analytical  reagent

           grade zinc  metal  and  dissolve  cautiously in 10 ml HNO_.   When

           solution is complete  make up to 1  liter  with  distilled water.  One

           ml  equals 1 mg Zn (1000  mg/1).

       2.   Prepare dilutions of  the stock solution  to be used as calibration

           standards at the  time of analysis.   Maintain  an acid strength of

           0.15% HNO,  in all calibration standards.

 Instrumental  Parameters  (General)

       1.   Zinc  hollow cathode lamp

       2.   Wavelength:   2139 A

       3.   Type  of burner:   Boling

       4.   Fuel:   Acetylene

       5.   Oxidant:  Air

       6.   Type  of flame:  Oxidizing

       7.   Photomultiplier tube:  IP-28


Notes

       1.  High  levels of silicon may interfere.

      2.  The air-acetylene flame  absorbs about 25% of the energy at the

          2139 A  line.

      3.  The sensitivity may be increased by the use of low-temperature  flames.
                                       120

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                                   MERCURY

                           (Flameless AA Procedure)
                                                       STORE! NO. 	
                                                       Total:     71900
                                                       Dissolved: 71890

1.  Scope and Application

    1.1  This method is applicable to surface waters,  saline waters, waste-

         waters and effluents.

    1.2  With proper digestion  other materials  such  as  fish tissue, mud and

         sediments may also be  analyzed  using the described technique  (see

         Appendix 11.1 and 11.2).

    1.3  In addition to inorganic  forms  of mercury,  organic mercurials may

         also be present in an  effluent  or surface water  sample.  These organo-
                           !
         mercury compounds will not respond  to  the flameless atomic absorption
                           i .

         technique unless they  are first broken down and  converted to mercuric

         ions.  Potassium permanganate oxidizes many of these compounds but

         recent studies have shown that  a number of  organic mercurials, in-

         cluding phenyl mercuric acetate and methyl  mercuric chloride, are only

         partially oxidized by  this method.

         Potassium persulfate has  been found to give approximately 100% recovery

         when used as the oxidant  with these compounds.   Therefore, a persulfate

         oxidation step following  the addition  of the  permanganate has been

         included to insure that organo-mercury compounds, if present, will be

         oxidized to the mercuric  ion before measurement.

    1.4  The range of the method may be  varied  through instrument and/or recorder

         expansion.   Using a 100 ml sample,  a detection limit of 0.2 yg Hg/1

         can be achieved; concentrations below  this  level  should be reported

         as <0.2 (see Appendix  11.4).
                                       121

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2.  Summary of Method




    2.1  The flameless AA procedure is a physical method based on the absorption




         of radiation at 253.7 nm by mercury vapor.  The mercury is




         reduced to the elemental state and aerated from solution in a closed




         system.  The mercury vapor passes through a cell positioned in the




         light path of an atomic absorption spectrophotometer.  Absorbance




         (peak height) is measured as a function of mercury concentration and




         recorded in the usual manner.




3.  Sample Handling and Preservation




    3.1  Until more conclusive data are obtained, samples should be preserved




         by acidification with nitric acid to a pH of 2 or lower immediately




         at the time of collection   .  If only dissolved mercury is to be




         determined, the sample should be filtered before the acid is added.




         For total mercury the filtration is omitted.




4.  Interference




    4.1  Possible interference from sulfide is eliminated by the addition of




         potassium permanganate.   Concentrations as high as 20 mg/1 of sulfide




         as sodium sulfide do not interfere with the recovery of added in-




         organic mercury from distilled water.




    4.2  Copper has also been reported to interfere; however, copper concen-




         trations as high as 10 mg/1 had no effect on the recovery of mercury




         from spiked samples.




    4.3  Sea waters, brines and industrial effluents high in chlorides require




         additional permanganate (as much as 25 ml).  During the oxidation




         step chlorides are converted to free chlorine which will also absorb




         radiation at 253 nm.  Care must be taken to assure that free chlorine




         is absent before the mercury is reduced and swept into the cell.   This




         may be accomplished by using an excess of hydroxylamine sulfate
                                         122

-------
         reagent (25 ml).   In addition,  the dead air space in  the  BOD bottle

         must be purged before the addition of stannous  sulfate.   Both  in-

         organic and organic mercury spikes have been quantitatively recovered

         from sea water using this technique.

    4.4  Interference from certain volatile organic materials  which will

         absorb at this wavelength is also possible.  A  preliminary run with-

         out reagents should determine if this type of interference is  present

         (see Appendix 11.3).

5.   Apparatus

    5.1  Atomic Absorption Spectrophotometer*:  Any atomic absorption unit

         having an open sample presentation area in which to mount the

         absorption cell is suitable. Instrument settings recommended  by the
                           i ^
         particular manufacturer should  be followed.

    5.2  Mercury Hollow Cathode Lamp: Westinghouse WL - 22847,  argon  filled,

         or equivalent.

    5.3  Recorder:  Any multi-range variable speed recorder that is compatible

         with the UV detection system is suitable.

    5.4  Absorption Cell:   Standard spectrophotometer cells 10 cm long, having

         quartz end windows may be used.  Suitable cells may be constructed from

         plexiglass tubing, 1" O.D. x 4-1/2".   The ends  are ground perpendicular

         to the longitudinal axis and quartz windows (1" diameter x  1/16"

         thickness) are cemented in place.  Gas inlet and outlet ports  (also

         of plexiglass but 1/4" O.D.) are attached approximately 1/2"  from

         each end.  The cell is strapped to a burner for support and  aligned

         in the light beam by use of two 2" by 2" cards.  One  inch diameter
         *Instruments designed specifically for the measurement of mercury using
          the cold vapor technique are commercially available and may be substituted
          for the atomic absorption spectrophotometer.
                                       123

-------
         holes are cut in the middle of each card; the cards are then placed




         over each end of the cell.  The cell is then positioned and adjusted




         vertically and horizontally to give the maximum transmittance.




    5.5  Air Pump:  Any peristaltic pump capable of delivering 1 liter of air




         per minute may be used.  A Masterflex pump with electronic speed




         control has been found to be satisfactory.




    5.6  Flowmeter:  Capable of measuring an air flow of 1 liter per minute.




    5.7  Aeration Tubing:  A straight glass frit having a coarse porosity.




         Tygon tubing is used for passage of the mercury vapor from the  sample




         bottle to the absorption cell and return.




    5.8  Drying Tube:  6" x 3/4" diameter tube containing 20 grams of magnesium




         perchlorate (see Note 1.)  The apparatus is assembled as shown  in  the




         accompanying diagram.




         NOTE 1:   In place of the magnesium perchlorate drying tube, a small




         reading lamp with 60W bulb may be used to prevent condensation  of




         moisture inside the cell.  The lamp is positioned to shine on the




         absorption cell maintaining the air temperature in the cell about




         10°C above ambient.




6.  Reagents




    6.1  Sulfuric Acid,  Cone:   Reagent grade




         6.1.1  Sulfuric acid, 1.0 N:   Dilute 28.0 ml of cone,  sulfuric  acid




                to 1.0 liter.




         6.1.2  Sulfuric acid, 0.5 N:   Dilute 14.0 ml of cone,  sulfuric  acid




                to 1.0 liter.




    6.2  Nitric  Acid,  Cone:   Reagent grade of low mercury content.




         NOTE 2:   If a high  reagent blank is obtained,  it may be necessary  to




         distill  the nitric  acid.
                                   124

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    6.3  Stannous Sulfate:  Add 25 g stannous  sulfate to  250 ml of  0.5 N

         sulfuric acid.  This mixture is  a suspension and should be stirred


         continuously during use.

         NOTE 3:  Stannous chloride and hydroxylamine hydrochloride may also

         be used.


    6.4  Sodium Chloride-Hydroxylamine Sulfate Solution:   Dissolve  12 grams


         of sodium chloride and 12 grams  of hydroxylamine sulfate in distilled

         water and dilute to 100.0 ml.

    6.5  Potassium Permanganate:  5% solution, w/v.   Dissolve  5 grams of

         potassium permanganate in 100 ml of distilled water.

    6.6  Potassium Persulfate:  5% solution, w/v.   Dissolve 5  grams of potassium

         persulfate in 100 ml of distilled water.
                           i •
    6.7  Stock Mercury Solution:  Dissolve 0.1354  grams of mercuric chloride  in

         75 ml of distilled water.  Add 10 ml  of concentrated  nitric acid  and

         adjust the volume to 100.0 ml.   1 ml  = 1  mg  Hg.

    6.8  Working Mercury Solution:  Make  successive dilutions  of the stock


         mercury solution to obtain a working  standard containing 0.1 yg per

         ml.  This working standard and the dilutions of  the stock  mercury

         solution should be prepared fresh daily.   Acidity of  the working


         standard should be maintained at 0.15% nitric acid.   This  acid should

         be added to the flask as  needed  before the addition of the aliquot.


7.  Calibration

    7.1  Transfer 0, 1.0, 2.0 and 5.0 ml  aliquots  of  the  working mercury solution


         containing 0 to 0,.5 yg of mercury to  a series of 300  ml BOD bottles.

         Add enough distilled water to each bottle to make a total  volume  of


         100 ml.  Mix thoroughly and add  5 ml  of concentrated  sulfuric acid


         and 2.5 ml of nitric acid to each bottle.
                                     125

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NOTE 4:  Loss of mercury may occur at elevated temperatures.   How-




ever, with the stated amounts of acid the temperature rise is only




13°C (25 -> 38°C) and no losses of mercury were observed.






Add 1 ml of KMnO. solution to each bottle and allow to stand  at




least 15 minutes.  Add 2 ml of potassium persulfate to each bottle




and allow to stand for at least 30 minutes additional. Add 2 ml  of




sodium chloride - hydroxylamine sulfate solution to reduce the excess




permanganate.  Treating each bottle individually, add 5 ml of the




stannous sulfate solution and immediately attach the bottle to the




aeration apparatus forming a closed system.  At this point the sample




is allowed to stand quietly without manual agitation.  The circulating




pump, which has previously been adjusted to a rate of 1 liter per minute,




is allowed to run continuously.




The absorbance will increase and reach maximum within 30  seconds.  As




soon as the recorder pen levels off, approximately 1 minute,  open the




bypass valve and continue the aeration until the absorbance returns to




its minimum value (see Note 5).  Close the bypass valve,  remove the




stopper and frit from the BOD bottle and continue the aeration.




Proceed with the standards and construct a standard curve by  plotting




peak height versus micrograms of mercury.




NOTE 5:  Because of the toxic nature of mercury vapor precaution  must




be taken to avoid its inhalation.  Therefore, a bypass has been in-




cluded in the system to either vent the mercury vapor into an exhaust




hood or pass the vapor through some absorbing media, such as:




    a)   equal volumes of 0.1 N KMn04 and 10% H2S04




    b)   0.25% iodine in a 3% KI solution
                             126

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          A specially treated charcoal that  will  adsorb  mercury vapor  is



          also available from Barnebey and Cheney,  E.  8th  Ave. and North



          Cassidy St., Columbus,  Ohio  43219,  Cat.  #580-13 or #580-22.



 8.  Procedure



     8.1  Transfer 100 ml or an aliquot diluted to  100 ml  containing not more



          than 0.5 yg of mercury to a 300 ml BOD  bottle.   Add 5 ml of  sulfuric



          acid and 2.5 ml of nitric acid mixing after  each addition  (see



          Note 4 under 7).  Add 1 ml of potassium permanganate solution  (6.5)



          to each sample bottle.   Shake and  add additional portions of potassium



          permanganate solution (6.5) until  the purple color persists  for  at



          least 15 minutes.  Add 2 ml of potassium  persulfate to  each  bottle



          and allow to stand an additional 30 minutes.  Add sodium chloride-



          hydroxylamine sulfate in 2 ml increments  to  reduce the  excess per-
                            i '


          manganate.  Add 5 ml of stannous sulfate  and immediately attach  the



          bottle to the aeration apparatus.   Continue  as described under



          Calibration.



 9.  Calculation



     9.1  Determine the peak height of the unknown  from  the chart and  read the



          mercury value from the standard curve.



     9.2  Calculate the mercury concentration in  the sample by the formula:



                  ygHg/1 = yg Hg    x            1000	

                         in aliquot       volume of aliquot



     9.3  Report mercury concentrations as follows:



          Below 0.2 yg/1, <0.2; between 1 and 10  yg/1, one decimal;  above  10 yg/1,



          whole numbers.



10.  Precision and Accuracy



    10.1  Using an Ohio River composite sample with a background  mercury con-



          centration of 0.35 yg/1, spiked with concentrations  of  1,  3  and  4
                                         127

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          Hg/1, the standard deviations were ±0.14,  ±0.10 and ±0.08,



          respectively.  Standard deviation at the 0.35 level was  ±0.16.



          Percent recoveries at the three levels were 89, 87, and  87%,



          respectively.



11.   Appendix



    11.1  For the measurement of mercury in fish tissue,  the procedure of


                                       (21
          Uthe, Armstrong,  and Stainton^ '  was found to be satisfactory.  The



          digestion step is carried out directly in  the BOD bottle.  After the



          potassium permanganate oxidation  step, the volume of the digest is



          adjusted to approximately 100 ml  with distilled water and the same



          procedure followed as used for water samples.



    11.2  For the analysis  of mud and sediment samples  a vigorous  digestion



          using a water cooled reflux condenser approximately 2 feet in length



          is used.   A 5.0 gram sample is placed in a 250 ml round  bottom flask



          and fitted to the condenser.   Add 10 ml  of redistilled nitric acid



          and apply heat using a heating mantle until the acid refluxes gently.



          Continue heating  for 2 hours  and  cool the  mixture.   Wash down the



          column with about 60 - 70 ml  of distilled  water.   Filter the sample



          through Whatman No.  42 paper  to remove the insoluble material and make



          the filtrate up to 100 ml with distilled water.   Take a  suitable



          aliquot for analysis and proceed  as  described under the  procedure for



          water samples.  If an aliquot of  less than 25 ml  is taken for analysis,



          additional nitric acid is added to make  a  total  of 2.5 ml.



    11.3  While the possibility of absorption  from certain  organic substances



          actually  being present in the sample  does  exist,  the AQC Laboratory



          has not encountered  such samples.  This  is  mentioned only to caution



          the analyst of the possibility.   A simple  correction that may be used



          is  as follows:




                                          128

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           If an interference has been found to be present (4.4), the

           organic vapor may be removed by bubbling air through the sample

           while under oxidizing conditions.  Before the hydroxylamine and

           stannous sulfate reagents are added, the sample bottle should be

           attached to the aeration apparatus and any deviation from a

           comparably-treated blank noted.  The reductants are then added

           and a second reading is made.  The true mercury value is then

           obtained by subtracting the observed deviation from the blank

           from this second reading.

     11.4  If additional sensitivity is required, a 200 ml sample with recorder

           expansion may be used provided the instrument does not produce

           undue noise.  Using a Coleman MAS-50 with a drying tube of magnesium
                           |
           perchlorate and a variable recorder, 2 mv was set to read full

           scale.  With these conditions, and distilled water solutions of

           mercuric chloride at concentrations of 0.15, 0.10, 0.05 and

           0.025 yg/1 the standard deviations were ±0.027, ±0.006, ±0.01 and ±0.004.

           Percent recoveries at these levels were 107, 83, 84 and 96%, respectively.

References

1.  Wallace, R.A., Fulkerson, W., Shults, W.D., and Lyon, W.S., "Mercury
    in the Environment - The Human Element", Oak Ridge National Laboratory,
    ORNL - NSF - EP - 1.  January, 1971, Page 31.

2.  Uthe, J.F. Armstrong, F.A.J. and Stainton, M.P., "Mercury Determination
    in Fish Samples by Wet Digestion and Flameless Atomic Absorption Spectro-
    photometry", Jour. Fisheries Research Board of Canada, 27, 805 (1970).

3.  Hatch, W.R., and Ott, W.L., "Determination of Sub-Microgram Quantities
    of Mercury by Atomic Absorption Spectrophotometry", Anal. Chem. 40,
    2085 (1968).

4.  Brandenberger, H. and Bader, H., "The Determination of Nanogram Levels of
    Mercury in Solution by a Flameless Atomic Absorption Technique", Atomic
    Absorption Newsletter, 6_, 101 (1967) .

5.  Brandenberger, H. and Bader, H., "The Determination of Mercury by Flameless
    Atomic Absorption II.  A Static Vapor Method", Atomic Absorption Newsletter,
    7, 53 (1968).
                                    129

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     SCHEMATIC ARRANGEMENT OF EQUIPMENT FOR MERCURY MEASUREMENT

                    BY COLD VAPOR AA TECHNIQUE
A - Sample container, approximately 300 ml (BOD bottle)
B - Drying tube, 150-200 ml capacity with MgciO,
C - Rotameter, = 1 liter of air/minute
D - Cell, with quartz windows
E - Air pump, = 1 liter of air/minute
F - Glass tube with fritted end
G - Hollow cathode Hg Lamp
H - AA Detector
J - Gas washing bottle containing 0.25% iodine in a 3% potassium
    iodide solution
K - Recorder, any compatible model
                                 130

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                      METHYLENE BLUE ACTIVE SUBSTANCES (MBAS)
                               (Methylene Blue Method)


                                                            STORET NO.  38260


1.  Scope and Application

    1.1  This method is applicable to the measurement of methylene blue
         active substances (MBAS) in drinking waters, surface  waters,
         domestic and industrial wastes.   It is not applicable to measure-
         ment of surfactant-type materials in saline waters.
    1.2  It is not possible to differentiate between linear alkyl
         sulfonate (LAS) and alkyl benzene sulfonate (ABS)  or  other isomers
         of this type compounds.   However, LAS has essentially replaced
         ABS on the surfactant market so  that measurable surfactant materials
                           i
                           i
         will probably be LAS type materials.
    1.3  The method is applicable over the range of 0.025 to 100  mg/1  LAS.

2.  Summary of Method
    2.1  The dye, methylene blue, in aqueous solution reacts with anionic-

         type surface active materials to form a blue colored  salt. The
         salt is extractable with chloroform and the intensity of color

         produced is proportional to the  concentration of MBAS.

3.  Comments
    3.1  Materials other than man-made surface active agents which react
         with methylene blue are organically bound sulfates, sulfonates,
         carboxylates,   phosphates, phenols, cyanates, thiocyanates and

         some inorganic ions such as nitrates and chlorides.  However,  the
                                     131

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                                                              (MB AS)
         occurrence of these materials at interference levels is




         relatively rare and with the exception of chlorides may




         generally be disregarded.




    3.2  Chlorides at concentration of about 1000 mg/1 show a positive




         interference but the degree of interference has not been




         quantified.  For this reason the method is not applicable to




         brine samples.




    3.3  Naturally occurring organic materials that react with methylene




         blue are relatively insignificant.   Except under highly unusual




         circumstances, measurements of MBAS in finished waters,  surface




         waters and domestic sewages may be  assumed to be accurate




         measurements of man-made surface active agents.




4.  Precision and Accuracy




    4.1  On a sample of filtered river water,  spiked with 2.94 mg LAS/liter,




         110 analysts obtained a mean of 2.98  mg liter with a standard




         deviation of 0.272.




    4.2  On a sample of tap  water spiked with  0.48 mg LAS/liter,  110




         analysts obtained a mean of 0.49 mg/1 with a standard deviation




         of 0.048.




    4.3  On a sample of distilled water spiked with 0.27  mg LAS/liter,




         110 analysts  obtained a mean of 0.24  mg/1 with a standard




         deviation of 0.036.




    4.4.  Analytical  Reference Service,  Water Surfactant No.  3,  Study




         No.  32,  (1968).
                                     132

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                                                             (MBAS)
5.  References

         The procedure to be used for this determination is found in:

             Standard Methods for the Examination of Water and Waste-
             waters, 13th Edition, pp 339-342, Method No. 159A (1971).

             American Society for Testing and Materials, Part 23,
             Method D2330-68, pp 721-727, (1970).
                                    133

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                               NITROGEN-AMMONIA
                            (Distillation Procedure)
                                                             STORE! NO.  00610
1.  Scope and Application

    1.1  This distillation method covers the determination of ammonia-nitrogen,

         exclusive of total Kjeldahl nitrogen, in surface waters, domestic and

         industrial wastes, and saline waters.  It is the method of choice where

         economics and sample load do not warrant the use of automated equipment.

    1.2  The method covers the range from about 0.05 to 1.0 mg/1 NH,/N per liter

         for the colorimetric procedures and from 1.0 to 25 mg/1 for the

         titrimetric procedure.

    1.3  This method is described for macro glassware; however, micro distillation

         equipment may also be used.

2.  Summary of Method

    2.1  The sample is buffered at a pH of 9.5 with a borate buffer in order

         to decrease hydrolysis of cyanates and organic nitrogen compounds, and

         is then distilled into a solution of boric acid.  The ammonia in the

         distillate can be determined either colorimetrically by nesslerization

         or titrimetrically with standard sulfuric acid with the use of a mixed

         indicator, the choice between these two procedures depending on the con-

         centration of the ammonia.

3.  Sample Handling and Preservation

    3.1  Until more conclusive data is obtained samples may be preserved by

         addition of 40 mg HgCl- per liter and stored at 4°C.  If only ammonia

         is to be determined on the sample it may be preserved with 1.0 ml  of

         concentrated H^SO. per liter and stored at 4°C.
                                        134

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                                                        (Nitrogen-Ammonia)




 4.  Interferences



    4.1  A number of aromatic and aliphatic amines, as well as other compounds,




         both organic and inorganic, will cause turbidity upon the addition of




         Nessler reagent, so direct nesslerization (i.e., without distillation),




         has been discarded as an official method.




    4,2, Cyanate, which may be encountered in certain industrial effluents,




       ,  =will hydrolyze to some extent even at the pH of 9.5 at which distillation




         is carried out.  Volatile alkaline compounds such as hydrazine will




         influence the titrimetric results.  Some volatile compounds, such as




         .certain ketones, aldehydes, and alcohols, may cause an off-color upon




         nesslerization in the distillation method.  Some of these, such as




         formaldehyde, may be eliminated by boiling off at a low pH (approximately




         2 to 3) prior to distillation and nesslerization.




    4.3  Residual chlorine must also be removed by pre-treatment of the sample




         with sodium thiosulfate before distillation.




    4.4  If the sample has been preserved with a mercury salt, the mercury ion




         must be complexed with sodium thiosulfate prior to distillation.




5.  Apparatus




    5.1  An all-glass distilling apparatus with an 800-1000 ml flask.




    5.2  Spectrophotometer or filter photometer for use at 425 nm and providing  ,




         a light path of 1 cm or more.




    5.3  Nessler tubes:  Matched Nessler tubes (APHA Standard) about 300 mm long,




         17 mm inside diameter, and marked at 225 mm ±1.5 mm inside measurement




         from bottom.




    5.4  Erlenmeyer flasks:  The distillate is collected in 500 ml glass-




         stoppered flasks.  These flasks should be marked at the 350 and the




         500 ml volumes.  With such marking, it is not necessary to transfer




         the distillate to volumetric flasks.
                                       135

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                                                       (Nitrogen-Ammonia)





6.   Reagents




    6.1  Distilled water should be free of ammonia.   Such water is  best




         prepared by passage through an ion exchange column containing a




         strongly acidic cation exchange resin mixed with a strongly basic




         anion exchange resin.   Regeneration of the  column should be carried




         out according to the manufacturer's instructions.




    6.2  Ammonium chloride,  stock solution,  (1.0 ml  = 1.00 mg NH,-N).  Dissolve




         3.819 g NH.C1 in water and bring to volume  in a  1 liter volumetric




         flask,




    6.3  Ammonium chloride,  standard solution,  (1.0  ml =  0.01 mg).  Dilute




         10  ml of this stock solution to 1  liter in  a volumetric flask for use




         as  the standard ammonium chloride  solution.




    6.4  Boric acid  solution (20 g/1)  -  Dissolve 20  g H_BO_ in  water and dilute




         to  1  liter.




    6.5   Mixed indicator - Mix  2 volumes  of  0.2  percent methyl  red  in 95 percent




         ethyl  alcohol with  1 volume of  0.2  percent  methylene blue  in 95 percent




         ethyl  alcohol.   This solution should be prepared  fresh  every 30 days.




         Note  1  -  Specially  denatured ethyl  alcohol  conforming  to Formula 3A




         or  30  of  the  U.S. Bureau of Internal Revenue may  be substituted for




         95  percent  ethanol.



    6.6   Nessler reagent  - Dissolve  100 g of mercuric  iodide and 70 g of




        potassium iodide in a small  amount  of water.  Add  this mixture slowly,




        with  stirring, to a cooled  solution of  160 g  of NaOH in 500 ml of




        water.  Dilute the mixture  to 1  liter.  If this reagent is stored in




        a Pyrex bottle out of direct sunlight,  it will remain stable for a




        period of up to 1 year.
                                      136

-------
                                               (Ni trogen-Ammoni a)




      Note  2 - This reagent should give the characteristic color with



      ammonia within 10 minutes after addition, and should not produce a



      precipitate with small amounts of ammonia (0.04 mg in a 50 ml



      volume).



 6.7  Borate buffer - Add 88 ml of 0.1 N NaOH solution to 500 ml of



      0.025 M sodium tetraborate solution (5.0 g Na^B.O- per liter) and



      dilute to 1 liter.



 6.8  Sulfuric acid, standard solution, (0.02 N,  1 ml = 0.28 mg NH_-N).
                                                                  O


      Prepare a stock solution of approximately 0.1 N acid by diluting



      3 ml of concentrated H-SO. (sp. gr.  1.84) to 1 liter with G0_-free



      distilled water.  Dilute 200 ml of this solution to 1 liter with



      (XL-free distilled Water.  Standardize the approximately 0.02 N



      acid so prepared against 0.0200 N Na?CO, solution.  This last solution



      is prepared by dissolving 1.060 g anhydrous Na-CO,, oven-dried at



      140°C, and diluting to 1 liter with (XL-free distilled water.



      Note 3 - An alternate and perhaps preferable method is to standardize



      the approximately 0.1 N H?SO. solution against a 0.100 N Na_CO_



      solution.   By proper dilution the 0.0200 N acid can then be prepared.



 6.9  Sodium hydroxide, 1 N.   Dissolve 40  g NaOH in ammonia-free water



      and dilute to 1 liter.



6.10  Dechlorinating reagents.   A number of dechlorinating reagents may



      be used to remove residual chlorine  prior to distillation.  These



      include:



      (a)  Sodium thiosulfate (1/70 N):  Dissolve 3.5 g Na2S203 in ammonia-



           free  water and dilute to 1 liter.   One ml of this solution will



           remove 1 mg/1 of residual chlorine in 500 ml of sample.
                                  137

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                                                   (Nitrogen-Ammonia)





         (b)  Sodium arsenite (1/70 N):   Dissolve 1.0 g NaAsCL  in ammonia-




              free water and dilute to  1 liter.




7.   Procedure




    7.1  Preparation of equipment - Add  500 ml of ammonia-free  water to an




         800 ml Kjeldahl flask.   The addition of boiling chips  which have been




         previously treated with dilute  NaOH will prevent bumping.  Steam out




         the distillation apparatus until  the distillate shows  no trace of




         ammonia with Nessler reagent.




    7.2  Sample preparation - To 400 ml  of sample add 1  N NaOH  until the pH




         is  9.5, checking the pH during  addition with a  pH meter  or by use of




         a short range pH paper.




    7.3  Distillation - Transfer the sample,  the pH  of which has  been adjusted




         to  9.5,  to an 800 ml Kjeldahl flask  and add 25  ml of the borate buffer.




         Distill 300 ml at the rate of 6-10 ml/min.  into 50 ml  of 2% boric acid




         contained  in a 500 ml glass stoppered Erlenmeyer flask.  Dilute the




         distillate to 500 ml in the flask and nesslerize an aliquot to obtain




         an  approximate value of the ammonia-nitrogen concentration.  For con-




         centrations above 1.0 mg/1  the  ammonia  should be determined titri-




         metrically.   For concentrations below this  value it is determined




         colorimetrically.




    7.4   Determination of ammonia in distillate  -  Determine the ammonia content




         of  the  distillate either titrimetrically  or colorimetrically as de-




         scribed below.   (See 7.4.1  and  7.4.2).




         7.4.1   Titrimetric  determination.  Add  3  drops  of the mixed indicator




             to the  distillate and  titrate the  ammonia with the  0.02 N H2SO ,




             matching  the  end point  against  a blank  containing the same volume
                                     138

-------
                                                    (Nitrogen-Ammonia)


            uf ammonia-free water and H BO  solution.
                                       3  3
     7.4.2  Colorimetric determination.   Prepare a series  of Nessler

            tube standards as follows:

               ml of Standard        Cone., When Diluted to
            1.0 ml = 0.01 mg NH3N    50.0 ml,  mg NHjN/liter

                   0.0 (Blank)               0.0
                   0.2                       0.04
                   0.5                       0.10
                   1.0                       0.20
                   1.5                       0.30
                   2.0                       0.40
                   3.0                       0.60
                   4.0                       0.80

            Dilute each tube to 50 ml with ammonia-free water,  add

            1.0 ml of Nessler reagent and mix.  After 20 minutes read
                        I
            the optical densities at 425 nm against the blank.   From

            the values obtained plot optical density (absorbance) vs.

            concentration for the standard curve.

     7.4.3  It is not imperative that all standards be distilled in the

            same manner as the samples.   It is recommended that at least

            two standards (a high and low)  be distilled and compared to

            similar values on the curve to insure that the distillation

            technique is reliable.  If distilled standards do not agree

            with undistilled standards the operator should find the cause

            of the apparent error before proceeding.

7.5  Determine the ammonia in the distillate by nesslerizing 50 ml or an

     aliquot diluted to 50 ml and reading the optical density at 425 nm

     as described above for the standards.   Ammonia-nitrogen content is

     read from the standard curve.
                                  139

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                                                  (Nitrogen- Ammonia)
8.   Calculations



    8.1  Titrimetric



         mg/l   NH.N  =
                 o



         in which :
9.
                        A X
                                100°
     A = ml 0.02 N H2S04 used
         S = ml sample



    8.2  Spectrophotometric



           /i MU M     A x
         ng/1 NH3N  =  -




         in which:
                    078-s
     A = NH_N read from standard curve
           O


     S = volume of distillate nesslerized



Precision and Accuracy



9.1  Twenty- four analysts in sixteen laboratories analyzed natural water



     samples containing exact increments of an ammonium salt,  with the



     following results:
Increment as
Nitrogen, Ammonia
mg N/ liter
.21
.26
1.71
1.92
Precision as
Standard Deviation
mg N/liter
0.122
0.070
0.244
0.279
Accuracy
Bias,
% mg
- 5.54
-18.12
+ 0.46
- 2.01
as
Bias,
N/ Liter
-.01
-.05
+ .01
-.04
(FWPCA Method Study 2, Nutrient Analyses)
                                  140

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                               NITROGEN, AMMONIA


                              (Automated Method)

                                                             STORE! NO. 00610


1.  Scope and Application



    1.1  This method pertains to the determination of ammonia present in



         surface and saline waters.  Depending upon the selection of the size



         of flow cell, and extent of dilution, concentrations in the range



         between .01 and 2LO mg/liter N present as NH  may be determined.
                                                    O


2.  Summary of Method



    2.1  The intensity of the indophenol blue color   , formed by the reaction



         of ammonia with alkaline phenol hypochlorite, is measured.   Sodium



         nitroprusside is used to intensify the blue color.



3.  Sample Handling and Preservation



    3.1  Preservation by addition of 40 mg HgCl9 per liter and refrigeration

                            I

         at 4°C.  Note HgCl- interference under 4.3.



4.  Interferences



    4.1  In sea water, calcium and magnesium ions are present in concentrations



         sufficient to cause precipitation problems during the analysis.  This



         problem is eliminated by using 5% EDTA.



    4.2  Any marked variation in acidity or alkalinity among samples should



         be eliminated, since the intensity of the color used to quantify  the



         concentration is pH dependent.  Likewise, the pH of the wash water and



         the standard ammonia solutions should approximate that of the samples.



         For example, if the samples have been preserved with 1 ml concentrated



         H2SO./liter, the wash water and standards should also contain 1 ml cone.



         H2S04/1.



    4.3  Mercury chloride, used as a preservative, gives a negative interference



         by complexing with the ammonia.  This is overcome by adding a comparable
                                       141

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                                                        (Nitrogen,  Ammonia)





         amount of HgCl2 to the ammonia standards used for the preparation




         of the standard curve.




5.  Apparatus




    5.1  Technicon AutoAnalyzer Unit consisting of:




         5.1.1  Sampler.




         5.1.2  Manifold.




         5.1.3  Proportioning pump.




         5.1.4  Heating bath with double delay coil.




         5.1.5  Colorimeter equipped with 15 mm tubular flow cell and 630




                or 650 nm filters.




         5.1.6  Recorder.




6.  Reagents




    6.1  Distilled Water:  Special precaution must be  taken to insure that




         distilled water is free of  ammonia.  Such water is prepared  by passage




         of distilled water through  an ion exchange column comprised  of a




         mixture of both strongly acidic cation and strongly basic  anion




         exchange resins.  Since organic contamination may interfere  with  this




         analysis,  use of the  resin  Dowex XE-75 or equivalent  which also tends




         to remove  organic impurities is advised.   The regeneration of the ion




         exchange column should be carried out according to the instruction




         of the  manufacturer.




    6.2  Segmenting Fluid:   Air scrubbed with 5N H-SO..   Ammonia free  concen-




         trated  sulfuric acid  and ammonia free distilled water used in the




         acid  preparation.




    6.3  Sodium  Phenolate:   Using a  1 liter Erlenmeyer flask,  dissolve 83 g




         phenol  in  500 ml distilled  water.   In small increments, cautiously




         add with agitation, 32 g of NaOH.   Periodically,  cool flask  under




         water faucet.   When cool, dilute  to 1  liter.




                                     142

-------
                                               (Nitrogen, Ammonia)




   6.4  Sodium Hypochlorite Solution ("Clorox"):   Dilute 250 ml of 5% "Clorox"



        to 500 ml with distilled water.  Available chlorine level should



        approximate 2 to 3%.  Since "Clorox" is a proprietary product and its



        formulation is subject to change, the analyst must remain alert to



        detecting any variation in this product significant to its  use in this



        procedure.



   6.5  EDTA (5%):  Dissolve 50 g of EDTA (disodium salt) and approximately



        six pellets of NaOH in 1 liter of ammonia-free water.



        Note:  On salt water samples where EDTA solution does not prevent



        precipitation of cations, sodium potassium tartrate solution may be



        used to advantage.  It is prepared as follows:

                            I

        6.5.1  Sodium Potassium Tartrate Solution:  10% NaKC.H.O,.   To 900 ml
                            i                                446


               distilled water add 100 g sodium potassium tartrate.  Add 2



               pellets of NaOH and a few boiling chips, boil gently for 45



               minutes.  Cover, cool, and dilute to 1 liter.  Adjust pH to



               5.2 ± .05 with H SO .  After allowing to settle overnight in a
                               £f  T1


               cool place, filter to remove precipitate.  Then add 1/2 ml


                      *

               Brij-35  solution and store in stoppered bottle.



   6.6  Sodium Nitroprusside (0.05%):  Dissolve 0.5 g of sodium nitroprusside



        in 1 liter of ammonia-free water.



   6.7  Stock Solution:  Dissolve 3.819 g of anhydrous ammonium chloride,



        NHLC1, dried at 105°C, in ammonia-free water, and dilute to 1 liter.



        1 ml = 1.0 mg NH_N.
           - -            O
Available from Technicon Corporation.
                                         143

-------
                                                    (Nitrogen, Ammonia)


 6.8  Standard Solution A:  Dilute 10.0 ml of stock solution to 1 liter

      with ammonia-free water.  1 ml = .01 mg NH_N.

 6.9  Standard Solution B:  Dilute 10.0 ml of standard solution A to

      100 ml with ammonia-free water.  1 ml = .001 mg NH_N.

6.10  Using standard solutions A and B, prepare the following standards

      in 100 ml volumetric flasks (prepare fresh daily):

             NH_N,  mg/1         ml Standard Solution/100 ml


                                         Solution B

                0.01                        1.0
                0.02                        2.0
                0.05                        5.0
                0.10                       10.0

                                         Solution A

                0.20                        2.0
                0.50                        5.0
                0.80                        8.0
                1.00                       10.0
                1.50                       15.0
                2.00                       20.0

      Note:   When  saline water samples  are analyzed,  Substitute Ocean Water

      (SOW)  should be  used for preparing  the above standards used for the

      calibration  curve; otherwise,  distilled water is used.   If SOW is

      used,  determine  its  blank background.

                           Substitute Ocean Water (SOW)

NaCl
MgCl_
Na~SO .
CaCl2
KC1
,./!.
24.53
5.20
4.09
1.16
0.70

NaHC03
KBr
H3B°3
SrCl2
NaF
g./l.
0.20
0.10
0.03
.03
.003
                                   144

-------
                                                        (Nitrogen, Ammonia)





7.  Procedure



    7.1  For a working range of 0.01 to 2.00 NH N mg/1, set up the manifold



         as shown in Figure 1.  Higher concentrations may be accommodated by



         decreasing sample size and/or through dilution of sample.



    7.2  Allow both colorimeter (with 650 nm filters and 15 mm flow cell) and



         recorder to warm up for 30 minutes.  Run a baseline with all reagents,



         feeding ammonia-free water through sample line.  Adjust dark current and



         operative opening on colorimeter to obtain stable baseline.



    7.3  Place a distilled water wash tube in alternate openings in sampler and



         set sample timing at 2.0 minutes.  All tubes must be rinsed with
                            |
                            j ;

         ammonia-free water before use.


                            i

    7.4  Arrange ammonia standards in sampler in order of decreasing concen-



         tration of nitrogen.  Complete loading of sampler tray with unknown



         samples.



    7.5  Switch sample line from distilled water to sampler and begin analysis.



8.  Calculations



    8.1  Prepare appropriate standard curve derived from processing ammonia



         standards through manifold.  Compute concentration of samples by



         comparing sample peak heights with standard curve.



9.  Precision and Accuracy



    9.1  In a single laboratory (AQC), using surface water samples at con-



         centrations of 1.41, 0.77, 0.59, and 0.43 mg NHj-N/1, the standard



         deviation was ±0.005.



    9.2  In a single laboratory (AQC), using surface water samples at con-



         centrations of 0.16 and 1.44 mg NH_-N/1, recoveries were 107% and




         99%, respectively.
                                     145

-------
                                                  (Nitrogen, Ammonia)







                             References






1.  D. Van Slyke and A. Killer, "Determination of Ammonia in Blood,"




    J. Biol. Chem. 102, 499 (1933).




2.  B. O'Connor, R. Dobbs, B. Villiers, and R. Dean, "Laboratory Distillation




    of Municipal Waste Effluents," JWPCF 39, R 25 (1967).




3.  J. E. O'Brien and J. Fiore, "Ammonia Determination by Automatic Analysis,"




    Wastes Engineering 55, 552 (1962).




4.  A wetting agent recommended and supplied by the Technicon Corporation




    for use in AutoAnalyzers.




5.  ASTM "Manual on Industrial Water and Industrial Waste Water," 2nd Ed., 1966




    printing, 418.
                                       146

-------

i

SMALL MIXING COIL (Sm)
E MIXING COIL (Lmj '
Qpoooooo
4

Lm
oooooobo
0000
Sm
1 1
7o/-Vil HF1TINC Ri

0000
P

I







r
TH
~~*~
M

PR
P B

G G
G G
w w
Wiif
ff
R R
P P
ml/min
,2.90 SAMPLE
SAMPLER ife O g
^0.80 5% EDTA Oi?jL
.2.00 FILTERED SAMPLE T3 {
^2.00 AIR* CONTINUOt
40.60 Na PHENOLATE
J.60 NaOCI
0.80 NITROPRUSSIDE
.2.50 WASTE
OPORTIONING PUMP
O
 Sm
     COLORIMETER
15mm TUBULAR f/c
650  nm FILTERS
                                      IX
                                              RECORDER
                                                             SAMPLING TIME',2.0  MINUTES
                                                             WASH  TUBES: ONE

                                                        'SCRUBBED THROUGH 5N H SO
                                                                           2  4
                    FIGURE  1.  AMMONIA  MANIFOLD

-------
                            NITROGEN KJELDAHL, TOTAL
                                                             STORET NO.   00625
1.  Scope and Application

    1.1  This method covers the determination of total Kjeldahl nitrogen in

         surface waters, domestic and industrial wastes, and saline waters.

         The procedure converts nitrogen components of biological origin such

         as amino acids, proteins and peptides to ammonia, but may not convert

         the nitrogenous compounds of some industrial wastes such as amines,

         nitro compounds, hydrazones, oximes, semi-carbazones and some re-

         fractory tertiary amines.

    1.2  Two alternatives are listed for the determination of ammonia after

         distillation; the titrimetric method which is applicable to concen-

         trations above 1 mg N/liter and the Nesslerization method which is
                           1
         applicable to concentrations below 1 mg N/liter.

    1.3  This method is described for a macro system of glassware; however, micro

         glassware which does not change the chemistry of the procedure is

         equally applicable.

2.  Definitions

    2.1  Total Kjeldahl is defined as the sum of free ammonia and organic

         nitrogen compounds which are converted to ammonium sulfate (NH.)2SO.,

         under the conditions of digestion described below.

    2.2  Organic Kjeldahl Nitrogen is defined as the difference obtained by

         subtracting the free ammonia value (cf Nitrogen, Ammonia, this Manual)

         from the total Kjeldahl nitrogen value.  This may be determined

         directly by removal of ammonia before digestion.

3.  Summary of Method

    3.1  The sample is heated in the presence of concentrated sulfuric acid,

         K9SO. and HgSO. and evaporated until S0_ fumes are obtained and the
          ^  ^T         *T                        O
                                       149

-------
                                                      (Nitrogen Kjeldahl, Total)





          solution becomes  colorless or pale yellow.   The residue is cooled,



          diluted, and  is treated  and made alkaline with a hydroxide-thio-



          sulfate solution.  The ammonia is distilled  and determined after



          distillation  either by nesslerization or titrimetrically.



4.  Sample Handling and Preservation



    4.1   Samples may be preserved by addition of 40 mg HgCl_/l and stored at



          4°C.  Even when so preserved, conversion of  organic nitrogen to ammonia



          may occur.  Preserved samples should be analyzed as soon as possible.



5.  Apparatus



    5.1   Digestion apparatus.  A  Kjeldahl digestion apparatus with 800 ml flasks



          and suction takeoff to remove SO- fumes and water is required.  Use



          of micro-Kjeldahl equipment is also permissible.



    5.2   Distillation  apparatus.  The Kjeldahl flask  is connected to a condenser



          and an adaptor so that the distillate can be collected for nesslerization



          or in indicating H_BO, solution for titration.



    5.3   Spectrophotometer for use at 400 to 425 nm with a light path of 1 cm or



          longer.



    5.4  Nessler tubes, tall form 50 ml.



6.  Reagents



    6.1  Distilled waters should be free of ammonia.   Such water is best prepared



         by the passage of distilled water through an ion exchange column con-



         taining a strongly acidic cation exchange resin mixed with a strongly



         basic anion exchange resin.  Regeneration of the column should be



         carried out according to the manufacturer's  instructions.



    6.2  Mercuric sulfate solution.   Dissolve 8 g red, mercuric oxide (HgO)  in




         50 ml of 1:5  sulfuric acid and dilute to 100 ml with distilled water.
                                       150

-------
                                                (Nitrogen Kjeldahl, Total)




 6.3  Sulfuric acid-mercuric sulfate-potassium sulfate solution.   Dissolve



      267 g K2S04 in 1300 ml water and add 400 ml concentrated H2SO..   Add



      50 ml mercuric sulfate solution and dilute to 2 liters.



 6.4  Sodium hydroxide-sodium thiosulfate solution.  Dissolve  500 g NaOH and



      25 g Na2S203.5H20 in water and dilute to 1 liter.



 6.5  Phenolphthalein indicator solution.  Dissolve 5 g phenolphthalein in



      500 ml 95% ethyl alcohol or isopropanol and add 500 ml water.  Add 0.02



      NaOH dropwise until a faint, pink color appears.



 6.6  Mixed indicator.  Mix 2 volumes of 0.2% methyl red in 95% ethanol with



      1 volume of 0.2% methylene blue in ethanol.   Prepare fresh every 30



      days.



 6.7  Boric acid solution.  Dissolve 20 g boric acid, H B0_, in water and dilute
                                                       O  «J


      to 1 liter with water.



 6.8  Sulfuric acid titrant, 0.020 N.  (1.00 ml = 0.28 mg N).



 6.9  Ammonium chloride, stock solution, (1.0 ml = 1.0 mg NH--N).  Dissolve



      3.819 g NH4C1  in water and make up to 1.0 liter with ammonia free water.



6.10  Ammonium chloride, standard solution, (1.0 ml = 0.01 mg  NH_-N).   Dilute



      10.0 ml of the stock solution to 1.0 liter.



6.11  Nessler reagent - Dissolve 100 g of mercuric iodide and  70 g of potassium



      iodide in a small volume of water.  Add this mixture slowly, with



      stirring, to a cooled solution of 160 g of NaOH in 500 ml of water.



      Dilute the mixture to 1 liter.  The solution is stable for at least one



      year if stored in a pyrex bottle out of direct sunlight.



      Note - Reagents 6.8, 6.9, 6.10, and 6.11 are identical to reagents 6.8, 6.2,


      6.3, and 6.6 described under Nitrogen, Ammonia.
                                    151

-------
                                                     (Nitrogen  Kjeldahl,  Total)





7.   Procedure



    7.1  The distillation apparatus should be pre-steamed before  use by



         distilling a 1:1 mixture of ammonia-free  water and  sodium hydroxide-



         sodium thiosulfate solution until the distillate is ammonia free.



         This operation should be repeated each time the apparatus is  out of



         service long enough to accumulate ammonia (usually  4 hours or more).



    7.2  Place a measured sample or the residue from the distillation  in  the



         ammonia determination (for Organic Kjeldahl only) into an 800-ml



         Kjeldahl flask.   The sample size  can be determined  from  the following



         table:
Kjeldahl Nitrogen
in Sample, mg/1
0 -
5 -
10 -
20 -
50 -
5
10
20
50
100
Sample Size
ml
500
250
100
50.0
25.0
         Dilute  the  sample,  if required,  to  500 ml,  and  add  100 ml sulfuric



         acid  -  mercuric sulfate  - potassium sulfate solution  (Note 2), and



         evaporate the mixture in the  Kjeldahl apparatus until S0» fumes are



         given off and the solution  turns  colorless  or pale  yellow.  Cool the



         residue and add 300 ml water.



         Note  2  - Alternately  digest the  sample with 1 Kel-Pac (Olin-Matheson)



         and 20  ml cone. H-SO..   Cut the  end from  the package and empty the



         contents into the digestion flask;  discard  the  container.



   7.3   Make the digestate  alkaline by careful addition of  the sodium hydroxide-



         thiosulfate solution  without  mixing ( 20  ml  of  36 N H_S04 requires



         approximately 60 ml of 12.5 N NaOH-Na2S20_  to neutralize).
                                       152

-------
                                                 (Nitrogen Kjedahl,  Total)




     Note - Slow addition of the heavy caustic solution down  the  tilted



     neck of the digestion flask will cause the heavier solution  to  underlay



     the aqueous sulfuric acid solution without loss  of free  ammonia.  Do



     not mix until the digestion flask has been connected to  the  distillation



     apparatus.



7.4  Connect the Kjeldahl flask to the condenser with the tip of  condenser



     (or an extension of the condenser tip) below the level of the boric



     acid solution in the receiving flask.



7.5  Distill 300 ml at the rate of 6-10 ml/min., into 50 ml of 2% boric acid



     contained in a 500-ml glass stoppered Erlenmeyer flask.

                      i

     7.5.1  If it is anticipated that the ammonia measurement will be  by



            nesslerization, 50 ml of boric acid is preferred.  If, however,



            sufficient ammonia is present to permit titration of  a larger



            volume of boric acid, either 100 or 200 ml, may be used.



7.6  Dilute the distillate to 500 ml in the flask and nesslerize  an  aliquot



     to obtain an approximate value of the ammonia-nitrogen concentration.



     For concentrations above 1.0 mg/1 the ammonia should be  determined



     titrimetrically.  For concentrations below this value it is  determined



     colorimetrically.



7.7  Determination of ammonia in distillate - Determine the ammonia  content



     of the distillate either titrimetrically or colorimetrically as



     described below.



     7.7.1  Titrimetric determination.  Add 3 drops of the mixed  indicator



            to the distillate and titrate the ammonia with the 0.02  N



            H-SO., matching the endpoint against a blank containing the



            same volume of ammonia-free water and H,BO  solution.
                                                   o  o
                                    153

-------
                                                    (Nitrogen Kjeldahl, Total)


          7.7.2  Colorimetric determination.  Prepare a series of Nessler tube

                standards as follows:

                    ml as Standard          Cone., When Diluted to
                1.0 ml = 0.01 mg NH3N      50.0 ml, mg NH3N/liter


                       0.0  (Blank)                  0.0
                       0.2                          0.04
                       0.5                          0.10
                       1.0                          0.20
                       1.5                          0.30
                       2.0                          0.40
                       3.0                          0.60
                       4.0                          0.80

                Dilute each tube to 50 ml with ammonia-free water, add 1.0 ml

                of Nessler reagent and mix.  After 20 minutes read the optical

                densities at 425 ran against the blank.  From the values obtained

                plot optical density (absorbance) vs. concentration for the

                standard curve.

         7.7.3  It is not imperative that all standards be distilled in the

                same manner as the samples.  It is recommended that at least 2

                standards (a high and low) be distilled and compared to similar

                values on the curve to insure that the distillation technique is

                reliable.  If distilled standards do not agree with undistilled

                standards the operator should find the cause of the apparent

                error before proceeding.

    7.8  Determine the ammonia in the distillate by nesslerizing 50 ml or ah

         aliquot diluted to 50 ml and reading the optical density at 425 nm

         as described above for the Standards.  Ammonia-nitrogen is read from

         the standard curve.

8.  Calculation

    8.1  If the titrimetric procedure is used calculate Total Kjeldahl Nitrogen,
                                        154

-------
                                                 (Nitrogen Kjeldahl, Total)






         in mg/l, in the original sample as follows:




              Total Kjeldahl nitrogen, mg/l = CA-B) x N x F x 1000
                                                        o



              where:



              A = milliliters of standard 0.020 N H SO. solution used in



                  titrating sample.



              B = milliliters of standard 0.020 N H-SO. solution used in



                  titrating blank.



              N = normality of sulfuric acid solution



              F = millequivalent weight of nitrogen (14 rag).



              S = milliliters of sample digested.



         If the sulfuric acid is exactly 0.02 N the formula is shortened to:




                               TKN, mg/l = CA-B) x 280
                                                 o



    8.2  If the Nessler procedure is used, calculate the Total Kjeldahl Nitrogen,



         in mg/l, in the original sample as follows:



                               T™  m /i   A x 1000
                               TKN, mg/l = 0-8 xg




              where:



              A = mg NH_N read from curve.
                       O


              S = volume of distillate nesslerized.



    8.3  Calculate Organic Kjeldahl Nitrogen in mg/l, as follows:



                               Organic Kjeldahl Nitrogen = TKN - NH N
                         • •                                         O


9.  Precision



    9.1  Thirty-one analysts in twenty laboratory analyzed natural water



         samples containing exact increments of organic nitrogen, with the



         following results:
                                      155

-------
                                                  (Nitrogen Kjeldahl, Total)
Increment as
Nitrogen, Kjeldahl
mg N/ liter
0.20
0.31
4.10
4.61
Precision as
Standard Deviation
mg N/liter
0.197
0.247
1.056
1.191
Accuracy
Bias,
% mg
+15.54
+ 5.45
+ 1.03
- 1.67
as
Bias,
N/liter
+ .03
+ .02
+ .04
-.08
(FWPCA Method Study 2, Nutrient Analyses)
                                      156

-------
                           NITROGEN, KJELDAHL, TOTAL
                         (Automated Phenolate Method)
                                                              STORET NO.   00625
1.  Scope and Application

    1.1  This automated method may be used to determine Kjeldahl nitrogen

         in surface waters, domestic and industrial wastes,  and saline waters.

         The applicable range is 0.05 to 2.0 mg N/l.  Approximately 20 samples

         per hour can be analyzed.

2.  Summary of Method

    2.1  The sample is automatically digested with a sulfuric acid solution

         containing potassium sulfate and mercuric sulfate as a catalyst to

         convert organic nitrogen to ammonium sulfate.  The solution is then

         automatically neutralized with sodium hydroxide solution and treated

         with alkaline phenol reagent and sodium hypochlorite reagent.  This

         treatment forms a blue color designated as indophenol.  Sodium nitro-

         prusside, which increases the intensity of the color, is added to

         obtain necessary sensitivity for measurement of low level nitrogen.

3.  Definitions

    3.1  Total Kjeldahl nitrogen is defined as the sum of free ammonia and of

         organic compounds which are converted to (NH.)-SO. under the conditions

         of digestion which are specified below.

    3.2  Organic Kjeldahl nitrogen is defined as the difference obtained by

         subtracting the free ammonia value from the total Kjeldahl nitrogen

         value.  Also, organic Kjeldahl nitrogen may be determined directly by

         removal of ammonia before digestion.

4.  Sample  Handling and Preservation

    4.1  Preservation by addition of 40 mg HgCl2 per liter and refrigeration

         at 4°C is necessary.
                                        157

-------
                                                 (Nitrogen, Kjeldahl, Total)




 5.   Interferences



     5.1   Iron and chromium ions tend to catalyze while copper ions tend to



          inhibit the indophenol color reaction.



 6.   Apparatus



     6.1   Technicon AutoAnalyzer consisting of:



          6.1.1  Sampler II, equipped with continuous mixer.



          6.1.2  Two proportioning pumps.



          6.1.3  Manifold I



          6.1.4  Manifold II



          6.1.5  Continuous Digester




          6.1.6  Peristaltic pump



         6.1.7  Five-gallon Carboy fume-trap



         6.1.8  80°C Heating bath



         6.1.9  Colorimeter equipped with 50 mm tubular flow cell and



                630 nm filters.



        6.1.10  Recorder equipped with range expander.



7.  Reagents



    7.1  Distilled Water:   Special precaution must be taken to insure that



         distilled water is free of ammonia.   Such water is prepared by passage



         of distilled water through an ion exchange column comprised of a




         mixture of both strongly acidic cation and strongly basic anion ex-



         change  resins.   Furthermore,  since organic contamination may interfere




         with this  analysis,  use of the resin Dowex XE-75 or equivalent which



         also tends  to remove organic  impurities is advised.   The regeneration




         of the  ion  exchange  column should be carried out according to the




         instruction of the manufacturer.
                                      158

-------
                                              (Nitrogen,  Kjeldahl, Total)






7.2  Sulfuric acid:   As it readily absorbs  ammonia, special precaution



     must also be taken with respect  to  its use.  Do not  store bottles



     reserved for this determination  in  areas  of potential ammonia con-



     tamination.




7.3  EDTA (2% solution):  Dissolve 20 g  disodium ethylenediamine



     tetraacetate in 1 liter of distilled water.  Adjust  pH to



     10.5-11.



7.4  Sodium hydroxide (30% solution): Dissolve 300 g NaOH in 1 liter



     of distilled water.



     NOTE:  The 30%  sodium .hydroxide  should be sufficient to neutralize



            the digestate.\  In rare cases it may be necessary to  increase



            the concentration of sodium  hydroxide in this solution to  insure



            neutralization of the digested  sample in the  manifold at the




            water jacketed mixing coil.



7.5  Sodium nitroprusside, Stock (1%  solution): Dissolve 10 g



     Na2Fe(CN)5NO-2H20  in 1 liter distilled water.



     NOTE:  This solution may be omitted if the nitrogen  in the sample



            =0.1 mg/1.




7.6  Sodium nitroprusside, working solution:   Dilute 50 ml  stock  solution



     to 1 liter with distilled water.



7.7  Alkaline phenol reagent:  Pour 550  mis liquid phenol (88-90%)  slowly



     with mixing and cooling into 1 liter of 40% NaOH.  Make up to  2




     liters with distilled water.



7.8  Sodium hypochlorite (1% solution):  Dilute commercial  "Clorox" -  200  ml




     to 1 liter with distilled water.
                                    159

-------
                                                   (Mtrogen,  Kjeldahl, Total)



     7.9  Digestion mixture:   Place 2  g  HgO  in  a  2-liter  container.  Slowly

          add,  with stirring,  300  ml of  acid water  (100 mi H..SO. - 200 ml HO)
                                                            £  Q           Z.
          and stir  until  cool.   Add 100  ml 10%  K^SO..  Dilute  to a volume of

          2  liters  with cone,  sulfuric acid  (approximately 500 ml at a time,
                                                                                ?•.
          allowing  time for cooling).

    7.10  Stock Solution:  Dissolve 4.7619 g of pre-dried ammonium sulfate

          (1  hour at  105°C) in distilled water  and dilute to 1.0 liter.

          Dissolve  2.1276 g of urea (desiccate  only) in distilled water and dilute

          to  1.0 liter.  Dissolve  10.5263 g  of  glutamic acid (desiccate only)

          in  distilled water and dilute  to 1.0  liter.  1 ml =  1.0 mg N.

    7.11   Standard  Solution:  Dilute 10.0 ml of respective stock solutions to

          1.0 liter.  1 ml = 0.01 mg N.

          7.10.1  Using the respective standard solutions, prepare the

                 following standards in 100.0 ml volumetric flasks:

                      Cone., mg N/l      ml Standard Solution/100 ml

                          0.00                     0.0
                          0.05                     0.5
                          0.10                     1.0
                          0.20                     2.0
                          0.40                     4.0
                          0.60                     6.0
                          0.80                     8.0
                          1.00                    10.0
                          1.50                    15.0
                          2.00                    20.0

8.   Procedure

    8.1  Set up manifolds as  shown in Figures 1,  2, and 3.

         8.1.1   In the operation of Manifold No.  1, the control  of three

                key factors  is required  to enable Manifold No. 2 to

                receive the mandatory representative feed.   First,  the digestate
                                      160

-------
                                               (Nitrogen,  Kjeldahl,  Total)







            flowing into the pulse chamber (PC-1)  must be  bubble  free,



            otherwise, air will accumulate in A-7, thus altering  the



            ratio of sample to digestate in digestor.   Second,  in main-



            taining even flow from the helix, the  peristaltic pump must



            be adjusted to cope with differences in density  of  the



            digestate and the wash water.   Third,  the  sample pick-up rate



            from the helix must be precisely adjusted  to insure that the



            entire sample is aspirated into the mixing chamber.   And



            finally, the contents of the "Mixing Chamber"  must  be kept



            homogeneous by the proper adjustment of the air  bubbling



            rate.



     8.1.2  In the operation of Manifold No. 2, it is  important in the



            neutralization of the digested sample  to adjust  the concen-



            tration of the NaOH so that the waste  from the C-3  debubbler



            is slightly acid to Hydrion B paper.



     8.1.3  The digester temperature is 390°C for  the  first  stage and



            360°C for the second and third stages.



8.2  Allow both colorimeter and recorder to warm up for 30 minutes.   Run



     a baseline with all reagents, feeding distilled water through the



     sample line.  Adjust dark current and operative opening on colorimeter




     to obtain stable baseline.



8.3  Set sampling rate of Sampler II at 20 samples per hour, using a wash



     to sample ratio of 2 to 1 (1 minute sample, 2 minute  wash).



     NOTE:  With a 2 minute sampling time plus two 2 minute  washes,  this




     actually represents 10 samples/hr.
                                  161

-------
                                                (Nitrogen, Kjeldahl, Total)







      8.4   Arrange  various standards in Sampler  cups in order of increasing



           concentration.  Complete loading of sampler tray with unknown



           samples.




      8.5   Switch sample line from distilled water to sampler and begin analysis.



           8.5.1  If equipment is operating properly, 100% nitrogen recovery



                 should be obtained for glutamic acid and urea when compared



                 to ammonium sulfate standards.



 9.  Calculation




     9.1  Prepare standard curve by plotting peak heights of processed standards



          against concentration values.   Compute concentration of samples  by



          comparing sample peak heights  with standard curve.



     9.2  Any sample that has a computed concentration that is less than 10%



          of the sample run immediately  prior to it must be rerun.



10.  Precision and Accuracy




     10.1  Six laboratories analyzed four natural water samples containing  exact



          increments of organic nitrogen compounds,  with the  following results:
Increment as
Kjeldahl-Nitrogen
mg N/ liter
1.89
2.18
5.09
5.81
Precision as
Standard Deviation
Kjeldahl-N, mg N/liter
0.54
0.61
1.25
1.85

Bias
%
-24.6
-28.3
-23.8
-21.9
Accuracy as
, Bias,
mg N/liter
- .46
- .62
-1.21
-1.27
     (FWQA Method  Study  4,  Automated Methods  -  In preparation).
                                       162

-------
                                                   (Nitrogen, Kjeldahl, Total)
                                References





1.  Kammerer, P. A.; Rodel, M. G.; Hughes, R.  A.; and Lee, G.  F.;  "Low Level




    Kjeldahl Nitrogen Determination on the Technicon AutoAnalyzer."  Environ-




    mental Science and Technology.  1:4:340 (April 1967).




2.  McDaniel, William H.; Hemphill, R. N.; Donaldson, W. T.; "Automatic




    Determination of Total Kjeldahl Nitrogen in Estuarine Waters."  Presented




    at Technicon Symposium on Automation in Analytical Chemistry,  New York,




    October 3, 1967.




3.  B. O'Connor, Dobbs, Villiers, and Dean, "Laboratory Distillation of




    Municipal Waste Effluents".  JWPCP 39_, R 25, 1967.
                                        163

-------
                   WASH WATER (TO SAMPLER 2
Ml)
COOLING WATER;* (
CUUM PUMP §
i
* * r^^f^V^XTru
- \liS\\\\\l r"™^
\l 1 \ V \ \ \ \1 1
INATARY
DIIUD
SMALL
(ING COIL
 *


4
*
0 <"
0 i
LARGE MIXING
COIL
- J

DIGESTOR
G G
BLUE BLUE
G G
BLUE BLUE
P B
P B
P W
P W

ml/min.
^2.00 WASH WATER
(1.60 SAMPLE
t2.00 DISTILLED WATER /6°®C
J.60 AIR* (o O
- \&
.2.03 DIGESTAHT -<
,1.11 OI6ESTAMT "»'"
t3.90 DISTILLED WATER
.3.90 DISTILLED WATER

                                                                           '•"X  * » *
                                                                             )  FOI
                                                                             > WA
                                                FOR SALT
                                                WATER
                                                SAMPLES
MIXING CHAMBER

    AIR
PROPORTIONING PUMP
                  *AIR IS  SCRUBBED THRU  5N H2S04
                  "TEFLON TUBING OR GLASS
                  ***FOR  FRESH WATER SAMPLES  USE:





r B
P
G
Y
P
G.
Y

z .bu n«ii
2.50 SAMP
2.00 DISTI
1.20 AIR*

                                                                            WATER
          FIGURE 1.  KJELDAHL NITROGEN - MANIFOLD 1

-------
                                CONTINUOUS DIGESTER &  MIXING CHAMBER ASSEMBLY
   TO ASPIRATOR
0\
ON
                               DILUTION WATER
5 GALLON
FUME CARBON  TRAP
HALF FILLED WITH
40%  NaOH
CONNECTED  TO
ASPIRATOR
                           TO SUMP U
                                TO ASPIRATOR
                                                                               LINE DESIGNATION:
                                                                               1. OXIDIZED SAMPLE
                                                                               2. AIR  AGITATION
                                                                               3. MIXING  CHAMBER OVERFLOW
                                                                               4. WASTE
                                                                               5. FEED TO MANIFOLD  NO. 2
                                                   TO MANIFOLD  NO. 2


                                            FIGURE 2. KJELDAHL NITROGEN

-------
                         C-3
CO
V
i
LM
i
J
LARGE MIXII
OOOOOOOO
I
••

^m
ACKETED R
46 COILS
OOOi
k
L
A A
*J \

AIXLH 1

(LM)
OMOO
*
f




SMALL MIXING COIL
N\ 2x40 '
l°yj) COIL LM
^ , oooooooo
WASTE.
i
COLORIMETER
50mm TUBULAR f/c
630 nm FILTERS
PROP
BLUE BLUE
G G
R R
Y Y
P 1
Y Y
R R
If It
Y Y
Y Y
Y Y
P 0
OPTIONING PI

1 1 _
51 r"
Tl f
ml/min.
.1.60 SAMPLE FROM MIXING CHAMBER
^.OO NaOH (SEE MANIFOLD 1 J
,0.80 DISTILLED WATER
1.20 AIR
72.90 SAMPLE 4
,1.20 EDTA
40.80 AIR
,0.80 DISTILLED WATER
,1.20 ALK. PHENOL
,1.20 NaOCL
(1.20 NITROPRUSSIOE
.3.40 WASTE
IMP
-
RECORDER
^ ^"


                               FIGURE 3. KJELDAHL NITROGEN MANIFOLD 2.

-------
1.  Scope and Application
                                NITROGEN, NITRATE


                                                               STORET NO.  00620
    1.1  This method is applicable to the analysis of surface waters,  domestic


         and industrial wastes, and saline waters.  Modification can be  made to


         remove or correct for turbidity, color,  salinity,  or dissolved  organic


         compounds in the sample.


    1.2  The applicable range of concentrations is 0.1 to 2 mg NO,N/liter.


2.  Summary of Method


    2.1  This method is based upon the reaction of the nitrate ion with  brucine


         sulfate in a 13 N H2S04 solution at a temperature of 100°C.  The color of


         the resulting complex is measured at 410 nut-   Temperature control  of the


         color reaction is extremely critical.
                         i
                         i
3.  Sample Handling and Preservation


    3.1  Until more conclusive data is obtained,  samples may be preserved by


         addition of 40 mg HgCl- per liter and storage at 4°C.


4.  Interferences


    4.1  Dissolved organic matter will cause an off color in 13 N H?SO.  and must


         be compensated for by additions of all reagents except the brucine-sul-


         fanilic acid reagent.  This also applies to natural color present  not


         due to dissolved organics.


    4.2  The effect of salinity is eliminated by addition of sodium chloride to


         the blanks, standards and samples.


    4.3  All strong oxidizing or reducing agents interfere.  The presence of


         oxidizing agents may be determined by the addition of orthotolidine


         reagent.


    4.4  Residual chlorine interference is eliminated by the addition of sodium


         arsenite.
                                         170

-------
                                                           (Nitrogen, Nitrate)





     4.5   Ferrous  and  ferric  iron  and quadrivalent manganese give slight




          positive interference, but in concentrations less than 1 mg/1 these




          are negligible.




     4.6   Uneven heating of the samples and standards during the reaction time




          will result  in erratic values.  The necessity for absolute control of




          temperature  during  the critical color development period cannot be too




          strongly emphasized.




5.   Apparatus




     5.1   Spectrophotometer or filter photometer suitable for measuring optical




          densities at 410 nm and  capable of accommodating 25 mm diameter cells.




     5.2   Sufficient number of 25  mm diameter matched tubes for reagent blanks,




          standards, and samples.




     5.3   Neoprene coated wire racks to hold 25 mm diameter tubes.




     5.4   Water bath suitable for  use at 100°C.  This bath should contain a




          stirring mechanism so that all tubes are at same temperature and should




         be of sufficient capacity to accept the required number of tubes without




         significant drop in temperature when the tubes are immersed.




    5.5  Water bath suitable for use at 10-15°C.




6.  Reagents




    6.1  Distilled water free of nitrite and nitrate is to be used in preparation




         of all reagents and standards.




    6.2  Sodium chloride solution (300 g/1).   Dissolve 300 g NaCl  in distilled




         water and dilute to .1.0  1.




    6.3  Sulfuric acid solution.   Carefully add 500 ml H2S04 (sp.  gr. 1.84)  to




         125 ml distilled water.   Cool  and keep tightly stoppered  to prevent




         absorption of atmospheric moisture.
                                         171

-------
                                                           (Nitrogen,  Nitrate)




    6.4  Brucine-sulfanilic acid reagent.   Dissolve 1 g brucine sulfate



         [CC23H26N204)2.H2S04.7H20] and 0.1 g sulfanilic acid
         in 70 ml hot distilled water.   Add 3 ml concentrated HC1,  cool,  mix and



         dilute to 100 ml.  Store in a dark bottle at 5°C.   This solution is stable



         for several months; the pink color that develops slowly does  not effect



         its usefulness.  Mark bottle with warning:  CAUTION:  Brucine Sulfate is



         toxic; take care to avoid ingest ion.



    6.5  Potassium nitrate stock solution (1 ml = 0.1 mg NCL-N) .  Dissolve 0.7218  g



         anhydrous potassium nitrate (KNO_) in distilled water and dilute to 1
                                         O


         liter.



    6.6  Potassium nitrate standard solution Q ml = Q.QQ1 me NO -N) .   Dilute 10.0 ml
                         \                                       o

         of the stock solution to 1 liter.  This standard solution should be



         prepared fresh weekly.



    6.7  Acetic acid (1 +3).  Dilute 1 vol. glacial acetic acid (CH-COOH) with



         3 volumes of distilled water.



7.  Procedure



    7.1  Adjust the pH of the samples to approximately pH 7 with 1:3 acetic acid



         and, if necessary, filter through a 0.45p pore size filter.



    7.2  Set up the required number of matched tubes in the rack to handle



         reagent blank, standards and samples.  It is suggested that tubes be



         spaced evenly throughout the rack to allow for even flow of bath water



         between the tubes.  Even spacing of tubes should assist in achieving



         uniform heating of all tubes.



    7.3  If it is necessary to correct for color or dissolved organic matter which



         will cause color on heating, a set of duplicate tubes must be used to



         which all reagents except the brucine-sulfanilic acid has been added.
                                        172

-------
                                                        (Nitrogen, Nitrate)





     7.4  Pipette 10.0 ml or an aliquot  of the  samples diluted to 10.0 ml




          into the sample tubes.




     7.5  If the  samples  are saline,  add 2 ml of the  30 percent sodium




          chloride solution  to  the  reagent blank, standards and samples.  For




          fresh water samples,  sodium chloride  solution may be omitted.  Mix




          contents of tubes  by  swirling  and place rack in cold water bath




          (0-10°C).




     7.6  Pipette 10.0 ml of sulfuric acid solution into each tube and mix




          by swirling.  Allow tubes to come to  thermal equilibrium in the




          cold bath.   Be  sure that  temperatures have equilibrated in all




          tubes before continuing.




     7.7  Add 0.5  ml brucine-sulfanilic  acid reagent to each tube (except the




          interference control  tubes)  and  carefully mix by swirling, then place




          the rack of  tubes  in  the boiling water bath for exactly 25 minutes.




          CAUTION:  Immersion of the tube rack into the bath should not decrease




          the  temperature of the bath more than 1 to 2°C.  Flow of bath water




         between  the  tubes  should not be restricted by crowding too many tubes




          into  the rack,  in  order to keep this temperature decrease to an




         absolute minimum.   If color development in the standards reveals




         discrepancies in the procedure the operator should repeat the procedure




         after reviewing the temperature control steps.




    7.8  Remove rack of  tubes from the hot water bath and immerse in the cold




         water bath and  allow to reach thermal  equilibrium (20-25°C).




    7.9  Dry tubes and read optical density against the reagent blank at 410 nm.




8.   Calculation




    8.1  Obtain a standard curve by plotting the optical densities  of standards




         run by the above procedure against mg  NO,-N.  (The color reaction  does
                                     173

-------
9.
                                                   (Nitrogen, Nitrate)







     not always follow Beer's law).




8.2  Subtract the absorbance of the sample without the brucine-sulfanilic




     reagent from the absorbance of the sample containing brucine-sul-




     fanilic acid and read the optical density in mg NO_-N.   Multiply by




     factor for converting mg per aliquot of sample to mg per liter.




Precision and Accuracy




9.1  Twenty-seven analysts in fifteen laboratories analyzed natural water




     samples containing exact increments of inorganic nitrate, with the




     following results:
Increment as 1
Nitrogen, Nitrate |
mg N/liter
0.16
0.19
1.08
1.24
Precision as
Standard Deviation
mg N/liter
.092
.083
.245
.214
Accuracy as
Bias, Bias,
% mg N/liter
-6.79 -.01
+8.30 +.02
+4.12 +.04
+2.82 +.04
    (FWPCA Method Study 2,  Nutrient Analyses).
                                        174

-------
                       NITROGEN,  NITRATE-NITRITE


                  (Automated Cadmium Reduction Method)



             ,  ,   ..    .                                      STORET NO.   00630
 1.   Scope  and  Application                                               	>—



     1.1  This  method pertains  to the determination of nitrates and nitrites,



         singly  or  combined, present in surface and saline waters.  The pre-



         scribed specifications  permit analyses of samples in the range of



         0.05  to 10  mg/liter,  N  present as N0_. -



 2.   Summary of Method' '


                         (2)
     2.1  The initial step   J is  to  reduce the nitrates to nitrites by using



         a cadmium-copper catalyst.  The nitrites (those originally present



         plus  reduced nitrates)  are then reacted with sulfanilamide to form



         the diazo compound which is then coupled in an acid solution (pH 2.0 -



         2.5) with N-l naphthyl-ethylenediamine hydrochloride to form the azo



         dye.  The azo dye intensity, which is proportional to the nitrate con-



         centration, is then measured.  Separate rather than combined nitrate-



         nitrite values are readily obtainable by carrying out the procedure—



         first with, and then without, the initial Cd-Cu reduction step.



3.  Sample Handling and Preservation



    3.1  Preservation by addition of 40 mg HgCl2 per liter and refrigeration



         at 4°C is necessary.



4.  Interferences



    4.1  Ammonia and primary amines which are frequently present in natural



         waters may react to some extent with nitrites to form nitrogen.  Thus,



         since, as in nature, the sample is not stable,  the analyses should be



         performed as soon as possible.
                                     175

-------
                                                     (Nitrogen,  Nitrate-Nitrite)







    4.2  In surface waters normally encountered in surveillance  studies,  the



         concentration of oxidizing or reducing agents and potentially inter-



         fering metal ions are well below the limits causing interferences.



         When present in sufficient concentration, metal ions may produce a



         positive error, i.e., Hg (II) and Cu (II), may form colored complex



         ions having absorption bands in the region of color measurement.



5.   Apparatus



    5.1  Technicon AutoAnalyzer consisting of the following components:



         5.1.1  Sampler II.



         5.1.2  Manifold (including Cu-Cd column).



         5.1.3  Colorimeter equipped with 50 mm tubular flow cell and
                         |


                540 nm filters.
                         i


         5.1.4  Range expander.



         5.1.5  Recorder.


                                        (2)
    5.2  Cadmium-copper reduction column   .



         5.2.1  Preparation:  Shake the 30 - 60 mesh av. diam. 0.5 mm cadmium



                turnings with a solution of 2% (wt/vol) copper sulfate



                pentahydrate solution.  A weight of solution equal to 10  times



                the weight of the cadmium is used.  The copper sulfate-treated



                cadmium catalyst is then placed in a 8 mm x 50 mm pyrex tubing



                and is followed by copper granules (0.6 mm x 3.0 mm) made from



                hydrogen treated copper wire (Note 1).  The volume ratio  of the



                cadmium bed to that of the copper should be about 3 - 1 to



                4-1.  (See Figure 1).  Pyrex wool, inserted at the lower end



                of the reactor, is used to prevent the catalyst from dropping



                out of the reactor.  The ends of the reactor are fabricated to
                                       176

-------
                                                      (Nitrogen, Nitrate-Nitrite)





                accomodate the reactor into the system.  :The sample enters




                the column at the copper granule-packed end.  To minimize




                back pressure due to a vertical position or channelling due




                to a horizontal position, the reductant tube is placed in an




                up-flow 20° incline.




                Note 1 - Supplied by F§M Scientific Corp,, Avondale, Pa.




         5.2.2  Regeneration:  HC1, diluted 1 to 4, is pumped through the




                NH.C1 line for one minute, followed by water for two minutes




                and then 2% copper sulfate solution for five minutes.  For




                complete cleaning and coating, remove the.column from the




                manifold.  Using a small funnel and a short plastic connecting




                tube, the acid water and copper sulfate solution are successively




                poured into the column and allowed to flow through by gravity.




                The cadmium should ultimately acquire a moss-black appearance




                and the copper,  a bright orange.




6.  Reagents



    6.1  Distilled water:  Because of possible contamination,  this should be




         prepared by passage through an ion exchange column comprised of




         a mixture of both strongly acidic-cation and strongly basic-anion




         exchange resins.   The regeneration of the ion exchange column should




         be carried out according to the manufacturer's instructions.




    6.2  Color reagent:   To approximately 800 ml  of distilled  water, add,  while




         stirring, 100 ml concentrated phosphoric acid, 40 g sulfanilamide,  and




         2  g N-l naphthylethylenediamine dihydrochloride.   Stir until  dissolved




         and dilute to one liter.   Store in brown bottle and keep in the dark




         when not  in  use.   This  solution is stable for several months.
                                        177

-------
                   •                                (Nitrogen, Nitrate-Nitrite)


6.3  Wash solution:  Use distilled water for unpreserved samples; samples

     preserved with H2S04, use 1 ml H2S04 per liter of wash water.

6.4  Ammonium Chloride Solution (8.5% NH.C1):  Dissolve 85 g of reagent

     grade ammonium chloride in distilled water and dilute to one liter

     with distilled water.  Add 1/2 ml Brij-35^4).

6.5  Stock nitrate solution:  Dissolve 7.218 g KNO_ and dilute to 1.0 1

     with distilled water.  Preserve with 2 ml of chloroform per liter.

     Solution is stable for 6 months.  1 ml = 1.0 mg NO_-N.

6.6  Stock nitrite solution:  Dissolve 6.072 g KNO_ and dilute to 1.0 1

     with distilled water.  Solution is unstable; prepare as reauired.

     1 ml = 1.0 mg NO -N.
                     |
6.7  Standard nitrate solution:  Dilute 10.0 ml of stock nitrate solution

     to 1 liter.  1 ml = 0.01 mg NO--N.  Preserve with 2 ml of chloroform
                                   O

     per liter.  Solution is stable for 6 months.

6.8  Standard nitrite solution:  Dilute 10.0 ml of stock nitrite solution

     to 1 liter.  1 ml = 0.01 mg NO^-N.  Solution is unstable; prepare as

     required.

6.9  Using either standard nitrate solution or standard nitrite solution,

     prepare the following standards in 100.0 ml volumetric flasks:

       Cone., mg N03-N or N02-N/1          Standard Solution/100 ml


                 0.0                                0
                 0.05                               0.5
                 0.10                               1.0
                 0.20                               2.0
                 0.50                               5.0
                 1.00                              10.0
                 2.00                              20.0
                 4.00                              40.0
                 6.00                              60.0

     Note:  When the samples to be analyzed are saline waters, substitute

            Ocean Water (SOW) (5) should be used for preparing the standards;
                                    178

-------
                  INDENTATIONS FOR
                SUPPORTING CATALYST
GLASS WOOL
Cd-TURNINGS
                                    Cu-FILINGS (FINE MESH)
            TILT COLUMN TO 20° POSTION
   FIGURE 1. CADMIUM-COPPER REDUCTION COLUMN
                (1 1/2 ACTUAL SIZE)
                         179

-------
                                                   (Nitrogen, Nitrate-Nitrite)





              otherwise,  distilled water is used.  A tabulation of SOW



              composition follows:



         NaCl  -   24.53  g/1           MgCl2  -  5.20 g/1     Na2S04  -  4.09 g/1



         CaCl2  -    1.16  g/1           KC1    -  0.70 g/1     NaHC03  -  0.20 g/1



         KBr    -    0,10  g/1           H3B03  -  0.03 g/1     SrCl2   -  0.03 g/1



         NaF    -    0.003 g/1



 7.  Procedure



    7.1  Set  up the manifold as shown in Figure 2.  Note that reductant column



         should be  in 20° incline position with Cu at lower end.



    7.2  Allow both colorimeter and recorder to warm up for 30 minutes.  Run



         a baseline with  all reagents, feeding distilled water through the

                        i

         sample line.  Adjust dark current and operative opening on colorimeter



         to obtain stable baseline.



    7.3  Place appropriate nitrate and/or nitrite standards in sampler in order



         of decreasing concentration of nitrogen.  Complete loading of sampler



         tray with unknown samples.



    7.4  Switch sample line to sampler and start analysis.



8.  Calculations



    8.1  Prepare appropriate standard curve or curves derived from processing



         N0_ and/or N0_ standard through manifold.  Compute concentration of
           O          £•


         samples by comparing sample peak heights with standard curve.  Any



         sample whose computed concentration is less  than 10% of its immediate



         predecessor must be rerun.



9.  Precision and Accuracy



    9.1  Three laboratories analyzed four natural water samples containing



         exact increments of inorganic nitrate, with  the following results:
                                       181

-------
                                                       (Nitrogen, Nitrate-Nitrite)
Increment as
Nitrate Nitrogen
mg N/Liter
0.29
0.35
2.31
2.48
Precision as
Standard Deviation
mg N/ liter
0.012
0.092
0.318
0.176
Accuracy
Bias,
%
+ 5.75
+18.10
+ 4.47
- 2.69
as
Bias,
mg N/ liter
+ .017
+ .063
+ .103
-.067
 (FWQA Method Study 4, Automated Methods - In preparation)
                                  References
1.  J. E. O'Brien and J. Fiore, "Automation in Sanitary Chemistry - parts




    1 £ 2 Determination of Nitrates and Nitrites."  Wastes Engineering, 33,




    128 5 238 (1962).




2.  J. D. Strickland, C. R. Stearns, and F. A. Armstrong, "The Measurement




    of Upwelling and Subsequent Biological Processes by Means of the Technicon




    AutoAnalyzer and Associated Equipment."  Deep Sea Research 14, 381-389




    (1967).




3.  "ASTM Manual on Industrial Water and Industrial Waste Water," Method D




    1254, page 465 (1966).




4.  Chemical Analyses for Water Quality Manual, Department of the Interior,




    FWPCA, R. A. Taft Sanitary Engineering Center Training Program, Cincinnati,




    Ohio  45226 (January 1966).




5.  "ASTM Manual on Industrial Water and Industrial Waste Water," Substitute




    Ocean Water, Table 1, page 418, 1966 edition.
                                       182

-------
                          WASTE
oo
OJ
               00000000
              DOUBLE MIXER
          WASTE
                                                                         TO SAMPLE WASH
                                                                      ml/min
PS-3

 oooo
                                                   HO
                                    C-3* MIXER
                                                WASTE
        [DO
COLUMN **
                                                         BLUE
                                 0

                               BLUE
                      BLUE
BLUE
      0.42

      1.60
       HoO
                                                                       0.80  AIR
                                                                       2.00
                                             H90
                                                                       0.42  COLOR REAGENT
                                     2.00
1.60  SAMPLE
      1.20  8.5% NHACL.
                                                                       1.20  AIR
             COLORIMETER
      50mm TUBULAR f/c
           540rrm FILTERS
                                                      PROPORTIONING PUMP
                 RECORDER
                                                               SAMPLER 2

                                                          RATE: 30 PER HR.
                                        * FROM C-3 TO SAMPLE LINE USE
                                          .030 x .048 POLYETHYLENE TUBING.

                                       ** SEE  FIGURE 1.  FOR DETAIL. COLUMN
                                          SHOULD BE IN 20° INCLINE POSITION
                                  RANGE  EXPANDER
                                                                             WITH Cu AT LOWER  END.
                                   FIGURE 2. NITRATE-NITRITE  MANIFOLD

-------
                        NITROGEN, NITRATE AND NITRITE

                     (Automated Hydrazine Reduction Method)

                                                              STORET NO.  00630
1.  Scope and Application


    1.1  This method is applicable to surface waters, and domestic and


         industrial wastes which contain less than 500 mg/1 calcium.   The


         applicable range of this method is 0.05-10 mg/1 nitrite or nitrate


         nitrogen.  Approximately 20 samples per hour can be analyzed.

2.  Summary of Method


    2.1  This method, using the Technicon AutoAnalyzer, determines NO.-N


         by the conventional diazotization-coupling reaction.  The NO--N is


         reduced with hydrazine sulfate in another portion of the sample and


         the nitrite thus formed is determined in the usual manner.
                       |
    2.2  Subtraction of the NCL-N originally present in the sample from the


         total NO--N found will give the original NO--N concentration in terms


         of N02-N.


3.  Sample Handling and Preservation

    3.1  Preservation by addition of 40 mg HgCl- per liter and refrigeration


         at 4°C.


4.  Interferences

    4.1  The following table lists the concentration of ions that cause no


         interference in the determination of nitrite and nitrate nitrogen.


         The same interfering ion concentration applies to either nitrite or


         nitrate:
                                        185

-------
                                               (Nitrogen, Nitrate and Nitrite)






              Ion                 mg/1  Ion  Not  Causing  Interference




              Cl~                            30,000




              P04"3                             50




              S"2                            Note




              NH3-N                             80




              Mg+2                              75




              Ca+2                              240




              Fe+3                              30




              ABS                               60




         Note 1.  —  The apparent NCL and  NCL concentrations varied




         * 10 percent with concentrations of  sulfide ion up to 10 mg/1.




    4.2  The  pH of the samples should be between 6 and 9.




5.  Apparatus




    5.1  Technicon AutoAnalyzer  consisting  of:




         5.1.1  Two proportional pumps.




         5.1.2  Two colorimeters each with  an 8 mm flow-through cell and




                520 nm filters.




         5.1.3  One continuous filter.




         5.1.4  One Sampler I.




         5.1.5  Two recorders.




         5.1.6  One 38°C temperature bath.




         5.1.7  Two time delay coils.




6.   Reagents




    6.1  Color developing reagent:  To approximately 3 liters of distilled




         water add 400 ml concentrated phosphoric acid (sp.  gr. 1.834), 60 g
                                     186

-------
                                                (Nitrogen, Nitrate and Nitrite)




     sulfanilamide  (H2H-C6H4S02NH2) followed by 3.0 g N (1-Naphthyl)



     ethylene-diamine dihydrochloride.  Dilute the solution to 4 liters



     with distilled water and store in a dark bottle in the refrigerator.



     This solution is stable for approximately 1 month.



     NOTE 2:  It may be necessary to apply heat in order to dissolve



     the sulfanilamide.



6.2  Copper sulfate; stock solution:  Dissolve 2.5 g of copper sulfate



     (CuS0..5H20) in distilled water and dilute to 1 liter.



6.3  Copper sulfate; dilute solution:  Dilute 20 ml of stock solution to



     2 liters with distilled water.



6.4  Sodium hydroxide; stock solution, CIO N):  Dissolve 400 g NaOH in



     750 ml distilled water, cool and dilute to 1 liter.
                    i
                    I

6.5  Sodium hydroxide (l.ON):  Dilute 100 ml of stock NaOH solution to



     1 liter.



6.6  Sodium hydroxide (0.3N):  Dilute 60 ml of stock NaOH to 2 liters.



6.7  Hydrazine sulfate; stock solution:  Dissolve 54.92 g of hydrazine



     sulfate (N2H .H2SOJ in 1800 ml of distilled water and dilute to



     2.0 1.  This solution is stable for approximately 6 months.



     CAUTION:  Toxic if ingested.  Mark container with warning.



6.8  Hydrazine sulfate; dilute solution:  Dilute 90 ml of stock solution



     to 4 liters with distilled water to obtain working solution.  Make



     up fresh daily.



6.9  Potassium nitiate; stock solution (1000 mg/1 . NO -N):  Dissolve



     7.2180 g of KNO,, oven dried at 100-105°C for 2 hours, in distilled
                    «J


     water and dilute to 1.0 1.  Add 1 ml chloroform as a preservative.



     Stable for 6 months.
                                   187

-------
                                                 (Nitrogen, Nitrate and Nitrite)

      6.10   Potassium nitrate;  standard  solution  (100 mg/1 NO--N):  Dilute

            50 ml of stock KNO_ solution to 500 ml in a volumetric flask.

            From this dilute'solution prepare the following standards in 500 ml

            volumetric flasks:

                  mg/1 NO--N                  ml Standard Solution

                     0.4                              2.0
                     1.0                              5.0
                     1.6                              8.0
                     3.0                             15.0
                     5.0                             25.0
                     7.0                             35.0
                    10.0                             50.0

     6.11   Sodium nitrite; stock solution (1000 mg/1 N02-N) :  Dissolve 4.9260 g

           NaNCL, oven dried at 100-105°C for two hours, in distilled water

           and dilute to 1-0 1-  Add 1  ml chloroform as preservative.  Store

           in the refrigerator.  Stable for 1 month.

     6.12  Sodium nitrite; standard solution (100 mg/1):  Dilute 50 ml of stock

           NaNO~ solution to 500 ml in a volumetric flask.  From this dilute

           solution prepare the same volumetric standards as in 6.9.   Prepare

           fresh each week.

7.    Procedure

     7.1   Set up the manifold as shown in Figures 1 and 2.   Allow both color-

           imeter (with the  proper filters)  and recorder to warm up for 30

           minutes,  then run a baseline with all reagents, feeding distilled

           water through the sample line.   Adjust dark current and operative

           opening on each colorimeter.   Adjust baseline to  0.01 optical  density.

           Place a distilled water wash tube in alternate openings on sampler

           and set  sample timing at 1.5 minutes.
                                      188

-------
     --'" '               .r--;.;•!                     (Nitrogen, Nitrate and Nitrite)




    7.2  Run a 2.0 mg/1 NO  -N and a 2.0 mg/1 N00-N standard through the
                          •J                    £,


         system to check for 100% reduction of nitrate to nitrite.  The two



         peaks should be of equal height.  If the NO  peak is lower than that



         of the N02 peak, the temperature of the reduction bath should be



         increased until they are equal.  If the NO  peak is higher than the
                                                   •J


         nitrate, the temperature should be reduced.  When the correct tem-



         perature of the bath has been determined,  no further adjustment should



         be necessary.



    7.3  Arrange standards in sampler in N0,-N0_ order with increasing con-
                                           £.   «J


         centration of nitrogen.  Place unknown samples in sampler tubes and



         place in alternate openings of sampler.  A N0_ and NO, standard of
          .  -        .  - |   -       ..                     23.


         equal nitrogen concentration should be placed after every 10 samples

                       1  -

         as a further check on the system and to more easily identify peaks.



8.  Calculation



    8.1  Prepare standard curve by plotting peak heights of processed standards



         against known concentrations.  Compute concentrations of samples by



         comparing sample peak heights with standard curve.



    8.2  Subtract the N0» concentration in the sample from the total N0_



         found (nitrite plus nitrate)  on the reduction side to calculate the



         NO, concentration in the sample.
           O  -      '     •          '


9.  Precision and Accuracy



    9.1  Nine laboratories  analyzed four natural water samples containing



         exact increments of inorganic nitrate, with the following results:
                                       189

-------
                                                    (Nitrogen, Nitrate and Nitrite)
Increment as
Nitrate Nitrogen
mg N/ liter
0.29
0.35
2.31
2.48
Precision as
Standard Deviation
mg N/liter
0.053
0.058
0.258
0.217

Bias,
%
-0.8
+ 1.9
+ 3.0
-1.2
Accuracy as
Bias,
mg N/liter
.002
.007
.07
.03
CFWQA Method Study 4, Automated Method - In preparation).




    9.2  In a single laboratory CAQC), using surface water samples at concen-



         trations of 0.1, 0.2, 0.8, and 2.1 mg-N/1, the standard deviations



         were 0.0, ±0.04, ±0.05, and ±0.05, respectively.



    9.3  In a single laboratory (AQC), using surface water samples at concen-



         trations of 0.2 and 2.2 mg N/l, recoveries were 100% and 96%, respec-



         tively.








References
1.  D. Jenkins and L. Medsker, "Brucine Method for Determination of Nitrate



    in Ocean, Estuarine, and Fresh Waters."  Anal. Chem., 56, 610 (1964).



2.  L. Kamphake, S. Hannah, and J. Cohen, "Automated Analysis for Nitrate



    by Hydrazine Reduction."  Water Research, 1_, 205 (1967).
                                       190

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-------
                               NITROGEN, NITRITE

                                                             STORET NO.   00615
1.  Scope and Application

    1.1  This method is applicable to the determination of nitrite in surface

         waters, domestic and industrial wastes and saline waters.

    1.2  The method is applicable in the range from 0.05 to 1.0 mg/1 NO-/N.

2.  Summary of Method

    2.1  The diazonium compound formed by diazotation of sulfanilamide by

         nitrite in water under acid conditions is coupled with N-(l-naphthyl)-

         ethylenediamine to produce a reddish-purple color which is read in  a

         spectrophotometer at 540 nm.

3.  Sample Handling and Preservation

    3.1  Until more conclusive data are obtained, samples may be preserved bv

         addition of 40 mg HgCl™ per liter and stored at 4°C.

4.  Interferences

    4.1  There are very few known interferences at concentrations less than  1,000

         times that of the nitrite; however, recent addition of strong oxidants

         or reductants to the samples will readily affect the nitrite concen-

         trations.  High alkalinity (>600 mg/1) will give low results due to a

         shift in pH of the color reaction.

5.  Apparatus

    5.1  Spectrophotometer equipped with 1.0 and 5.0 cm cuvettes for use at

         540 nm.

    5.2  Nessler tubes, 50 ml or volumetric flasks, 50 ml.

6.  Reagents

    6.1  Distilled water free of nitrite and nitrate is to be used in preparation

         of all reagents and standards.
                                       195

-------
       •                                                   (Nitrogen, Nitrite)

    6.2  Buffer-color reagent.  To 250 ml of distilled water, add 105 ml

         concentrated hydrochloric acid, 5.0 g sulfanilamide and 0.5 g N-

         (1-Naphthyl) ethylenediamine dihydrochloride.  Stir until dissolved.

         Add 136 g of sodium acetate and again stir until dissolved.  Dilute

         to 500 ml with distilled water.  This solution is stable for several

         weeks if stored in the dark.

    6.3  Nitrite-nitrogen stock solution, 1.0 ml = 0.10 mg NCL-N.  Dissolve

         0.4926 g of dried anhydrous sodium nitrite (24 hours in desiccator)

         in distilled water and dilute to 1.0 1.  Preserve with 2 ml chloroform

         per liter.

    6.4  Nitrite-nitrogen standard solution, 1.0 ml = 0.001  mg NO--N.   Dilute

         10 ml of the stock solution to 1.0 liter.

7.   Procedure

    7.1  If the sample has a pH greater than 10 or a total alkalinity  in excess

         of 600 mg/1, adjust to approximately pH 6 with 1:3  HC1.

    7.2  Filter the sample through a 0.45 y pore size filter using the first

         portion of filtrate to rinse the filter flask.

    7.3  Place  50 ml of sample, or an aliquot diluted to 50  ml,  in a 50 ml

         Nessler tube;  hold until  preparation of standards is completed.

    7.4  At the same time prepare  a series  of standards  in 50 ml  Nessler tubes

         as follows:

                ml  of Standard  Solution          Cone.,  When Diluted to
                1.0 ml  = 0.001  mg  NC>2-N          50 ml,  mg/1 of N02-N

                        0.0  (Blank)                       0.0
                        0.5                               0.01
                        1.0                               0.02
                        1.5                               0.03
                        2.0                               0.04
                        3.0                               0.06
                        4.0                               0.08
                        5.0                               0.10
                       10.0                               0.20
                                      196

-------
                                                           (Nitrogen,  Nitrite)


    7.5  Add 2.0 ml of buffer-colored reagent to each standard and sample,

         mix and allow color to develop for at least 15 minutes.   The  color

         reaction medium should be between pH 1.5 and 2.0.

    7.6  Read the color in the spectrophotometer at 540 nm against the blank

         and plot concentration of NO--N against optical density.

8.  Calculation

    8.1  Read the concentration of N02-N directly from the curve.

    8.2  Calculate the concentration of NO_-N in the sample in milligrams per

         liter as follows:

             wn  N    /i   absorbance of sample x mg/1 standard x  50
              U2  ' mg/  ~   absorbance of standard x ml sample

9.  Precision and Accuracy

    9.1  Precision and accuracy data are not available at this time.
                                        197

-------
                          NITROGEN, ORGANIC + AMMONIA

                          (Automated Phenolate Method)

                                                             STORE! NO.  00635
1.  Scope and Application

    1.1  This automated method is applicable to surface and saline waters.

         The applicable range is 1.0 to 10.0 mg N/l.  Approximately 15 samples

         per hour can be analyzed.

2.  Summary of Method

    2.1  Organic nitrogen is determined by manually digesting the sample with

         potassium persulfate and sulfuric acid to convert the organic nitrogen,

         and any ammonia present, to ammonium sulfate.  Subsequently,  the

         automated phenol-hypochlorite procedure is used to measure the ammonia

         nitrogen.  Nitrate-nitrite nitrogen is not measured by this procedure.

3.  Sample Handling and Preservation

    3.1  Preservation by addition of 40 mg HgCl2 per liter and refrigeration

         at 4°C is necessary.

4.  Interferences

    4.1  No significant interferences.

5.  Apparatus

    5.1  Technicon AutoAnalyzer consisting of:

         5.1.1  Sampler I.

         5.1.2  Continuous  Filter.

         5.1.3  Manifold.

         5.1.4  Proportioning Pump.

         5.1.5  Colorimeter equipped with 15 mm tubular flow cell and  650 nm

                filters.

         5.1.6  Recorder equipped with  range expander.

    5.2  Hot  plate.
                                       198

-------
                                                        (Nitrogen,  Organic
                                                           + Ammonia)


6.  Reagents

    6.1  Distilled Water:  Special precaution must be  taken to  insure  that

         distilled water is free of ammonia.   Such water is prepared by

         passage of distilled water through an ion exchange column  comprised

         of a mixture of both strongly acidic cation and strongly basic  anion

         exchange resins.  Since organic contaminants  may interfere with this

         analysis, use of the resin Dowex XE-75 or equivalent which also tends

         to remove organic impurities  is advised.  The regeneration of the  ion

         exchange column should be carried out according to the instructions of

         the manufacturer.

         Note:  All glassware must be  pre-rinsed with  this ammonia-free  water

         to prevent contamination.
                          \
    6.2  Sulfuric Acid:   As it readily absorbs ammonia,  special precaution  must

         also be taken with respect to its use. Do not store bottles  reserved

         for this determination in areas of potential  ammonia contamination.

    6.3  Potassium persulfate, low N (0.001%):  Certain lots of this reagent do

         not meet this specification for nitrogen content. In  order to  insure

         this purity, dissolve 50 g of the reagent in  500 ml of distilled water

         at 60° to 70°C.  Make alkaline with 10 ml of  sodium hydroxide solution,

         2.2M.  Bubble air that has been passed through a 10% sulfuric acid

         solution through a tube which has been drawn  into a capillary into the

         solution while withdrawing air from the solution, which is contained in

         a suction flask, under reduced pressure.  Control the  air  flow  so  that

         a rather vigorous bubbling through the solution is maintained.  After

         30 minutes of vigorous bubbling, cool the solution overnight  in a  re-

         frigerator at about 4°C.  Filter the crop of  crystals  through a No. 40
                                        199

-------
                                                    (Nitrogen, Organic
                                                       + Ammonia)

     Whatman filter paper previously washed with ammonia-free water.   Wash

     the crystals repeatedly with ice-cold ammonia-free water until pH is

     no longer basic.  Dry the crystals at 60 to 70°C and store in a  tightly

     closed reagent bottle.

6.4  Sulfuric acid solution:  Add slowly and with stirring 310 ml of  reagent

     grade, concentrated sulfuric acid to 600 ml of ammonia-free water.

     Cool and dilute to 1.0 1.

6.5  Phenol solution:  Dissolve 83 g of phenol in 500 ml of ammonia-free

     water by stirring with a Teflon coated magnet for 10 minutes.  Add 32 g

     NaOH and dilute to 1 liter.

6.6  Sodium hypochlorite solution:  Dilute 250 ml.of bleach solution  contain-

     ing a 5.25% NaOCl to 500 ml with ammonia-free water.

6.7  Neutralizing solution:   Dissolve 6 g EDTA disodium salt and 65 g of

     NaOH in 500 ml of distilled water.  Dilute to 1.0 1.

6.8  Stock solution:   Dissolve 4.7168 g of ammonium sulfate analytical reagent

     in ammonia-free  water and dilute to 1.0 1.   1.0 ml =  1.00 mg N.

6.9  Standard solution:  Dilute 10.0 ml of stock solution  to 100.0  ml.

     1  ml  = 0.10 mg N.

     6.9.1   Using standard solution, prepare the following standards  in

            100-ml volumetric flasks:

                        mg N/l          ml Standard Solution/100 ml

                         0.0                        0
                         1.0                        1.0
                         2.0                        2.0
                         3.0                        3.0
                         4.0                        4.0
                         5.0                        5.0
                         6.0                        6.0
                         8.0                        8.0
                        10.0                       10.0

     Note:   Standards  should be processed through complete procedure  in same

            manner as samples.

                                     200

-------
                       -    -                           (Nitrogen, Organic
                                                         + Ammonia)


7.  Procedure          ,.'.,"•      , .>':  • ..,••;


    7.1  Transfer a 25 ml sample of water to a 125 ml Erlenmeyer flask.


    7.2  Add 3 ml of sulfuric acid solution and evaporate on a hot plate to


         light fumes of SO,.  This step may require approximately one hour. :. ,


         Close attention is not required of the sample; however, it should not


         be allowed to go 'to dryness.  Cool the sample.


    7,3  Add 1 ml of ammonia-free water and 1 g of potassium persulfate, low N,


         and swirl the flask.            .


    7.4  Digest the sample on the hot plate for 15 minutes.  Fumes of SO-


         should begin coming off after 7 minutes.  The samples should become clear


         and transparent after this step, except in the presence of large amounts
                           i

         of silica.  Cool the sample; dilute to 25 ml with ammonia-free water.


         The sample is now ready for automatic analysis.


    7.5  Set up manifold as shown in Figure 1.                              ,


    7.6  Allow both colorimeter and recorder to warm up for 30 minutes. : Run a


         baseline with all reagents, feeding distilled water through the sample


         line.  Adjust dark current and operative opening on colorimeter to


         obtain stable baseline.


    7.7  Place distilled water wash tubes in alternate openings in Sampler and


         set sample timing at 2.0 minutes.


    7.8  Arrange standards in Sampler, in order of decreasing concentration.


         Complete loading of Sampler tray with unknown samples from 7.4.


    7.9  Switch sample line from distilled water to Sampler and begin analysis.


8.  Calculation


    8.1  Prepare standard curve by plotting peak heights of processed standards


         against concentration values.  Compute concentration of samples by
                                        201

-------
                                                       (Nitrogen, Organic
                                                          + Ammonia)


         comparing sample peak heights with standard curve.

9.  Precision and Accuracy

    9.1  Precision and accuracy data are not available at this time.



                                References
1.  E. C. Julian and R. C. Kroner, "Determination of Organic Nitrogen in Water

    by Semi-Automatic Analysis," Automation in Analytical Chemistry, Technicon

    Symposia, 1966, Vol. 1, Mediad Inc., White Plains, N.Y. (1967), p 542.

2,  D. D. Van Slyke and A. J. Killer, Biol. Chem., 102, 499 (1933).
                                       202

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                           FIGURE 1 • ORGANIC  NITROGEN & AMMONIA MANIFOLD

-------
                                     NTA



                            (Zinc-Zincon Method)





                                                      STORE! No:  00695



1.  Scope and Application



    1.1  In this method, NTA refers to the tri-sodium salt of nitrilotriacetic



         acid, N(CH COONa)_.
                   w      O


    1.2  This method is applicable to surface waters in the range of 0.5 - 10.0



         mg/1 NTA.



2.  Summary of Method ^



    2.1  Zinc forms a blue-colored complex with 2 carboxy-2'-hydroxy-5'-



         sulfoformazylbenzene (Zincon) in a solution buffered to pH 9.2.  When



         NTA is added, the Zn-Zincon complex is broken which reduces the optical



         density in proportion to the amount of NTA present.



3.  Sample Handling and Preservation



    3.1  Samples should be analyzed as soon as possible, as NTA has been shown


                            (2)
         to be biodegradable



4 -r  Interferences



    4.1  Cations, such as calcium, magnesium, zinc, copper, iron, and manganese,



         complex with NTA and give a negative interference.  These ions are



         removed by batch treating samples with ion-exchange resin.  At  concen-



         trations higher than expected in typical river waters *• •*, only zinc,



         copper, and iron were not completely removed with ion-exchange treat-



         ment.   Results are summarized in Table 1.
                                       205

-------
                               TABLE 1




                   Interference of Common Metals
                                                          (NTA)
Metal
Blank
Zinc
Boron
Iron
Molybdenum
Manganese
Aluminum
Copper
Strontium
mg/1
added
0.0
2.0
5.0
5.0
2.0
4.0
3.0
0.5
5.0
1.0 mg/1
NTA

1.1
<0.5
1.1
0.95
1.0
1.1
0.85
<0.5
1.0
5.0 mg/1
NTA
Recoveries
5.5
0.6
5.5
4.6
5.5
5.6
5.2
3.4
5.4
4.2  This method has not been found applicable to salt waters.



Apparatus



5.1  Shaking machine, tray type, for stirring sample-resin mixtures in



     125 ml Erlenmeyer flasks



5.2  Photometer, suitable for measurements at 620 nm.



Reagents



6.1  Sodium hydroxide, 6N:  Dissolve 120 g NaOH in distilled water and




     dilute to 500 ml.



6.2  Buffer:  Dissolve 31 g boric acid and 37 g potassium chloride in



     800 ml distilled water.  Adjust pH to 9.2 with 6N NaOH.  Dilute to




     1 liter.



6.3  Hydrochloric acid, 2N:  Dilute 83 ml concentrated HC1 to 500 ml with




     distilled water.



6.4  Zinc:  Dissolve 0.44 g ZnS04>7H 0 in 100 ml 2N HC1 and dilute to 1




     liter with distilled water.



                                    206

-------
                                                                  (NTA)
    6.5  Sodium Hydroxide, IN:  Dissolve 4 g NaOH in distilled water and dilute


         to 100 ml.


    6.6  Zinc-Zincon:  Dissolve 0.13 g Zincon (2-carboxy-2'-hydroxy-5'-


         sulfoformazyl benzene) in 2 ml IN NaOH (6.5).   Add 300 ml buffer (6.2),


         While stirring, add 15 ml Zinc solution (6.4)  and dilute to 1 liter


         with distilled water.


    6.7  Ion-Exchange Resin:  Dowex 50W-X8, 50-100 mesh, Na* form (or equivalent).


    6.8  Stock NTA Solution:  Dissolve 1.0700 g N(CH COONa) .H-0 in distilled
                                                    2      3  *•

         water and dilute to 1 liter.  1.0 ml = 1 mg NTA.


    6.9  Working NTA Solution A:  Dilute 10 ml Stock NTA solution (6.8) to 100 ml


         with distilled water.  1 ml = 0.1 mg NTA.   Prepare fresh daily.


   6.10  Working NTA Solution B:  Dilute 10 ml Working  NTA Solution,A to 100 ml


         with distilled water.  1 ml = 0.01 mg NTA.


7.  Procedure                                                                  '


    7.1  Filter approximately 50 ml of well-mixed sample through a 0.45y


         membrane filter.


    7.2  Prepare a series of standards from 0.5 to 10 mg/1 NTA, including a blank


         of distilled water.  Treat standards and blank in same manner as filtered


         samples.


    7.3  To a 25 ml sample in a 125 ml Erlenmeyer flask add approximately 2.5 g


         ion-exchange resin.  Agitate sample for at least 15 minutes.


    7.4  Filter through coarse filter paper to remove resin.  Pipette 15 ml of


         filtrate into a 50 ml beaker.  Add 25 ml zinc-Zincon by pipette.


    7.5  Read absorbance against distilled water at 620 run in a 1 cm or 2 cm cell.


8.  Calculation


    8.1  Prepare standard curve by plotting absorbance of standards vs. NTA


         concentrations.  Calculate concentrations of NTA, mg/1, directly from



         this curve.
                                        207

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                                                                  (NTA)
9.  Precision and Accuracy

    9.1  In a single laboratory  (AQC), using spiked surface water samples at

         concentrations of 0.5,  2, 6, and  10 mg/1 NTA, standard deviations

         were ±0.17, ±0.14, +0.1, and ±0.16, respectively.

    9.2  In a single laboratory  (AQC), using spiked surface water samples at

         concentrations of 1.0 and 7.5 mg/1 NTA, recoveries were 120% and

         103%, respectively.




                                 REFERENCES

1.  Thompson, J. E. and Duthie, J.R.,"The  Biodegradability and Treatment of

    NTA".  Jour. WPCF, 40_, No. 2, 306 (1968).

2.  Shumate, K.  S. et al, "NTA Removal by  Activated Sludge - Field Study".

    ibid.,  42_, No. 4, 631 (1970).
  I          '    •          •
3.  Kopp, J. F.  and Kroner, R. C., "Trace  Metals in Waters of the United States",

    USDI, FWPCA, DPS, 1014 Broadway, Cincinnati, Ohio  45202.
                                       208

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                                     NTA



                       (Automated Zinc-Zincon Method)





                                                            STORE! No:   00695



1.  Scope and Application



    1.1  In this method, NTA refers to the tri-sodium salt of nitrilotriacetic



         acid, N-(CH2COONa)3.



    1.2  This method is applicable to surface waters in the range of 0.04 to



         1.0 mg/1 and 0.5 to 10.0 mg/1 NTA, depending on which manifold system



         is used.  It does not apply to saline waters;, a positive interference



         of 0.5 to 1.0 mg/1 is present in sewage-type samples.



    1.3  Approximately 13 samples per hour can be analyzed.



2.  Summary of Method    j
                         I
                         j

    2.1  Zinc forms a blue-colored complex with 2-carboxy-2'-hydroxy-5'-



         sulfoformazylbenzene (Zincon) in a solution buffered to pH 9.2.  When



         NTA is added, the Zn-Zincon complex is broken which reduces the optical



         density in proportion to the amount of NTA present.



3.  Sample Handling and Preservation



    3.1  Samples should be analyzed as soon as possible, as NTA has been shown


                             f2)
         to be biodegradable. v



4.  Interferences



    4.1  Cations, such as calcium, magnesium, zinc, copper, iron, and manganese,



         complex with NTA and give a negative interference.  These ions are



         removed automatically by passing the sample through an ion-exchange

                                                                                 (3)

         column.  At concentrations higher than expected in typical river waters,



         only iron was not completely removed by this column treatment.  Results,



         summarized in Tables 1 and 2, show that iron gives a negative inter-



         ference in concentrations above 3.0 mg/1 NTA.
                                       209

-------
                                                                   (NTA)
                                    TABLE 1




                         Interference of Common  Metals
Metal
Blank
Zinc
Iron*
Manganese
Copper
mg/1
added
0.0
2.0
5.0
4.0
0.5
1.0 mg/1
NTA

1.0
0.9
0.8
1.0
1.2
5.0 mg/1
NTA
Recoveries
5.0
4.9
3.8
4.9
4.9
                                   TABLE  2




               Effect of  Iron on NTA Recovery in River Water
Iron Added
: mg/1
0.0
0.5
1.0
2.0
3.0
4.0
5.0
NTA Recovered, mg/1
(0.5 mg/1 added)
0.52
0.52
0.52
0.52
0.48
0.45
0.39







    4.2  At concentration levels below 0.05 mg/1 NTA, negative peaking may occur




         during analyses.




5.  Apparatus




    5.1  Technicon AutoAnalyzer consisting of:




         5.1.1  Sampler I and II




         5.1.2  Manifold




         5.1.3  Proportioning pump
*See Table 2
                                        210

-------
                                                                        (NTA)
         5.1.4  Colorimeter equipped with 15 mm tubular flow cell and 600 or



                625 nm filter.



         5.1.5  Recorder




6.  Reagents




    6.1  Sodium Hydroxide,  6N:   Dissolve 120 g NaOH in  distilled water and



         dilute to 500 ml.




    6.2  Buffer:  Dissolve  31 g boric acid and 37  g potassium  chloride in




         800 ml distilled water.  Adjust pH of solution to  9.2 with  6N NaOH.



         Dilute to one liter.




    6.3  Hydrochloride acid,  2N:  Dilute 83 ml concentrated HC1  to 500 ml with




         distilled water.!




    6.4  Zinc:   Dissolve 0.44 g ZnS04«7H20 in 100  ml 2N HC1.   Dilute to one  liter




         with distilled water.




    6.5  Sodium Hydroxide,  IN:   Dissolve 4 g NaOH  in distilled water and  dilute




         to  100 ml.




    6.6  Zinc-Zincon  Reagent  A  (0.04-1.0 mg/1 NTA):   Dissolve  0.065  g Zincon




         powder (2-carboxy-2'-hydroxy-5'sulfoformazyl benzene) in 2  ml of IN




         NaOH (6.5).   Add 300 ml buffer  (6.2).  Place on a  magnetic  stirrer  and




         add 7.5 ml zinc solution  (6.4).   Dilute to one liter  with distilled




         water.  This  solution  is  stable for 12 hrs.




    6.7  Zinc-Zincon  Reagent  B  (0.5-10 mg/1  NTA):   Dissolve 0.13 g Zincon in




         2 ml IN NaOH (6.5).  Stir on magnetic stirrer.   Add 300 ml  buffer (6.2)




         and 15  ml  zinc solution (6.4).   Stir while mixing.  Dilute  to 1  liter




         with distilled water.   Stable for one week.




    6.8  Ion-Exchange  Resin, H+  Form:  20-50 mesh  or 30-80  mesh,  Dowex 50W-XB




         or  equivalent.
                                        211

-------
                                                                   (NTA)
      NOTE:  Column is prepared by sucking a water slurry of the resin into

      12 inches of 3/16-inch OD sleeving.  This may be conveniently done by

      using a pipette and a loose-fitting glass wool plug in the sleeve.

 6.9  Stock NTA Solution:  Dissolve 1.0700 g of N(CH2CooNa) -H 0 in 500 ml

:      of distilled water and dilute to one liter.  1 ml = 1.0 mg NTA.

6.10  Working Solution A:  Dilute 10 ml of stock NTA solution to 100 ml

      with distilled water.  1 ml = 0.1 mg NTA.  Prepare daily.

6.11  Working Solution B:  Dilute 10 ml of Solution A to 100 ml with

      distilled water.  1 ml = 0.01 mg NTA.   Prepare daily.

6.12  Working Solution C:  Dilute 10 ml of Solution B to 100 ml with

      distilled water.  1 ml = 0.001 mg NTA.   Prepare daily.

6.13  Prepare a series of standards by diluting suitable volumes of working

      solutions to 100.0 ml with distilled water.  The following dilutions

      are suggested:

           ml of Solution C/100 ml              Cone., mg NTA/1

                    2                                0.02
                    4                                0.04
                    6                                0.06
                    8                                0.08
                   10                                0.10

           ml of Solution B/100 ml

                    2                                0.20
                    4                                0.40
                    6                                0.60
                    8                                0.80
                   10                                .1.00

           ml of Solution A/100 ml

                   2                                2.0
                   4                                4.0
                   6                                6.0
                    8                                8.0
                   10                               10.0
                                    212

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                                                                      (NTA)
7.  Procedure

    7.1  Set up manifold as shown in Figure 1.

    7.2  Allow both colorimeter and recorder to warm up for 30 minutes.   Run

         a baseline with all reagents, feeding  distilled water through  the

         sample line.  Adjust dark current and   operative opening on colorimeter

         to obtain suitable baseline.

    7.3  Place wash water tubes in sampler in sets of two, leaving every third

         position vacant.  Set sampling time at 1.5 minutes.

    7.4  Place NTA standards in sampler in order of increasing or decreasing

         concentration.  Complete filling of sampler tray with unknown  samples.
                        I
    7.5  Switch sample line from distilled water to sampler and begin analysis.
                        i
8.  Calculation

    8.1  Prepare standard curve by plotting peak heights of processed NTA

         standards against known concentrations.  Compute concentration of samples

         by comparing sample peak heights with  standard curve.

9.  Precision and Accuracy

    9.1  In a single laboratory (AQC), using surface water samples at concen-

         trations of 0.1, 0.18, 0.27,  and 0.44  mg/1, the standard deviations were

         ±0.01, ±0.004, ±0.004, ±0.005, respectively.   At concentrations of 1.3,

         4.0, 5.8, and 7.4 mg/1, the standard deviations were ±0.05, ±0.05, ±0.07,

         and ±0.1, respectively.

    9.2  In a single laboratory (AQC), using surface water samples at concen-

         trations of 0.18 and 0.27 mg/1, recoveries were 101% and 106%,

         respectively.  At concentrations of 4.0 and 5.8 mg/1, the recoveries

         were 98% and 96%, respectively.
                                        213

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                                                                      (NTA)
                                 References



1.  Thompson, J. E. and Duthie, J. R., "The Biodegradability and Treatment



    of NTA."  Jour. WPCF, 40_, No. 2, 306  (1968).




2.  Shumate, K. S. et al, "NTA Removal by Activated Sludge - Field Study."



    ibid, 42_, No. 4, 631 (1970).



3.  Kopp, J. F. and Kroner, R. C., "Trace Metals in Waters of the United States."



    USDI, FWPCA, DPS, 1014 Broadway, Cinti, Ohio  45202.
                                        214

-------
N)
hJ
01
1
1
s
V
ION EXCHANGE

00000000 , °< o. o,
f 1
LARGE
•*- MIXING
rnn ^ __________

P
P B
«--.WMMMM-M»-M----.--»
R R
6 G
0 0
R R
R R
G G
^PORTIONING PUI
1
1,
1 	 "3 -I*
71 1
)X
ml /min
2.90 C-l SAMPLE
i •• 	 5»r?s>^ • 	 * WASTE
oTJ /S59^ AO
B o «
V^
2.00 SAMPLE
0.42

i'8 MR
2.00
W
FOR CONCENTRATION RANGE
OF 0.5 to I0.0mg/l NTA (RECORDER at 2X)
ml /min
Rn 0 ft 1
i\ J— v.w I pinnir
AMPLING TIME -1.5 min ^ 1 0 W ^0.23 niirrrn
VASH IUBbSUJ-i.Um,MCOLOR|METER RECORDER
15 mm Tubular l/c
600-625 my Filters

R R .0.8 ,.„

                 Figure I. NTA  MANIFOLD  (0.04-1.0 mg/l NTA)

-------
1.  Scope and Application
                                 OIL AND GREASE

                                                             STORE! NO.  00550
    1.1  This method includes the measurement  of hexane  extractable matter

         from waters, industrial wastes,  and sewages.  It  is applicable  to  the

         determination of relatively non-volatile hydrocarbons,  animal fats

         and waxes, grease and other types  of  greasy-oily  matters.

    1.2  The method is not applicable to  measurement  of  light hydrocarbons  that

         volatilize at temperatures below 80°C.

    1.3  The method covers the range from 5 to 1000 mg/1 of extractable  material.

2.  Summary of Method

    2.1  The sample is acidified to a low pH (<3) and extracted  with hexane

         using a Soxhletj extraction.  The solvent is  evaporated  from the separated
                        i
         extract and the! residue weighed.

3.  Definitions

    3.1  The definition of grease and oil is based on the  procedure used.   The

         source of the oil and/or grease, the  solvent used, and  presence of ex-

         tractable non-oily matter will influence the material measured  and

         interpretation of results.

4.  Purity of Reagents

    4.1  Reagent grade hexane shall be used.

5.  Sampling and Storage

    5.1  A representative sample should be  collected  in  a  wide-mouth bottle

         marked at the 1 liter volume. The initial step of acidification shall

         be carried out in the sample bottle.   The entire  sample is used for

         the test.

    5.2  Because losses of grease will occur on sampling equipment,  collection

         of a composite sample is impractical, and the examination of individual
                                       217

-------
                                                          (Oil and Grease)





          portions  collected  at prescribed time intervals must be used to obtain



          the  average  concentration over an extended period.




 6.  Apparatus



    6.1   Extraction apparatus consisting of:




          6.1.1  Soxhlet Extractor, medium size (Corning No. 3740 or equivalent).



          6.1.2  Soxhlet thimbles, to fit in Soxhlet Extractor, 6.1.1.



          6.1.3  Flask, 125 ml (Corning No. 4100 or equivalent).



          6.1.4  Condenser, Allihn (bulb) type, to fit extractor.



    6.2   Vacuum pump, or other source of vacuum.



    6.3   Buchner funnel, 12  cm.



 7.  Reagents



    7.1   Sulfuric acid, 1:1.  Mix equal volumes of cone. H_SO. and distilled water.



    7.2   Hexane,   b.p. 69°C.



    7.3   Filter paper, Whatman No. 40, 11 cm.



    7.4  Muslin cloth discs, 11 cm (muslin cloth available at sewing centers).



    7.5  Diatomaceous - silica filter aid suspension, 10 g/1 distilled water.



         Note 1 - Hyflo Super-Gel (Johns-Manvilie Corp.) or equivalent is used



         in the preparation of the filter aid suspension.



8.  Procedure



    8.1  In the following procedure,  all steps must be rigidly adhered to if




         consistent results are to be obtained.



    8.2  Acidify the 1 liter sample with 1:1 H-SO. to a pH below 3.   For most samples



         about 2 ml of the 1:1 acid will be sufficient.   Use of a pH sensitive



         paper is recommended when checking the pH of the sample to  avoid possible




         loss  of oil and grease by adherence to glass electrodes.



         Note:   If the sample has been acidified in the  field at the time of




         collection this  step may be  omitted.
                                        218

-------
                                                       (Oil and Grease)





8.3  Prepare a filter consisting of a muslin cloth disc overlaid with




     filter paper.  Place the assembled filter in the Buchner funnel and




     wet the filter, pressing down the edges to secure a seal.  Using a vac-




     uum, add 100 ml of the filter aid suspension through the filter and




     then wash with 3-100 ml volumes of distilled water.  Continue the




     vacuum until no more water passes through the filter.




8.4  Filter the acidified sample under vacuum and again continue the vacuum




     until no more water passes through the filter.




8.5  Remove the filter paper from the funnel with a pair of forceps and




     carefully place in the Soxhlet thimble.  Wipe the sides and bottom




     of the collecting vessel, the stirring rod, and the Buchner funnel with




     pieces of filter, paper soaked in hexane.  Add all pieces of filter




     paper to the thimble.  In general, care must be taken to remove all




     grease and oil films and to collect all solid material for placement in




     the thimble.




8.6  Dry the extraction thimble containing the filter paper in an oven at




     103°C for exactly 30 minutes.  Fill the thimble with small glass beads




     or glass wool.




8.7  Weigh the extraction flask (pre-dried in oven at  105°C and stored  in




     desiccator), add the hexane,  and connect to the Soxhlet apparatus in




     which the extraction thimble has been placed.  Extract at the rate of




     20 cycles per hour for four hours.  The four hours is timed from the first




     cycle.




8.8  Distill the solvent from the extraction flask in a water bath at 85°C.




     Dry by placing the flask on a steam bath and draw air through the flask




     by means of an applied vacuum for 15 minutes.
                                    219

-------
                                                           (Oil and Grease)
     8.9  Cool in a desiccator for 30 minutes and weigh.


 9.  Calculation


     n n    ,, .  .  ,          mg increase in weight of flask x 1,000
     9.1  mg/1 total grease = -&	mi sLple	l	



10.  Precision and Accuracy


     10.1  Precision and accuracy data are not available.
                                        220

-------
                              ORGANIC CARBON               NliffiERS.
                           (Total and Dissolved)             TOTAL:   00680
                                                            DISSOLVED:  00681
1.  Scope and Application                                                   ~~r


    1.1  This method includes the measurement of organic carbon in surface


         waters, domestic and industrial wastes, and saline waters.   Ex-

         clusions are noted under Definitions and Interferences.


    1.2  The method is applicable to measurement in the range of 1 to

         150 mg/liter.

2.  Summary of Method


    2.1  A micro sample of the wastewater to be analyzed is injected into


         a catalytic combusion tube which is enclosed by an electric furnace

         thermostated at 950°C.  The water is vaporized and the carbonaceous
                        i
         material is oxidized to carbon dioxide (CO,,) and steam in a carrier


         stream of pure oxygen or air.  The oxygen flow carries the  steam and


         C02 out of the furnace where the steam is condensed and the condensate


         removed.  The C02, oxygen, and remaining water vapor enter  an  infrared


         analyzer sensitized to provide a measure of CO-.  The amount of CO™


         present is directly proportional to the concentration of carbonaceous


         material in the injected sample.


3.  Definitions


    3.1  The carbonaceous  analyzer measures all of the carbon in a sample


         after injection into the combustion tube.  Because of various  properties


         of carbon-containing compounds in liquid samples, preliminary  treat-


         ment of the sample prior to injection dictates the definition  of the


         carbon as it is measured.

         Forms pf carbon that are measured by the combustion-infrared method


         are:
                                      221

-------
                                                     (Organic  Carbon)




               A)   soluble,  nonvolatile organic carbon;  for  instance,



                   natural  sugars.



               B)   soluble,  volatile  organic  carbon;  for instance, mercaptans.



               C)   insoluble,  partially volatile carbon;  for instance, oils.



               D)   insoluble,  particulate  carbonaceous materials, for



                   instance, cellulose  fibers.



               E)   soluble or  insoluble carbonaceous  materials adsorbed or



                   entrapped on  insoluble  inorganic suspended matter; for



                   instance, oily matter adsorbed on  silt particles.



    3.2  The  final usefulness of the carbon  measurement is  in assessing the



         potential oxygen-demanding load  of  organic  material on a receiving



         stream.  This statement applies  whether the carbon measurement is



         made  on a sewage plant effluent, industrial waste, or on water taken



         directly from the stream.  In  this  light, carbonate and bicarbonate



         carbon are not a part of the oxygen demand  in the stream and there-



         fore  should be discounted in the final calculation or removed prior



         to analysis.  The manner of preliminary treatment therefore defines



         the types of carbon which are measured.



4.  Sample Handling and Preservation



    4.1  Sampling and storage of samples in glass bottles is preferable.



         Sampling and storage in plastic bottles such as conventional poly-



         ethylene and cubitainers is permissible if it is established that



         the containers do not contribute contaminating organics to the



         samples (Note 1).



         Note 1 -  A brief study performed in the AQC Laboratory indicated



         that distilled water  stored in new,  one quart cubitainers  did not



         show any  increase  in  organic carbon after two weeks exposure.
                                     222

-------
                                                     (Organic Carbon)


    4.2  Because of the possibility of oxidation or bacterial decomposition


         of some components of aqueous samples, the lapse of time between


         collection of samples and start of analysis should be kept to a


         minimum.  Also, samples should be kept cool (4°C) and protected


         from sunlight and atmospheric oxygen.


    4.3  In instances where analysis cannot be performed within two hours


         (2 hours) from time of sampling, it is recommended that the sample be


         acidified (pH = 2) with HC1 or H2S04.


5.  Interferences


    5.1  Carbonate and bicarbonate carbon represent an interference under


         the terms of this test and must be removed or accounted for in the

                        I
         final calculation.


    5.2  This procedure is applicable only to homogeneous samples which can


         be injected into the apparatus reproducibly by means of a microliter


         type syringe.  The needle openings of the syringe limit the maximum


         size of particles which may be included in the sample.  (Cf 6.3)


6.   Apparatus


    6.1  Apparatus for blending or homogenizing samples:


         Generally, a Waring-type blender is satisfactory.


    6.2  Apparatus for total and dissolved organic carbon:


         6.2.1  Dow-Beckman Carbonaceous Analyzer, (single channel) or


         6.2.2  Dow-Beckman Carbonaceous Analyzer Model No. 915 (dual


                channel).


    6.3  Hypodermic syringe, 0-50 ul, needle opening of approximately


         150 microns;  Hamilton No. 705 N or equivalent is satisfactory.


         6.3,1  Hamilton No. 750 N, 0-500 yl has a needle opening of approxi-


                mately 400 microns and may be used for samples containing large
                                     223

-------
                                                         (Organic Carbon)

                particulates.

         6.3.2  Hamilton No. CR-700-20 for 20 pi size and No.  CR-700-200

                for 200 yl size, needle point style No.  3,  are push button

                syringes which insure uniformity of injection  rate.

7.   Reagents and Materials

    7.1  Distilled water used in preparation of standards and  for dilution

         of samples should be ultra pure to reduce the size of the blank.

         Carbon dioxide-free, double distilled water is  recommended.   Ion

         exchanged waters are not recommended because of the possibility of

      ,   contamination with organic materials from the resins.

    7.2  Potassium Hydrogen Phthalate,  stock solution, 1000 mg carbon/liter:

         Dissolve 0.2128 g of potassium hydrogen phthalate  (Primary Standard

         Grade)  in double distilled water and dilute to  100.0  ml.

         Note:   Sodium oxalate and acetic acid are not recommended as  stock

         solutions.

    7.3   Potassium Hydrogen Phthalate,  standard solutions:   Prepare standard

         solutions  from the stock solution with double distilled water as

         follows:

                   ml  of Stock Solution              Standard
                   Diluted to 100 ml                mg C/liter

                          1.0                         10
                          2.0                         20
                          3.0                         30
                          4.0                         40
                          5.0                         50
                          6.0                         60
                          8.0                         80
                         10.0                         100

   7.4   Carbonate-bicarbonate, stock solution,  1000  mg carbon/liter:  Weigh

         0.3500 g of sodium bicarbonate  and 0.4418  g  of sodium carbonate

         and transfer both  to  the same  100 ml volumetric flask.  Dissolve with
                                    224

-------
                                                   (Organic Carbon)




     double distilled water.




7.5  Carbonate-bicarbonate, standard solution:   Prepare a series  of



     standards similar to 7.3.




7.6  Blank solution:  Use the same distilled water (or similar quality



     water) used for the preparation of the standard solutions.



7.7  Packing for total carbon tube.  Dissolve 20 g of Co(N0_)2.6H~0



     (cobalt nitrate hexahydrate) in 50 ml of distilled water. Add this



     solution to 15 grams of long-fiber asbestos in a porcelain evaporating



     dish.  Mix and evaporate to dryness on a steam bath.   Place  the dish



     in a cold muffle furnace and bring to a temperature of 950°C.   After



     one to two hours at this temperature, remove the dish and allow to



     cool.  Break up any large lumps and mix adequately but not excessively.



     With the combustion tube held in a vertical position, taper  joint up,



     put about 1/2" of untreated asbestos in the tube first, then transfer,



     in small amounts, approximately one gram of catalyst  into the tube



     with forceps or tweezers.  As it is added,  tap or push the material



     gently with a 1/4" glass rod.  Do not force the packing.   The weight



     of the rod itself is sufficient to compress the material. When



     completed, the length of the packing should be about  five or six



     centimeters.  Test the packed tube by measuring the flow rate of



     gas through it at room temperature, and then at 950°C.  The  rate



     should not drop more than 20%.



7.8  Packing for carbonate tube, (dual channel  instrument).  Place a small



     wad of quartz wool or asbestos near the exit end of the carbonate



     evolution tube.  From the entrance end add 6-12 mesh quartz  chips,



     allowing these to collect against the wad to a length of 10  cm.  Pour
                                 225

-------
                                                           (Organic  Carbon)





          an excess of 85 percent phosphoric acid into  the  tube while holding




          it vertically,  and allow the excess to  drain  out.




 8.   Instrument Adjustment




     8.1   Turn on the infrared analyzer,  recorder,  and  tube furnances, setting




          the total carbon furnace at  950°C  and the carbonate furnace at 175°C.




          Allow a warm-up time of at least 2 hr.  for attainment of stable




          operation;  in daily use the  analyzer can  be left  on continuously.




          Adjust  the  oxygen flow  rate  to  80  to 100  ml/min through the total




          carbon  tube.  With the  recorder set at  the appropriate mv range,




          adjust  the  amplifier gain so  that  a 20-nl  sample of the 100 mg/liter




          carbon  standard gives a peak  height of  approximately half the recorder




          scale  (see  7.3).   At  this setting  the noise level should be less than




          0.5 percent of  full  scale.  If  the  noise  level is higher, the analyzer




          or the  recorder may require servicing.




          8.1.1   Single channel unit may  be  equipped with a large-diameter com-




                bustion  tube and  the dual channel unit with a Hastalloy tube for




                the total carbon  channel.   In such  cases, a 100-yl sample may be




                injected and appropriate standards  in the range of 1 to 30




                mg/1 carbon used.




9.  Calibration - Dual Channel Instrument




    9.1  Successively introduce 20 yl  of each phthalate standard into the




         total carbon tube and read the height of the corresponding peak.




         Between injections allow the  recorder pen to return to its base line.




         The actual injection technique is as follows:   Rinse the syringe




         several times with the solution to be analyzed, fill,  and adjust to




         20 yl.  Wipe off the excess with soft paper tissue, taking care that
                                      226

-------
                                                         (Organic Carbon)




          no lint adheres to the needle.  Remove the plug from the syringe



          holder, insert the sample syringe, and inject the sample into



          the combusion tube with a single, rapid movement of the index



          finger.  Leave the syringe in the holder until the flow rate returns



          to normal, then replace it with the plug.  Run duplicate determinations



          on each solution and on a water blank.



     9.2  Correct standards for blank correction as follows:  Standard peak



          height minus blank peak height = correct peak height in mm.   Prepare



          a standard curve of total carbon versus peak height.



     9.3  In the same way, prepare a series of diluted carbonate standards



          containing 20, 40, 60, 80, and 100 mg of inorganic carbon per liter.



          Turn the four-rway valve of the apparatus to direct the gas flow



          through the low temperature tube and to the analyzer.   Adjust the flow



          rate to 80 to 100 ml/min and allow the baseline to become stabilized.



          Successively introduce 20 pi of each standard and a water blank  in



          duplicate into the low temperature tube and read the peak heights as



          previously described.



     9.4  Prepare a standard curve of inorganic carbon versus peak height



          applying the correction as noted in 9.2.



10.   Procedure - Dual Channel Instrument - Unpreserved samples.



    10.1  Mix or blend each sample thoroughly and carry out any appropriate



          dilution to bring the carbon content within the range of the standard




          curve.



    10.2  Following the technique described in 9.1 and 9.3, inject 20-pl



          samples successively (in duplicate) into each tube and read the  peak



          heights corresponding to total carbon and inorganic (carbonate)  carbon.
                                       227

-------
                                                          (Organic Carbon)





            From the  appropriate  calibration curve and each peak height



            observed, read  the  corresponding carbon concentration in mg/liter.



      10.3   Substract the inorganic carbon value from the total carbon value.



            The  difference  thus obtained is operationally defined as Total



            Organic Carbon.  These values may be different from values obtained



            on acid-blown samples.  Results may be verified by operating the



            unit  as a single channel system, i.e., injecting an acidified



            nitrogen-purged sample into the high temperature furnace side and



            comparing results.




      10.4   Filter a 100 ml aliquot through a pre-rinsed 0.45 p pore size filter.



            Repeat sample injection as in 10.2.



      10.5   Subtract the dissolved inorganic carbon value from the dissolved



            carbon value.  The difference thus obtained is operationally defined



            as Dissolved Organic Carbon.  These values may be different from



           values obtained on acid-blown samples.  Results may be verified by



           operating the unit as a single channel system, i.e., injecting an



           acidified nitrogen-purged sample into the high temperature furnace



           side and comparing results.



11.  Calibration - Single Channel Instrument



     11.1  Standardize the instrument according to directions given in 9.1 and



           9.2.



12.  Procedure - Single Channel Instrument



     12.1  Transfer a representative aliquot of about 10 - 15 ml to a 30 ml



           beaker.  If not already acid preserved, add 2 or more drops of con-



           centrated HC1 until the pH is reduced to = 2 and purge with C02



           nitrogen gas for about 5-10 minutes (do not use plastic tubing).
                                        228

-------
13.
                                                       (Organic Carbon}



      Place the beaker on a magnetic stirrer and while stirring withdraw

      a 20 ul sample.  Inject the sample as in 9.1.

12.2  Obtain concentration directly from standard curve.   The carbon thus

      measured is operationally defined as Total Organic  Carbon.

12.3  Filter a 100 ml aliquot through a pre-rinsed 0.45 y pore size filter

      and proceed as in 12.1.

12.4  Obtain concentration directly from standard curve.   The carbon thus

      measured is operationally defined as Dissolved Organic Carbon.

Precision and Accuracy

13.1  Twenty-eight analysts in twenty-one laboratories analyzed distilled

      water solutions containing exact increments of oxidizable organic

      compounds, with the following results:
      Increment as
      TOC
      mg/liter
                              Precision as
                              Standard Deviation
                              TOC,  mg/liter
    Accuracy as
 Bias,
  Bias,
mg/liter
         4.9

         107
                                   3.93

                                   8.32
+15.27      + .75

+ 1.01      +1.08
      (FWQA Method Study 3, Demand Analyses)
                                          229

-------
                                   pH




                                                 STORE! Number:  00400



1.  Scope and Application



    1.1  This method is applicable to drinking waters and surface waters,



         domestic and industrial wastes, and saline waters.



2.  Summary of Method



    2.1  The pH of a sample is an electrometric measurement, using either



         a glass electrode in combination with a reference potential



         (saturated calomel electrode) or a combination electrode (glass



         and reference).



3.  Comments



    3.1  The sample must be analyzed as soon as practical; preferably within



         a few hours.  Do not open sample bottle before analyses.



    3.2  Oil and greases, by coating the pH electrode, may interfere by



         causing sluggish response.



    3.3  At least three buffer solutions must be used to initially standardize



         the instrument.  They should cover the range of pH of the samples



         to be measured.



    3.4  Field pH measurements using comparable instruments are reliable.




4.  Precision and Accuracy



    4.1  Forty-four analysts in twenty laboratories analyzed six synthetic



         water samples containing exact increments of hydrogen-hydroxyl ions,




         with the following results:
                                     230

-------
                                                         CpH)
Increment as
pH Units
3.5
3.5
7.1
7.2
8.0
8.0
Precision as
Standard Deviation
pH Units
0.10
0.11
0.20
0.18
0.13
0.12
Accuracy
Bias,
%
-0.29
-0.00
+1.01
-0.03
-0.12
+0.16
as
Bias,
pH Units
-0.01
—
+0.07
-0.002
-0.01
+0.01
(FWPCA Method Study 1, Mineral and Physical Analyses)


    4.2  In a single laboratory (AQC),  using surface water samples at an

         average pH of 7.7, the standard deviation was ±0.1.

5.   Reference

    5.1  The procedure to be used for this determination is found in:
                        \
         Standard Methods for the Examination of Water and Wastewater,

         13th Edition, p. 276, Method 144A (1971).

         ASTM Standards, Part 23, Water; Atmospheric Analysis, p. 280,

         Method D1293-65 (1970).
                                     231

-------
                                PHENOLICS




                     (4-AAP Method With Distillation)
                                                            STORET NO. 32730
1.  Scope and Application




    1.1  This method is applicable to the analysis of drinking waters,




         surface waters, domestic and industrial wastes and saline waters.




    1.2  The method is capable of measuring phenolic materials from




         about 5 yg/1 to about 1000 yg/1 when the colored end product is




         extracted and concentrated in a solvent phase using phenol as a




         standard.




    1.3  The method is capable of measuring phenolic materials from about




         SO yg/1 to about 5000 yg/1 in the aqueous phase (without solvent




         extraction) using phenol as a standard.




    1.4  It is not possible to use this method to differentiate between




         different kinds of phenols.




2.  Summary of Method




    2.1  Phenolic materials react with 4-aminoantipyrine in the presence of




         potassium ferricyanide at a pH of 10 to form a stable reddish-




         brown colored antipyrine dye.  The amount of color produced is a




         function of the concentration of phenolic material.




3.  Comments




    3.1  For most samples a preliminary distillation is required to remove




         interfering materials.




    3.2  Color response of phenolic materials with 4-aminoantipyrine is




         not the same for all compounds.  Because phenolic type wastes
                                      232

-------
                                                            (Phenolics)





         usually contain a variety of phenols,  it  is  not possible  to


         duplicate a mixture of phenols  to be used as a standard.   For


         this reason phenol itself has been selected  as a  standard and


         any color produced by the reaction of other  phenolic  compounds  is


         reported as phenol.  This value will represent the  minimum con-


         centration of phenolic compounds present  in  the sample.


    3.3  Control of the pH of the reaction may be  accomplished using


         the procedure detailed in Standard Methods (Page  506, 13th


         Edition) or ASTM, Part 23, Page 523 (Nov. 1970) or  by the use


         of the ammonium hydroxide-ammonium chloride  buffer  used  in the


         water hardness test Standard Methods,  13th Edition, Page 181,


         (1971).        !
                        I

4.  Precision and Accuracy


    4.1  Using the extraction procedure  for concentration  of color, six


         laboratories analyzed samples at concentrations of  9.6,  48.3


         and 93.5 yg/1.  Standard deviations were, respectively,  0.99,


         3.1 and 4.2 yg/1.


    4.2  Using the direct photometric procedure,  six  laboratories analyzed


         samples at concentrations of 4.7, 48.2 and 97.0 mg/1.


    4.3  American Society for Testing and Materials,  Part  23,  pp. 524-525


         Method D-1783-70 (1970).
                                      233

-------
                                                        (Phenolics)
5.  References

         The procedure to be used for this determination is found in:

             Standard Methods for the Examination of Water and Waste-
             water, 13th Edition, pp. 501-510, Method No. 222 through
             222E (1971).

             American Society for Testing and Materials, Part 23,
             pp. 519-525, Method D-1783-70 (1970).
                                    234

-------
                             PHOSPHORUS, ALL FORMS

                            (Single Reagent Method)         STORET NO:

                                                              SEE TABLE 1
1.  Scope and Application


    1.1  These methods cover the determination of specified forms of phosphorus


         in surface waters, domestic and industrial wastes, and saline waters.


         They may be applicable to sediment-type samples,  sludges, algal  blooms,

         etc., but sufficient data is not available at this time to warrant  such


         usage when measurements for phosphorus content are required.

    1.2  The methods are based on reactions that are specific for the ortho-


         phosphate ion.  Thus, depending on the prescribed pre-treatment  of  the


         sample, the various forms of phosphorus given in  Figure 1 may be determined.


         These forms are, in turn, defined in Table 1.


         1.2.1  Except for in-depth and detailed studies,  the most commonly


                measured forms are phosphorus and dissolved phosphorus, and  ortho-


                phosphate and(dissolved orthophosphate. Hydrolyzable phosphorus


                is normally found only in sewage-type samples and insoluble  forms


                of phosphorus, as noted, are determined by calculation.


    1.3  The methods are usable in the 0.01 to 0.5 mg/1 P  range.


2.  Summary of Method


    2.1  Ammonium molybdate and potassium antimonyl tartrate react in an acid


         medium with dilute solutions of phosphorus to form an antimony-phospho-

         molybdate complex.  This complex is reduced to an intensely blue-colored


         complex by ascorbic acid.  The color is proportional to the phosphorus


         concentration.


    2.2  Only orthophosphate forms a blue color in this test.  Polyphosphates (and


         some organic phosphorus compounds) may be converted to the orthophosphate


         form by sulfuric-acid-hydrolysis.  Organic phosphorus compounds may be
                                        235

-------
NJ
w
c\
        Residue
                               SAMPLE
                                              Total Sample (No Filtration)
                                                   V
                                                          Direct
                                                          Colorimetry
                         Hydrolysis
                      _\ r  Pn 1 iyg_i ffl^n
                                                  Orthophosphate
                       Hydrolyzable §
                       Orthophosphate
                                       Filter (through 0.45 p membrane filter)
                                \/
                                                       \/
Filtrate
>
Direct
Colorimetry
/
Dissolved
Orthophosphate

s
H2S04
Hydrolysis §
i Colorimetry .
Diss. Hydrolyzable
§ Orthophosphate

Persulfate
Digestion §
.Colorimetry
Dissolved
Phosphorus
    Persulfate
    Digestion
Phosphorus
                   Figure 1.  Analytical  Scheme for Differentiation of Phosphorus Forms.

-------
                                                             (Phosphorus)



        converted to the orthophosphate form by sulfuric-acid-hydrolysis.


        Organic phosphorus compounds may be converted to the orthophosphate

                                     (2i
        form by persulfate digestion. *• '


3.  Definitions


    3.1  The various forms of phosphorus are defined in Table 1.


4.  Sampling Handling and Preservation


    4.1  If benthic deposits are present in the area being sampled,  great  care


        should be taken not to include these deposits.


    4.2  Sample containers may be of plastic material, such as cubitainers,  or


       .of Pyrex glass.


    4.3  If the analysis cannot be performed the same day of collection, the


        sample should be preserved by the addition of 40 mg HgCl- per liter  and


        refrigeration at 4°C.  Note HgCl- interference under 5.4.
                                        238

-------
                                                              (Phosphorus)

                                 TABLE 1 .
                         PHOSPHORUS TERMINOLOGY

 1.   Phosphorus (P)  - all of the phosphorus  present  in  the  sample,  regardless
     of form,  as measured by the persulfate  digestion procedure.   (00665)
     a.   Orthophosphate (P,  ortho)  - inorganic phosphorus  [(P04)~  ]  in  the sample
         as  measured by the  direct  colorimetric analysis procedure.  (70507)
     b.   Hydrolyzable Phosphorus (P, hydro)  -  phosphorus in the sample  as
         measured by the sulfuric acid hydrolysis procedure, and minus  pre-
         determined  orthophosphates.  This hydrolyzable phosphorus  includes poly-
                          "
        phosphates  [(PoO-)"  ,  (P30^o)~>  etc.]  +  some organic phosphorus. (00669)
     c.  Organic  Phosphorus  (P, org)  - phosphorus  (inorganic + oxidizable organic)
        in the sample  as measured by the  persulfate digestion procedure, and
        minus hydrolyzable phosphorus and orthophosphate .  (00670)
2.   Dissolved Phosphorus (P-D) - all of the phosphorus present in the filtrate
     of a sample  filtered through a phosphorus -free filter of 0.45 micron pore
     size and measured by the persulfate digestion procedure.  (00666)
     a.  Dissolved Orthophosphate (P-D, ortho) - as measured by the direct color-
        imetric  analysis procedure.  (00671)
    b.  Dissolved Hydrolyzable Phosphorus (P-D, hydro) - as measured by the
        sulfuric acid hydrolysis procedure and minus pre-determined dissolved
        orthophosphates . (00672)
    c.  Dissolved Organic Phosphorus (P- D, org) - as measured by the persulfate
        digestion procedure, and minus dissolved hydrolyzable phosphorus and
        orthophosphate.  (00673)
3.  The following forms, when sufficient amounts of phosphorus are present in
    the sample to warrant such consideration, may be calculated:
                                       239

-------
                                                            (Phosphorus)





                          TABLE 1  (Continued)




    a.  Insoluble Phosphorus (P-I) = (P) - (P-D).  (00667)
                             *

        (1)  Insoluble orthophosphate (P-l, ortho) =  (P, ortho) -  (P-D, ortho).  (00674)



        (2)  Insoluble Hydrolyzable Phosphorus  (P-I, hydro) = (P, hydro) -



             (P-D, hydro). (00675)



        (3)  Insoluble Organic Phosphorus (P-I, org) = (P, org) -  (P-D, org).(00676)



4.  All phosphorus forms shall be reported as P, mg/1 , to  the third place.



5.  Interferences



    5.1  It is reported  (1) that no interference is caused by copper, iron, or



         silicate at concentrations many times greater than their greatest re-



         ported concentration in sea water.  However, high iron concentrations



         can cause precipitation of phosphorus through the formation of clumps



         in the bottom of the sample.

                            i

    5.2  The salt error  forisamples ranging from 5 to 20 percent salt content was
                            i
                            \

         found to be less than 1 percent(l).



    5.3  Arsenate, in concentrations greater than found in sea water, does not



         interfere*-1'.



    5.4  Mercury chloride, used as a preservative, interfers when  the chloride



         level of the sample is low (<50 mg cl/l).  This interference is overcome



         by spiking samples with a minimum of 50 mg/1 of sodium chloride.



6.  Apparatus



    6.1  Photometer - A  spectrophotometer or filter photometer suitable for



         measurements at 880 nm, and providing  a light path of 1 inch  (2.54 cm)



         or longer, should be used.
                                       240

-------
                                                         (Phosphorus)






    6.2  Acid-washed glassware:  All glassware used in the determination should




         be washed with hot '1:1"HCVand rinsed with distilled water.   The acid-




         washed glassware should be filled with distilled water and treated with




         all the reagents to remove the'last traces of phosphorus that might be




         adsorbed on the glassware.  Preferably, this glassware should be used




         only for the determination of phosphorus and after use it should be




         rinsed with distilled water and kept covered until needed again.   If




         this is done,  the treatment with 1:1 HC1 and reagents is only required




         occasionally.   Commercial detergents should never be used.




7.   Reagents




    7.1  Sulfuric acid  solution,  5N:  Dilute 70 ml of cone.  H2SO. with distilled




         water to 500 ml.




    7.2  Potassium antimonyl tartrate solution:   Weigh 1.3715 g K(SbO)C4H406.




         1/2 H20,  dissolve in 400 ml distilled water in 500 ml volumetric flask,




         dilute to volume.   Store at 4°C in a dark,  glass-stoppered bottle.




    7.3  Ammonium molybdate solution:  , Dissolve 20 g (NH.)^07024.4H.-0 in  500 ml




         distilled water.   Store  in a plastic bottle at 4°C.




    7.4  Ascorbic acid,  0.1M:   Dissolve 1.76 g of ascorbic acid in 100 ml  of




         distilled water.   The solution is  stable for about  a week if  stored at




         4°C.




    7.5  Combined  reagent:   Mix the above reagents in the  following proportions




         for 100 ml of the mixed  reagent:   50 ml  of  5N H2S04,  5 ml  of  potassium




         antimonyl  tartrate  solution,  15 ml of ammonium molybdate solution,  and




         30  ml  of  ascorbic  acid solution.   Mix after addition of  each  reagent.
                                      241

-------
                                                        (Phosphorus)





         All reagents must reach room temperature before they  are mixed  and



         must be mixed in the order given.   If turbidity forms in the



         combined reagent, shake and let it stand for a few minutes until the



         turbidity disappears before processing.  The reagent  is stable  for



         one week if stored at 4°C.



    7.6  Strong-acid solution:  Slowly add  310 ml cone.  H-SCK  to 600 ml  dis-



         tilled water.  When cool,  dilute to 1 liter.



    7.7  Ammonium persulfate.



    7.8  Stock Solution:  Dissolve  in distilled water 0.2197 g of potassium




         dihydrogen phosphate, KH PO., which has  been dried in an oven at



         105°C.  Dilute the solution to 1.0 1; 1.00 ml equals  0.05 mg  P.



    7.9  Standard Solution:  Dilute 10.0 ml of stock phosphorus solution to



         1.0 1 with distilled water; 1.00 ml equals 0.5 yg P.



         7.9.1  Using standard solution, prepare  the following standards



                in 50.0 ml volumetric flasks:



                        ml of Standard Solution     Cone., mg/1
0
1.0
3.0
5.0
10.0
20.0
30.0
40.0
50.0
0.00
0.01
0.03
0.05
0.10
0.20
0.30
0.40
0.50
8.   Procedure



    8.1  Phosphorus



         8.1.1  Add 1 ml of strong-acid solution to a 50 ml sample in a




                125-ml Erlenmeyer flask.
                                    242

-------
                                                       (Phosphorus)




      8.1.2  Add 0.4 gram of ammonium persulfate.



      8.1.3  Boil gently on a pre-heated hot plate  for approximately



             30-40 minutes or until a final volume  of about  10 ml  is



             reached.   Do not allow sample to go to dryness.  Alter-



             natively,  heat for 30 minutes in an autoclave at 121°C



             (15-20 psi).




      8.1.4  Add phenolphathalein and adjust sample to pink with IN NaOH.



             Bring back to colorless  with one drop  of strong acid  solution.



             Cool and dilute  the sample  to 50.0  ml.   If sample is  not clear



             at  this point,  filter.



      8.1.5  Determine  phosphorus  as  outlined in 8.3.2 Orthophosphate.



 8.2   Hydrolyzable Phosphorus



      8.2.1   Add 1 ml of strong-acid  solution to a  50-ml sample in a. 125-ml



             Erlenmeyer flask.



      8.2.2   Boil  gently on a pre-heated hot  plate  for 30-40 minutes or until




             a final volume of  about  10 ml  is  reached.  Do not allow sample



             to  go to dryness.   Alternatively, heat  for 30 minutes in an



             autoclave  at  121°C  (15-20 psi).



      8.2.3  Add phenolphthalein and  adjust sample to pink with 1  N NaOH.



            Bring back  to colorless with one drop strong-acid solutions.  Cool




            and dilute  the sample to 50 ml.



      8.2.4  The sample  is now ready  for determination of phosphorus as outlined



            in 8.3.2 Orthophosphate.



8.3  Orthophosphate



     8.3.1  Add 1 drop of phenolphthalein indicator to the 50.0 ml sample.



            If a red color develops, add strong-acid solution drop-wise




            to just discharge the color.
                                243

-------
                                                              (Phosphorus)




          8.3.2  Add 8.0 ml of combined reagent to sample and mix thoroughly.



                 After a minimum of ten minutes, but no longer than thirty



                 minutes, measure the color absorbance of each sample at 880



                 nm with a spectrophotometer, using the reagent blank as the



                 reference solution.



 9.  Calculation




     9.1  Prepare standard curve by plotting absorbance values of standards




          as ordinates and the corresponding phosphorus concentrations as abscissas.



          9.1.1  Process standards and blank exactly as the samples.   Run at



                 least a blank and two standards with each series of samples.   If



                 the standards do not agree within *2% of the true value,



                 prepare a new calibration curve.



     9.2  Obtain concentration value of sample directly from prepared standard



          curve.  Report results as P, mg/1.



10.  Precision and Accuracy  1



    10.1  Thirty-three analysts in nineteen laboratories analyzed natural water



          samples containing exact increments of organic phosphate, with the



          following results:
Increment as
Total Phosphorus
rag P/liter
0.110
0.132
0.772
0.882
Precision as
Standard Deviation
mg P/liter
0.033
0.051
0.130
0.128
Accuracy
Bias,
% mg
+ 3.09
+11.99
+ 2.96
- 0.92
as
Bias,
P/liter
+ .003
+ .016
+ .023
-.008 ,
     (FWPCA Method Study 2, Nutrient Analyses).



    10.2  Twenty-six analysts in sixteen laboratories analyzed natural water



          samples containing exact increments of orthophosphate,  with the




          following results:






                                      244

-------
                                                         (Phosphorus)
Increment as
Orthophosphate
mg P/liter
0.029
0.038
0.335
0.383
Precision as
Standard Deviation
mg P/liter
0.010
0.008
0.018
0.023
Accuracy
Bias,
% mg
-4.95
-6.00
-2.75
-1.76
as
Bias,
P/liter
.001
.002
.009
.007
     (FWPCA Method Study 2, Nutrient Analyses)
                                     References
1.  J. Murphy and J. Riley, "A Modified Single Solution Method for the




    Determination of Phosphate in Natural Waters."  Anal.  Chim. Acta., 27,  31




    (1962).




2.  M. Gales, Jr., E. Julian, and R. Kroner, "Method for Quantitative  Deter-




    mination of Total Phosphorus in Water."  Jour AWWA, 58, No. 10, 1363 (1966)
                                       245

-------
                           PHOSPHORUS, ALL FORMS

                     (Automated Single Reagent Method)       STORE! NO-
                                                              SEE TABLE 1
1.  Scope and Application

    1.1  These methods cover the determination of specified forms of phosphorus

         in surface waters, domestic and industrial wastes, and saline waters.

         They may be applicable to sediment-type samples, sludges, algal blooms,

         etc., but sufficient data is not available at  this time to warrant such

         usage when measurements for phosphorus content are required.

    1.2  The methods are based on reactions that are specific for the ortho-

         phosphate ion.  Thus, depending on the prescribed pre-treatment of

         the sample, the various forms of phosphorus given in Figure 1 may be

         determined.  These forms are, in turn, defined in Table 1.

         1.2.1  Except for in-depth and detailed studies, the most commonly

                measured forms are phosphorus and dissolved phosphorus, and

                orthophosphate and dissolved orthophosphate.  Hydrolyzable

                phosphorus is normally found only in sewage-type samples and

                insoluble forms of phosphorus, as noted, are determined by

                calculation.

    1.3  The methods are usable in the 0.01 to 1.0 mg P/l range.  Approximately

         20 samples per hour can be analyzed.

2.  Summary of Method

    2.1  Ammonium molybdate and potassium antimonyl tartrate react in an acid

         medium with dilute solutions of phosphorus to form an antimony-ph.osph.o-

         molybdate complex.  This complex is reduced to an intensely blue-colored

         complex by ascorbic acid.  The color is proportional to the phosphorus

         concentration.
                                       246

-------
N)
                                  SAMPLE
                                                     Total Sample  (No  Filtration)
                                                                                   \/
                                                               Direct

                                                               Colorimetry
    Hydrolysis
\/  Colorimetrv
                                                       Orthophosphate
 Hydrolyzable §
  Orthophosphate
                                           Filter (through 0.45 y membrane filter)
\
Direct
Colorimetry
/ \
Dissolved
Orthophosphate

H2S04
Hydrolysis §
/ Colorimetry ^
Diss. Hydrolyzable
§ Orthophosphate

Persulfate
Digestion §
/ Colorimetry
Dissolved
Phosphorus
   Persulfate

   Digestion
\l/ Colorimetrv
 Phosphorus
                     Figure 1.   Analytical Scheme for Differentiation of Phosphorus Forms.

-------
                                                               (Phosphorus)





    2.2  Only orthophosphate forms a blue color in this  test.   Polyphosphates




         (and some organic phosphorus compounds)  may be  converted  to  the




         orthophosphate form by manual sulfuric-acid-hydrolysis.   Organic




         phosphorus compounds may be converted to the orthophosphate  form by




         manual persulfate digestion   .   The developed  color  is measured




         automatically on the AutoAnalyzer.




3.  Definitions




    3.1  The various forms of phosphorus  are defined in  Table  1.




4.  Sample Handling and Preservation




    4.1  If benthic deposits are present  in the area being sampled, great  care




         should be taken not to include these deposits.




    4.2  Sample containers may be of plastic material, such as cubitainers,  or




         of Pyrex glass.




    4.3  If the analysis cannot be performed the same day of collection,  the




         sample should be preserved by the addition of 40 mg HgCl2 per liter




         and refrigeration at 4°C.  Note HgCl- interference under 5.4.
                                        249

-------
 TABLE I:  PHOSPHORUS TERMINOLOGY                         (Phosphorus)




 1.  Phosphorus - all of tb_e phosphorus present in the sample regardless of



     form, as measured by the persulfate digestion procedure.  (00665)

                                                            _T

     a.  Orthophosphate (P-ortho)-inorganic phosphorus [PO.)   ]  in the  sample



         as measured by the direct colorimetric analysis  procedure. (70507)



     b.  Hydrolyzable Phosphorus (P-hydro)-phosphorus  in  the  sample as



         measured by the sulfuric acid hydrolysis procedure,  and minus  pre-



         determined orthophosphates.   This  hydrolyzable phosphorus includes


                               -4         -5
         polyphosphates [(PJD-)   , (P 0  )   ,  etc.]  +  some  organic phosphorus. (00669)



     c.  Organic Phosphorus (P-org)-phosphorus (inorganic + oxidizible  organic)



         in the sample as  measured by the persulfate digestion procedure,  and



         minus  hydrolyzable phosphorus and  orthophosphate.  (00670)



 2.   Dissolved  Phosphorus  (P-D)  - all of the phosphorus present  in the  filtrate



     of a sample filtered  through a phosphorus-free  filter of 0.45 micron  pore



     size and measured by  the persulfate digestion procedure.  (00666)



     a.   Dissolved Orthophosphate (P-D,  ortho)  -  as  measured by  the direct



         colorimetric  analysis procedure.  (00671)



    b.   Dissolve Hydrolyzable Phosphorus (P-D, hydro)  -  as measured by  the



         sulfuric acid  hydrolysis  procedure  and minus pre-determined dissolved



         orthophosphates.  (00672)



    c.   Dissolved Organic  Phosphorus  (P-D,  org)  - as measured by  the persulfate



         digestion procedure, and  minus  dissolved hydrolyzable phosphorus  and



        orthophosphate.  (00673)



3.   The following forms, when sufficient amounts of phosphorus  are present in



    the sample to warrant such consideration, may be calculated:
                                       250

-------
                                                             (Phosphorus)





    a.  Insoluble Phosphorus (P-I) = (P) - (P-D).   (00667)




        (1)  Insoluble orthophosphate (P-I, ortho) = (P, ortho) -




             (P-D, ortho).  (00674)




        (2)  Insoluble Hydrolyzable Phosphorus (P-I,  hydro) =




             (P, hydro) - (P-D, hydro).  (00675)




        (3)  Insoluble Organic Phosphorus (P-l, org)  = (P, org) -




             (P-D, org).  (00676)




4.  All phosphorus forms shall be reported as P, mg/1, to the third place.




5.  Interferences




    5.1  It is reported^ ' that no interference is caused by copper, iron, or




         silicate at concentrations many times greater than their greatest




         reported concentration in sea water.  However, high iron concentrations




         can cause precipitation of phosphorus through the formation of clumps




         in the bottom of the sample.




    5.2  The salt error fox* samples ranging from 5 to 20 percent salt content




         was found to be less than 1 percent^ •*.




    5.3  Arsenate, in concentrations greater than found in sea water, does




         not interfere  '.




    5.4  Mercury chloride, used as a preservative, interferes.  This interference




         is overcome by substituting a solution of sodium chloride  (2.5 g/1) in




         place of the distilled water (Line YY, 1.20 ml/min).




6.  Apparatus




    6.1  Technicon AutoAnalyzer consisting of:




         6.1.1  Sampler I




         6.1.2  Manifold




         6.1.3  Proportioning Pump
                                         251

-------
                                                            (Phosphorus)




          6.1.4  Heating Bath,  50°C




          6.1.5  Colorimeter  equipped with 50 nan tubular flow cell and



                 650  nm filters



          6.1.6  Recorder




    6.2   Hot  Plate or Autoclave



    6.3   Acid-washed  glassware:  All glassware used in the determination



          should  be washed with hot 1:1 HC1 and rinsed with distilled water.



          The  acid-washed glassware should be filled with distilled water



          and  treated with all the reagents to remove the last traces of



         phosphorus that might be adsorbed on the glassware.  Preferably,



         this  glassware should be used only for the determination of phosphorus



         and after use it should be rinsed with distilled water and kept



         covered until needed again.   If this is done, the treatment with



         1:1 HC1 and reagents is only required occasionally.  Commercial



         detergents should never be used.



7.   Reagents



    7.1  Sulfuric acid solution, 5N:   Dilute 70 ml of cone.  H-SO. with distilled



         water to 500 ml.



    7.2  Potassium antimonyl  tartrate solution:  Weigh 0.3 g KCSbCOC.H.CL.l^



         H-0,  dissolve in 50  ml distilled water in 100 ml  volumetric flask,



         dilute to volume.  Store at  4°C  in  a dark,  glass-stoppered  bottle.



    7.3  Ammonium molybdate solution:   Dissolve 4  g  (NH.)6Mo_0_4.4H  0 in 100 ml



         distilled water.  Store in a plastic bottle at 4°C.



    7.4  Ascorbic acid,  0.1M:   Dissolve 1.8  g of ascorbic  acid  in 100 ml



         of  distilled  water.  The solution is  stable for about  a  week if stored




         at  4°C.
                                      252

-------
                                                       (Phosphorus)





 7.5  Combined reagent:  Mix the above reagents in the following proportions



      for 100 ml of the mixed reagent:  50 ml of 5N JUSO.,  5 ml  of potassium



      antimonyl tartrate solution, 15 ml of ammonium molybdate solution,  and



      30 ml of ascorbic acid solution.  MX after addition  of each reagent.



      All reagents must reach room temperature before they  are mixed and



      must be mixed in the order given.   If turbidity forms in the combined



      reagent, shake and let it stand for a few minutes until the turbidity



      disappears before processing.  This volume is sufficient for 4 hours



      operation.  Since the stability of this solution is limited, it must



      be freshly prepared for each run.



 7.6  Strong-acid solution:  Slowly add 310 ml cone. H_SO.  to 600 ml



      distilled water.  When cool, dilute to 1 liter.



 7.7  Ammonium persulfate.



 7.8  Wash water:  Add 40 ml of strong acid solution (7.6)  to 1  liter of



      distilled water andjdilute to 2 liters.  (Not to be used when  only



      orthophosphate is being determined).



 7.9  Stock Solution:  Dissolve 0.4393 g of pre-dried KH2P04 in  distilled



      water and dilute to 1 liter.  1 ml = 0.1 mg P.



7.10  Standard Solution A:  Dilute 100 ml of stock solution to 1 liter.




      1 ml = 0.01 mg P.



7.11  Standard Solution B:  Dilute 100 ml of standard solution A to  1 liter.



      1 ml = 0.001 mg P.



7.12  Prepare a series of standards by diluting suitable volumes of standard



      solutions A and B to 100.0 ml with distilled water.  The following




      dilutions are suggested:
                                    253

-------
                                                           (Phosphorus)



                                                   Cone.,
               ml of Standard Solution B           mg P/l

                         0.0                        0.00
                         2.0                        0.02
                         5.0                        0.05
                        10.0                        0.10

               ml of Standard Solution A

                         2.0                        0.20
                         5.0                        0.50
                         8.0                        0.80
                        10.0                        1.00

         Note:  When the samples to be analyzed are saline waters, Substitute

         Ocean Water (SOW) should be used for preparing the standards, other-

         wise, distilled water is used.  A tabulation of SOW composition

         follows:

                                                                 -   4.09g/l

                                                                 -   0.20g/l

                                                                     0.03g/l
                                 •J  «J                       *•

                     0.003g/l

8.   Procedure

    8.1  Phosphorus

         8.1.1  Add 1 ml of strong-acid solution to a 50 ml sample in a 125-ml

                Erlenmeyer flask.

         8.1.2  Add 0.4 grams of ammonium persulfate.

         8.1.3  Boil gently on a pre-heated hot plate for approximately

                30-40 minutes or until a final volume of about 10 ml is reached.

                Do not allow sample to go to dryness.  Alternatively, heat for

                30 minutes in an autoclave at 121°C (15-20 psi).

         8.1.4  Cool and dilute the sample to 50.0 ml.  If sample is not clear

                at this point, filter.
                                       254
NaCl
CaCl2 -
KBr
NaF
24.53g/l
1.16g/l
0.10g/l
0.003g/l
MgCl2 -
KC1
H3B03 -

5.20g/l
0.70g/l
0.03g/l

Na2S04
NaHC03
SrCl2


-------
                                                        (Phosphorus)





         8.1.5  Determine phosphorus as outlined in 8.3 Orthophosphate.



    8.2  Hydrolyzable Phosphorus



         8.2.1  Add 1 ml of strong-acid solution to a 50 ml sample in a



                125 ml Erlenmeyer flask.



         8.2.2  Boil gently on a pre-heated hot plate for 30-40  minutes  or



                until a final volume of about 10 ml is reached.   Do not



                allow sample to go to dryness.   Alternatively, heat for



                30 minutes in an autoclave at 121°C (15-20 psi) .



         8.2.3  Cool and dilute the sample to 50.0 ml.  If sample is not



                clear at this point, filter.



         8.2.4  The sample is not ready for determination of phosphorus  as



                outlined in 8.3 Orthophosphate.



    8.3  Orthophosphate



         8.3.1  Set up manifold as shown in Figure 1.



         8.3.2  Allow both colorimeter and recorder to warm up  for 30 minutes.



                Run a baseline with all reagents, feeding distilled water



                through the sample line.  Adjust dark current and operative



                opening on colorimeter to obtain stable baseline.



         8.3.3  Place wash water tubes  (see 7.8) in Sampler, in sets of 2,



                leaving every third position vacant.  Set sample timing at 1.0




                minutes.



         8.3.4  Place standards in Sampler in order of decreasing concentration.



                Complete filling of sampler tray with unknown samples.



         8.4.5  Switch sample line from distilled water to Sampler and begin




                analysis.




9.  Calculation



    9.1  Prepare standard curve by plotting peak heights of processed standards



         against known concentrations.  Compute concentrations of samples by




                                     255

-------
                                                            (Phosphorus)






           comparing sample peak heights with standard curve.   Any  sample whose




           computed value is less than 5% of its immediate predecessor must be




           rerun.




 10.  Precision and Accuracy




      10.1  Six laboratories analyzed four natural  water samples  containing exact




            increments of orthophosphate, with the  following results:
Increment as
Orthophosphate
mg P/liter
0.04
0.04
0.29
0.30
Precision as
Standard Deviation
mg P/liter
0.019
0.014, ... .
0.087
0.066
Accuracy
Bias,
%
+ 16.7
- .8.3.:. .
-15.5
-12.8
as
Bias,
mg P/liter
+ .007
-.003
-.05
-.04
      (FWQA Method Study  4, Automated Methods - In preparation).




      10.2  In  a single laboratory, using surface water samples at concentrations




           of  .04, 0.19, 0.35, and 0.84 mg P/l, standard deviations were ±0.005,




           ±0.000, ±0.003, and ±0.000, respectively (AQC Laboratory).




      10.3  In  a single laboratory, using surface water samples at concentrations




           of  0.07 and 0.76 mg P/l, recoveries were 99% and 100%, respectively




           (AQC Laboratory).







                                      References
1.  J. Murphy and J. Riley, "A Modified Single Solution Method for the




    Determination of Phosphate in Natural Waters."  Anal. Chim. Acta., 27,




    31 (1962).




2.  M. Gales, Jr., E. Julian,  and R. Kroner, "Method for Quantitative Deter-




    mination of Total Phosphorus in Water."  Jour AWWA, 58y No. 10,  1363 (1966)
                                        256

-------
N)
cn
 LARGE MIXING COIL  (LM)
	QQQQOQQQ
             HEATING BATH
              SM
             OQQQ
 SM
0000
                                            62
                COLORIMETER
           50mm TUBULAR f/c
           650  nm FILTERS
                                                        •*•
                                    WASTE
                                                                                          SAMPLER 1
                                                                            .l/.l..
                                                                            2.90    SAMPLE
                                                                            0.80    AIR
                                                                            1.20   ^DISTILLED WATER
                                                                            0.42    MIXED REAGENT
                                                           PROPORTIONING PUMP
                                                   IX
                                                          RECORDER
                                      SAMPLING TIME: 1.0 MIN.
                                      WASH TUBES: TWO
                              FIGURE  1.  PHOSPHORUS SINGLE REAGENT  MANIFOLD

-------
                           PHOSPHORUS,  ALL FORMS


                   (Automated Stannous  Chloride Method)
                                                           STORE! NO:

,    0       , .                                              SEE TABLE 1
1.  Scope and Application



    1.1  These methods cover the determination of specified forms of phosphorus



         in surface waters, domestic and industrial  wastes.   They may  be



         applicable to sediment-type samples,  sludges,  algal  blooms, etc.,  but



         sufficient data is not available at this time  to warrant such usage


         when measurements for phosphorus content are required.


    1.2  The methods are based on reactions that are specific for the  ortho-


         phosphate ion.  Thus, depending on the prescribed pre-treatment of the


         sample, the various forms of phosphorus given  in Figure 1  may be


         determined.  These forms are,  in turn, defined in Table 1.


         1.2.1  Except for in-depth and detailed studies, the most  commonly



                measured forms are phosphorus  and dissolved phosphorus, and



                orthophosphate and dissolved orthophosphate.   Hydrolyzable



                phosphorus is normally  found only in sewage-type samples 'and


                insoluble forms of phosphorus, as noted, are determined by



                calculation.



    1.3  The methods are usable in the  0.01 to 1.0 mg P/l range.



         Approximately 15 samples per hour can be analyzed.



2.  Summary of Method


    2.1  Phosphorus is determined by manually digesting the samples with ammonium


         persulfate and sulfuric acid to convert the various forms  of phosphorus


         to the orthophosphate form and measurement of this orthophosphate on the



         AutoAnalyzer.


    2.2  In this colorimetric method, ammonium molybdate reacts with the ortho-



         phosphate in an acid medium to form a heteropoly acid, molybdophosphoric
                                         259

-------
to
ON
O
                                  SAMPLE
                                               Total Sample  (No Filtration)
                                                             Direct

                                                             Colorimetry
                       H2S°4

                       Hydrolysis
                       Colorimetry
                                                      Orthophosphate
                    Hydrolyzable §

                     Orthophosphate
                                          Filter  (through 0.45p membrane filter)
                                    \/
_v
                                                       Filtrate
\
Direct
Colorimetry
/
Dissolve
Orthophosphate

Ji
H2S04
Hydrolysis §
/ Colorimetry v
Diss. Hydrolyzable
§ Orthophosphate

Persulfate
Digestion 5
i Colorimetry
Dissolved
Phosphorus
                   Figure 1.  Analytical Scheme for Differentiation of Phosphorus Forms
    Persulfate

    Digestion
\/  Colorimetry
Phosphorus

-------
                                                          (Phosphorus)





         acid.  This acid is reduced by stannous  chloride  to  form the




         intensely colored complex,  molybdenum blue, which is directly




         proportional to the amount  of phosphorus.




3.  Definitions




    3.1  The various forms of phosphorus are defined in Table 1.




4.  Sample Handling and Preservation




    4.1  If benthic deposits are present in the area being sampled,  great




         care should be taken not to include these deposits.




    4.2  Sample containers may be of plastic material,  such as  cubitainers,




         or of Pyrex glass.




    4.3  If the analysis cannot be performed the same  day of collection,  the




         sample should be preserved by the addition of 40 mg HgCl2  per liter




         and refrigeration at 4°C.
                                     262

-------
                                                             (Phosphorus)



                                  TABLE 1

                           PHOSPHORUS TERMINOLOGY



 1.  Phosphorus (P) - all of the phosphorus present in the sample regardless


     of form, as measured by the persulfate digestion procedure.   (00665)


     a.  Orthophosphate (P, ortho)-inorganic phosphorus [(PO.)   ]  in the


         sample as measured by the direct colorimetric analysis procedure. (70507)


     b.  Hydrolyzable Phosphorus (P, hydro)-phosphorus in the sample as


         measured by the sulfuric acid hydrolysis procedure, and  minus  pre-


         determined orthophosphates.   This hydrolyzable phosphorus  includes


         polyphosphates [(P_0_)~ ,  (P3°i{P~ '  etc-]  + some organic  phosphorus.  (00669)


     c.  Organic Phosphorus  (P,org)-phosphorus (inorganic + oxidizable
                                                                   *

         organic)  in the sample  as  measured by the persulfate digestion procedure,


         and  minus  hydrolyzable  phosphorus and orthophosphate.  (00670)


 2.   Dissolved  Phosphorus  (P-D)  -  all  of the phosphorus present in  the  filtrate


     of a sample filtered  through  a phosphorus-free  filter of 0.45  micron pore


     size and measured  by  the persulfate digestion procedure. (00666)


     a.   Dissolved  Orthophosphate  (P-D,  ortho)  -  as  measured by the direct


         colorimetric analysis procedure.  (00671)


    b.  Dissolved Hydrolyzable Phosphorus  (P-D, hydro)  - measured by the sulfuric


        acid hydrolysis procedure  and minus pre-determined dissolved


        orthophosphates.   (00672)


    c.  Dissolved Organic Phosphorus  (P-D, org)  - as measured by the persulfate


        digestion procedure, and minus  dissolved hydrolyzable phosphorus and


        orthophosphate.  (00673)


3.   The following forms, when sufficient amounts of phosphorus are present in


    the sample to warrant such consideration, may be calculated:
                                       263

-------
                                                           (Phosphorus)





    a.  Insoluble Phosphorus =  (?) -  (P-D) •   (00667)




        (1)  Insoluble orthophosphate (P-I,  ortho)  =. (P,  ortho)  - (P-D,  ortho).  (00674)




        (2)  Insoluble Hydrolyzable Phosphorus (P-I, hydro) = (P, hydro) -



             (P-D, hydro).  (00675)




        (3)  Insoluble Organic Phosphorus (P-I, org) = (P, org)  - (P-D,  org).  (00676)




4.  All phosphorus forms shall be reported as P, mg/1,  to the third  place.



5.  Interferences




    5.1  Method does not work on saline waters.




6.  Apparatus




    6.1  Acid-washed glassware:  To prevent contamination, all glassware used




         in the preparation of standards and actual determinations should be washed




         with hot 1:1 HC1 and rinsed with distilled water.  The acid-washed glass-




         ware should be filled with distilled water and treated with all the reagents




         to remove the last traces of phosphorus that might be adsorbed on the




         glassware.  Preferably, this glassware should be used only for the deter-




         mination of phosphorus and after use it should be rinsed with distilled




         water and kept covered until needed again.  If this is done-, the treatment




         with 1:1 HC1 and reagents is only required occasionally.  Commercial




         detergents should never be used.




    6.2  Technicon AutoAnalyzer consisting of:




         6.2.1  Sampler I.




         6.2.2  Continuous Filter.




         6.2.3  Manifold




         6.2.4  Proportioning Pump.




         6.2.5  Colorimeter equipped with 15 mm tubular  flow cell and 650 nm




                filters.
                                         264

-------
                                                        (Phosphorus)





         6.2.6  Recorder.



    6.3  Hot Plate or Autoclave



7.  Reagents



    7.1  Sulfuric acid solution:   Cautiously add 310 ml  of  concentrated



         sulfuric acid slowly and with stirring to  about 600 ml of distilled



         water.   Cool and  dilute  to 1  liter.



    7.2  Ammonium molybdate solution:   Dissolve 12.5 g of (NH.)fiMo_CL. .4H_0 in




         175 ml  of distilled water.  Cautiously add 77.5 ml of concentrated



         sulfuric acid slowly and with stirring to  400 ml of distilled water.



         Cool.   Add the molybdate solution  to the acid solution and dilute to



         1  liter.



    7.3  Stannous  chloride solution:   Dissolve 2.5  g of  fresh SnCl_.2H?0 in



         20 ml of hydrochloric acid.   Warming on a  hot plate will aid in dissolving



         this material.  Dilute to 400 ml.   Stable  for 1 week at room temperature;



         one month at 4°C.



    7.4   Wash water:   Add  40  ml of sulfuric  acid solution (Reagent 7.1) to



         1  liter of distilled water and dilute to 2 liters.




    7.5   Stock Solution:   Dissolve 0.4393 g of pre-dried KH2P04 *n distilled



         water and dilute  to  1 liter.   1 ml =  0.1 mg P.



    7.6   Standard  Solution A:   Dilute  100 ml  of stock solution to 1 liter.




         1  ml =  0.01  mg P.



    7.7   Standard  Solution B:  Dilute  100 ml of standard solution A to 1 liter.




         1 ml =  0.001  mg P.



    7.8   Prepare a  series of  standards by diluting  suitable volumes of standard




         solutions A  and B to  100.0 ml with distilled water.  The following




        dilutions are suggested:
                                      265

-------
                                                          (Phosphorus)


                                                 Cone.,
        ml  of Standard Solution  B                mg P/l

                    1.0                            0.01
                    2.0                            0.02
                    5.0                            0.05
                   10.0                       •     0.10

        ml  of Standard Solution  A

                    2.0                            0.20
                    5.0                            0.50
                    8.0                            0.80
                   10.0                            1.00

    7.9 Ammonium persulfate,  reagent grade.

    7.10 NaOH-EDTA Solution:   Dissolve 65 g NaOH and 6 g EDTA in distilled

        water and dilute to 1 liter.

8.   Procedure

    8.1  Phosphorus

         8.1.1  Add 1 ml  of sulfuric acid solution to  a 50-ml sample in a

                125-ml Erlenmeyer flask.
                              !
         8.1.2  Add 0.4 g ammonium persulfate.

         8.1.3  Boil gently on a pre-heated hot plate  for approximately 30-40

                minutes or until a final volume of about 10 ml is reached.  Do

                not allow sample to go to dryness.  Alternatively, heat for 30

                minutes in an autoclave at 121°C (15-20 psi) .

         8.1.4  Cool and dilute  the sample to 50.0 ml.  If sample is not  clear

                at  this point, filter.

         8.1.5  The sample is now ready for automatic analysis  as outlined in

                8.3 Orthophosphate.

     8.2  Hydrolyzable Phosphorus

         8.2.1  Add 1 ml of sulfuric acid solution to a 50-ml sample in a

                125-ml Erlenmeyer  flask.
                                       266

-------
                                                            (Phosphorus)





          8.2.2  Boil gently on a pre-heated hot plate for approximately



                 30-40 minutes or until a final volume of about  10  ml  is



                 reached.  Do not allow sample to go to dryness.  Alter-



                 natively, heat for 30 minutes in an autoclave at 121°C (15-20



                 psi).



          8.2.3  Cool and dilute the sample to 50.0  ml.   If sample  is  not clear



                 at this point, filter.



          8.2.4  The sample is now ready for automatic analysis  as  outlined



                 in 8.3 Orthophosphate.



     8.3  Orthophosphate



          8.3.1  Set up manifold as  shown in Figure  1.



          8.3.2  Allow both colorimeter  and recorder to warm up  for 30 minutes.



                 Run a baseline with all  reagents, feeding  distilled water



                 through the sample  line.   Adjust dark  current and  operative




                 opening on colorimeter to  obtain stable baseline.



          8.3.3  Place wash water  tubes  (see  7.4) in alternate openings in



                 Sampler and set sample timing at 2.0 minutes.  Use distilled



                 water,  instead of acid-wash water when only Orthophosphate




                 is being determined.



          8.3.4  Place standards in  Sampler in order of decreasing concentration.



                 Complete  filling  of sampler tray with unknown samples.



          8.3.5   Switch  sample  line  from distilled water to Sampler and begin




                 analysis.



         8.3.6  At end of run,  clean out manifold system with NaOH-EDTA solution.




9.  Calculations



    9.1  Prepare standard curve by plotting peak heights of processed standards




         against known concentrations.  Compute concentration of samples  by




         comparing sample peak heights with standard curve.




                                     267

-------
                                                        (Phosphorus)




10.  Precision and Accuracy




     10.1  In a single laboratory, using surface water samples at concen-



           trations of 0.06, 0.11, 0.48, and 0.62 mg P/l,  the standard deviation




           was ±0.004 (AQC Laboratory).



     10.2  In a single laboratory, using surface water samples at concen-



           trations of 0.11 and 0.74 mg P/l, recoveries were 90% and 95%,



           respectively (AQC Laboratory).








                                   References
1.  Standard Methods for the Examination of Water and Wastewater, 12th Edition,




    p. 234, Amer. Pub. Health Assoc., Inc., New York, N.Y. (1965).




2.  M. Gales, Jr., E. Julian, and R. Kroner, "Method for Quantitative Determination




    of Total Phosphorus in Water."  Jour. AWWA, 58, No. 10, 1363 (1966).
                                       268

-------
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                                                    IX
SAMPLING TIME • 2 MIN.

WASH TUBES  • ONE
                                   COLORIMETER     RECORDER
                                   15mm TUBULAR f/c
                                   650 " m FILTERS
                               FIGURE 1 • PHOSPHORUS MANIFOLD

-------
                                   SELENIUM

                           (Diaminobenzidine Method)
                                                          STORE! NUMBERS:
                                                            DISSOLVED   01145
                                                            TOTAL       01147
1.  Scope and Application

    1.1  This colorimetric method covers  the determination  of selenium  in

         drinking waters and surface waters, domestic and industrial

         wastes, and saline waters.

    1.2  The method covers the range from 0.003 -  0.05 mg selenium per

         liter.

2.  Summary of Method

    2.1  All selenium compounds present in the sample are first oxidized to

         selenate by acid permanganate.  The selenate is  then reduced to

         selenite.  Addition of diaminobenzidine reagent  forms the piaz-

         selenol complex which is subsequently extracted  into toluene and

         the absorbance measured at  420 nm.   The piazselenol  color is

         stable, but evaporation of  toluene concentrates  the  color to a

         marked degree in a few hours.

3.  Comments

    3.1  For the measurement of dissolved selenium,  the sample must  first

         be filtered through a 0.45  y membrane filter.

    3.2  Evaporation of solutions of sodium selenate to complete  dryness can

         result in substantial loss  of selenium unless calcium has been added

         to the sample.

    3.3  Temperature, time, and acid concentrations  are critical  to  obtain

         quantitative reduction without loss of selenium.  The optimum  pH

         for the formation of piazselenol is approximately  1.5.
                                     271

-------
                                                                  (Selenium)








     3.4  No inorganic compounds are known to give a positive interference.




          Negative interference results  from compounds  that  lower  the  con-




          centration of diaminobenzidine by oxidizing this reagent.  The




          addition of EDTA eliminates  negative interference  from at least




          2.5  mg ferric iron.   Iodine, and to a lesser  extent bromide, causes




          low  results.




     3.5   When iodide  or bromide interferences  are encountered, a  distillation




          step is  required.  This entails  the addition  of 50 ml KBr-FLSO.




          reagent  and  1  ml  30% H?0_  to the  residue remaining after the




          evaporation step.  The mixture is  distilled until the color of




         bromine  is gone  from the flask.   Diaminobenzidine is then added




          to the distillate and the  piazselenol  complex extracted into toluene.



4.  Precision  and Accuracy




    4.1  A synthetic unknown sample containing  20 Mg/1 Se, 40 yg/1 As,




         250 yg/1 Be, 240 yg/1 B, and 6 yg/1 V  in distilled water was




         determined by the diaminobenzidine method, with a relative standard




         deviation of 21.2% and a relative error of 5.0% in 35 laboratories.




5.  Reference




    5.1  The procedure to be used for this determination is  found in:




         Standard Methods for the Examination of Water and Wastewater,




         13th Edition, p 296 Method 150  A  (1971).
                                      272

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                           SILICA,  DISSOLVED




                                                    STORE! NUMBER:   00955




1.  Scope and Application -




    1.1  This method is applicable  to drinking waters  and surface waters,




         domestic and industrial wastes,  and saline  waters.




    1.2  Working range of method is approximately 2  to 25 mg silica/1.




         The upper range can be extended  by taking suitable aliquots;




         the lower range can be extended  by the addition of amino-naphthol-




         sulfonic acid solution, as described in ASTM  reference.



2.  Summary of Method




    2.1  A well-mixed sample is filtered  through a 0.45 y membrane  filter.




         The filtrate, upon the addition  of molybdate  ion in acidic




         solution, forms a greenish-yellow color complex proportional  to




         the dissolved silica in the sample.  The color complex is  then




         measured spectrophotometrically.




3.  Comments




    3.1  Excessive color and/or turbidity interfere.  Correct by running




         blanks prepared without addition of the ammonium molybdate solution.




4.  Precision and Accuracy




    4.1  Photometric evaluations by the amino-naphthol-sulfonic acid pro-




         cedure have an estimated precision of ±0.10 mg/1 in the range from




         0 to 2 mg/1 (ASTM).




    4.2  Photometric evaluation of  the silico-molybdate color in the range




         from 2 to 50 mg/1 have an  estimated precision of approximately 4




         percent of the quantity of silica measured (ASTM).
                                      273

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                                                     (Silica,  Dissolved)






5.   Reference




    5.1  The procedure to be used for this determination is found in:




         Standard Methods for the Examination of Water and Wastewater,




         13th Edition, p. 303, Method 151B U971).






         ASTM Standards,  Part 23, Water;  Atmospheric Analysis,  p.  91,




         Method D859-68 (1970).
                                     274

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                              SOLIDS,  FILTERABLE  (DISSOLVED)

                                                               STORET NO.  70500
1.  Scope and Application                                                 ~~


    1.1  This method is applicable to  surface waters,  domestic  and  industrial


         wastes, and saline waters.


    1.2  The practical range of the determination is  10  mg/1 to 20,000  mg/1.


2.  Summary of Method


    2.1  A well-mixed sample is filtered through  a standard glass fiber filter.


         The filtrate is evaporated and dried to  constant weight at 180°C.


3.  Definitions


    3.1  Filterable solids are defined as those solids capable  of passing


         through a standard glass fiber filter and dried to constant weight


         at 180°C.


4.  Sample Handling and Preservation


    4.1  Samples should be analyzed as soon as practicable.


5.  Interferences


    5.1  Highly mineralized waters containing significant concentrations of


         calcium, magnesium, chloride  and/or sulfate may be hygroscopic and will


         require prolonged drying and  desiccation and quick weighing.


    5.2  Samples containing high concentrations of bicarbonate  will require


         careful and possibly prolonged drying at 180°C  to insure  that all the


         bicarbonate is converted to carbonate.


    5.3  Too much residue in the evaporating dish will crust over  and entrap


         water that will not be driven off during drying.  Total residue should


         be limited to about 200 mg.


6.  Apparatus


    6.1  Glass fiber filter discs, 4.7 cm or 2.2  cm, without organic binder,
                                        275

-------
                                                   (Solids, Filterable - Dissolved)







         Reeve Angel type 984 H, Gelman type A, or equivalent.




    6.2  Filter holder, membrane filter funnel or Gooch crucible adapter.




    6.3  Suction flask, 500 ml.




    6.4  Gooch crucibles, 25 ml (if 2.2 cm filter is used).




    6.5  Evaporating dishes, porcelain, 100 ml volume.   (Vycor  or platinum




         dishes may be substituted).




    6.6  Steam bath.




    6.7  Drying oven, 180°C±2°C.



    6.8  Desiccator.




    6.9  Analytical balance, 200 g capacity, capable of weighing to  0.1 mg.




7.   Procedure




    7.1  Preparation of glass fiber filter disc:   Place the disc on  the membrane




         filter apparatus or insert into bottom of a suitable Gooch  crucible.




         While vacuum is applied,  wash the disc with three successive 20 ml




         volumes of distilled water.   Remove all  traces of water by  continuing




         to apply vacuum after water  has passed through.  Remove filter from




         membrane filter apparatus or both crucible and filter  if Gooch crucible




         is used, and dry in an oven  at 103-105°C for one hour.   Remove to




         desiccator and store until needed.




    7.2  Preparation of evaporating dishes:   Heat the clean dish to  550°C  for




         one hour in a muffle furnace.   Cool in desiccator and  store until needed.




         Weigh immediately before  use.




    7.3  Assemble the filtering apparatus  and begin suction.  Shake  the sample




         vigorously and rapidly transfer 100 ml to the  funnel by means of  a 100




         ml  volumetric  cylinder.   If  suspended  matter is low, a  larger volume




         may be  filtered.
                                       276

-------
                                                 (Solids,  Filterable -  Dissolved)





    7.4  Filter the sample through the glass fiber filter and continue to



         apply vacuum for about 3 minutes after filtration is complete to



         remove as much water as possible.



    7.5  Transfer 100 ml (or a larger volume) of the filtrate to a weighed



         evaporating dish and evaporate to dryness on a steam bath.



    7.6  Dry the evaporated sample for at least one hour at 180±2°C.  Cool



         in a desiccator and weigh.  Repeat the drying cycle until a constant



         weight is obtained or until weight loss is less than 0.5 mg.



    7.7  Note:  The filtrate from the test for SOLIDS, NON-FILTERABLE, may be



         used for this determination.



8.  Calculation            :

                           i

    8.1  Calculate filterable solids as follows:


         _.,„    ,. ,      ,,   (Wt. of dried residue + dish) -fwt. of dish) x 1000
         Flit. SOlldS, mg/1 = V	rr-^	 -. , ./	^	1	
                     '  6                   Volume of filtrate used



9.  Precision and Accuracy



    9.1  Precision data are not available at this time.



    9.2  Accuracy data on actual sample cannot be obtained.
                                        277

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                      SOLIDS, NON-FILTERABLE  (SUSPENDED)




 1.  Scope and Application                                      STORET NO.  00550




    1.1  This method  is applicable to surface waters, domestic and industrial




         wastes, and  saline waters.




    1.2  The practical range of the determination is 20 mg/1 to 20,000 mg/1.




 2.  Summary of Method




    2.1  A well-mixed sample is filtered through a standard glass fiber filter,




         and the residue retained on the filter is dried to constant weight at




         103-105°C.




 3.  Definitions




    3.1  Non-filterable solids are defined as those solids which are retained by




         a standard glass fiber filter and dried to constant weight at 103-105°C.




 4.  Sample Handling and Preservation




    4.1  Non-homogenous particulates such as leaves, sticks, fish, and lumps of




         fecal matter should be excluded from the sample.




    4.2  Preservation of the sample is not practical; analysis should begin as




         soon as possible.




 5.  Interferences




    5.1  Too much residue on the filter will entrap water and may require




         prolonged drying.




6.  Apparatus




    6.1  Glass fiber filter discs, 4.7 cm or 2.2 cm, without organic binder,




         Reeve Angel type  934-H or  984-H,  Gelman  type A,  or equivalent.




    6.2  Filter holder, membrane filter funnel or Gooch crucible adapter.




    6.3  Suction flask, 500 ml.




    6.4  Gooch crucibles,  25 ml  (if 2.2 cm filter is used).







                                        278

-------
                                           (Solids, Non-Filterable - Suspended)





    6.5  Drying oven,  103-105°C.


    6.6  Desiccator.



    6.7  Analytical balance,  200  g capacity,  capable of weighing to 0.1 mg.


7.   Procedure


    7.1  Preparation of glass fiber filter  disc:   Place the  disc on the


         membrane filter apparatus or insert  into  bottom of  a suitable Gooch


         crucible.  While vacuum  is applied,  wash  the  disc with three


         successive 20 ml volumes of distilled water.  Remove all traces of


         water by continuing to apply vacuum  after water has passed through.


         Remove filter from membrane filter apparatus  or both crucible and


         filter if Gooch crucible is used,  and dry in  an oven at 103-105°C for
                            \

         one hour.  Remove to desiccator  and  store until needed.  Weigh


         immediately before use.


    7.2  Assemble the filtering apparatus and begin suction. Shake the  sample


         vigorously and rapidly transfer 100  ml to the funnel by means of a


         100 ml volumetric cylinder.  If suspended matter  is low, a larger


         volume may be filtered.


    7.3  Carefully remove the filter from the membrane filter funnel  assembly.


         Alternatively, remove crucible and filter from  crucible  adapter.  Place


         in drying oven and dry at 103-105°C  to constant weight.


8.   Calculations


    8.1  Calculate non-filterable solids as follows:

                 ...      ,.   (Wt. of filter  + residue)-Cwt. of filter)  x 1000
Non-filterable solids, mg/1 =  	ml of sample filtered	



9.   Precision and Accuracy


    9.1  Precision data are not available at this time.


    9.2  Accuracy data on actual  samples cannot be obtained.
                                        279

-------
 1.   Scope and Application
                                  SOLIDS, TOTAL
                                                         STORET NO.    00500
     1.1   This  method  is  applicable  to  surface waters, domestic and industrial
          wastes,  and  saline waters.
     1.2   The practical range of the determination is from 10 mg/1 to 30,000 mg/1.
 2.   Summary of Method
     2.1   A well mixed aliquot of the test sample is quantitatively transferred
          to a  pre-weighed evaporating  dish and evaporated to dryness at 103-105°C.
 3.   Definitions
     3.1   Total Solids are defined as the sum of the homogenous suspended and
          dissolved materials in a sample.
 4.   Sample Handling and  Preservation
     4.1   Samples  should be analyzed as soon as practicable.
 5.   Interferences
     5.1   Large, floating particles or  submerged agglomerates (non-homogenous
         materials) should be excluded from the test sample.
     5.2  Floating oil and grease, if present, should be included in the sample
         and dispersed by a blender device before aliquoting.
6.  Apparatus
    6.1  Evaporating dishes, porcelain, 90 mm, 100-ml capacity.   (Vycor or
         platinum dishes may be substituted and smaller size dishes may be
         used if required.)
7.  Procedure
    7.1  Heat the clean evaporating dish to 550±50°C for 1 hour  in a muffle
         furnace.   Cool,  desiccate,  weigh and store in desiccator until ready
         for use.

                                        280

-------
                                                          (Solids, Total)





    7.2  Transfer a measured aliquot  of  sample  to the pre-weighed dish and


         evaporate to dryness on a steam bath or in  a drying oven.


         7.2.1  Choose an aliquot of  sample  sufficient to  contain a residue


                of at least 25 mg.  To obtain a weighable  residue, successive


                aliquots of sample may be  added to the same dish.


         7.2.2  If the evaporation is performed in a drying oven, the temperature


                should be lowered to  approximately 98°C  to prevent boiling and


                splattering of the sample.


    7.3  Dry the evaporated sample for at  least 1 hour at  103-105°C.  Cool in a


         desiccator and weigh.  Repeat the cycle of  drying at  103-105°C,  cooling,


         desiccating and weighing until  a  constant weight  is obtained or  until


         loss of weight is less than  4%  of the  previous  weight,  or 0.5 mg,


         whichever is less.


8.  Calculation


    8.1  Calculate total solids as follows:

             -, c i-j     /i   (Wt- of sample  +  dishl-(wt. of  dish)  1000
         Total Solids, mg/1 =l	P  Vol.  of  Sample	


9.  Precision and Accuracy


    9.1  Precision and accuracy data are not available at this time.
                                        281

-------
                               SOLIDS,  VOLATILE
                                                    STORE! No:      Total 00505
                                                                Suspended 00515
                                                                Dissolved 00520

 1.   Scope  and Application

     1.1  This method determines  the weight of solid material combustible at

         550°C.

     1.2  The  test  is useful in obtaining a rough approximation of the amount

         of organic  matter present in  the solid fraction of sewage, activated

         sludge, industrial wastes, or bottom sediments.

 2.   Summary of Method

     2.1  The  residue obtained  from the determination of total, suspended, or

         dissolved solids is ignited at 550°C in a muffle furnace.  The loss

         of weight on ignition is reported as mg/1 volatile solids.

 3.   Comments

     3.1  The  test  is  subject to many errors due to loss of water of crystalliza-

         tion, loss  of volatile organic matter prior to combustion, incomplete

         oxidation of certain  complex  organics, and decomposition of mineral

         salts during combustion.

     3.2  The  results  should not be considered an accurate measure of organic

         carbon in the sample, but maybe useful in the control of plant

         operations.

     3.3  The principal source of error in the determination is failure to obtain

         a representative sample,

4.  Precision and Accuracy

         A collaborative study involving three laboratories examining four

         samples  by means of ten replicates  showed a standard deviation of

         ±11 mg/1 at  170 mg/1 volatile solids concentration.   (Reference)
                                       282

-------
                                                            (Solids, Volatile)

5.   Reference

    The procedure to be used for this determination is found in:

         Standard Methods for the Examination of Water and Wastewater, 13th
         Edition, P. 538, Method 224D (1971).
                                        283

-------
                           SPECIFIC  CONDUCTANCE




                                                      STORET NUMBER:  00095




 1.   Scope and Application




     1.1   This method is  applicable  to  drinking waters and surface waters,




          domestic  and industrial wastes, and saline waters.




 2.   Summary of Method




     2.1   The  specific conductance of a sample is measured by use of a self-




          contained conductivity meter, Wheatstone bridge-type, or equivalent.




     2.2   Samples are  preferably analyzed at 25°C.  If not, temperature cor-




          rections  are made and results reported at 25°C.




 3.   Comments




     3.1   Instrument must be standardized with KC1 solution before daily use.




     3.2   Conductivity cell must be kept clean.




     3.3   Field measurements with comparable instruments are reliable.




4.   Precision and Accuracy




     4.1   Forty-one analysts in 17 laboratories analyzed six synthetic water




         samples containing increments of inorganic salts, with the following




         results:
Increment as
Specific Conductance
ymhos/cm
100
106
808
848
1640
1710
Precision as
Standard Deviation
ymhos/cm
7.55
8.14
66.1
79.6
106
119
Accuracy as
Bias,
%
-2.02
-0.76
-3.63
-4.54
-5.36
-5.08
Bias,
ymhos/cm
-2.0
-0.8
-29.3
-38.5
-87.9
-86.9
(FWPCA Method Study 1,  Mineral and Physical Analyses).
                                      284

-------
                                                      (Specific Conductance)






    4.2  In a single laboratory (AQC), using surface water samples with an




         average conductivity of 536 ymhos/cm @ 25°C, the standard deviation




         was ±6.




5.  References




    5.1  The procedure to be used for this determination is found in:




         Standard Methods for the Examination of Water and Wastewater, 13th




         Edition, p. 323, Method 154  (1971).






         ASTM Standards, Part 23, Water; Atmospheric Analysis, p. 179,




         Method D1125-64 (1970).
                                      285

-------
                               SULFATE




                                                         STORET NUMBER:  00945




1.  Scope and Application




    1.1  This method is applicable to drinking waters and surface waters,




         domestic and industrial wastes.




    1.2  The method is suitable for all concentration ranges of sulfate;




         however, in order to obtain reliable readings, use a sample aliquot




         containing not more than 40 mg SO./I.



2.  Summary of Method




    2.1  Sulfate ion is converted to a barium sulfate suspension under




         controlled conditions.  The resulting turbidity is determined by




         a photoelectric colorimeter or spectrophotometer and compared to




         a curve prepared from standard sulfate solutions.




    2.2  Suspended matter and color interfere.  Correct by running blanks




         from which the barium chloride has been omitted.




3.  Comments




    3.1  Proprietary reagents, such as Hach SULFAVER or equivalent, are




         acceptable.




4.  Precision and Accuracy




    4.1  Thirty-four analysts in 16 laboratories analyzed six synthetic




         water samples containing exact increments of inorganic sulfate,




         with the following results:
Increment as
Sulfate
mg/liter
8.6
9.2
110
122
188
199
Precision as
Standard Deviation
mg/liter
2.30
1.78
7.86
7.50
9.58
11.8
Accuracy as
Bias,
%
-3.72
-8.26
-3.01
-3.37
+0.04
-1.70
Bias,
mg/liter
-.3
-.8
-3.3
-4.1
+ .1
-3.4
(FWPCA Method Study 1,  Mineral and Physical Analyses).




                                     286

-------
                                                               (Sulfate)






5.  Reference




    5.1  The procedure to be used for this determination is found in:




         Standard Methods for the Examination of Water and Wastewater,




         13th Edition, p. 334, Method 156C (1971).






         ASTM Standards, Part 23, Water; Atmospheric Analysis, p. 54,




         Method D516-68 (1970).
                                       287

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                                    SULFATE




                         (Automated Chloranilate Method)



1.  Scope and Application                                     STORE! NO.  00945




    1.1  This automated method is applicable to surface waters,  domestic and




         industrial wastes, and saline waters, in the range of 10 to 400 mg




         SO./I.  Approximately 15 samples per hour can be analyzed.




2.  Summary of Method




    2.1  When solid barium chloranilate is added to a solution containing




         sulfate, barium sulfate is precipitated, releasing the  highly colored




         acid chloranilate ion.  The color intensity in the resulting chloranilic




         acid is proportional to the amount of sulfate present.




3.  Sample Handling and Preservation




    3.1  No special requirements.




4.  Interferences




    4.1  Cations, such as calcium, aluminum, and iron, interfere by precipitating




         the chloranilate.   These ions are removed automatically by passage




         through an ion exchange column.




5.  Apparatus




    5.1  Technicon AutoAnalyzer consisting of:




         5.1.1  Sampler I.




         5.1.2  Continuous  filter.




         5.1.3  Manifold.




         5.1.4  Proportioning pump.




         5.1.5  Colorimeter equipped with 15 mm tubular flow cell and 520 nm




                filters.




         5.1.6  Recorder.
                                       288

-------
                                                           (Sulfate)






         5.1.7  Heating bath,  45°C.




    5.2  Magnetic stirrer.




6.  Reagents




    6.1  Barium chloranilate:   Add 9  g  of barium  chloranilate  (BaC-C^O.)




         to 333 ml of ethyl alcohol and dilute to 1  liter with distilled



         water.




    6.2  Acetate buffer, pH 4.63:   Dissolve  13.6  g of sodium acetate in




         distilled water.  Add 6.4 ml of acetic acid and dilute to  1 liter with




         distilled water.  Make fresh weekly.




    6.3  NaOH-EDTA Solution:   Dissolve  65 g  of NaOH  and 6 g of EDTA in distilled




         water and dilute to 1 liter.




         Note:  This solution  is also used to clean  out manifold system at end




         of sampling run.




    6.4  Ion Exchange Resin:   Dowex-50  W-X8, ionic form -H  .




         Note:  Column is prepared by sucking a slurry of the resin into  12




         inches of 3/16-inch OD sleeving.  This may  be conveniently done  by




         using a pipette and a loose-fitting glass wool plug in the sleeve.




         The column, upon exhaustion, turns  red.




    6.5  Stock solution:  Dissolve 1.4790 g  of pre-dried Na-SO  in  distilled




         water and dilute to 1 liter.  1 ml  = 1 mg.




         6.5.1  Prepare a series of standards by  diluting suitable  volumes of




                stock solution to 100.0 ml with distilled water.  The  following




                dilutions are  suggested:
                                        289

-------
                                                             (Sulfate)


                 ml  of Stock  Solution          Cone., mg/1

                          1.0                       10
                          2.0                       20
                          4.0                       40
                          6.0                       60
                          8.0                       80
                         10.0                      100
                         15.0                      150
                         20.0                      200
                         30.0                      300
                         40.0                      400

 7.  Procedure

    7.1  Set up manifold as shown in Figure 1.   (Note that any precipitated

         BaSO. and the  unused barium chloranilate are removed by filtration.

         If any BaSO. should come through the filter, it is complexed by the

         NaOH-EDTA reagent).

    7.2  Allow both  colorimeter and recorder to warm up for 30 minutes.  Run

         a baseline with all reagents, feeding distilled water through the

         sample line.   Adjust dark current and operative opening on colorimeter

         to obtain suitable baseline.

    7.3  Place distilled water wash tubes in alternate openings in sampler and

         set sample timing at 2.0 minutes.

    7.4  Place working  standards in sampler in order of decreasing concentration.

         Complete filling of sampler tray with unknown samples.

    7.5  Switch sample  line from distilled water to sampler and begin analysis.

8.  Calculation

    8.1  Prepare standard curve by plotting peak heights of processed standards

         against known  concentrations. . Compute concentration of samples by

         comparing sample peak heights with standard curve.

9.  Precision and Accuracy

    9.1  In a single laboratory (AQC), using surface water samples at concentra-

         tions of 39, 111, 188, and 294 mg SO./I, the standard deviations were

                                       290

-------
                                                            (Sulfate)







         ±0.6, ±1.0,  ±2.2, and ±0.8,  respectively.




    9.2  In a single  laboratory (AQC)  using surface  water samples  at  concen-




         trations of 82 and 295 mg SO./I,  recoveries were 99%  and  102%,




         respectively.




                                   Reference




1.  R.J. Bertolocini  and J.E.  Barney,  Anal. Chem.,  29,  283 (1957).




2.  M.E. Gales, Jr.,  W.H. Kaylor and J.E.  Longbottom, "Determination of




    Sulphate by Automatic Colorimetric Analysis."  Analyst, 95, 97 (1968).
                                         291

-------
            LM
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to
to
t
1 EXCHANGE
	 1

^




0 < W
P € P
P tf P

ml/min >
0.2} AIR
2,50
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STIRRER [hp
iu I 0 \f4-
LARGE
                       COIL
                       (LM)  g
                             SMALL
                             MIXING
                             COIL
                             (SM)
                              COLORIMETER
                        15mm TUBULAR f/c
                           520 nm  FILTERS
                                                                                 CHLORANILATE
    BLUE    BLUE  1.60  AIR
             R  0.80  BUFFER


               JJJ  EDTA-NaOH
                                                                                           CONTINUOUS FILTER
                          WASTE
                                                                        0  3.40
         <   P  2.50

PROPORTIONING PUMP
SAMPLE

 WASTE

                                                  t
•

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                                                                 SAMPLING TIME • 2 MIN.
                                                                 WASH TUBES •  ONE
                                             RECORDER
                                           FIGURE  1  -  SULFATE  MANIFOLD

-------
                                   SULFIDE

                         Titrimetric (Iodine) Method
                                                            STORET NO.
                                                            Total:     00745
                                                            Dissolved: 00746

1.  Scope and Application

    1.1  This method is applicable to the measurement of total and dissolved

         sulfides in drinking waters, surface waters, domestic and industrial

         wastes, and saline waters.

    1.2  Acid insoluble sulfides are not measured  by the use of this test.

         (Copper sulfide is the only common  sulfide in  this class).

    1.3  This method is suitable for the measurement of sulfide in concen-

         trations above 1 mg/1.

2.  Summary of Method

    2.1  Sulfides are stripped from the acidified  sample with an  inert  gas  and

         collected in a zinc acetate solution.   Excess  iodine added to  the

         zinc sulfide suspension reacts with the sulfide under acidic conditions.

         Thiosulfate is used to measure unreacted  iodine to  indicate the

         quantity of iodine consumed by sulfide.

3.  Comments

    3.1  Reduced sulfur compounds, such as  sulfite, thiosulfate and hydrosulfite,

         which decompose in acid may yield  erratic results.  Also, volatile

         iodine-consuming substances will  give  high results.

    3.2  Samples must be taken with a minimum  of aeration.  Sulfide

         may be volatilized by aeration and any oxygen inadvertently added

         to the sample may convert the sulfide to  an  unmeasurable form.

    3.3  If the sample is not preserved with zinc  acetate, the  analysis must

         be started immediately.  Similarly, the measurement of dissolved

         sulfides must also be commenced  immediately.
                                        294

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                                                           (Sulfide)





4.  Precision and Accuracy




    4.1  Precision and accuracy for this method have not been determined,




         but it is claimed that the iodimetric titration of the zinc




         sulfide is quite accurate.




5.  References




    5.1  The procedure to be used for this determination is found in:




             Standard Methods for the Examination of Water and Wastewaters,




             13th Edition, pp 551-555, Method No. 228A (1971).
                                        295

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                               TEMPERATURE

                                                  STORET Number:   00010



1.  Scope and Application


    1.1  This method is applicable to drinking waters  and surface  waters,

         domestic and industrial wastes,  and saline waters.

2.  Summary of Method

    2.1  Temperature measurements may be  made with any good grade  of

         mercury-filled or dial type centigrade thermometer, or a


         thermistor.

3.  Comments

    3.1  Measurement device should be checked against  a precision

         thermometer certified by the National Bureau  of Standards.
                           I
4.  Precision and Accuracy,
                           i
    4.1  There is no acceptable procedure for determining the precision

         and accuracy of this test.


5.  Reference

    5.1  The procedure to be used for this determination is found  in:

         Standard Methods for the Examination of Water and Wastewater,


         13th Edition, p. 348, Method 162 (1971).
                                     296

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                                 THRESHOLD ODOR                STORET NO-


                            (Consistent Series Method)            60°C:        00086

                                                                 ROOM TEMP:   00085
 1.   Scope and Application                                                    	


     1.1  This method is applicable to the determination of threshold odor of


         finished waters, surface waters, domestic and industrial wastes, and


         saline waters.


     1.2  Highly odorous samples are reduced in concentration proportionately


         before being tested.  Thus, the method is applicable to samples


         ranging from nearly odorless natural waters to industrial wastes with


         threshold odor numbers in the thousands.


2.   Summary of Method  '


     2.1  The sample of water is diluted with odor-free water until a dilution


         that is of the least definitely perceptible odor to each tester is


         found.  The resulting ratio by which the sample has been diluted is


         called the "threshold odor number" (T.O.).


     2.2  People vary widely as to odor sensitivity, and even the same person


         will not be consistent in the concentrations he can detect from day to


         day.  Therefore, panels of not less than five persons, and preferably


         10 or more, are recommended to overcome the variability of using one


         observer.^ '


         2.2.1  As an absolute minimum, two persons are necessary:   One to make


                the sample dilutions and one to determine the threshold odor.


3.  Sample Handling and Preservation


    3.1  Water samples  must be collected in glass bottles with glass or Teflon-


         lined closures.
                                          297

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                                                           (Threshold Odor)




         3.1.1  Plastic containers are not  reliable  for odor  samples and must

                not be used.

    3.2  Odor tests should be eompleted as  soon  as possible after collection

         of the sample.  If storage is necessary, collect at  least 1000 ml of

         sample in a bottle filled to the top.   Refrigerate,  making sure no

         extraneous odors can be drawn into the  sample as the water cools.

4.  Interferences

    4.1  Most tap waters and some waste waters are chlorinated.  It is often

         desirable to determine the odor of the  chlorinated sample as well as

         of the same sample after removal of chlorine.  Dechlorination is

         achieved using sodium thiosulfate  in exact  stoichiometric quantity.
                            j
         4.1.1  It is important to check a  blank to  which a similar amount of

                dechlorinating agent has been added  to determine if any odor

                has been imparted.  Such odor usually disappears upon standing

                if excess reagent has not been added.

5.  Apparatus

    5.1  Odor-free glassware:  Glassware must be freshly  cleaned shortly before

         use, with non-odorous soap and acid cleaning solution  followed by

         rinsing with odor-free water.  Glassware used in odor  testing  should

         be reserved for that purpose only.  Rubber, cork,  and  plastic  stoppers

         must not be used.

    5.2  Constant temperature bath:  A water bath or electric hotplate  capable

         of maintaining a temperature control of ±1°C for performing  the  odor

         test at 60°C.  The temperature bath must not contribute  any  odor  to

         the odor flasks.

    5.3  Odor Flasks:  Glass stoppered 500  ml (ST 32) Erlenmeyer  flasks,  or
                                         298

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                                                          (Threshold Odor)








         wide-mouthed 500 ml Erlenmeyer Flasks equipped with Petri dishes as



         cover plates.



         NOTE:  Narrow-mouth vessels are not suitable for running odor tests.



                Potential positive bias due to color and/or turbidity of water



                sample under observation can be eliminated by wrapping odor



                flasks in aluminum foil, painting flasks with non-odorous



                paint, or by using red actinic Erlenmeyer flasks.



    5.4  Sample Bottles:  Glass bottles with glass or Teflon-lined closures.



    5.5  Pipets, measuring:  10.0 and 1.0 ml graduated in tenths.



    5.6  Graduate cylinders:  250, 200, 100, 50, and 25 ml.



    5.7  Thermometer:  0-110°C (±1°C), chemical or metal stem dial type.



    5.8  Odor free water generator:  See Figure 1.



6.  Reagents



    6.1  Odor-free water:  Odor-free dilution water must be  prepared as needed



         by filtration through a bed of activated carbon. Most tap waters are



         suitable for preparation of odor-free waters, except that it is



         necessary to check the filtered water for chlorine  residual, unusual



         salt concentrations, or unusually high or low pH.   All these may



         affect some odorous samples.



              Where supplies are adequate, distilled water avoids these problems



         as a source of odor-free water.   A convenient odor-free water generator



         may be made as shown in Figure 1.  Pass tap or distilled water through



         the odor-free water generator at a rate of 0.1 liter/minute.  When the



         generator is first started,  it should be flushed to remove carbon fines


                                                                   f31
         before the odor-free water is used.   The carbon cartridge,  '  or a



         comparable assembly, is also suitable.
                                        299

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                   2 HOLE
               RUBBER  STOPPER
                                               GRANULAR
                                              4xlO-MESH

                                               ACTIVATED
                                                CARBON
I in.
PEA SIZE
 GRAVEL
Fig. 1. Odor-free  water  generator
                            300

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                                                          (Threshold Odor)









         6.1.1  The quality of water obtained  from the odor-free water




                generator should be checked daily at the temperature  tests




                are to be conducted (room  temperature and/or 60°C).   The life




                of the carbon will  vary with the condition and amount of water




                filtered.  Subtle odors of biological origin are often found




                if moist carbon filters are permitted to stand idle between




                test periods.  Detection of odor in the water coming  through




                the carbon indicates a change  of carbon is needed.




7.   Procedure




    7.1  Precautions:  Selection of persons to make odor tests should be




         carefully made.  Extreme sensitivity  is not required, but insensitive




         persons should not be used.  A good observer has a  sincere  interest




         in the test.  Extraneous odor stimuli such as those caused  by smoking




         and eating prior to the test or through the use of  scented  soaps,




         perfumes, and shaving lotions must be avoided.  The tester  should be




         free from colds or allergies that affect odor-response.   Frequency of




         tests must not be so great as to  induce fatigue.  Frequent  rests  in an




         odor-free atmosphere are recommended.




              The room in which the tests  are  to be  conducted  should be  free




         from distractions, drafts, and other  odor.   In  certain  industrial




         atmospheres, a special odor-free  room may be  required,  ventilated by




         air filtered through activated carbon and maintained  at a constant



                                             (4")
         comfortable temperature and humidity    .




              For precise work a panel of five or more testers  should be used.




         The persons making the odor measurements  should not prepare the samples




         and should not know the dilution  concentrations being  evaluated.  These
                                        302

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                                                       (Threshold Odor)
      persons  should have been made familiar with the procedure before

      participating in a panel test.  Always start with the most dilute

      sample to  avoid tiring the senses with the concentrated sample.

      The temperature of the samples during testing should be kept within

      1 degree of the specified temperature for the test.

7.2   Threshold  Measurement:  The ratio by which the odor-bearing sample

      has to be  diluted with odor-free water for the odor to be just

      detectable by the odor test is the "threshold odor number" (T.O.).

      The total volume of sample and odor-free water used in each test is

      200 ml.  The proper volume of odor-free water is put into the flask

      first; the sample is then added to the water.  Table 1 gives the

      dilutions and corresponding threshold numbers.
              Table 1.  Threshold Odor Number Corresponding
                           to Various Dilutions
Sample Volume (ml)
Diluted to 200 ml
200
100
50
25
12.5
6.3
3.1
1.6
0.8
Threshold Odor
Number
1
2
4
8
16
32
64
128
256
7.3  Determine the approximate range of the threshold odor by:

     7.3.1  Adding 200 ml, 50 ml,  12.5 ml, and 3.1 ml of the

            sample to separate 500 ml glass-stoppered Erlenmeyer

            flasks containing odor-free water to make a total volume

            of 200 ml.  A separate flask containing only odor-free water

            serves as the reference for comparison.   If run at 60°C, heat

                                     303

-------
                                                      (Threshold Odor)










            the dilutions and the reference  in  the constant temperature




            bath to 60°C (±1°C).




     7.3.2  Shake the flask containing  the odor-free water, remove the




            stopper, and sniff the vapors.   Test the sample containing




            the least amount of odor-bearing water in the same way.  If




            odor can be detected  in this  dilution, more dilute samples




            must be prepared as described in 7.3.3.  If odor cannot be




            detected in the first dilution,  repeat the above procedure




            using the sample containing the  next higher concentration of




            the odor-bearing water,  and continue this process until odor




            is clearly detected.




     7.3.3  If the sample being tested  requires more extensive dilution




            than is provided by Table 1,  an  intermediate dilution is




            prepared from 20 ml of sample diluted to 200 ml with odor-free




            water.  Use this dilution for the threshold determination.




            Multiply the T.O. obtained  by ten to correct for the intermediate




            dilution.  In rare cases more than  one tenfold  intermediate




            dilution step may be  required.




7.4  Based on the results obtained in the preliminary test, prepare a set of




     dilutions using Table 2 as a guide.  One or more blanks are inserted in




     the series, in the vicinity  of the expected threshold, but  avoiding any




     repeated pattern.  The observer does not know which dilutions are




     odorous and which are blanks.  He  smells each flask in sequence, beginning




     with the least concentrated  sample and  comparing with  a known flask of




     odor-free water, until odor  is detected with utmost certainty.
                                     304

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                                                           (Threshold Odor)
                Table 2.  Dilutions for Various Odor Intensities
                    Sample Volume in Which Odor First Noted
200 ml
50 ml
12.5 ml
3.1 ml
Volume (ml) of Sample to be Diluted to 200 ml
200
100
50
25
12.5
100
50
25
12.5
6.3
50
25
12.5
6.3
3.1
(Intermediate
Dilution,
See 7.3.3)


    7.5  Record the observations of each tester by indicating whether odor is

         noted (+ sign) in each test flask.

         For example:


                ml sample
                diluted to 200 ml  12.5   0    25    0    50    100    200
                Response                        +    -    +      +      +

8.  Calculations

    8.1  The threshold odor number is the dilution ratio at which odor is just

         detectable.   In the example above (7.5), the first detectable odor

         occurred when 25 ml sample was diluted to 200 ml.   Thus, the threshold

         is 200 divided by 25, equals 8.  Table 1 lists the threshold numbers

         that correspond to common dilutions.

    8.2  Anomalous responses sometimes occur;  a low concentration may be called

         positive and a higher concentration in the series  may be called

         negative.  In such a case, the threshold is designated as that point of

         detection after which no further anomalies occur.   For instance:
                ml sample
                diluted to 200 ml
6.3
12.5   0   25   50   100
                Response
                                                       -
                                                     threshold
                                         305

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                                                          (Threshold Odor)



    8.3  Calculations of panel results  to  find  the most probable average

         threshold are best accomplished by  appropriate statistical methods.

         For most purposes, the threshold  of a  group can be expressed as the

         geometric mean (G.M.) of the individual  thresholds.  The geometric

         mean is calculated in the following manner:

         8.3,1  Obtain odor response as outlined  in Procedure and record

                results.   For example:

                                 Table 3.  Sample Odor Series
ml of Odor- ml of
free Water Sample
188 12.5
175 25
200 ; 0
150 50
200 0
100 100
0 200
Observer Response*
1

-
-
^
-
+
+ •
2
.
®
-
4-
-
+
+
3
_
-
-
-
- -
^^
+
4
_
+
-
-
-
Q
+
5
_
©
-
+
-
+
+
                   *Circled plus equals threshold level.

         8.3.2  Obtain individual threshold odor numbers  from Table 1.
                         Observer
                            1
                            2
                            3
                            4
                            5
T.O.

 4
 8
 2
 2
 8
         8.3.3  The geometric mean is equal to the nth root of the product of

                n numbers.  Therefore:

                4x8x2x2x8= 1024,
                and
                                           30103
                and anti-log of 0.6021 = 4 = T.O.

9.  Precision and Accuracy

    9.1  Precision and accuracy data are not available at this time.
                                         306

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                                                            (Threshold Odor)









     9.2  A threshold number  is not  a precise value.   In the case of the single




          observer,  it represents a  judgment at the time of testing.  Panel




          results  are more meaningful because individual differences have less




          influence  on the result.   One or two observers can develop useful data




          if comparison with  larger  panels has been made to check their sensi-




          tivity.  Comparisons of data from time to time or place to place should




          not be attempted unless all test conditions have been carefully stand-




          ardized  and some basis for comparison of observer intensities exists.






                                 References




1.  Standard Methods,  13th Edition, Amer. Public Health Asso., New York, N.Y.




    p. 248, Method  136 (1971).




2.  ASTM, Comm E-18,  STP 433, Basic Principles of Sensory Evaluation; STP 434,




    Manual on Sensory Testing Methods; STP 440, Correlation of Subjective-




    Objective Methods in the Study of Odors and Taste; Phil.,  Pennsylvania




    (1968).




3.  Standard Methods, 12th Ed., Amer.  Public Health Asso., New York, N.Y., 1965,




    p. 213.




4.  Baker, R.A., "Critical Evaluation of Olfactory Measurement".   Jour WPCF, 54,




    582 (1962).
                                        307

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                                   TURBIDITY            STORET No:  QQQ70





1.  Scope and Application




    1.1  This method is applicable to surface and saline waters in  the range




         of turbidity from 0 to 40 Jackson units.




2.  Summary of Method




    2.1  The method is based upon a comparison of the  intensity of  light




         scattered by the sample under defined conditions with the  intensity




         of light scattered by a standard reference suspension.   The higher the




         intensity of scattered light, the higher the  turbidity.  Readings, in




         Jackson units, are made in a nephelometer designed according to




         specifications outlined in Apparatus, 5.   A standard suspension  of




         Formazin, also prepared under closely defined conditions,  is used to




         calibrate the instrument.




         2.1.1  Formazin polymer is used as the turbidity reference suspension




                for water because it is more reproducible than other types of




                standards previously used for turbidity standards.




3.  Sample Handling and Preservation




    3.1  Samples taken for turbidity measurements should be analyzed as  soon as




         possible.  Preservation of samples is not recommended.




4.  Interferences




    4.1  The presence of floating debris and coarse sediments which settle out




         rapidly wiJl give false high readings.  Finely divided  air bubbles will




         also affect the results in a positive manner.




    4.2  The presence of true color, that is the color of water which  is  due to




         dissolved substances which absorb light will  cause turbidities  to be




         low, although this effect is generally not significant with  finished




         waters.
                                        308

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                                                                (Turbidity)





5.  Apparatus




    5.1  The turbidimeter shall consist of a nephelometer with  light source




         for illuminating the sample and one or more photo-electric detectors




         with a readout device to indicate the  intensity of light scattered




         at right angles to the path of the incident light.  The turbidimeter




         should be so designed that  little stray light reaches  the detector in




         the absence of turbidity and should be free from significant drift




         after a short warm-up period.




    5.2  The sensitivity of the instrument should permit detection of turbidity




         differences of 0.02 unit or less  in waters having  turbidities less than




         1  unit.   The instrument should measure from 0 to 40 units turbidity.




         Several  ranges will be necessary  to obtain both adequate coverage and




         sufficient  sensitivity for  low turbidities.




    5.3  The sample  tubes  to be used with  the available instrument must be of




         clear,  colorless  glass.   They  should be  kept scrupulously clean, both




         inside  and  out,  and discarded  when they  become scratched or etched.




         They must not  be  handled at all where  the light strikes them, but




         should be provided  with sufficient extra length, or with a protective




         case, so  that  they  may be handled.




    5.4   Differences  in physical  design  of turbidimeters will cause differences




         in  measured values  for turbidity  even  though the same suspension is




         used for  calibration.   To minimize such  differences, the following




         design criteria should be observed:




         5.4.1  Light source:   Tungsten  lamp  operated at not less than 85% of




               rated voltage or more than  rated voltage.
                                       309

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                                                               (Turbidity)





         5.4.2  Distance traversed by incident  light  and scattered light




                within the sample tube:   Total  not  to exceed  10 cm.




         5.4.3  Angle of light acceptance of  the  detector:  Centered at 90°




                to the incident light path and  not  to exceed  ±30° from 90°.




         5.4.4  Maximum turbidity to be  measured:   40 units.




    5.5  At the time of this writing, the only  instrument  commercially available




         with these specifications is the Hach  Turbidimeter,  Model 2100 and  2100A.




         This instrument is recommended.



6.  Reagents




    6.1  Turbidity-free water - Pass distilled  water  through  a 0.45 p pore




         size membrane filter if such filter  and  water  shows  a lower turbidity




         than the distilled Water.




    6.2  Stock turbidity suspension:




              Solution 1:  Dissolve l.OOg hydrazine sulfate,  (HN  )_.H2S04, in




        • distilled water and dilute to 100 ml in  a  volumetric flask.




              Solution 2:  Dissolve lO.OOg hexamethylenetetramine in distilled




         water and dilute to 100 ml in a volumetric flask.




              In a 100-ml volumetric flask, mix 5.0 ml  Solution 1 with  5.0 ml




         Solution 2.  Allow to stand 24  hours at  25 ± 3°C,  then dilute  to the




         mark and mix.




    6.3  Standard turbidity suspension:   Dilute 10.00 ml  stock turbidity




         suspension to 100 ml with turbidity-free water.   The turbidity of




         this suspension is defined as 40 units.  Dilute  portions of the  standard




         turbidity suspension with turbidity-free water as required.




         6.3.1  A new stock turbidity suspension  should be prepared  each  month.




                The standard turbidity suspension and dilute turbidity  standards
                                       310

-------
                                                              (Turbidity)





                should be prepared weekly by dilution of the  stock turbidity




                suspension.




7.   Procedure




    7.1  Turbidimeter calibration:  The manufacturer's  operating instructions




         should be followed.   Measure standards  on  the  turbidimeter covering




         the range of interest.   If the instrument  is already calibrated in




         standard turbidity  units, this procedure will  check  the accuracy of the




         calibration scales.   At  least one standard should be run in each




         instrument range to  be used.   Some instruments permit adjustments of




         sensitivity so that  scale values  will correspond to  turbidities.




                Reliance on  a manufacturer's  solid  scattering standard for




         setting overall instrument  sensitivity  for all ranges is not an acceptable




         practice unless the  turbidimeter  has been  shown  to be free of drift on




         all  ranges.   If a pre-calibrated  scale  is  not supplied,  then calibration




         curves  should be prepared for each range of the  instrument.




    7.2   Turbidities  less than 40  units:   Shake  the sample to  thoroughly disperse




         the  solids.   Wait until air bubbles disappear then pour the sample into




         the  turbidimeter tube.  Read  the  turbidity directly  from the instrument




         scale or from the appropriate calibration  curve.




    7.3   Turbidities  exceeding 40  units:   Dilute the  sample with one or more




         volumes  of turbidity-free water until the  turbidity  falls below 40 units.




         The  turbidity  of the  original sample is then computed from the turbidity




         of the diluted  spjnple and the dilution factor.   For example, if 5 volumes




         of turbidity-free water were  added to 1 volume of sample, and the diluted




        sample showed  a  turbidity of  30 units, then the turbidity of the




        original sample was 180 units.
                                       311

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                                                           (Turbidity)


         7.3.1  The Hach Turbidimeters, Models  2100  and 2100A,  are  equipped

                with 5 separate scales:  0-.02, 0-1.0,  0-10.0,  0-100,  and

                0-1000 JTU.  It is strongly recommended, however, that the

                upper scales be used  as indications  of  required dilution

                volumes to reduce readings to less than 40  JTU.  (NOTE:

                Comparative work performed in the AQC Laboratory indicates

                a progressive error on sample turbidities in  excess of

                40 units.)

8.  Calculation

    8.1  Multiply sample readings by  appropriate dilution to  obtain final

         reading.

    8.2  Report results as follows:

                        Jackson Turbidity               Record
                              Units                  to nearest:
                           0.0-1.0                       0.05
                             1-10                        0.1
                            10-40                        1
                            40-100                       5
                           100-400                       10
                           400-1000                      50
                              >1000                      100
9.  Precision and Accuracy

    9.1  Precision and accuracy data  are not  available  at  this time.
                                     312        * U. S. GOVERNMENT PRINTING OFFICE : 1911 O - 427-263

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