CHEMISTRY LABORATORY MANUAL
BOTTOM SEDIMENTS
COMPILED BY
GREAT LAKES REGION
COMMITTEE ON ANALYTICAL METHODS
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TABLE OF CONTENTS
Page
FOREWORD iii
ACKNOWLEDGEMENTS iv
INTRODUCTION 1
CHEMICAL OXYGEN DEMAND 5
CYANIDE 7
IRON
Total and Soluble Ferrous Iron 12
Total Ferrous Iron by Titration 16
METALS
Atomic Absorption l8
Polarographically 21
NITROGEN
Ammonia 28
Nitrate and Nitrite (AutoAnalyzer) 32
Nitrate (Manual) 36
Organic and Total Kjeldahl 38
OIL AND GREASE 42
OXYGEN DEMAND AND CHLORINE DEMAND
Immediate Dissolved Oxygen Demand and 44
Biochemical Oxygen Demand
Oxygen Uptake 47
Chlorine Demand 53
PESTICIDES
Preparation of Sample 56
Gas Chromatography with Electron Capture 59
Microcoulometric Gas Chromatograph 64
Thin Layer Chromatography 69
Infrared 75
PHENOL 77
PHOSPHORUS
Total Soluble 79
Total 82
SOLIDS - Total ($) and Volatile ($) 85
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TABLE OF CONTENTS
Page
SULFIDE 87
SILICA 92
MANGANESE 98
OXIDATION-REDUCTION POTENTIAL MEASUREMENTS 101
11
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FOREWORD
Water pollution control agencies during the past two or three years
have become concerned over the U. S. Army Corps of Engineers dumping dredg-
ings from shipping channels and harbors into the deep waters of the Great
Lakes. The state and federal agencies and the Corps of Engineers recognized
the necessity of knowing the chemical content of these dredgings or bottom
sediments.
The Corps of Engineers then requested that the Federal Water Pollution
Control Administration sample and analyze all bottom sediments in areas to
be dredged, prior to dredging. As a result of this request, the Lake Michi-
gan Basin Office developed analytical methods suitable for the analysis of
these bottom sediments. It was not long before other FWPCA Basin Offices
in the Great Lakes Region requested the Lake Michigan Basin Office's methods.
Cther Dasin Offices soon modified the Lake Michigan Basin Office's methods
to suit their particular need.
In October 1967 chemists of several agencies in the Great Lakes Region
were requested to develop uniform sampling and analytical methods. A meeting
including FWPCA Basin Offices, U. S. Army Corps of Engineers, International
Joint Commission and U.S. Lake Survey was held in Cleveland to discuss
sampling and analytical methods and establish uniform methods. A committee
was appointed to compile a chemistry manual for bottom sediments. The
committee consisted of members from all of the above agencies.
After extensive correspondence, exchange of methods among the committee
members and several committee meetings, the present manual was compiled.
This manual is being used by all of those agencies mentioned above in
the Great Lakes Region and many other federal, state, municipal, consulting
firm and university laboratories.
Frederic D. Puller
Chairman and Editor
Lake Michigan Basin Office
ill
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ACKNOWLEDGMENTS
Various tests as given in Standard Methods for the Examination of Water
and Wastevater have been modified to better suit Great Lakes Region's
objectives and needs. In some instances, new methods have been devised
as superior to those in Standard Methods.
For these endeavors by members of the many laboratories in the Great
Lakes Region, full credit is given.
Original Methods
Total Ferrous Iron, by C. Ross and C. Potos,
Lake Erie Basin Office
Pesticides, by W. D. Johnson and G. Frye,
Lake Michigan Basin Office
Modified Methods
Toxic Metals, including preparation of sample and methods for
Cu, Cd, Ni, Zn, Pb, Cr. Al and Mn, by E. T. King and S. Zarbin,
Lake Michigan Basin Office.
Cyanide, by E. T. King, Lake Michigan Basin Office.
Sulfide, by E. T. King, and S. Zarbin, Lake Michigan Basin Office.
Total Phosphorus and Total Soluble Phosphorus, by F. D. Fuller,
R. H. Hall, and M. Huston, Lake Michigan Basin Office.
Silica and Manganese, by A. C. Smith, Lake Erie Basin Office.
In addition to those chemists mentioned above, credit is given to all
chemists in the region for their contributions of thoughts and suggestions,
iv
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INTRODUCTION TO
BOTTOM SEDIMENT ANALYSIS
1. General Discussion
Bottom sediment analysis gives information as to the chemical and
biochemical characteristics of the overlying water mass and the
immediate underlying sediment itself.
The productivity of a stream or lake is reflected in the chemical
composition of the bottom sediments.
Comprehensive bottom studies show potential pollutional loadings
of toxic materials, nutrients, and organic substance.
2. Sampling
2.1 Bottom sediment samples are collected with a Petersen or
Shipek dredge lowered slowly in order to cause the least possible
disturbance to the surface sediment (water-sediment interface).
A satisfactory core sampler would be more desirable.
2.2 When hopper dredging is employed, inflow grab samples are taken
from two forward and two aft inflow chutes over an eight hour
period and composited. The composite is thoroughly mixed and
samples withdrawn. Overflow samples are collected at four over-
flow weir locations and composited in the same manner. Sampling
from the hopper itself is accomplished by allowing a 20-quart
bucket to remain in the bottom of the hopper at four locations
for five minutes and compositing these grabs similar to the
inflow and outflow samples.
2.3 When bucket dredging is used, five samples from each compartment
would be taken after the barge is filled. A one-inch diameter
aluminum tube, ten feet long will be used to take samples. One
composite is made for each barge and two barges per week.
2.k When hydraulic dredging is employed, grab samples are taken from
the discharge pipe and composited. The sample is taken from the
well-mixed composite.
3- Preservation and Storage
All samples should be well iced and no preservative added. If the
samples can not be analyzed the day they are collected, they should
be frozen as soon as possible. Sample containers should be filled
only three-fourths full to prevent breaking, when frozen.
^. Preliminary Preparation of Bottom Sediment Samples
The sample is passed through a 2 mm (approximately 10 mesh) sieve
by rubbing with a rubber stopper, if necessary. This removes large
pieces of foreign material such as stones and twigs.
The sieved sample is blended to a homogeneous mixture in a
"blender for 2 minutes at high speed. The sample is now ready for
analysis.
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PHENOL
BOD
NH -N
SCHEMATIC ANALYSIS OP SEDIMENT
^ and pH performed in field
SIEVED BLENDED NO ADD SAMPLE
10-50K
.3-lg
S-lO
10 K
•5-ig
5-iog
METALS
COD
POL5
OIL & GREASE
CYANIDE
Residue
digested
10 g
Dry in oven at 103°-105°C - overnight
Org.-N
1.
Percent Solids
ignite residua at 600°C for one hour
I
Volatile Solids
Decomposition and dehydration of residue using HC1-HNO
I
Silica
Filtrate
A
Iron Manganese
FIGURE 1
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Introduction to Bottom Sediment Analysis
5. Schematic Analysis
If the sample has been frozen, thaw the sample and proceed with
preparation of sample. Several portions of the wet, sieved,
blended sample are weighed depending on the parameter concentration
expected (Figure l). The amount of sample necessary for any given
test is determined by the analyst based on test sensitivity and
concentration in the sample examined.
5.1 One weighed portion of wet sample is placed on aluminum
strips for the BOD test.
5.2 A portion of the sample is weighed for the COD test. Fifty ml
of distilled water is added, followed by three drops of con-
centrated sulfuric acid. The acid preserves the sample until
the analysis can be completed.
5.3 A portion of the wet sample is weighed for nitrate determination.
Approximately 50 ml of distilled water are added and the sample
preserved with sulfuric acid for later analysis. The procedure
used for nitrates is the Modified Brucine Method as in Standard
Methods, 12th Ed., pp 393~39^ or the automated method using a
reduction column, sulfanilic acid and naphthylamine hydrochloride.
5.k A portion of the wet sample is weighed for NHo-N and Org-N and
approximately 50 ml of water are added with three or four drops
of concentrated sulfuric acid for preservation and ammonia
stabilization. The sample is analyzed using the distillation
method for ammonia nitrogen followed by a Kjeldahl digestion
on the residue with subsequent neutralization and distillation.
An aliquot of the distillate is nesslerized and read on a
spectrophotometer and reported as Org-N. NOTE: Samples are
distilled into 0.02 N H2SO^.
5.5 A portion of the wet sample is weighed and percent total solids,
volatile solids, silica, manganese, and iron are determined.
Total solids are determined by drying the sample overnight at
103°-105°C. The fixed solids are determined by ignition in a
muffle furnace at 600°C for an hour. Volatile solids are
determined by calculation. A silica analysis is then made on
the residue (Fixed Solids). An aliquot of filtrate from the
silica determination is analyzed for iron using the Phenanthroline
Method described in Standard Methods, 12th Edition, pp 156-159.
Another aliquot of the filtrate is analyzed for manganese using
the Persulfate Method described in Standard Methods, 12th Edition
pp 1^9-^92 with modifications as shown in procedures.
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Introduction to Bottom Sediment Analysis
5.6 A portion of the wet sample is weighed for determination of
phosphorus (as P^). Due to the incomplete oxidation of the
large amounts of organic matter present by the persulfate-
sulfuric acid mixture, a dry ash method using Mg (NO^)2*6H:0
was found to accomplish complete oxidation. After ashing,
the Potassium Antimonyl Tartrate Method is used and the
resulting color development read on a spectrophotometer.
5-7 A portion of the wet sample is weighed for oil and grease
analysis. A procedure, which is essentially the same as in
Standard Methods, 12th Edition, pp. 531-532, is employed.
5.8 For special studies, a portion of the wet sample is weighed
for long-term BOD determination in the same manner as the
5-day BOD analysis. The long-term BOD's are checked for DO
content at various intervals over a period of 30 days. A DO
analyzer is used to measure this parameter. One-inch glass
rods are added to the DO bottle after each electrode insertion
to return liquid level to a point where a water seal can be
maintained upon cap replacement. By the use of a DO analyzer,
a long-term BOD analysis can be made using a single bottle
throughout the entire period of 30 days.
5.9 A portion of the wet sample is weighed for determination of
cyanide. The procedure used for cyanide is Colorimetric
Method as in Standard Methods, 12th Ed., pp ^55-457, with
minor modifications as described in procedure.
5.10 A portion of the wet sample is weighed for determination of
phenol. The method used for phenol is essentially the same
as in Standard Methods. 12th Ed., pp 517-519-
5.11 A portion of the wet sample is weighed for determination of
metals. The procedures used for metals are new or modified
methods developed by the Lake Michigan Basin Office - EWPCA.
5.12 A portion of the wet sample is weighed for determination of
sulfide. The procedure used for sulfide is a modified method
developed by the Lake Michigan Basin Office - FWPCA.
5.13 A portion of the wet sample is weighed for determination of
chlorine demand. The method used for chlorine demand is
essentially the same as in Standard Methods, 12th Ed., pp 112-llU.
6. References
Standard Methods for the Examination of Water and Wastewater, 12th ed.,
APHA, Inc., N.Y., 1965.
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CHEMICAL OXYGEN DEMAND OF BOTTOM SEDIMENTS
1. General Discussion
(See Standard Methods. 12th Ed., p. 510-11, 1965)
2. Apparatus
Reflux apparatus, consisting of 250 ml Erlenmeyer flasks with ground-
glass 2liA° neck* and 300 mm jacket Liebig, West, or equivalent
condensers*"* with 2U/UO ground-glass joint, and a hot plate with
sufficient power to produce at least 9 watts/sq. in. of heating
surface, or equivalent, to insure an adequate boiling of the contents
of the refluxlng mixture„
3• Reagents
3«1 Sulfuric acid reagent, cone. H2SOr.
3,2 Silver sulfate is dissolved in the HpSO. acid.
3.3 Mercuric sulfate, analytical grade crystals
3.U Ferroin indicator solution, 0.025 M: Dissolve 1.^85 g
1,10-phenanthroline monohydrate, together with 0.695 g FeSOi .
?H20 in water and dilute to 100 ml. This indicator solution
may be purchased already prepared.
3o5 Standard potassium dichromate solution, 0.500N: Dissolve
120259 g K2Cr20-7, primary standard grade, previously dried
at 103°C for 2 hours,in distilled water and dilute to 1000 ml.
3»6 Standard ferrous ammonium sulfate, 0.500N: Dissolve 98 g
Fe(NHk)2(SOjp2.6H20 in distilled water. Add 20 ml cone.
^SOjj, cool and dilute to 1000 ml. This reagent must be
standardized daily.
3<>7 Standardization of ferrous ammonium sulfate: Dilute 25 ml
standard potassium dichromate solution to approximately 250 ml.
Add 50 ml cone. H2SOi and allow to cool. Titrate with the
ferrous ammonium sulfate titrant, using 2 or 3 drops of ferroin
indicator.
Normality - * K2Cr2°7 * °2*
ml "
* Corning 5000 or equal
** Corning 23^0, 9l5b8, or equal
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Chemical Oxygen Demand cf Bottom Sediments
Procedure
U.I Add 25 ml KjCrgOy (0.2500N) to a suitable sized sample (0.5g-1.0g)of
bottom sediment that will consume one-half of the
U.2 Add loO g HgSO^ and 0.75 g
Iio3 Add 50 ml of distilled water.
UoU Add 75 ml conce KpSOj^ (cautiously) and nix thoroughly.
Iu5 Add boiling stones and reflux for 2 hours.
U.6 Cool and rinse condenser with distilled H20 (approximately
50 ml) while condenser is still connected to flask.
Iu7 Disconnect and add approximately 150 ml distilled HpOo Cool
to room temperature and then titrate (after adding 3 to 5
drops ferrion indicator) to end point (the color changes
sharply from blue-green to reddish-brown).
U«8 For standard, use 25 ml I^C^Oy + 50 ml conca HgSO^ and dilute
to approximately 250-300 ml. Cool and titrate.
For blank,use 25 ml K2Cr2Oy, 75 ml H2SOr, 50 ml distilled
H20, 1 g HgSOj^, 0.75 g Ag2SO^j reflux for 2 hours and continue
in the same manner «.s the sample.
5. Calculations
5«1 Wet basis
mg/kg« (a-b)c* x 8 x 1000
grams sample
5«2 Dry basis
mgyfccr= mg/Jcg wet basis
% solids
* a * mis of Fe(NH.) (SO, )2 required for blank
b - " " " " sample
c » normality of Fe(NH|;) 2(^0^)2
6. Reference
Standard Methods for the Examination of Water and Wastewater,
12th ed., APHA, Inc., N.Y., 1965, 510-511.
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7
CYANIDE IN BOTTOM SEDIMENTS
1. Scope
Principle: Simple cyanide salts will form hydrogen cyanide under
acidic conditions. Hydrogen cyanide has a boiling point of 26°C
and can be easily isolated by distillation. On the other hand, some
complex cyanides are not easily decomposed and others, such as
cobalticyanides are essentially non-responsive to this test.
However, the conversion can be hastened by the addition of magnesium
and mercuric salts.
2. Summary of Method
The liberated cyanides are converted to sodium salts and reacted
with chloramine T under slightly alkaline conditions to form cyanogen
chloride. A pyridine-pyrazolone reagent reacts with the cyanogen
chloride to form a blue dye, the absorbance of which is measured at
620 mii. Increased sensitivity can be obtained by extracting the dye
into n-butyl alcohol and reading the absorbance at 630 np.
3. Interference
Most of the substances known or thought to interfere can be removed
via the distillation procedure. Common interferences are heavy metal
ions, thiocyanates, cyanate, and other substances which may form cyanide.
Sulfides and fatty acids interfere with the analysis and are not
eliminated by distillation. However, these materials are not often
found in surface waters. If they are known to be present, procedures
for their removal are listed in the 12th Edition Standard Methods^ 1963.
k. Minimum Detectable Concentration
The minimum detectable concentration is 0.02 mg/1 as cited in the
12th Edition Standard. Methods. 1963.
5« Apparatus
5.1 Modified Claissen flask, 1,000 ml.
5.2 Allihn condenser. (200 mm)
5.3 Gas washer bottles (Sargent #39623) or equivalent.
5.4 Suction flask, 500 ml.
5.5 Water aspirator, air inlet tube.
5.6 Heating element, for modified Claissen flask or bunsen burner.
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8
Cyanide in Bottom Sediments
5»7 pH meter.
5.8 Reaction tubes (test tubes).
5.9 Spectrophotometer or filter photometer providing a 1 cm light
path (or longer) and a wave length of 630 inn.
6. Reagents
6.1 Sulfuric acid, cone.
6.2 Sodium hydroxide, IN: Dissolve 4 g NaOH in 100 ml of vater.
6.3 Mercuric chloride solution: Dissolve 3^ g of EgCl2 in 500 ml
of distilled water.
6.k Magnesium chloride solution: Dissolve 51 S °f MgClp'SHgO in
100 ml of distilled water.
6.5 Acetic acid, glacial.
6.6 Chloranine T, 1.0^ aqueous solution. (Prepare daily. If
reagent does not dissolve readily, degradation of the reagent
is indicated and it should be replaced.)
6.7 l-phenyl-3-nethyl-5-pyrazolone, saturated aqueous solution (7 g/l)
(Eastman Reagent #1397).
6.8 Bis-pyrazolone: Dissolve 0.025 g in 25 ml pyridine. Prepare
fresh daily. (Eastnan reagent #6969).
6.9 Mixed reagent immediately prior to use; nix 125 ml of reagent
#6.7 with 25 nl of reagent #6.8.
6.10 Stock cyanide standard: Dissolve 0.251 g KCN in one liter of
distilled water (add two pellets of sodiun hydroxide for
stability). Solution contains 0.1 ng/znl cyanide. This is a
primary standard and must be prepared fresh each week.
6.11 working Standard: Dilute stock standard 100 fold, 1 ml - 1 ng.
Take 0 - 5 ml of the resulting solution for standard curve.
Prepare fresh daily.
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Cyanide in Bottom Sediments
6.12 5% disodium hydrogen phosphate.
6.13 N-butyl alcohol - reagent grade.
6.lA The buffer solution is prepared by adding 35-0 ail 0.1 N.
NaOH to 50.0 ml 0.1M KH2P% and diluting to 100 ml. This
buffer gives a pH of 7*2 •
The vater used in preparing both solutions should be free of
carbon dioxide. This can be accomplished fairly well by heating
distilled vater to boiling in a flask and cool while stoppered
lightly. If stopper is tight while water is hot, cooling may
freeze the stopper.
7« Procedure
7.1 Distillation: An aliquot of a well-mixed bottom sediment sample,
containing not more than 500 mg of cyanide (lOg) is added to a
Claissen flask and brought to approximately 500 ml with distilled
water. ?ifty ml of 1.0 N sodium hydroxide and 75 ml of distilled
water are added to the gas washer receiving vessel and the unit is
assembled. Air, drawn through the unit via vacuum aspiration, is
adjusted so that its flow rate is approximately one bubble per second
through the receiving unit, or as many as necessary to prevent flow
back.
After the air inlet tube is positioned, 1.0 ml of mercuric chloride
and 4.0 ml of inagnesium chloride solutions are added through the
tube and two minutes are allowed for mixing. After rinsing the tube with
distilled water, 5 ml of concentrated sulfuric acid are then added
through the tubej at this point, if it is not fcaown whether the pH is
2.0 or lower, the pH should be determined on a separate -volume of the
sample with the same amount of sulfuric acid added as in the distilled
sample.
Heat is applied to the system at a rate that will produce boiling,
as soon as possible but will not allow a flow back. Refluxing,
which should begin within 30 minutes, is carried on for l£ hours.
Occasionally during distillation the air flow rate may have to
be readjusted to prevent the reverse flowing of the cample solution.
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10
Cyanide in Bottom Sediments
7. Procedure (continued)
7.1 (continued)
When the heating is discontinued, the air flow proceeds for an
additional 15 minutes for cooling purposes.
7.2 The contents of the gas washer vessel are drained into a 250 ml
volumetric flask and the accessible components of the distillation
unit rinsed twice with distilled water. The washings are added to
the distillate and the solution brought to volume.
Pipette a 15 ml aliquot-or other suitable volume- of the solution
into a 25 ml volumetric flask.
Neutralize to phenolphthalein end-point using acetic acid (1:4 or
weaker).
Add 0.2 ml Chloramine-T, stopper, mix, and after one minute, add
2 ml of the buffer solution.
Add 5 ml of the mixed pyrazolone, dilute the solution to volume
with distilled water, stopper, mix, and allow to stand for 20 minutes
for color development.
The optical densities of the standard and samples are read against
a reagent blank at 620 my on a spectrophotometer within one hour,
at maximum.
7.3 Alcohol extraction: The sensitivity of detection is slightly
increased by determining the optical density of the colored dye
in butyl alcohol. Some interferences which may pass through the
distillation may also be eliminated.
After color development in the aqueous system, add 2 ml of disodium
hydrogen phosphate solution and 10 ml of n-butyl alcohol. Mix and
withdraw an aliquot of the alcohol layer. Measure optical density
at 630 my.
7.4 Samples are to be compared with distilled standards.
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11
Cyanide in Bottom Sediments
8. Calculation
8.1 Wet Basis:
,q' x ?'D- Sample OOQ
O.D. Std. (grams sample '
in aliquot)
8.2 Dry Basis
- - mg/kg vet basis
__/,,_
ag/K6
~ # Solids (decimal fraction
References
9-1 Standard Methods for the Examination of Water and Wastewater,
12th ed., APHA, Inc., N.Y., 1965,
9.2 Ludzack, et al., Analytical Chemistry 26: IjQk
9.3 Jarrell, R., Report, Colorado River Basin Project Laboratory.
9.4 Recovery of Cyanide by a Modified Surf ass Distillation,
Charles T. ELly, Unpublished.
9.5 Babcock, R., American Oil Co., Unpublished Report.
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12
TOTAL AND SOItfBLE FERROUS IRON IN BOTTOM SEDIMENTS
1. General Discussion
lol Principle: Iron is brought into solution and reduced to the
ferrous state by boiling with acid and hydroxylamine, and
treated with 1,10-phenanthroline at pH 3.2-3.3. Three
molecules of phenanthroline are required to chelate each atom
of ferrous iron to form an orange-red complex. The colored
solution obeys Beer's law; its intensity is dependent upon
pH and is stable for at least 6 months. A pH between 2o9 and
3.1j insures rapid and maximum color development in the
presence of an excess of phenanthroline.
1<>2 Interference: Among the interfering substances are strong
oxidizing reagents, cyanide, nitrite, and phosphates - poly-
phosphates more so than orthophosphate; chromium; zinc in
concentrations exceeding ten times that of iron; cobalt and
copper in excess of 5 rog/l» and nickel in excess of 2 mg/1.
Bismuth, cadmium, mercury, molybdate, and silver precipitate
phenanthroline. The initial boiling with acid reverts polv-
phosphates to orthophosphate and removes cyanide and nitrite,
which would otherwise interfere. The addition of more hvdroxyl-
amine will eliminate errors caused by excessive concentrations
of strong oxidizing reagents. In the presence of interfering
metal ions, a larger excess of phenanthroline is required to
replace that which is conplexed by these interferences. With
excessive concentrations of interfering metal ions, the
extraction method is preferred.
If much color or organic matter is present, it may be necessary
to evaporate the sample, gently ash the residue, and then re-
dissolve in acid. The ashing may be carried out in silica,
porcelain, or platinum crucibles which have previously been
boiled for several hours in 1 + 1 HC1.
1.3 A separate sediment sample oust be taken for ferrous iron, preserved
with 12 ml cone. HC1 per 300 ml bottle, if sample is not
preserved by freezing.
2. Apparatus
2.1 Colorimetric equipment: One of the following is required:
a. Spectrophotometer, for use at 510 jD^i) providing a light
path of 1 inch or longer.
b. Filter photometer, providing a light path of 1 inch or
longer and equipped with a green filter having maximum
transmittance near 510 mm.
2.2 Hot Plate.
2.3 Centrifuge and 50 ml tubes with caps.
2.4 Magnetic Stirrer.
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13
Total and Soluble Ferrous Iron in Bottom Sediments
2.5 Acid-washed glassware: All glassware must be washed with
cone. HC1 and rinsed with distilled water prior to use, in
order to remove the thin film of adsorbed iron oxide which
is frequently present as a result of employing the glassware
for other purposes.
3» Reagents
All reagents must be low in iron. Iron-free distilled water is
required. Glass -stoppered bottles are recommended for storage.
The hydrochloric acid, ammonium acetate solution, and stock iron
solutions are stable indefinitely, if tightly stoppered. The
hydroxylamine and phenanthroline solutions are stable for several
months. The standard iron solutions are not stable and must be
prepared fresh, as needed, bv diluting the stock solution.
Visual standards in nessler tubes are stable for 3 months if pro-
tected from light.
3.1 85$ Phosphoric Acid.
3.2 Hydrochloric Acid, cone,
3.3 Hydrochloric Acid, 1/1 (oxygen free
3.4 Hvdroxylamine solution: Dissolve 10 g NH2OH.HC1 in 100 ml
distilled water.
3.5 Ammonium acetate buffer solution: Dissolve 250 g NHj^HoOp in
150 ml distilled water. Add 700 ml glacial acetic acid and
dilute to 1 liter. (Since even good grade NH^C2Ho02 contains
a significant amount of iron, new reference standards should
be prepared with each buffer preparation.)
3.6 Phenanthroline solution: Dissolve 0.1 g 1,10 phenanthroline
monohydrate, CipHo^oI^O in 100 ml distilled water by stirring
and heating to 80°Cj do not boil. Discard the solution if it
darkens. Heating is not necessary if 2 drops of cone. HC1 are
added to the distilled water. (Note that 1 ml of this reagent
is sufficient for no more than 0.1 mg Fe.)
3,7 Stock iron solution: The metal (a) or the salt (b) may be used
for the preparation of the stock solution, which contains
0.200 mg Fe per 1»00 ml,
a. Use electrolytic iron wire, or "iron wire for standardizing,"
to prepare the solution. If necessary, clean the wire with
fine sandpaper to remove any oxide coating and to produce a
bright surface. Weigh 0.2000 g wire and place in a 1-liter
volumetric flask. Dissolve in 20 ml 6N H2SO^ and dilute to
the mark with iron-free distilled water.
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Ik
Total and Soluble Ferrous Iron in Bottom Sediments
b. If ferrous ammonium sulfate is preferred, add slowly
20 ml cone. H2SOK to 50 ml distilled water and dissolve
l.UOU g Fe (NHii)2(SOit)2.6H20. Add dropwise 0.1N KMnO^
until a faint pink color persists. Dilute with iron~
free distilled water to 1,000 ml and mix.
3.8 Standard iron solutions: These should be prepared the day
they are used.
a. Pipat 5>0.00 ml stock solution into a 1-liter volumetric
flask and dilute to the mark with iron-free distilled
waterj 1.00 ml = 10.0 ngFe.
b. Pipet £.00 ml stock solution into a 1-liter volumetric
flask and dilute to the mark with iron-free distilled
waterj 1»00 ml = l.OOng Fe.
3.9 Ammonium hydroxide (1:1).
3.10 Standard potassium dichromate solution, 0.25 normal (use
oxygen-free HrjD ).
3.11 Diphenylamine sulfonate indicator solution. Prepare by
dissolving 3-lTg of barium diphenylamine sulfonate in
distilled water and adding a solution of l.Tg of sodium
sulfate decahydrate (Na2S04 • 10H20) to precipitate the
barium and dilute to one liter with oxygen-free HgO.
3.12 Oxygen-free water.
3.13 Ferrous ammonium sulfate approximately 0.25N (use oxygen-free
U. Procedure - Total Iron
U.I Weigh 10 grams of a well-mixed sediment sample into kQQ ml beaker
and add 5 ml HNO^, 005 ml H202 (3C#), plus 1 ml NaN03 (1$),
and evaporated to dryness.
U.2 Ash in muffle furnace at 550°C for £Q minutes.
li.3 Cool, add liO ml HC1 (1:1), cover with watch glass, and heat
gently for 20 minutes.
h.U Allow to stand 5 minutes to cool (or longer) and filter into
a 100 ml volumetric flask.
IN£ Dilute to volume, mix, and take 50 ml or an aliquot contain-
ing 0.25 mg iron (diluted to 50 ml) into a 100 ml volumetric
flask.
li.6 The sample is then made alkaline to phenophthalein (l drop)
with ammonium hydroxide (1:1).
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15
Total and Soluble Ferrous Iron in Bottom Sediments
U.7 Add 2 ml HC1, 2 ml hydroxylamine hydrochloride solution and boil,
reducing the volume to approximately 20 ml.
U.8 Add 10 ml acetate buffer*, 10 ml phenanthroline solution and
dilute to 100 ml. Mix thoroughly and allow 15 minutes for
maximum color development. Read adsorbance against a blank
at a wave length of 510 my. on a spectrophotometer .
^.9 Calculations are as shown in"6" below.
Jj. Procedure - Soluble Ferrous Iron
5-1 Weigh 10 grams of a well-mixed sediment sample into a 250 ml
beaker, add 100 ml of oxygen-free distilled water and digest
on hot plate for 30 minutes .
5.2 Filter into a 100 ml volumetric flask.
5.3 Dilute to volume, mix and take 50 ml or an aliquot containing
0.25 mg of iron (diluted to 50 ml) into a 100 ml volumetric
flask.
5.U Then proceed as in total iron sections k.6 and k.8
6. Calculation
6.1 Wet basis
°'D- SagPle
-
O.D. Std. (grams sample
in aliquot)
x 1000
6.2 Dry basis
_ mg/g wet basis
solids (decimal fraction)
* Check pH of solution sample on pH meter. Range should be 2.9-3.1*.
units for good color development.
-------
16
Total and Soluble Ferrous Iron in Bottom Sediments
J. Procedure - Total Ferrous Iron "by Titration
7-1 Weigh an 8-10 gram sample of well-mixed sediment in a
150 ml beaker and add sufficient hydrochloric acid to
extract the expected iron concentration, 10 ml of 85
percent phosphoric acid, plus enough oxygen-free water
to bring total volume to approximately 50 ml.
(a) For each mg of total iron expected add 1.2
mg of HC1 plus a 10 percent excess. (20 ml 1/1 HCl)
(fc) In moderately dilute solution and at room temp-
erature, dichromate does not react with chloride ion.
(c) Phosphoric acid is added for two reasons:
(l) To complex any ferric ion initially present in
the specimen, thus preventing its reduction to
the ferrous state by hydrogen sulfide during
extraction.
(2) To prevent the indicator from changing color
before reaching equivalence point by increasing
oxidation potential to — .85.
7.2 Boil on a hot plate for 15 minutes. Take care to avoid
frothing by adding more deoxygenated water or by removing
from heat and stirring.
Note: Volume must be 50 mis or less at conclusion of
15-minute boiling period.
7-3 Transfer and rinse with small aliquots of deoxygenated water
into a 50 ml centrifuge tube with cap and centrifuge for
10 minutes.
7-^ Decant solution into a 500 ml Erlenmeyer flask containing
approximately 200 ml of oxygen-free water. Rinse centri-
fuge tube with small aliquots of water.
7.5 Add 1 ml of indicator solution. Titrate with standard
dichromate until the first permanent coloration appears.
-------
17
Total and Soluble Ferrous Iron in Bottom Sediments
8. Calculation
Iron, mg/kg = pC * ??'? X 1000
A - milliliters KpCrpO_ solution required to titrate sample
B = milliliters KgCrpO to titrate blank
C = normality of K^Cr^O^
D = grams sample used (dry basis)
9. References
9-1 Patterson, A., Ihomas, H.C., Quantitative Analysis, Henry Holt
and Co., New York 1952, pp 278-287.
9.2 Fisher, R.B., Quantitative Chemical Analysis, W.B. Saunders Co.,
Philadelphia, 1957, PP 281*-5.
9.3 Standard Methods for the Examination of Water and Wastewater,
12th ed., APHA, Inc., N.Y., 1965, 156-159-
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18
METALS IN BOTTOM SEDIMENTS
Atomic Absorption
1. General Discussion
Metal complexes axe freed by digestion of bottom sediment samples
with concentrated HNOj acid KgO^ (30/o). A wide range of elements
can be determined by atomic absorption with the selection of the
proper source (hollow cathode lamp).
1.1 Principle: The principle of atomic absorption and its application
to the analysis of metals is based upon the element of interest
being dissociated from its chemical bonds and placed into an
unexcited, un-ionized "ground" state. It is then capable of
absorbing at discrete lines of narrow band width radiation
provided by a hollow cathode lamp with a cathode made of the
element being sought. The absorption of the light by the metal
in the ground state is related to the concentration of the metal
being sought.
1.2 Interference: The atomic absorption method is relatively free
of interferences.
2. Apparatus
2.1 Atomic absorption spectrophotometer.
2.2 Muffle furnace.
2.3 Pipettes.
2.k 250 ml beakers.
2.5 Watch glasses.
2.6 250 ml volumetric flasks-
2-7 Polyethylene bottles (60 ml).
2.8 Centrifuge (20,000 rpm).
3. Reagents
3-1 Nitric acid (cone, metal-free).
3.2 Hydrogen peroxide (30$).
3.3 Hydrochloric acid (cone, metal-free)•
-------
19
Metals in Bottom Sediments- Atomic Absorption
3.4 Ammonium chloride.
3.5 Calcium nitrate.
3.6 Redistilled water or double deionized water (metal-free).
3.7 Bottled acetylene gas •
3.8 Bottled nitrous oxide gas.
3-9 Compressed air.
h. Preparation of Standards
k.I. Using a commercial certified atomic absorption standard,
containing 1,000 mg/1 of the metal, prepare an appropriate
dilute stock standard. Standards may be prepared in the
laboratory using pure metals.
U.2 Make up working standards to approximate the concentration
in the sample using the dilute stock standard .
5 • Preparation of Samples
5.1 Place 2.5 g of a well mixed bottom sediment sample in a
250 ml beaker, add 10 ml of cone. HNO-^ acid and 0.5 ml of
(30$) and evaporate to dryness.
5-2 Ash at 400-^25°C for one hour in a muffle furnace and cool.
5-3 Add 25 ml of acid mixture (200 ml of cone, mo^, 50 ml cone. HC1
and 750 ml of redistilled water), 20 ml of lOfcTSH^Cl and 1 ml
of Ca (NOQ)2 • ^H20 (11.8 g/100 ml). Heat gently for 15 minutes
and cool for five minutes or longer.
5.U Transfer sample to centrifuge tube and centrifuge for 10 minutes
at 20,000 rpm. Transfer the supernatant to a 250 ml volumetric
flask. Rinse the residue in the centrifuge tube twice with
redistilled water and add washings to supernatant and dilute to
volume. Then transfer sample to a small plastic bottle.
6. Method for Cu, Cd, Ni, Znt Cr, Pb, Mn, Al and Other Metals
Follow procedures as outlined in manufacturer's manual.
-------
20
Metals in Bottom Sediments -Atomic Absorption
7- Calculations
T.I Wet Basis
By use of table from manufacturer's manual, convert percent
absorption to absorbance.
= absorbancfof std. X *"" factor X absorbance of sample X
1,000
g of s ample /L
7.2 Dry Basis
- mg/kg wet basis
~ ^solids (decimal fraction
Atomic absorption is the preferred method because it is much faster,
more accurate and there are less interferences.
-------
21
METALS IN BOTTOM SEDIMENTS
Polarographically
1. General Discussion
~sediment
Metal complexes are freed by digestion of / with HNO^ acid.
Simultaneous determination of copper, cadmium, nickel, and zinc
is possible, also a wide range of other elements can be determined
polarographically with the selection of the proper supporting
electrolyte.
1.1 Principle: Cations are reduced on the surface of a dropping
mercury electrode to form an amalgam in a current producing
reaction. This current is reflected in a galvanometer and
may be recorded as a measurable wave which is proportional to
the concentration of a specific cation that is being reduced
at its specific half-wave potential. The wave height produced
by an unknown is compared to that made by a known standard
for determining the amount of an unknown metal in the sample.
1.2 Interference: Any volatile or organic interference is
eliminated by the ashing process in which carbon is destroyed.
In addition, iron, chromium, turbidity, chlorides, oxidizing,
and reducing substances, and dissolved oxygen are major inter-
ferences that are likely to be encountered. The following
procedures are designed to eliminate or reduce to a minimum
these types of interferences.
1.3 Precautions: The one most precautionary measure to take is
the washing of all glassware and other containers with hot
HC1 (l:l) and rinse with distilled water. Etched beakers
should be avoided since they could possibly retain metals.
Any wasted mercury should be removed to prevent the poisonous
fumes from volatilizing into the air.
2» Apparatus
2.1 Sargent Model XV Recording °olarograph
2.2 MicroRange Extender
2.3 Muffle Furnace
2.h Pipettes (Kohr and Volumetric)
2.5 600 ml Beakers
2.6 Watch Glasses (to cover 600 ml beakers)
2,7 10 ml Beakers
2.8 Hot Plate
2.9 ^O ml Volumetric Flask
2.10 Folded Filter Paper (Whatman #12, 18.5 cm or equivalent)
2.11 Polyethylene Bottles (60 ml, 2 liter, and wash bottles)
-------
i 22
Metals in Bottom Sediments -Polarographically
3. Reagents (Not mentioned in procedures)
3.1 Mercury (high-grade, metal- free)
3.2 Nitric Acid (cone., metal-free)
3.3 Hydrochloric Acid (conc0, metal -free)
3oli Redistilled Water (metal-free, stored in polyethylene bottles)
3.5 Sodium Sulfite, reagent grade
3.6 Bottled Nitrogen Gas (water-pumped)
U. Preparation of Standards
li.l A stock standard solution io made by dissolving the salts of
the metals in water or the metals in nitric acid in such
proportions that 1.0 ml of standard equals 00010 mg of each
of the six metals (Cu, Cd, Ni, Zn, Pb, and Cr).
h.2 A working standard is prepared by diluting 100 ml of stock
standard to 1 liter. 5.0 ml contains 0.005 mg of each of the
metals .
Iu3 A 5.0 ml portion of the working standard is pipetted into a
10 ml beaker and evaporated to dryness. This standard is
treated exactly as the samples and the comparative wave heights
are used in calculating the amount ~of the particular metal
in the samples .
Sediment
**• Preparation of Bottom /Samples for Hetals on the Polarograph
^.1 To a 10 gram sample of well-mixed bottom mud in a 600 ml beaker,
add 10 ml HNO-, (cone.) and 0.5 ml K202 (3Qro) and evaporate to
dryness „ (if sample is not very uniform, use 20 grams.)
5.2 Ash at l<50-500o for 30 minutes in muffle furnace and cool.
ml
5.3 Add 25 ml acid mixture , 200/HNO-j cone. + 50 ml HC1 cone. +
750 ml redistilled water , heat gently 15 minutes and cool
5 minutes or longer.
5.h Filter and dilute the filtrate to 50 ml in volumetric flask,
then transfer to a snail plastic sample bottle.
5.5 Pipette three 5 ml portions into 10 ml beakers and evaporate
to dryness for analysis .
6. Method for Cu, Cd, Ni, and Zn on the Polarograph
6-1 Reagents: Prepare all reagents in metal-free distilled water.
a. Electrolyte: Dissolve 10? grams of IIK^C!, 11. U grams (
and 6? ml NH|i(OH)2 in distilled water. Add 10 ml of 0,?.%
trlton-X and dilute to 1 liter. The strength of this solution
is 2.0M NH^Cl, OclM (NH^CO^ and 1M NH, OH.
-------
23
Metals in Bottom Sediments - Polarographically
b. Sulfuric Acid (1:5).
c. Sodium Sulfite Solution (saturated)
d. Water-pumped Nitrogen Gas (This' gas passed through a saturated
solution of sodium sulfite just prior to use.)
6,2 Procedure
a. To the dried sample or standard, add 2 drops ^SOi (1:5) and
heat gently until near dryness.
b. Heat strongly until fumes cease.
c. Cool, add 5oO ml electrolyte and allovr 5 minutes contact time.
d. Police the beaker and transfer sample to cell.
6t Add 5 drops sodium sulfite solution and allow nitrogen gas*
to flow through cell for one minute.
f, Add Mercury pool and, if any air bubbles are present, swirl
gently to remove0
gt Record, polarogram.
h. Recommended settings: Sensitivity 0.002 (if range extender
is available, otherwise use 00003), voltage range 0 to ~2.
Compensation and damping should not be used unless necessary.
7. Method for Lead on the Polarograph
The normal interference of iron is minimized by the use of hydro-
xylamine hydrochloride in this method.
7.1 Reagents
a. {.--. Electrolyte - 0.1M KC1
b0 Hydroxylamine-hydrochloride - 10$
C0 Hydrochloric acid - 1:25
d0 Water-pumped nitrogen gas (passed through saturated
sodium sulfite just prior to use)
*- The nitrogen gas is first washed by passing through a
flask containing sodium sulfite (saturated).
-------
Metals in Bottom Sediments _ Polarographically ^
7,2 Procedure
a. To the dried sample or standard, add 1.0 ml KG1 (1:2^) and
heat gentlv for about 3 minutes (heat must be such that
solution does not go to dryness).
b. Add 2 drops hydroxylamine-hydrochloride solution and heat
3 more minutes (again solution must not go to dryness). If
a yellowish color due to high iron content persists, add
hydroxylamine hydrochloride dropwise until the color disappears
and heat for 1 more minute.
c. Remove, cool, and add 5.0 ml electrolyte.
d« Police, transfer to cell, and allow nitrogen gas to flow
through sample for J> minutes.
e. Add mercury pool and record polarogram, using nitrogen blanket•
f. Recommended settings: Sensitivity -0.001, compensation and
damping as needed.
8. Method for Total Chromium (10)
This method is based upon the oxidation of chromium bv alkalibromite
and the simultaneous precipitation of the normally interfering iron,,
8.1 Reagents:
a. Oxidizing solution - 100 ml 0«5>N NaOH solution mixed with
5 ml saturated bromine water.
b. Electrolyte - 0.2N NaOH solution anr3 0.1 g gelatin/liter.
c. Sodium sulfite - saturated anhydrous solution.
d. Nitrogen gas - water pumped.
B o2 Procedure
a. To the dried sample or standard, add O.h ml oxidizing
solution and heat for 2 minutes on hot plate just below
boilingo
be Remove and allow to cool for 3> minutes or longer.
c. Add £.0 ml electrolyte and transfer to cell, policing.
d« Add 2 drops sodium sulfite solution and allow nitrogen gas
to flow through sample for 5 minutes.
e. Add mercury pool and record polarogram, using nitrogen
blanket.
f0 Recommended settings: Sensitivitv -0.003, compensation -0,
damping -0.
-------
25
Metals in Bottom Sediments . Polarographically
bottom sediments
9* Calculation of Metals in / (or any solid material) in mg/kg
9.1 Wet Basis:
mg/kg = S. sample H. sample x O.OC£ 1 x 1000
S. standard Ho standard 1 (grams sample
in aliquot)
where S = sensitivity
H «* wave height in mm
0.005 e mg metal in 5 ml std. (assuming 5 nl std. and sample
are usedj this figure is changed if different amounts-
of std. are used)
solids = decimal fraction of solids in wet sediment
Example
wet basis
ing/kg - .0.006 x $6 y. 0.005 1
0.002 2F 1 Tgrams sa^ll X 100°
in aliquot
9.2 Dry Basis:
mg/kg = mg/^cg wet has is
IT solids(decimal fraction)
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26
Metals in Bottom Sediments - Polarographically
REFERENCES
1. Report of the Advisory Committee on Revision of the Public Health
Service 19^6 Drinking Water Standards. (Mimeo.)
2. Doudoroff, P. and Katz, M. Critical Review of Literature on the
Toxicity of Industrial Wastes and Their Components to Fish. II.
The Metals, as Salts. Sewage and Industrial Wastes, 23, 802 (1953).
3. Kroner, R. C., Ballinger, D. G., and Kramer, H.P. Evaluation of
Laboratory Methods for Analysis of Heavy Metals in Water. Journal
of American Water Works Association, 52, 117 (i960).
k. Love, S. K. Analytical Instruments Used in the Modern Water Plant
Laboratory. Journal of American Water Works Association, j^, 731 (l95l)
5. Wyatt, J. W. Instrumentation in the Laboratory. Journal of American
Water Works Association, k%, 138 (1953).
6. Butts, P. G., and Mellon, M. G. Polarographic Determination of Metals
in Industrial Wastes. Sewage and Industrial Wastes, 2g, 59 (1951).
7. Lingane, J. J. Systeriatic Polarographic Metal Analysis Characteristics
of Arsenic, Antimony, Bismuth, Tin, Lead, Cadmium, Zinc, and Copper, in
Various Supporting Electrolytes. Industrial and Engineering Chemical
Analysis. Ed. 1^, 583 (19^3).
8. Manzel, R. C., and Jackson, M. L. Determination of Copper and Zinc
in Soils and Plants. Analytical Chemistry, £3_, l86l (l95l) .
9. Lingane, J. J., and Kolthoff, I. M. Polarographic Study of the Reaction
of Chromate Ion at the Dropping Mercury Electrode. Journal of American
Chemical Society, 62, 852 (19^0).
10. Standard Method for Polarographic Determination of Lead and Chromium
in Zinc. ASTME-68-56. American Society of Testing Materials.
11. Hawkins, R. C., and Thode, H. G. Polarographic Determination of
Copper, Lead, and Cadmium in High Purity Zinc Alloys. Industrial and
Engineering Chemical Analysis, Ed. 16, 71
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27
Metals in Bottom Sediments - Polarographically
REFERENCES (continued)
12. McFarren, E. F., Campbell, J. E., and Engle, J. B. Variations in
Zinc and Copper Content of Bivalves, (in Press).
13. Official Methods of Analysis of the Association of Official
Agricultural Chemists, Ninth Edition, page 333, (i960).
14. Standard Methods for the Examination of Water and Wastewater,
12th ed., APHA, Inc., N.Y., 1965, 458-466.
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28
AMMONIA NITROGEN IN BOTTOM SEDIMEJJS - DISTILLATION
1. General Discussion
1.1 Principle: Free ammonia nitrogen can "be recovered by
distillation of a sample at pH T.k. Since natural waters
exhibit varying pH values and buffering properties, a phos-
phate buffer is applied to maintain the required pH during
the distilD.ation process. The free ammonia distillate is
collected in boric or sulfuric acid solutions to minimize
emmonia losses.
Samples containing high airrnonia concentrations (5-10 ng/l)
should be analyzed following the procedure described in
"Standard Methods for the Examination of Water and Wastewater"
12th2d., 1965, Method A, page 191, Sec. k.k.
The concentration of ammonia in the distillate det-Mnines
the final method for measurement.
If the sample contains from 0.01 to 0.2 Eg/1 ammonia
nitrogen, the distillate from 5^0 ml of sample is collected
in 0.02N HgSOj.. The acid solution is concentrated on a
steam, bath to 50 ml producing a 10:1 concentration. The
ammonia in the concentrated solution is then reacted with
Kessler's reagent to form a characteristic yellow-brown
color which is measured at a wave length of ^25 EH.
Samples which contain from 0.2 to 1.0 mg/1 are distilled
into dilute boric acid solution. The acid distillates
are diluted to the original 500 ml volume and a 50 ^1
aliquot is taken for Nesslerization as outlined above.
Samples that contain more than 1.0 mg/1 aKconia nitrogen
ere distilled ia'co boric acid and can then be titrated
vith standard sulfuric acid using an appropriate indicator.
1.2 Interference: Ammonia recovery will be low on water samples
containing nore than 250 mg/1 calcium unless the treatment
prescribe?, in Sec. k.2 is followed. The calcium and the
phosphate buffer react to precipitate calcium phosphate,
releasing hydrogen ions and lowering the pH. A number of
aliphatic and aromatic amines, organic chloramines, acetone/
aldehydes, and alcohols, and other undefined organic
compounds, cause trouble in direct nesslerization. Compounds
of this type have been found to yield a yellowish or greenish
Off color or a turbidity following the addition of nessler
reagent to distillates collected from chlorinated samples.
-------
29
Ammonia Nitrogen in Bottom Sediments - Distillation
tit.ration procedure is also subject to amine inter-
ference "because the standard acid can react with such
alkaline bodies. However, the titration procedure is
free of interference from neutral organic compounds.
Sulfjd.e Ms eLso been reported to cause turbidity
following nesslerization, a condition which may be
avoided by adding lead carbonate to the flask prior
to distillation. Vola.tile substances such as formal-
dehyde can be removed by boiling at low pH, after which
the scmple con be distilled and nesslerized in the
normal .manner .
2. Apparatus
2.1 Distillation apparatus: A glass flask of 800 ml capacity
attached to a vertical condenser is so arranged that the
distillate falls directly into the collecting glassware.
2.2 Digestion apparatus: Provided with a suction take-off
to remove water vapor and sulfur trioxide fumes.
2.3 Colorimetric equipment: A spectrophotometer for use at
400 to 425 nvi, providing a light path of 1 inch or longer.
2. If Kessler tubes: Matched 50 ml* tall forms.
3. Reagents
3.1 Ammonia-free water.
3.2 Phosphate Buffer Solution pH jA: Dissolve 1^.3 g
anhydrous potassium dihydrogen phosphate, KH2POlj., and
68.8 g anhydrous dipotassium hydrogen phosphate
and dilute to 1 liter with ammonia- free water.
3^3 Boric Acid Solution: Dissolve 20 g anhydrous boric
acid H^BO^ in ammonia-free water and dilute to 1 liter.
3.1j. Sodium Hydroxide-Sodium Thiosulfate reagent: Dissolve
500 g NaOH and 25 g ITa2S2Oo • 51^0 in ammonia-free
vater and dilute to 1 liter.
-------
30
.Ammonia Nitrogen in Bottom Sediments - Distillation
3-5 Phenalphthalein Indicator Solution: Dissolve 5 &
phenalphthalein in 500 ml 95 per cent ethyl alcohol
and add 500 ml distilled water. Then add 0.02N NaOH
dropwise until a faint pink color appears.
3.6 Mixed Indicator: Mix 2 volumes of 0.2 per cent
methyl red in 95$ alcohol with 1 volume of 0.2 per cent
methylene blue in 95 per cent ethyl alcohol. This
solution must be made fresh every 30 days.
3-7 Standard Sulfuric Acid Titrant 0.02N: In this strength
1.00 ml equals 0.28 mg N.
3-8 Nessler reagent: Dissolve 100 g mercuric iodide, HgI2
and 70 g potassium iodide, KI, in a small quantity of
ammonia-free water, and add this mixture slowly, with
stirring, to a cool solution of 160 g NaOH in 500 ml
ammonia-free water. Dilute to 1 liter and store in dark
pyrex bottle out of sunlight. Stable about one year.
[Caution Toxic)
3.9 Standard Ammonium Solution: Dissolve 3.819 g anhydrous
ammonium chloride, NH. Cl, dried at 100°C in ammonia free
vater and dilute to 1,000 ml: 1 ml = 1.0 mg N-(1022 mg NH,),
Then dilute 10.0 ml stock ammonium chloride solution to
1,000 ml with ammonia-free water. 1 ml z 10.00 jig N
( 12.2 ng NH ).
3-10 Standard Organic Nitrogen Solution: Dissolve 1.0503 g
of glutamic acid dried at 100°C in ammonia-free water and
dilute to 1,000 ml = 1 ml = 0.1 mg N.
Procedure
4.1 Add 500 ml distilled water, 10 ml phosphate buffer solution
and a few boiling chips to an 800 ml flask and steam out
the entire distillation apparatus until the distillate shows
no trace of ammonia.
k.2 Place a previously prepared add sample in~a
800 ml kjeldahl flask and add 500 ml of ammonia-free distilled
vater. * Neutralize to about pH 6.6 using a pH meter if
necessary then add 10 ml phosphate buffer solution. Add a
few boiling chips.
* Boil to remove HpS,. if present.
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31
Ammonia Nitrogen in Bottom Sediments - Distillation
U.3 Distillation: Distill over 300 ml at the rate of 6-10 ml/min.
collecting the distillate in 50 ml of .02N I^SOlj..* Place
distillate in a glass stoppered 500 ml graduate cylinder and
bring up to 500 ml with ammonia free water and mix.
4.U Color Development: Place 50 ml portion of the distillate in
a 50 nil nessler tube. Add 1 ml of nessler reagent and mix
thoroughly by inverting the tube six times. Allow to stand
20 minutes and read at ^25 DVI •
4.5 A standard and blank should also be run in the same manner
as the sample.
Calculation
5.1 Wet Basis:
rc^ in Std» x P.P. Sample x 1000
O.D. Stdo ( g Sample
,. « T^ T, j in aliquot)
5.2 Dry Basis: H
- mg/kg wet basis _
" % Solids (decimal fraction)
*Boil to remove H?S if present.
6. Reference
Standard Methods for the Examination of Water and Wastevater,
12th ed., APHA, Inc., N.Y., 1965, 191.
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32
NITRATE AND NITRITE NITROGEN IN BOTTOM SEDIMENTS-AUTOANALYZER
1. General Discussion
1.1 Principle: The nitrate in bottom sediment is reduced to
nitrite by passing the sample stream through a ten-inch
column of zinc granules (20 mesh) in the presence of sodium
acetate and hydrochloric acid buffer. The hydrogen gas is
allowed to escape through a T vent. The sample stream is then
joined by the color reagent vhere the nitrite is determined by
the formation of a reddish purple azo dye, at a pH 2.0 to 2.5,
by coupling of diazotized sulfanilic acid vith naphthylanine
hydrochloride. The stream then passes through a delay column
to allow more time for color development, and then through the
colorimeter where the optical density is measured at a wave
length of 520 millimicrons.
1.2 Interference: See Standard Methods, 12th Edition, 1965,
page 205.
1.3 Minimum Detectable Concentration: 0.01 mg per liter can be
detected with a reasonable degree of precision and accuracy.
2. Apparatus
Technicon Auto-Analyzer, consisting of large sampler, proportioning
pump, colorimeter and recorder. See flow diagram in Figure 1.
3. Reagents
3.1 Sodium acetate solution M/lf: Dissolve 3^ g NaC?H 0 •311 0 in
distilled water and dilute to 1,000 ml. ^
3.2 Sodium acetate hydrochloric acid buffer solution: Mix 100 ml
of HC1 (1/99) vith 1,000 ml of sodium acetate solution M/4.
3.3 Sulfanilic acid reagent: Completely dissolve 3-0 g of
sulfanilic acid in 350 ml hot distilled water, cool, add 100 ml
concentrated hydrochloric acid, dilute to 500 ml with distilled
vater and mix thoroughly.
3-4 Naphthylamine hydrochloride reagent: Dissolve 3-0 g naphthyl-
amine hydrochloride in a solution containing 150 ml distilled
vater, 5 ^1 concentrated hydrochloric ecid and 250 ml of 95$
ethyl alcohol. Dilute to 500 ml with distilled water and mix
thoroughly.
3«5 Color reagent: Mix equal volumes of sulfanilic acid reagent
and naphthylamine hydrochloride reagent. Protect from light
and refrigerate to increase stability.
-------
33
Nitrate and Nitrite Nitrogen in Bottom Sediments- Auto-Analyzer
3.6 Zinc metal: 20 mesh granular reagent grade; wash with
1/99 HC1, rinse with distilled water followed with a
rinse of ethyl alcohol, dry and rinse with chloroform.
3.T Stock nitrate solution: Dissolve 7.2180 g anhydrous KNO.,
in distilled water and dilute to 1,000 ml. This solution
contains 1.00 mg of nitrate nitrogen per ml.
3.8 Lower working standards are prepared from the stock solution.
Concentrations dependent upon anticipated levels to be found
In sample.
4. Procedure
4.1 Place a previously prepared sample into a 200 ml pyrex
volumetric flask and add distilled HpO to approximately half-
fill volumetric flask and add 5 or 6 drops of cone. HgSO, .
4.2 Boil for 15 minutes to dissolve all nitrates from the sediment
and cool.
4.3 Centrifuge at 2,000 RPM for 5 or 10 minutes, then decant into
volumetric flask. Wash residue with distilled water by
thoroughly mixing residue with a stirring rod, follow by
centrifuging.
4.£ Decant wash solution into volumetric flask and repeat a second
time.
4.5 Make up to volume with distilled water.
4.6 Filter aliguot through membrane filter (having a porosity
of 0.45n) into test tube.
4.7 Place samples in Technicon Auto-Analyzer sampler with one
distilled water wash between each sample.
4.8 Permit 30 minutes for instrument warm-up and establish a
base line.
4.9 Set the instrument for two minute sampling time and. slightly
greater than two minutes for relay time.
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34
Nitrate and Nitrite Nitrogen in Bottom Sediments- Auto-Analyser
5. Calculation
5.1 Mg/1 in aliquot may be calculated by comparing peak height
of sample vith standards, employing a chart reader.
wet basis:_ fa in aliquot x Dil. Factor x 1000
mg'kg " g/L 'of "sample in sample" volT
dry basis:
, - ffi.^g (yet basis)
"'S/fcS ' # solids (decimal fraction)
Nitrite may be determined on the auto-analyzer by by-passing
the zinc column and manually according to Standard Methods,
12th Edition, 1965, pages 205-208.
6. References
6.1 James E. O'Brien and Janece Fiore Dio of Laboratories and
Research, New York State Department of Health
6.2 Standard Methods for the Examination of Water and Wastewater,
12th ed., APHA, Inc., N.Y., 1965, 205-208.
6.3 L. J. Kamphake, Robert A. Taft Sanitary Engineering Center,
Cincinnati, Ohio.
6.4 Chemistry of the Soil, ACS Monograph No. 160, 2nd Ed.,
p. 264 (1964).Reinhold Pub. Co., N.Y.
-------
35
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UJ
<
cc
J ~
^ ul
II
Figure 1
-------
36
NITRATE NITROGEN IN BOTTOM SEDIMENTS - BRUCINE METHOD
1. General Discussion
1.1 Principle: See Standard Methods. 12th Ed., 1965, Method B,
page 198-199.
1.2 Interferences: See Standard Methods, 12th Ed., 1965,
Method B, page 198-199.
2. Apparatus
Spectrophotometer for use at klQ mu, providing a light path
of 1 inch or longer.
3« Reagents
3.1 Stock nitrate solution: Dissolve 0.7218 g anhydrous potassium
nitrate, KNO^, and dilute to 1,000 ml with distilled water.
This solution contains 100 mg/1 N.
3.2 Standard nitrate solution: Dilute 100 ml stock nitrate solution
to 1,000 ml with distilled water; 1.00 ml = 0.010 mg N.
3-3 Brucine-sulfanilic acid reagent: Dissolve 1 g brucine sulfate
and 0.1 g sulfanilic acid in approximately 70 ml hot distilled
water. Add 3 ml concentrated HC1, cool, and make up to 100 ml.
This solution is stable for several months. The pink color
that develops slowly does not affect its usefulness.
3.1* Sulfurie acid solution: Carefully add 500 ml of cone. H2SO. to
75 ml distilled water. Cool to room temperature before use.
Keep tightly stoppered to prevent absorption of atmospheric
moisture.
h. Procedure
4.1 Transfer a portion of the previously clarified sample ^ 10 ml to
one of the matched 1" colorimetric tubes.
4.2 If less than a 10 ml aliquot is taken for analysis, add sufficient
distilled water to make the volume 10 ml.
4.3 Add 2.0 ml of 30$ NaCl to each tube and mix.
k.k Transfer the rack containing these tubes to an ice water
bath.
-------
37
Nitrate Nitrogen in Bottom Sediments - Brucine Method
U.5 Add 10 ml of the sulfuric acid solution to each tube (one
tube at a time) mix and return to the ice bath. Allow the
tubes to reach thermal equilibrium before proceeding to
the next step.
k.6 Add 0.5 ml of brucine reagent (caution - poison) to each
tube, mix thoroughly and return to the rack.
4.7 Transfer the rack, with tubes, to a water bath and
hold for 20 min. at a temperature just below boiling.
k.Q At the end of 20 min. return the rack to the ice bath and
cool to room temperature .
U.9 Read the absorbance of the sample versus a blank in a
spectronic-20, set at 4lO mn within 30 min.
4.10 Prepare a calibration curve using standards which were
run concurrently with the samples.
5. Calculations
5.1 Wet Basis:
x X 1000
1
OD Std (grams sample
5.2 Dry Basis: in ali1uot)
- mg/kg wet basis
% Solids (decimal fraction)
6. References
6.1 Standard Methods for the Examination of Water and Wastewater,
12th ed., APHA, Inc., N.Y., 1965, 198-199-
6.2 Chemical Analysis for Water Quality, A Training Course Manual,
U.S. Dept. of Interior, FWPCA, Aug. 1966, pp 13, 11-13, 12.
-------
38
ORGANIC AND TOTAL KJELDAHL NITROGEN IN BOTTOM SEDIMENTS
Organic nitrogen may be determined by digestion of the sample after
removal of free ammonia, vith subsequent distillation and titration with
standard acid or as the difference between the value obtained for total
kjeldahl nitrogen and that for free ammonia.
1. General Discussion
1.1 Principle: The kjeldahl method, using mercuric sulfate
as a catalyst, converts organically bound nitrogen in
the trinegative state to ammonium bisulfate by digestion with
sulfuric acid to which potassium sulfate has been added to raise
the boiling point to 345° - 370°C. The temperature should not
exceed 382°C or loss of nitrogen will result. After dilution,
the solution is made alkaline with sodium hydroxide and the
ammonia is distilled into 0.2N Ho SO], or boric acid solution.
If distillate is collected in 0.02N H2SO^ acid the ammonia
nitrogen should be determined by nesslerization and if distillate
is collected in 2$ boric acid, the ammonia nitrogen should be
determined by titration with 0.02N H2SO^, using a mixed indicator.
1.2 Interference: In the presence of large quantities of nitrogen-
free organic matter, it is necessary to add an additional 50 ml
of sulfuric acid-mercuric sulfate-potassium sulfate solution for
each gram of solid material in the sample.
1.3 Storage: Because organic nitrogen in unsterilized sewage and
sludges is continually ammonified, the determination must be made
on a freshtycollected sample. If the analysis cannot be made at
once, the sample must be preserved with sufficient sulfuric acid
to obtain a concentration of 1,500 mg/1 H2SO^ or mo re (.8 ml/l).
2. Apparatus
2.1 Digestion apparatus, provided with a suction take-off to remove
water vapor and sulfur trioxide fumes.
2.2 Distillation apparatus: See Nitrogen (Ammonia), Standard Methods
for the Examination of Water and Wastewater. p. 1&7-193.
3. Reagents
3.1 Ammonia-free water
-------
39
Organic and Total Kjeldahl Nitrogen in Bottom Sediments
3.2 Sodium Sulfate (lov in nitrogen).
3.3 Mercuric Sulfate.
3>H Litmus Paper.
3.5 Sodium hydroxide-sodium thiosulfate solution: Dissolve 500 g
NaOH and 25 g Na2S20o • 5H20 in distilled vater and dilute to
1 liter.
3.6 Phenolphthalein indicator solution: Either the aqueous (a) or
alcoholic (b) solution may be used.
a. Dissolve 5 g phenolphthalein disodium salt in distilled
water and dilute to 1 liter. If necessary, add 0.02N NaOH
dropwise until a faint pink color appears.
b. Dissolve 5 g phenolphthalein in 500 ml 95 per cent ethyl
alcohol or isopropyl alcohol and add $00 ml distilled water.
Then add 0.02N NaOH dropwise until a faint pink color appears.
3-T Mixed indicator: Mix 2 volumes of 0.2 per cent methyl red in
95 per cent alcohol with 1 volume of 0.2 per cent methylene
blue in 95 per cent ethyl alcohol. This solution must be made
fresh every 30 days.
3.8 Standard sulfuric acid titrant, 0.02N. In this strength, 1.00 ml
- 0.28 mg N. Other strengths of standard acid may be used.
3.9 Sulfuric acid, cone.
3.10 Dissolve 20 g anhydrous boric acid, ^303, in ammonia-free
water and dilute to 1 liter.
3-11 Antifoam.
. Procedure
4.1 Take either the residue from the free ammonia analysis for
organic nitrogen or a new sample for total kjeldahl nitrogen
(1 or 2 g).
^•2 Add 35 ml of cone. HgSO^ plus 15 g Na2SO^, plus 3 g mercuric sulfate
and a little antifoam and allow to boil until white fumes appear.
-------
40
Organic and Total Kjeldahl Nitrogen in Bottom Sediments
4.3 After fumes appear, allow to digest for 30 minutes turning the
flask from time to time. Cool to room temperature.
4.4 To cooled sample, add 500 ml of ammonia-free water, 0.3 ml
(l dropper full) of phenolphthalein or litmus paper, and then
add 50 to 75 ml of 50$ NaOH-thiosulfate solution being careful
not to mix. Place on distillation rack and mix. If the solution
is not red or litmus paper is not blue, add more NaOH until a
red color appears or litmus is blue.
4.5 Distill over 300 ml collecting the distillate in 50 ml of
2$ boric acid. To this add 10 drops of mixed indicator and
titrate with 0.02N I^SOij. which has been standardized against
0.02N Na2C03.
4.6 Blanks and standards should be run in the same manner as the
samples.
5. Calculation
5.1 Wet basis (titration)
ml of 0.02 NH2S04 X 0.28
g sample
5.2 Dry basis
rag/kg « mg/k:g wet basis _
% Solids (decimal fraction)
5.3 Wet basis (colorimetric)
g » mg in Std x P.P. Sample x 1000
O.D. Std (g Sample
5.4 Dry basis in ali4uot)
mg/kg « mg/kg wet basis _
% solids (decimal fraction)
6. Nitrogen (Total Kjeldahl) - (Bottom Sediments)
Total kjeldahl nitrogen includes ammonia and organic nitrogen, but
does not include nitrite and nitrate nitrogen. The method is the same
as that for organic nitrogen, except that the ammonia removal step is
omitted. The procedure therefore begins with Sec. 4. Place an appropriate
aliquot of a well-mixed sample in an 800-ml kjeldahl flask. (l or 2 g)
-------
Organic and Total Kjeldahl Nitrogen in Bottom Sediments
7. Reference
Standard Methods for the Examination of Water and Wastewater.
12th ed., APHA, Inc., N.Y., 1965, 187-193.
-------
OIL AND GREASE IN BOTTOM SEDIMENTS
General Discussion
1.1 Definition: Grease is defined as that material extracted by
hexane from an acidified sample vhich would not be voltatilized
during the procedure; it includes soaps, fats, waxes, and oils.
1.2 Principle: Drying of acidified sludges by heating leads to
low results. Magnesium sulfate monohydrate is capable of
combining 75 per cent of its own weight in water in forming
the heptahydrate. Magnesium sulfate monohydrate can be used
to dry sludge. After drying, the grease can be extracted with
hexane.
1.3 Interference: Elemental sulfur; certain organic dyes;
oxidation of extract and loss in weight of residue due to
volatilization of low boiling components.
lA Sampling and Storage: Every possible precaution must be taken
to obtain a representative sample. When analyses can not be
made immediately, samples may be preserved with 1 ml cone
H2SOij. for each 80 g of sample, or by freezing.
Apparatus
2.1 Extraction apparatus, soxhlet or A.S.T.M. apparatus.
Reagents
3.1 Hydrochloric acid cone.
3.2 Magnesium sulfate monohydrate: Prepare Mg SOj, • H^O by
drying overnight a thin layer of Mg SOj^ • T^O in an oven
at 103°C.
3.3 N-Hexane, boiling point 69°C.
3A Grease free cotton: Nonabsorbent cotton after extraction
with N-hexane.
Procedure
l*.l In a 150 ml beaker weigh a 20 g sample of wet sludge, of
which the dry-solids content is known.
U.2 Acidify to a pH 2.0 (generally 0.3 ml cone HC1 is sufficient.
-------
Oil and Grease in Bottom Sediments
4.3 Add 25 g magnesium sulfate monohydrate. Stir to a smooth
paste and spread on the sides of the beaker to facilitate
subsequent moisture removal. Allow to stand until solidified
15 to 30 minutes.
k.k Remove the solids and grind in a porcelain mortar.
4.5 Add the powder to a paper extraction thimble. Wipe the
beaker and mortar with small pieces of filter paper moistened
with hexane and add to the thimble. Fill the thimble with
small glass beads.
h.6 Extract in a soxhlet apparatus using hexane at a rate of
20 cycles per hour for k hours.
If.7 If any turbidity or suspended matter is present in the
extraction flask,remove by filtering through grease-free
cotton into another weighed flask. Rinse flask and cotton
with hexane.
4.8 Distill hexane from the extraction flask in water at 85°C.
Dry by placing on a steam bath and drawing air through the
.flask with a vacuum for 15 minutes.
4.9 Cool in a desiccator for 30 minutes and weigh.
Calculation
5.1 Wet basis
ag of residue x 1000
grams of sample
5.2 Dry basis
/ mg/jcg wet basis
mg'kg=! T» solids (decimal fraction)
6. Reference
Standard Methods for the Examination of Water and Wastewater,
12th Ed., APHA, Inc., N.Y., 1965, 531-532.
-------
kk
IMMEDIATE DISSOLVED OXYGEN DEMAND AND BIOCHEMICAL OXYGEN DEMAND
OF BOTTOM SEDIMENTS
1. General Discussion
1.1 See Standard Methods for the Examination of Water and Waste-
Water, 12th Edition, page 415.
1.2 The extremely high dilutions used vill help to minimize any
interferences due to toxic materials.
2. Apparatus
2.1 Incubation bottles, 300 ml bottles with water seal. Ground-
glass stoppered bottles should be cleaned with a good
detergent or dichromate cleaning solution and thoroughly
rinsed v-i-f-.h distilled H^O and drained. Satisfactory water
seals are obtained by aading water to the top of the BOD
bottles each morning.
2.2 Air incubator, thermostatically controlled at 20 °C ± 1°C
(All light should be excluded to prevent formation of DO
by algae in the sample.)
3. Reagents
3.1 Distilled water used for solution and for preparation of the
dilution water must be of the highest quality, distilled from
a block tin or all-glass still, contain less than 0.01 mg/1
copper, and be free of chlorine, chloramines, caustic
alkalinity, organic material, or acids and have a specific
resistance of 750,000 OHMS or higher. The distilled water
used for dilution water should be aged or stabilized in the
dark for 30 days prior to using it.
3.2 Phosphate buffer solution: Dissolve 8.5 g potassium
dihydrogen phosphate, 'KE^^-'k > 21.75 8 dipotassium hydrogen
phosphate, K^HPO^ ; 33 .^ B disodium hydrogen phosphate hepta-
hydrate, Na2HPO^ • THpO and 1.7 g ammonium chloride, NH^Cl,
in about 500 ml distilled water and dilute to 1 liter.
The pH of this buffer should be 7.2.
3.3 Magnesium sulfate solution: Dissolve 22.5 g MgSOjj. • 7H20
in distilled water and dilute to 1 liter.
3 A Calcium chloride solution: Dissolve 27.5 g CaCl2 in distilled
water and dilute to 1 liter.
3.5 Ferric chloride solution: Dissolve 0.25 g °f FeCl^ . 6H20 in
distilled water and dilute to 1 liter.
-------
Immediate Dissolved Oxygen Demand and Biochemical Oxygen Demand of
Bottom Sediments
3.6 BOD standard: Dissolve 00l£0 g each of reagent grade glucose
and glutamic acid which have been dried at 103°C for 1 hour
in distilled water and dilute to 1 liter.
3,7 Seeding material: A satisfactory seed may be obtained by
using the supernatant liquor from raw domestic sewage which
has been stored at 20°C for 2\\ hours.
it. Procedure
lul Preparation of dilution water: The distilled water used should
have been aged in cotton-plugged bottles for a sufficient length
of time to insure stabilization and to give blank depletions of
not more than 0.2 mg, preferably 0.1 mg, oxygen. Usually 30
days are required. The water should be aerated just prior to
use to insure saturation at 20°C. Add 1 ml each
of phosphate buffer, magnesium sulfate, calcium chloride, and
ferric chloride solutions for each liter of dilution vrater.
k.2. Seeding: Add proper amount of seed (to give 2 mg/1
depletion), which has been filtered through
two thicknesses of Kimwipes for each liter of water. The
amount of seed required may vary with the source of seed and
will have to be established through experience,,
U«3 Weigh appropriate size sample directly into the BOD bottle,
suggested weight 6 grams.
h»h Fill BOD bottle with dilution water and place in incubator.
Iu5> Make sure that there is a water seal in the neck of each
bottle when placed in the incubator. Each morning replenish
the water seal on all bottles.
It.6 Determination of initial DO: Determine the initial DO of
the dilution water by means of the azide modification of the
iodometric method. This DO value is used as the initial DO
of the sample. This method is used because it is not possible
to obtain an exact initial DO of the bottom sediment due to
he rapid consumption of oxygen.
a)lf a DO probe is used, IDOD and BOD can be run on the same bottle.
ll.7 Incubation: Incubate the blank (dilution water) and the diluted
samples for 5 days at 20°C. Then determine the DO in the
incubated samples using the above methods. Those dilutions
showing a residual DO of 2 mg/1 and a depletion of 2 mg/1 are
considered the most reliable.
Uo8 Dilution water control: Fill two BOD bottles with unseeded
dilution water. Stopper and water-seal one of these for
incubation„ The other bottle is for determining DO prior to
incubation. The DO results on these two bottles are used as
a check on the quality of the unseeded dilution water.
The depletion obtained should not be more than 0.2 ml and
preferably not more than Oel ml.
-------
Immediate Dissolved Oxygen Demand and Biochemical Oxygen Demand of
Bottom Sediments
Ue9 Glucose-glutamic acid check: To check the dilution water,
the seed material and the technique of the analyst, make up
a two percent dilution of the primary BOD standard. Fill
three bottles and incubate at 20°C for 5 days. A two percent
dilution of the BOD standard solution should give a BOD of
218 mg/L with a standard deviation of ^ 11 mg/lo If the
results deviate from this value appreciably, the quality of
the seed, water and the technique is questionable0
Immediate Dissolved Oxygen Demand
5»1 This test is carried out in the same manner as the 5-day
BOD test, except that the sample is held for only 1$ minutes
and the DO is determined.
5.2 Calculation:
Wet basis /^ n \
I DOD mgAg • ° " * Xa3 __ x 1000
grams of sample in aliquot
Dry basis
I DOD mg/kg « mg/kg I POP (wet basis)
, „_„ „ , n .. % solids (decimal fraction)
6, BOD Calculation v
6.1 Wet basis
- x 1000
grams of sample in aliquot
6,2 Dry basis
mgAg * mgAg. -(wet basis j _
% solids (decimal fraction )
6.3 Definitions
DQ » DO of original dilution water.
D^ « DO of diluted sample 15 min0 after preparation.
D3 * DO of diluted sample after incubation (after 5 days),
7- Reference
Standard Methods for the Examination of Water and Wastewater,
12th ed., APHA, Inc., N.Y., 1965,
-------
OXYGEN UPTAKE OF BOTTOM SEDIMENTS
1. General Discussion
The oxygen demand of bottom sediments is a complex phenomenon
occurring at the water-sediment interface, where chemical and
biochemical oxidation and reduction reactions take place at
various rates depending upon conditions existing at a particular
time.
Since bottom sediments tend to be of a reducing character, water
flowing over these sediments lose oxygen to the sediment inter-
face, which becomes an oxidized microzone of ferric oxide. Under
these conditions, the water-sediment interface is a brown color
and the radox potential in this system is greater than 0.2 volts.
When stagnation progresses and conditions become anaerobic, the
radox potential is less than 0.2 volts and the brown color dis-
appears .
The presence or absence of the oxidized microzone makes an
immense difference in the amount and nature of materials that are
leached from these sediments and the rate of oxygen uptake from
the waters above.
The amount of oxygen consumed by bottom sediments is often great
enough so that it causes the overlying waters to become void of
oxygen several feet above the water-sediment interface. There-
fore, it is important to know the characteristics of these bottom
sediments and their oxygen uptake rates.
2. Apparatus
2.1 Laboratory Oxygen Analyzer.
2.2 Magnetic Stirrer with one-inch teflon coated magnets.
2.3 Incubator, 20°C.
2.1*. Wide-mouth Cylindrical Jars with screw cap and sealed probe;
minimum mouth opening of 11 cm; height 25 cm; for use in
making ©2 uptake apparatus (see attached diagram).
2.5 Glass Petri Dish with cover.
2.6 Glass Petri Dish Support.
2.7 Asbestos Sheet, 15 x 15 x 0.5 cm.
-------
Figure No. 1
-------
Oxygen Uptake of Bottom Sediments
3. Reagents
3-1 Distilled water: Water used for solutions and for preparation
of the dilution vater must be of the highest quality, distilled
from a block tin or all-glass still, contain less than 0.01 mg/1
copper, and be free of chlorine, chloramines, caustic alka-
linity, organic material, or acids .
3.2 Phosphate buffer solution: Dissolve 8.5 g potassium dihydrogen
phosphate, KH^PO^; 21.75 g dipotassium hydrogen phosphate,
K^HPO^; 33 -^ g disodium hydrogen phosphate heptahydrate,
Na^HPO^'THgO, and 1.75 g ammonium chloride, NH^Cl, in about
500 ml distilled water and dilute to 1 liter. The pH of this
buffer should be 7.2 without further adjustment. If dilution
vater is to be stored in the incubator, the phosphate buffer
should be added just prior to using the dilution water.
3.3 Magnesium sulfate solution: Dissolve 22-5 g MgSO^'T^O in
distilled water and dilute to 1 liter.
3. If Calcium chloride solution: Dissolve 27.5 g anhydrous CaCl2 in
distilled water and dilute to 1 liter.
3,5 Ferric chloride solution: Dissolve, 0.25 g FeCl3'6H20 in
distilled water and dilute to 1 liter.
3.6 Acid and alkali solutions, IN. For neutralization of waste
samples which are either caustic or acidic.
3.7 Sodium sulfite solution, 0.025N. Dissolve 1.575 g anhydrous
Na2SO_ in 1,000 ml distilled water. This solution is not
stable and should be prepared daily.
3.8 Seeding material: A satisfactory seed may be obtained by
using the supernatant liquor from raw domestic sewage which
has been stored at 20 °C for 2k- hours.
Procedure
U.I Preparation of dilution water: The distilled water used
should have been stored in cotton-plugged bottles for a
sufficient length of time to become saturated with DO. The
water may also be aerated by shaking a partially filled
bottle or with a supply of clean compressed air. Situations
may be encountered where it is desired to use stabilized
river water to check stream performance with laboratory
procedure. The distilled water used should be as near 20 °C
as possible and of the highest purity. Place the desired
volume of distilled water in a suitable bottle and add 1 ml
each of phosphate buffer, magnesium sulfate, calcium chloride,
and ferric chloride solutions for each liter of water.
-------
50
Oxygen Uptake of Bottom Sediments
k.2 Place a covered petri dish containing a weighed amount of
well-mixed sediment in place, as shown in the sketch of
oxygen uptake apparatus.
k-3 Fill the jar with dilution water, measuring volume of
added water, then remove the petri dish cover.
k.k Insert qxygen probe with cap after standardizing probe
against Winkler DO method, following the manufacturer's
manual and place sample in a 20°C incubator.
4.5 Seal system and with magnetic stirrer set to give approxi-
mately the same flow occurring in the lake or streams. Take
dissolved oxygen readings at various time intervals. In
general, time intervals of 0, 0.5, 1, 2, 3, k, 5, 6, 8, 10,
15, 20 and 30 days are satisfactory. The frequency of read-
ings is dependent upon the rate of oxygen uptake.
5. Calculation of oxygen uptake
Wet basis Dry basis
A x 1000 ** mg/kg mg/kg B mg/kg wet basis
B % solids (decimal fraction)
A « Initial reading - Final reading
B = Weight of sample in grams per liter
Oxygen uptake may be calculated on the basis of weight or unit area
by substituting surface area of sediment exposed to the dilution
water in place of B (the weight of sediment) in the above formula.
6. Calculation of K^ values
6.1 From the 5-^ay BOD values (y), calculate the daily differences
as shown below:
t Op-demand Differences
0.72
O.kQ
0.35
0.27
0.20
0
0.5
i
1-5
2
2.5
3
3-5
^
5
0.72
1.20
1-55
1.82
2.02
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51
Oxygen Uptake of Bottom Sediments
6.2 Plot the differences on semi-log paper with differences
on the log scale and time on linear scale. The time
coordinates are 0.5, 1-5, 2-5, etc.
6.3 Draw a straight line through the points, extending the
line to t = 0 (left margin).
6.h Determine the slope of this line by using values at 5 days
and 0 days .
5 days = 0.175 and 0 days = 0.74.
Slope X 100 = $ remaining in 5 days = 23.7$
6-5 Using the formula, log % BOD remaining = 2.0-K,t; 1^ can be
calculated as follows:
log 23.7 :2.0 -K.5
1.374 =2.0 — K£5
Kq =2.0 -1.374
5
Kj_ =0.13
— TT "f*
6.6 The formula Y z L (l-lO 1 ) and the above data will permit
the calculation of L, L being the ultimate BOD, Y the 5-day
BOD, and (l-10"KltHhe fraction oxidized.
Fractions oxidized = 1 — fraction remaining
= 1-0.237
= 0.763
Therefore 2.02 ; L X 0.763
L r 2.02
0.763
L I 2.7 mg/l
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52
Oxygen Uptake of Bottom Sediments
7. References
7-1 Sheehy, J. P. "Rapid Methods for Solving Monomolecular
Equations," J.W.P.C.F., 32:646, June 1960.
7-2 Moments Methods: Moore, E.W., Thomas, H.A., and Snow, W.B.,
"Simplified Method for Analysis of BOD Data," Sewage and
Industrial Wastes, 22: 10, 1950.
7-3 Tsivoglou, E.G., "Oxygen Relationships in Streams," Technical
Report W-58-2, Robert A. Taft Sanitary Engineering Center, 1958.
7.4 Muhlman, F.W., "Oxygen Demand of Sludge Deposits,"
J. Sewage Works, 10, 613 (1938).
7.5 Rudolfs, Willem, "Relation between Biochemical Oxygen
Demand and Volatile Solids of Sludge Deposits in the
Connecticut River. J. Sewage Works, U, 317 (1932).
7.6 Beckman Instructions #1223, Beckman Instruments, Inc. (1962).
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53
CHLORINE DEMAND OF BOTTOM SEDIMENTS
1. General Discussion
"The chlorine demand of a water is caused by such inorganic reductants
as ferrous, manganous, nitrite, sulfide, and sulfite ions. Ammonia
and cyanide consume considerable chlorine during the free residual
chlorination process. Chlorine substitutes on phenols and other
similar aromatic compounds to form chloro derivative compounds, but
may also oxidize the aromatic compounds when larger amounts of chlorine
are added. It may also react with ammonia and naturally occurring
amino compounds to form chloramines with an active or oxidizing chlorine
atom. The destruction of the chloramine compounds can be achieved by
the addition of more chlorine and subsequently with the addition of
enough chlorine a free available residual (hypochlorous acid) may be
attained.
"The chlorine demand of water is the difference between the amount of
chlorine applied to a treated supply and the amount of free, combined,
or total available chlorine remaining at the end of the contact period.
The chlorine demand of any given water varies with the amount of chlorine
applied, time of contact, pH, and temperature. For comparative purposes
it is imperative that all test conditions be stated. The smallest amount
of residual chlorine considered significant is 0.1 mg/1 Cl. Presented
here is a method for laboratory use and a field procedure which gives
less exact results.
1.1 Principle:
The laboratory method is designed to determine the so-called
immediate demand as well as other demands at longer contact
periods. Chlorine demand determinations are made to determine
the amount of chlorine that must be applied to a water to pro-
duce a specific free, combined, or total available chlorine
residual after a selected period of contact. If the amount of
chlorine applied to waters containing ammonium or organic
nitrogen compounds is not sufficient to reach what is termed
the "breakpoint" chloramines and certain other chloro derivatives
which react as combined available residual chlorine are produced.
When sufficient chlorine has been added to reach the breakpoint,
which depends on pH, ratio of chlorine to nitrogenous compounds
present, and other factors, subsequent additions of chlorine
remain in the free available state." (Standard Methods, 12th
Edition, pp.112-113)
-------
Chlorine Demand of Bottom Sediments
2. Reagents
2.1 Acetic acid, cone.
2.2 Potassium iodide, crystals.
2.3 Standard thiosulfate, 0.037 N.
2.4 Solution of starch, 5 grams of starch per liter of water.
2.5 Chlorine solution adjusted so that 1 ml contains approximately
1 mg of chlorine.
2.6 Aged distilled chlorine free water.
3. Apparatus
3.1 Stirrer and magnetic stirring bars.
3.2 500 ml erlenmeyer flasks-
3-3 50 ml buret.
3-^ Aluminum foil.
4. Procedure
4.1 Weigh 1-2 grams of well-mixed bottom sediment onto prepared
aluminum strips.
4.2 Wash sediment from aluminum strips into an erlenmeyer flask
containing 200 ml of aged chlorine free water by moving
aluminum strip up and down below surface in flask.
4.3 Pipet 20 ml of standardized chlorine solution into sample
with rapid stirring to insure instantaneous mixing and then
stir slowly in darkness for exactly 15 minutes.
4.4 Add 5 ml of acetic acid, approximately 1 gram of potassium
iodide, 1 to 2 ml of starch solution and titrate with
0.0370 N thiosulfate to the point of disappearance of the
blue color. Note - it is necessary to add the starch at
the beginning of the titration due to the difficulty in
detecting the end point in the presence of turbidity pro-
duced by the sediment.
-------
55
Chlorine Demand of Bottom Sediments
5« Calculation
One ml of 0.037 N thiosulfate is equivalent to 1.3010 nag chlorine.
5-1 Wet Basis:
mg/kg Cl demand = "* g *f 6d " ""g C1 residual X 1000
^" ^ Wt of sediment
5.2 Dry Basis:
vet basis
_ _
* ^ Solids (decimal fraction)
6. Reference
Standard Methods for the Examination of Water and Wastewater,
12th ed., APHA, Inc., N.Y., 1965, 112-113.
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56
PESTICIDES IN BOTTOM SEDIMENTS
Preparation of Sample
1. General Discussion
1.1 Principle: Pesticides sorbed on particulate matter may be
desorbed by the continuous Soxhlet Extraction of a ground and
dried bottom sediment sample with suitable organic solvent(s).
The extract containing the pesticide(s) is cleaned up and
analyzed by gas chromatography, thin layer chromatography, and
infrared spectrescopy.
2. Apparatus
2.1 Soxhlet extractor, flask capacity (500 ml), with Allihn
condenser.
2.2 Extraction thimbles, Whatman single thickness, 43 x 123 mm or
a convenient size.
2.3 Chromatographic tube 20 x 400 mm.
2.4 Thin layer chromatography equipment.
2.5 Gas chromatograph equipped with microcoulometric titration
cells.
3. Reagents
3.1 Hexane, redistilled in glass b.p. 68° - 69°C.
3.2 Ethyl ether, redistilled in glass b.p. 34° - 35°C.
3.3 Chloroform, redistilled in glass b.p. 60° - 6l°C.
3.4 6 parts ethyl ether and 94 parts hexane.
3-5 15 parts ethyl ether and 85 parts hexane.
3.6 30 parts ethyl ether and TO parts hexane.
3-7 50 parts ethyl ether and 50 parts hexane.
3.8 Florisil 60-100 mesh commercial products of this grade may
be reactivated by heating 5 hours at 130°C.
-------
57
Pesticides in Bottom Sediments, Preparation of Sample
k. Procedure
k.l Preparation for Extraction
a. Allow the bottom sediment sample to dry thoroughly at
room temperature for about a week or cover samples with
open mesh cheesecloth and accelerate moisture removal
employing a cooling fan. This is best accomplished by
breaking up the large particles and spreading out in a
glass dish or aluminum foil.
b. Grind up sample with a mortar and pestle and pass it
through a 30 mesh sieve.
c. Select a 100 g aliquot and place in a pre-extracted
thimble. Place a small wad of pre-extracted glass wool
or cotton on top of the sample.
4.2 Soxhlet Extraction
a. Using 300 ml chloroform, extract bottom sediment sample
for 18 hours (at 60°C).
b. Transfer extract to 250 ml beaker and concentrate on
a steam bath to about 10 ml; add one drop 0.005$ paraffin
oil in hexane prior to evaporation.
4.3 Wet Extraction Procedure
Extraction of soils and bottom sediments. Weigh a lOOg sample
into a liter erlenmeyer flask. Add distilled water to effect
a slurry. Add 2 ml of extraction solvent (hexane/IPA, 3^l)
per gram of sample and shake vigorously for 20 minutes using a
wrist action shaker or equivalent. Decant and collect the
hexane phase into a separatory funnel. Repeat extraction of
the bottom sediment/aqueous phase two more times quantitatively
decanting the hexane portions each time into the separatory
funnel. Wash any remaining alcohol from combined hexane extracts
with water, dry over sodium sulfate, and concentrate to an approp-
riate volume.
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Pesticides in Bottom Sediments, Preparation of Sample
k.k Column Chromatography
a. Prepare a five inch column with 3/V at top and 1/2" at
bottom anhydrous sodium sulfate plus 15 gram Florisil
which has been activated 5 hours at 130°C and stored in
a desiccator to cool; or for samples containing large
quantities of waxes and pigments, use a column containing
a mixture of Nuchar C-190 (5g) plus Oelite (10 grams).
Column may be reduced to 3/8" diameter x 12" (made from
glass tubing drawn to approximately l/l6"tip) packed with
1/2" x 1/2" glass wool; reagents must be reduced by a
factor of 10.
b. Pre-wet the column with 50 ml of hexane.
c. Place the extract on the column and elute into a 200 ml
volumetric flask with 200 ml 6%, 15$ and 30% or 50$ ethyl
ether in hexane.
d. Concentrate the sample from step c to approximately 5 nil
in a 250 ml beaker; then transfer to a 15 ml centrifuge
tube and concentrate to a volume of 0.1 to 1 ml.
e. The following pesticides are eluted by the above mixtures
of ethyl ether and hexane.
ETHYL ETHER IN HEXAME
Lindane
BHC
Kelthane
Aldrin
Heptachlor
DDE
IDE (DDD)
DDT
Perthane
Heptachlor or epoxide
Methoxychlor
Toxaphene
Strobane
Chlordane
Endosulfan I
Dieldrin
Endrin
Endosulfan II
Lindane
Kel thane { pos s ible
trace of total)
30$ or 50$
Generally elute
Thiophosphate Pesticides
50$ E. Ether elutes
Guthion
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PESTICIDES IN BOTTOM SEDIMENTS
Gas Chromatography with Electron Capture
1. Nonpolar Column
1.1 General Discussion: This procedure is applicable to the
analysis of most chlorinated hydrocarbons, a number of esters
of the phenoxy-alkanoic acid herbicides, and a few organic
phosphates.
1.2 Apparatus:
a. Gas chromatograph equipped with dual glass columns and
electron capture detector, spare electron capture detector
recommended.
b. Strip chart recorder — 1 mv.
c. Microsyringes—10- and 50 M-l capacity.
d. Glass Columns: Non-Polar 6 feet by 1/4" O.D. packed
with Gas Chrom Q 60/80 mesh, coated with 5$ by weight
of OV-1T.
e. Nitrogen tank equipped with regulator valve and tubing
to connect with gas chromatograph.
1.3 Reagents:
a. Stock pesticide standards are made to contain 1 M-g/ml
of lindane; heptachlor; aldrin; dieldrin; endrin; o,p-DDT;
p,p'-DDT; DDD, DDE, methachlor, and chlordane in hexane.
b. Pesticide working standards - Pesticide stock standards
are diluted with hexane to give the following concentrations:
Standard 1 Standard 2 Standard 3
ng/M.1
Chlordane 10.0
Methoxychlor 10.0
Lindane
Heptachlor
Aldrin
DDE
o, p-DDT
p, p'-DDT
ng/jil
0.5 Dieldrin
1.0 Endrin
1.0
7-0
8.0
8.0
ng/M-1
3-0
8.0
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60
Pesticides in Bottom Sediments, Gas Chromatography with Electron Capture
l.U Column Conditioning:
a. Install the packed column in the gas chromatograph
without connecting to the detector device. Heat the
column to 270°C without gas flow for two hours. Allow
the column to cool to 225°C and maintain this temperature
for 10 minutes; then adjust carrier gas to about 50 rol Per
minute. After one hour, increase column temperature to
2M3°C and condition the column for 2k-kQ hours. Cool the
column down to operating temperatures 180-215°C and hook up
to the detector system. Columns prepared and conditioned
in the prescribed manner should yield good chromatograms
without major losses of heptachlor or DDT with no further
treatment. Even with the most advanced equipment,the
analyst is reminded that the system can be no better than
the condition of the column. Injection of samples which
have not been adequately prepared will undoubtedly shorten
the life of the column and yield poor quality chromatograms.
b. Conditioning of the column can also be done in a separate
oven capable of maintaining temperatures up to 270°C and
equipped to maintain a flow of carrier gas through the
column. This permits conditioning of a standby column
while the instrument is being used for residue analysis.
c. At the end of the preliminary conditioning period, the
chromatographic system should be evaluated using pesticide
mixtures and standards injected singly. Recovery of
chlorinated hydrocarbons should be 75$ or higher, and
peak shapes should be symmetrical. Evaluation of the
chromatographic column can also be done by using the
pesticide endrin as a guide. It has been shown that columns
not properly conditioned give two peaks for this pesticide
at low temperatures owing to catalytic decomposition, but,
upon further conditioning, it will give only one peak.
Double peaks, however, still can be obtained at high temp-
eratures as a result of thermal decomposition. Individual
laboratories must judge whether or not the chromatographic
column is operating at maximum efficiency. Before the
column is ready for residue analysis, it should give high
recoveries of most pesticide standards, good resolution,
and symmetrical peaks.
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6l
Pesticides in Bottom Sediments, Gas Chromatography with Electron Capture
d. If further conditioning of the column is indicated, the
column should be heat-conditioned for an additional twenty-
four hours before reevaluation. It may also be necessary
to make several injections of 25 ul each of the strong
pesticide mixture. This should be followed up with several
injections of 5 M-l each of the moderate pesticide mixture;
if this still does not give a satisfactory chromatogram,
injection of purified sample extracts may be necessary.
If these materials are available, it is recommended that
several 10 |il injections be made in an attempt to condition
the column for residue analysis.
e. Once a column has been properly conditioned and is ready
for residue analysis, it may be necessary to make several
injections of the standard pesticide mixture each morning
prior to running sample extracts.
1-5 Procedure:
a. After the nonpolar column has been thoroughly conditioned
as described in Section 1.4, on conditioning of the column,
it is ready for use. The operating parameters for this
column are as follows: column temperature, 195°C; injection
block, 230°C; electron capture detector, 200°C; the flow rate
of nitrogen through the column is maintained at 120 ml/min.,
or other optimum conditions.
b. Optimum operating conditions for the electron capture
detector must be determined in the individual laboratory by
varying the voltage applied to the detector to find a region
where sensitivity is good and response is linear.
c. For the operation of the gas chromatograph, follow instructions
in the manufacturer's manual.
d. To obtain relative retention times on this column using the
electron capture detector, individual pesticides, mixtures
(containing aldrin), and unknowns should be injected at the
1 to 10 ng level.
e. Relative Retention Time (R.R.T.) =
Pesticide's Actual Retention Time in Minutes
Actual Retention Time of Aldrin in Minutes
(Sulphenone is usually the referenced pesticide when computing
R.R.T. of thiophosphate pesticides.)
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62
Pesticides in Bottom Sediments, Gas Chromatography with Electron Capture
2. On the Polar Column
2.1 General Discussion: This procedure is applicable to the
analysis of chlorinated hydrocarbons, a few organic phosphates
and some of the phenoxyalkanoic acids and their esters. This
column has been selected to give a different pattern of separation
of the pesticide standards in order to facilitate identification.
2.2 Apparatus:
a. (Same as for nonpolar column except the column)
b. Glass columns - 6 feet in length by 1/V O.D. packed with
Gas Chrom Q 60/80 mesh coated with 5$ QF-1 plus 3% DC-200.
2.3 Reagents: (Same as given for non-polar column)
2.4 Column Conditioning: (Same as for nonpolar column)
2.5 Procedure:
a. The operating conditions for the polar column are as
follows: column temperature, l80°C; injection block, 230°C;
detector, 200°C; flow rate of nitrogen at 100 ml/min. The
optimum operating voltage for the direct current mode of
operation of the electron capture detector should be deter-
mined by injecting a standard solution of lindane and adjust-
ing the voltage until maximum sensitivity and a linear res-
ponse is obtained. If the two are not compatible, a voltage
is chosen that will yield a linear response in the range of
1-10 ng of standards. Then make unknown sample injections
in the same manner as standards.
b. The polar column should be used to assist in identification
of unknown compounds chromatographed on the nonpolar column.
This type of confirmation is of great importance when using
the electron capture method since some non-pesticide impurities
in sample extracts give high responses with this detector.
3. Calculations
Employ the calculations given under Microcoulometric Section -
"Measurement of Unknown."
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63
Pesticides in Bottom Sediments, Gas Chromatography with Electron Capture
4. References
4.1 Burchfield, H.P. and Johnson, D.E., 1965. Manual of Methods
for the Analysis of Pesticide Residues. Southwest Research
Institute (Prepared for DHEW, PHS), Vol. I and II.
4.2 Organic Pesticide Subcommittee of Committee on Methods
Validation and Analytical Quality Control, FWPCA, 1968.
Provisional Interim Official Methods for Chlorinated Hydro-
carbon Pesticides in Water and Wastewater by Gas Chromatography,
1968.
4.3 Breidenbach, A.W., et. al. 1966. The Identification and
Measurement of Chlorinated Hydrocarbon Pesticides in Surface
Waters. U.S. Department of Health, Education, and Welfare,
Public Health Service WP-22 November.
4.4 Burke, J. and Giuffrida, A.L. 1964. Investigation of Electron
Capture Gas Chromatography for the Analysis of Multiple
Chlorinated Pesticide Residues in Vegetables. J. Assoc.
Off. Agr. Chemists 47:326.
4.5 Hundley, J. C. et. al., 1964. Pesticide Analytical Manual
(Vol. II). U. S. Department of Health, Education, and
Welfare, Food and Drug Administration.
4.6 Shuman, H. and Collie, J.R., 1963. Gas Chromatographic Columns
for Optimum Recovery of Chlorinated Pesticides. J. Assoc. Off.
Agr. Chemists. 46: 992.
4.7 U.S. Dept. of the Interior, FWPCA, 1968. Report on Insecticides
in Lake Michigan prepared by Pesticide Committee of the Lake
Michigan Enforcement Conference, Donald I. Mount, Ph. D.,
Chairman, National Water Quality Laboratory, Duluth, Minn.
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6k
PESTICIDES IN BOTTOM SEDIMENTS
Microcoulometric Gas Chromatograph
1. General Discussion
Principle: The microcoulometric titration cell used as a gas
chromatographic detector has for its basis the coulometric
titration of resultant ions with electrically generated ions.
Inorganic ions are produced when the effluent from the gas
chromatographic column enters the combustion furnace where any
organic pesticide hydrocarbons present are broken down into
inorganic species.
2. Apparatus
2.1 Dohrmann Model C-200 microcoulometer equipped with microcoulometric
titration cells.
2.2 Glass, aluminum, or stainless steel 6 ft. column.
3. Reagents
3.1 Solid support Chromosorb W, P, G or Gas Chrom Q, or
Anachrom ABS (acid washed dimethyl-dichlorosilance treated.
AW-DMCS).
3.2 Stationary phase DC-200, QF-1, 0V 17, OV-101, etc.
k. Procedure
h.l Recommended Operating Conditions*
a. Furnace temperature 850°C.
b. Inlet temperature 300°C .
c. 02 flow rate 50 cc/min.
d. N2 sweep rate 20 cc/min.
e. Column temperature 190°C or other temperature,
f. Flow rate (Ng) 100-200 ml/min.
g. Diameter 1/8 inches (inside diameter) .
•^Recommended condition may be adjusted depending upon
choice of column.
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Pesticides in Bottom Sediments, Microcoulometric Gas Chromatograph
k.2 Measurement of Standard Chloride Solution
a. Set FUNCTION switch to BIAS READ and adjust BIAS
MILLIVOLTS with BIAS SET knob to 12 divisions to the
left of zero. This supplies 2^0 bias millivolts to
the cell.
b. Adjust stirring rate in titration cell to about 1/2
full position (NOTE: Be sure the magnet does not
decouple.)
c. Set FUNCTION switch to GENERATOR READ. Generator
volt meter should read 0 or to the left of 0. If the
meter reads to the right of 0, add fresh electrolyte
to the cell and flush through both stopcocks with
electrolyte (?0$ acetic acid) until the meter reads
zero or to the left of zero. (NOTE: Final level of
electrolyte should be at black mark on cell.)
d. Turn recorder power and chart on and adjust needle on
recorder to zero with RECORDER ZERO knob on coulometer
amplifier. (NOTE: Needle on recorder is at 0 when
integrator draws a straight line.)
e. Set FUNCTION switch to OPERATE. Set RANGE OHMS to
500 or desired setting and vait until cell generates
as much titrant as it needs to reach null.
f. Using a 10 ul syringe, inject a few micrograms of
standard chloride solution directly into the titration
cell through the filling funnel. (NOTE: Tip of needle
must be below the level of the electrolyte before
injection.)
4.3 Measurement of Area Under Peak
a. Each traverse of the integrator pen represents 10 disc
integrator units (DU). Find the total number of DU
under the peak.
b. 1 DU - TTTTT square inch
Calculate the area in square inches under the peak.
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66
Pesticides in Bottom Sediments, Microcoulometric Gas Chromatograph
c. Calculate the micrograms of chloride represented by
this area using the following formula:
1,1 „•* - Peak area (in sq . in.) x 442
ug chloride * Range QHMS^ - 3 - lOCT
d. Calculate the recovery of chloride ion in the titration
cell using the following formula:
% Recovery , Mg chloride recovered
Titration Cell = (as neasured area under peak)
M-g chloride injected
If % recovery is below $0%, clean electrodes in NH^OH
and rinse thoroughly with distilled water before
returning to titration cell. Check % recovery again
before injection samples into the gas chromatograph .
4.4 Measurement of Standard Pesticide Solution
a. With RANGE-OHMS at 000 and the vent closed, zero the
recorder. Increase RANGE-OHMS to 050 or other desired
range-OHMS and wait until cell reaches null.
b. With VENT open inject 200 ng of aldrin into the gas
chromatograph. Depress MARK button.
c. After one minute, close vent and wait for aldrin peak.
d. Using the disc integrator, calculate the area under the
peak.
e. Calculate the micrograms of aldrin represented by this
area using the following formula: (or by calculation
given under injection of unknown)
_ Peak Area (in sq . in . ) x 442 _
ug compound - Range OHMS x (% chlorine in compound;
(Reference 7.6 gives the percentage chloride composition
of some common chlorinated hydrocarbons . )
f . Calculate the recovery of pesticide in the gas chromato-
graphic system using the following formula:
lag of pesticide recovered
/rf .L. j. -i - (as measured by area under peak)
% recovery total -- ^g of pesticide injected - L
g. Measure peak area using triangulation and the half -width
methods and compare the results with integration.
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67
Pesticides in Bottom Sediments, Microcoulometric Gas Chromatograph
4.5 Measurement of Unknown
a. With RANGE-OHMS at 000 and vent closed, zero the recorder.
Set RANGE-OHMS to desired ohms and wait until cell reaches
null.
b. With VENT open, inject appropriate amount of unknown.
Depress MARK button.
c. After one minute, close the vent and wait for unknown
peak(s).
5• Calculations
(A unk) ~
|i£ -ngG'JCD(A STD) F. V. x KT
kg nl inj. x g sample
|jg a Micrograra
ng = Nanogram
A unk ~ Area Peak of Unknown
A GTD " Area Peak of Standard
Hi inj. = Microliters extract injected
g sample ~ Grams of Sample
F. V. = Final volume in milliliters
6. Recovery
6.1 Weigh 100 g of bottom sediment sample into a biologically
clean sampling bottle.
6.2 To 50 nil hexane in a small beaker, add a known amount of
pesticide standard (in the concentration range of interest).
6.3 Carefully add the pesticide standard solution (with stirring)
onto the sample.
6.4 Allow the solvent to evaporate at room temperature (stir
periodically; this may take a day or two).
6.5 When solvent has completely evaporated, transfer sample to
Soxhlet extractor and carry out procedure for analysis as
in Section 4.2.
6.6 Calculate the recovery using the following formula:
i s amount of pesticide found by MCGC
known amount of pesticide added
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68
Pesticides in Bottom Sediments, Microcoulometric Gas Chromatograph
7. References
T.I Barry, H. C. et. al.,1965.Pesticide Analytical Manual
(Vol. I revised). U.S. Department of Health, Education,
and Welfare, Food and Drug Administration.
7.2 Breidenbach, A. ¥. et al., 1966. The Identification and
Measurement of Chlorinated Hydrocarbon Pesticides in Surface
Waters. U.S. Department of Health, Education, and Welfare,
Public Health Service WP-22 November.
7.3 Hundley, J. C. et. al.,1964. Pesticide Analytical Manual
(Vol. II). U. S. Department of Health, Education, and
Welfare, Food and Drug Administration.
7.4 Burchfield, H. P. and Johnson, D.E., 1965. Manual of Methods
for the Analysis of Pesticide Residues. Southwest Research
Institute (Prepared for DHEW, PHS), Vol. I and II.
7.5 Burke, J. and Giuffrida, A. L., 1964. Investigation of
Electron Capture Gas Chromatography for the Analysis of
Multiple Chlorinated Pesticide Residues in Vegetables.
J. Assoc. Off. Agr. Chemists 47:326.
7.6 Dohrmann Instruments Company, 1966. Preliminary Operation
Instruction for Dohrmann Microcoulometric Titrating System.
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69
PESTICIDES IN BOTTOM SEDIMENTS
Thin Layer Chromatography
1. General Discussion
Thin layer Chromatography (TLC) is one of the most widely used
analytical and clean up techniques employed in Chromatography.
Separation of compounds having various polarities, water solubilities
and having different carbon chain lengths can be separated by TLC.
1.1 Principle:
a. Separation and purification of a chemical mixture is
effected in thin layer Chromatography by forced move-
ment of a spot of material with the aid of a suitable
migrating solvent through a thin layer of sorbent
material which has been applied to an appropriate
support. The mechanism of separation is one or more
of the following: adsorption, partitioning or reversed
phase partitioning.
b. Adsorption is useful for the separation of lipophilic
organic compounds of low or medium polarity. The
adsorption material used is silica gel or aluminum oxide.
c. Partitioning is useful for the separation of water soluble,
inorganic compounds or quite polar organic materials.
(Paper was formerly used, but now, cellulose crystalline
powcbror ground fibers is being used; although unactivated
silica gel, carrying an absorbed phase of water can be
used.)
d. Reversed phase partition TLC is good for resolving closely
related lipophilic materials like an homologous series
differing only in carbon chain length.
2. Apparatus
2.1 Plates, 200 mm x 200 mm (8" x 8") glass.
2.2 Chamber, glass developing, with lid, 8£" x V x 8^".
2.3 Spreader, variable thickness.
2.4 Spotting template.
2.5 Chromatography sprayer.
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70
Pesticides in Bottom Sediments, Thin Layer Chromatography
2.6 Desiccator to accommodate 200-mm plates.
2.T UV light box.
2.8 Micropipets, 1^1-5^1-10^1, lOOjal.
2.9 Eye droppers.
2.10 Spatulas.
2.11 Graduated centrifuge test tubes, capacity 15 ml.
2.12 Glass wool, pre-extracted with chloroform.
2.13 Centrifuge.
2.14 Cylinder, 100 ml.
2.15 Drying rack to hold 8" x 8" glass plates.
2.16 Volumetric flask, 10 ml.
3. Reagents
3.1 Pesticide standards.
3-2 Rhodamine B base, spirit soluble 0.10 mg/ml in ethanol.
3.3 Aluminum Oxide G.
3.^ All solvents are redistilled before use.
3.5 Hexane: ethyl ether; k:IO mixture.
3.6 Carbon Tetrachloride.
3.7 Hexane.
h. Procedure
^.1 Preparation of Plates
a. Weigh a kO gram aliquot of AL^O? in a 500 ml centrifuge
bottle and add 80 ml 0.03 W HNOg. Shake well and centri-
fuge at 1200 rpm for 1-2 minutes.
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71
Pesticides in Bottom Sediments, Thin Layer Chromatography
b. Decant the supernatant liquid into a 100 ml graduated
cylinder, and record the volume (35-^-0 ml should be
recovered).
c. Add 80 ml distilled H20, break up cake on the bottom
of the bottle with a glass rod, shake well and centri-
fuge as before, and decant and record the volume of
the supernatant liquid recovered (70-80 ml).
d. Repeat the washing step with two additional 80 ml
portions of HgO. Centrifuge and decant as before.
e. Weigh the Al20o and 1^0 which has been retained
(approximately 100 g).
f. Add 10 ml 1.0$ AgN03 and enough HgO to make the total
weight 120 g, and shake well, place in applicator and
prepare plates.
g. Let plates dry on mounting board for approximately
15 minutes.
h. Place in a drying rack in a vertical position at 100°C
for 30 minutes.
i. Remove the plates and store in a desiccator.
Spotting Plates
a. Position plate on Kimwipe or clean surface and scrape
1/4" area on two sides of plate.
b. Insert (5 M-l) capillary spotting tube in small beaker
of hexane and touch to folded Kimwipe until all hexane
has been removed from capillary. Repeat this five times.
c. Place template with graduated edge over the aluminum
oxide AgNOo impregnated plate about 1" from bottom.
d. Mark this position with pencil on both sides of plate.
e. Rinse capillary twice with standard pesticide solution
removing contents each time on kimwipe.
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72
Pesticides in Bottom Sediments, Thin Layer Chromatography
f . At graduation 1 of template, touch capillary filled
with standard once lightly on plate removing approxi-
mately I/if of contents of capillary (plate position #l) .
g. At position #2, spot two times putting 1/2 the contents
of the capillary on the plate. Permit each spot to dry
before respotting.
h. At position #3, spot the contents of the capillary
standard by lightly touching the capillary to the plate,
removing about 1/4 of the contents with each spotting.
Permit the spots to dry before respotting.
i. At positions $4 - #6 spot sample labelled "unknown,"
repeat spotting procedure as described in items f - h.
Repeat above procedure for other pesticide solutions and
standards .
4.3 Spot Development
a. Place plate, coated surface facing solvent saturated paper,
in developing tank containing 1 cm depth of carbon tetra-
chloride with marked spotting line down; develop to the
10 cm line.
b. Lift off top of jar, mark solvent front on side of plate
and remove plate, lifting plate with finger tips of both
hands. Dry in air for 10 minutes.
c. Place in an ultraviolet light box and expose for 15 minutes.
d. Measure the distance of centers of the spots from starting
line and compute the Rf values. Record data on data sheet.
4.4 Identification and Estimation Using Rhodamine B
a. Repeat spotting procedure described above employing aluminum
oxide plain plates. Spot the standards and bottom sediments
extract sample and develop in solvent tank.
b. Place plate in hood and spray with Rhodamine B 0.1 g/1 in
ethanol. The spray should be a fine mist giving an even,
smooth light pink color to surface of plate.
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73
Pesticides in Bottom Sediments, Thin Layer Chromatography
c. Place plate in dark and observe spots with UV light.
d. Measure distance (cm) of spotting line to solvent front.
Measure distance of spots from starting line.
5. Calculations
5.1 Calculate Rj> of spots which appear in samples.
Distance of spot from starting line ...._
R
f Distance of solvent front from starting line
5.2 Identify unknowns by comparing R value with standards.
5-3 Estimation of concentration in unknown spots may be done
by comparing with standard pesticide spots.
6. Preparation of Thin Layer Spots for Gas Chromatography
6.1 Marking off Spot Area on Plate
a. Place template below lower spot line. Mark surface with
spatula across plate.
b. Move template above these spots and similarly mark surface.
c. Move template to a line above the pesticide spots and mark
surface.
d. Select the lowest concentration of pesticide spots showing
best color development, such as, 1.25, 2.50, $.0 or 10 nl
spots.
e. Turn template perpendicular to selected spot; mark surface
across plate.
f. Move template to other side of spot and mark surface.
6.2 Removal of Spot from Plate
a. Insert a tuft of glass wool and position at the tapered
end of medicine dropper.
b. Mark the medicine dropper to identify the pesticide spot
collected.
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74
Pesticides in Bottom Sediments, Thin Layer Chromatography
c. Connect vacuum tubing over tapered end of medicine dropper.
d. Collect all of adsorbent surface enclosed between boundaries
of marked off area by sucking the adsorbent and pesticide
by vacuum and depositing in glass wool of medicine dropper.
6.3 Elution of Pesticide
a. Mark a 10 ml volumetric flask according to the pesticides
studied.
b. Place paper clip over tapered end of medicina dropper
approximately 2/3 distance from large end.
c. Insert tappered end of dropper into volumetric flask
supported by paper clip.
d. Elute pesticide with 5 ral of 4:1 hexane-ether mixture.
e. Pill to mark with hexane.
f. The elute is now ready for further identification by
gas chromatography.
7. Reference
Barry, H. C., et. al. 1965 Pesticide Analytical Manual (Revised Vol.l),
U.S. Department of Health, Education, and Welfare, Food and Drug
Administration.
-------
75
PESTICIDES IN BOTTOM SEDIMENTS
Infrared
1. General Discussion
This method is suitable for rag amounts; but with beam condenser
or internal reflectance accessories, |ig quantities may be analyzed.
2. Apparatus
2.1 Twelve ton press with a KBr pellet maker.
2.2 Agate mortar and pestle - approximately 40-75 mm OD.
2.3 I. R. spectrophotometer with beam condenser, internal
reflectance, and scale expansion.
3. Reagents
Potassium bromide, infrared quality.
4. Procedure
k-.l Grind 50-100 mg of KBr (dried overnight at 150°C) and mix
50 ng of sample or standard. (This may be done under IR lamp.)
4.2 Press into KBr-disc. (Disc should be clear.)
4.3 Dry 2 hours in a vacuum oven at 50 °C and 1 mm/Hg.
4.4 Place disc in spectrophotometer and record IR spectrum.
4.5 Run standards in the same manner.
5• Calculations
Compare IR fingerprints with standards for positive identification.
6. References
6.1 Breidenbach, A.W., et.al. 1966. The Identification and Measurement
of Chlorinated Hydrocarbon Pesticides in Surface Waters. U.S.Dept.
of Health, Education, and Welfare, Public Health Service WP-22
November.
6.2 Burchfield, H.P. and Johnson, D.E., 1965. Manual of Methods for
the Analysis of Pesticide Residues. Southwest Research Institute
(Prepared for DHEW, PHS), Vol. I and II.
-------
76
Pesticides in Bottom Sediments, Infrared
6.3 Perkin-Elmer Corp., 1967. How to Collect Fractions from the
Model 800 Series Gas Chroraatograph. GC Newsletter, Vol.. 3>
No. 1, Norwalk, Connecticut.
6.k Sadtler, T. and P. Sadtler, 1965. Improved KBr Techniques
presented: Pittsburg Conference on Analytical Chemistry and
Applied Spectroscopy, Sadtler Research Labs., Inc., 331^- Spring
Garden Street, Philadelphia, Pa.
-------
11
PHENOL IN BOTTOM SEDIMENTS
1. General Pisous sion
1.1 Principle: Phenolic types of compounds but not paracresol
and similar parasubstituted phenol's react with amino anti-
pyrine at a pH 10.0 ± 0.2 in the presence of ferricyanide
to form an antipyrine dye. The dye is extracted with
chloroform from the aqueous solution and the absorbance
read at k60 m..
1.2 Interference: Most interferences are eliminated or reduced
to a minimum by using the distillate of the original sample.
1.3 Minimum Detectable Concentration: The minimum detectable
quantity is 0.5 microgram with a 25 ml extraction and when a
5 cm cell is used in the photometric measurement.
2. Apparatus
2.1 Distillation apparatus, all glass. A suitable assembly
consists of a 1 liter pyrex distilling apparatus with Grahm
condenser.
2.2 Separatory funnels, Squibb form with teflon stoppers 1,000 ml
capacity.
2.3 Spectrophotometer.
3. Reagents
3.1 Phenol Stock Solution: Dissolve 1.0000 g of phenol in
distilled water and dilute to 1,000 ml with distilled water.
1 ml = 1 mg phenol
3.2 Phenol Working Solution: (Must be prepared daily) Pipette
20.0 ml of stock solution into a 1 liter volumetric flask
and dilute to volume with distilled water. 1 ml = 0.020 mg
3.3 Phenol Standard Solution: Pipette 25.0 ml of working
solution into a 500 volumetric flask and dilute to volume
with distilled water. 1 ml z 0.001 mg
3A Ammonium Chloride Solution: Dissolve 67.5 g of NH^Cl in
570 ml of cone. NH^OH and dilute to one liter with distilled
water.
3.5 Aminoantipyrine Solution: Dissolve 2.0 g of 4 - amino-
antipyrine in distilled water and dilute to 100 ml volume.
3.6 Potassium Perricyanide Solution: Dissolve 8.0 g KoFe(CN)6
in distilled water and dilute to 100 ml.
-------
78
Phenol in Bottom Sediments
3,7 Chloroform: Reagent grade of chloroform (redistilled).
3C8 Phosphoric Acid Solution: Mix 10 ml of phosphoric acid
with distilled water and dilute to 100 ml.
3.9 Copper Sulfate Solution: Dissolve 10 g of CuSO^HgO in
distilled water and dilute to 100 ml.
U. Procedure
U.I An aliquot of sample containing not more than 50 ug of
phenol is placed in the distilling flask. (20 g)
lt.2 Add 550 ml of distilled water.
h.3 If the sample has not been preserved, add 5 ml of 10$ CuSO^
and phosphoric acid and a few drops of methyl orange indicator.
U.lt Add a few boiling chips and distill over 500 ml of distillate.
4.4a If oil is present in distillate, filter through two thick-
nesses of dry Ho. 12 Whatman filter paper into separatory
funnel to remove oil.
ii.5 Transfer the distillate to a one liter separatory funnel,
add 3 ml of NH^Cl and nix, 3 ml of aminoantipyrine and mix,
and 3 ml of potassium ferricyanide and mix« Let stand at
least 3 minutes e
ll.6 Add 25 ml of CHClo and shake vigorously for 30 seconds:
after the layers have separated, shake once more for 30 seconds.
h*7 When the layers have separated, draw the CHClo layer off
through a cotton pledget placed in the stem of the separatory
funnel into a 2? ml graduate cylinder (Do not make to volume.)
Iu8 Read the optical density at a wave length of Ii60 m^i.
Uo9 Standards and blanks are treated exactly as the sample.
5. Calculations
5»1 Wet basis
mg/kg = ag in Stdp x P.P. Sample x 1000
OeDo Std0 grams Sample
5.2 Dry basis
mg^Ag wet basis
^ _
% Solids (decimal fraction;
Reference
Standard Methods for the Examination of Water and Wastewater 12th
Ed., APHA, Inc., N.Y., 1965, 514-520.
-------
79
TOTAL SOLUBLE PHOSPHORUS BJ BOTTOM SEDIMENTS
1. General Discussion
1.1 Principle: Ammonium molybdate and potassium antimonyl tartrate
react in an acid medium with dilute solutions of ortho-
phosphate to form a heteropoly acid (phosphomolybdic acid)
which is reduced to the intensely colored molybdenum blue by
ascorbic acid.
1.2 Interferences: Arsenates react with the molybdate reagent to
produce a blue color similar to that formed with phosphate.
Concentrations as low as 0.10 mg/1 of arsenic interfere with
the phosphate determination. Hexavalent chromium and nitrite
interfere to give results about 3$ l°w a"t concentrations of
1.0 mg/1 and 10-15$ low at concentrations of 10 mg/1
chromium and nitrite. Sulfide (Na2S) and silicate do not
interfere in concentrations of 1.0 and 10 mg/1.
1.3 Precautions: All glassware should be washed with hot 1:1
hydrochloric acid and then rinsed thoroughly with distilled
water. The glassware is then filled with distilled water
and all reagents added and allowed to stand 15 or 20 minutes,
followed by a distilled water rinse. Commercial detergents
should not be used.
2. Apparatus
Colorimetric equipment: A spectrophotometer with an infrared
phototube for use at 880 rajj., providing a light path of 1" or longer,
should be used.
3- Reagents
3-1 1.0 N H2SO^.
3-2 10 N NaOH.
3-3 1.0 N NaOH.
3«fc Sulfuric Acid, 8tJ: Dilute 112 ml of cone. H2SO, with
distilled water to 500 ml.
3-5 Potassium Antimonyl Tartrate: Dissolve ^.3888 g K(SbO)C, H, 0,.'
1/2 H?0 in 200 ml of distilled water. Store in dark bottle
at k°C.
-------
80
Total Soluble Phosphorus In Bottom Sediments
3.6 Ammonium Molybdate Solution: Dissolve 20 g
in 500 ml of distilled water. Store in plastic bottle a
3.7 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 h°C.
3.8 Combined Reagent: Mix the above reagents in the following
order and proportions for 100 ml of the combined reagent:
to 50 ml of 8N I^SO^ add 5 ml of potassium antimonyl tartrate
solution and mix, then add 15 ml of ammonium molybdate solution
and mix, and finally, 30 ml °? ascorbic acid solution and mix.
All reagents must be at room temperature before mixing. The
combined reagent should be prepared fresh each day just before
use.
3.9 Alcohol, ethyl (95 P6*" cent) or isopropyl.
3.10 Stock Phosphorus Solution: Dissolve in distilled water 2.1968 g
of potassium dihydrogen phosphate, KI^PO^, which has been dried
in an oven at 105 °C. Dilute this solution to 1,000 ml. One ml
equals 0.50 mg P.
3.11 Working Phosphorus Standard #1: Dilute 20 ml of stock phosphorus
solution to 1,000 ml with distilled water, 1 ml equals 0.01 mg P.
3.12 Dilute 100 ml of working standard #1 to 1,000 ml with distilled
water, 1 ml equals 0.001 mg P.
3.13 Strong Acid Solution: Slowly add 300 ml cone. I^SO^ to 600 ml
distilled water. When cool, add ^.0 ml cone. HN03 and dilute
to 1 liter.
3«1^ Potassium or ammonium Persulfate, analytical grade.
3.15 Concentrated HNOo.
k. Procedure
k.1 Place 5 g of well blended sample into a 100 ml beaker. Add
50 ml of distilled water and mix. Let this solution set
overnight at room temperature.
k.2 Filter the above mixture through a membrane filter
O.k^i porosity and place entire filtrate in a 250 ml beaker.
Do no wash residue on filter.
4.3 Add 1 ml of strong acid and O.k g of potassium persulfate
(K2SpOg). Boil gently for 90 minutes, adding distilled water
if necessary to keep the volume between 25 and 50 ml.
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81
Total Soluble Phosphorus in Bottom Sediments
k.k Cool, neutralize to a faint pink color with IN NaOH and
transfer to 100 ml nessler tubes. Dilute to volume.
4.5 Add 5 mi of ethyl or ispropyl alcohol and mix thoroughly.
4.6 Add 5 nil of combined reagent. Mix thoroughly and allow to
stand 10 minutes for color development. Read at 880 i^.
h.J A standard and blank should also be run with each analysis.
5. Calculations
5.1 Wet Basis
A mg in Std. P.P. Sample -,rs\n
"*/** ~ CM). Std. X (grams sample X 10°°
in aliquot)
5.2 Dry Basis
rag/kg wet basis
mg/kg
^solids (decimal fraction7
6. References
6.1 "Methods for the Collection and Analysis of Water Samples,"
Geological Survey Water Supply Paper ik^k, I960, pp 245-250.
6.2 Official Methods of Analysis, A.O.A.C., 7th Ed., 1950, p 370.
6.3 Journal AWWA, July 1965, PP 917-925-
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82
TOTAL PHOSPHORUS IN BOTTOM SEDIMENTS
1. General Discussion
1.1 Principle: Ammonium molybdate and hydrazine sulfate react
in an acid medium with dilute solutions of orthophosphate to
form a heteropoly acid (phosphomolybdic acid) which is reduced
to the intensely colored molybdenum blue by sodium sulfite.
1.2 Interferences: Arsenic, iron, tungsten, silica, titanium,
zirconium and vanadium do not interfere.
1.3 Precautions: All glassware should be washed with hot 1:1
hydrochloric acid and then rinsed thoroughly with distilled
water. The glassware is then filled with distilled water
and all reagents added and allowed to stand 15 to 20 minutes,
followed by a distilled water rinse. Commercial detergents
should not be used.
2. Apparatus
Colorimetric equipment: A spectrophotometer with an infrared
phototube for use at 8lO mn, providing a light path of 1" or longer
should be used.
3. Reagents
3.1 3
3.2 Perchloric acid •
3.3 50$ Mg (NO )2 • eHgO: Dissolve 500 g Mg (N03)2 . 6HgO in 1,000 ml
of distilled water.
3 A Concentrated hydrochloric acid.
3.5 10/o NagSO^: Dissolve 100 g Na2SOo (phosphate free) in 1,000 ml
of distilled water. Prepare fresn daily.
3.6 0.15$ Hydrazine Sulfate: Dissolve 1.5 g of the salt in 1,000 ml
of distilled water. Prepare fresh daily.
3.7 Ammonium Molybdate: Add 300 ml of cone. H2S04 to 500 ml of
distilled water and cool to room temperature. Dissolve 20g of
ammonium molybdate in the HgSOj^ solution and dilute to 1,000 ml
with distilled water. (Do not use the regular 1:1 - H2SO^ for
this - mix as directed.)
-------
83
Total Phosphorus in Bottom Sediments
3.8 Mixed Reagent: Dilute 25 ml of ammonium molybdate solution
with 45 ml of distilled water. Add 10 ml of the hydrazine
sulfate solution and 20 ml of the sodium sulfite solution, and
dilute to 100 ml with distilled water. The reagent is stable
for about one-half hour.
4. Procedure
4.1 Weigh 1.00 g of well-blended sample into a 250 ml vycor dish.
4.2 Add 10 ml of 3% I^Og and heat on hot plate for 10 or 15 minutes
with stirring to prevent overflowing from frothing.
4.3 Add 10-15 ml of distilled water and continue to boil until
frothing has ceased and almost all of the water has evaporated.
4.4 Add 10 ml of 50$ Mg (NOg^^I^O and place in a cold muffle
furnace. (Keep stirring rod in Vycor dishes and make sure
dishes are permanently marked.)
4.5 Start at 100°C and increase the heat gradually until the
samples are dry (about 350°C). Then increase heat to
500-550°C and ash for one hour.
4.6 Remove samples from furnace and let cool on asbestos pads.
4.7 When cool, add 20 ml of cone. HC1, place on hot plate and
heat with stirring until effervescence has stopped.
4.8 Add approximately 50 ml of distilled water and clean the
sides of the dish with a rubber policeman.
4.9 Filter through membrane filter O.V?(i into a 250 ml
volumetric flask, wash dish and filter paper with distilled
water and make up to volume.
4.10 Take a 25 ml aliquot, add 4 ml perchloric acid and fume until
fumes reach the mouth of the flask.
4.11 Cool, then add 10 ml of distilled water, 15 ml of 10%
and boil for at least one minute, but not longer than two
minutes.
4.12 Cool, then add 20 ml of the mixed reagent and heat in a boiling
water bath for 15 minutes and cool rapidly to 20°C.
4.13 Transfer to a 100 ml nessler tube and make up to volume with
distilled water and read at 8lO rap. against distilled water.
The usual blank for reagents is 0.015.
-------
84
Total Phosphorus in Bottom Sediments
5« Calculations
5.1 Wet Basis
/, _ mg in Std. v P.P. Sample v ., _.._-.
mg/kg s 7*r — =5-3 - x / • ^ — — X 1.000
^" ^ O.D. Std. (grams sample '
in aliquot)
5.2 Dry Basis
_ rag/kg wet basis
_
solids (decimal fraction)
6. References
6.1 "Methods for the Collection and Analysis of Water Samples,"
Geological Survey Water Supply Paper 1^54, I960, pp 2^5-250.
6.2 Official Methods of Analysis, A.O.A.C., 7th Ed., 1950, p 370.
6.3 Journal AWWA, July 1965, pp 917-925.
6.4 Chemical Analysis of Iron and Steel, Lindell, Hoffman and Bright,
1931, PP 209-231.
6.5 U.S. Bureau of Mines, Minneapolis, Minnesota,
Personal Communication.
-------
85
SOLIDS - TOTAL AMD VOLATILE IN BOTTOM SEDIMENTS
1. General Discussion
1.1 Principle: The sample is dried in a weighed dish in an oven
at 103-10£°C to constant weight. The increase in weight over
that of the empty dish represents the total solids.
1,2 The volatile solids are determined by placing the oven dried
sample from 1.1 in the muffle furnace for one hour at 600°C.
The decrease in weight of residue after ashing represents the
volatile solids.
1,3 Minimum detectable concentration: Dependent on the sensitivity
of the analytical balance used for weighing.
2. Apparatus
2.1 Drying Oven.
2.2 Muffle Furnace.
2.3 Porcelain Crucibles.
2»h Porcelain Evaporating Dishes.
2.5 Analytical Balance.
3. Procedure
3.1 Wash dishes and number with heat-resistant marking pencil.
3.2 Place evaporating dishes in a muffle furnace at a temperature
of 600-650°C for one hour.
3.3 Remove evaporating dishes from the furnace and allow them to
cool for 1-2 minutes in air, but not more than 3-h minutes.
Then place them in a dessicator for 1 hour0
3.1i Weigh and record this weight as the tare weight„
3«5> Weigh 10 grams of bottom sediment to the nearest 0.01
grams in the tared evaporating dishes.
3.6 Place the sample in the oven at 103-105°C overnight.
3.7 Remove samples from the oven and place them in a dessicator
for 1 hour.
3<>8 Weigh and record this weight as the oven-dry weight.
3.9 Place the overt dried sample in the muffle furnace at 600°C
for 1 hour0
-------
86
Solids - Total and Volatile in Bottom Sediments
3.10 Remove samples from the furance and allow them to cool
for 1-2 minutes in air, but not more than 3-h minutes.
Afterwards, place them in a dessicator for 1 hour.
3.11 Weigh and record this weight as the furnace weight.
li. Calculation
lul Oven dry- weight x 100 = % total solids
Initial wt. of.sample
U.2 Oven dry weight - furnace weight x 100 = % volatile solids
Oven dry weight
5>. Reference
Standard Methods for the Examination of Water and Wastewater,
12th ed., APHA, Inc., N.Y., 1Q65, 53^-535.
-------
87
TOTAL SULFIDE IN BOTTOM SEDIMENTS
1. General Discussion
Total sulfide includes dissolved hydrogen sulfide and its ionization
products as well as acid-soluble metallic sulfides present in sus-
pended matter. Sulfide ion Is also determined by the following
method, but it is not present in significant concentrations "below
a pH of 13.
1.1 Principle: Sulfides are removed from suspended matter and
other interfering substances in solution by distillation
under acidic conditions. Air oxidation of the evolved
hydrogen sulfide is minimized by passing nitrogen gas
through the system which displaces the oxygen prior to
acid addition. The distilled hydrogen sulfide is collected
in zinc acetate which reacts to form insoluble zinc sulfide.
The zinc sulfide is reacted with N,N-Dimethyl-p-phenylene-
diamine in sulfuric acid to produce an intermediate that is
oxidized by ferric chloride to an intensely blue colored dye
called methylene blue. The intensity of the blue color is
proportional to the original concentration of sulfide in the
distillate and is measured at a wave length of 650 mji.
1.2 Sampling and storage: Samples must be taken with a minimum
of aeration, for not only are sulfides volatilized by aeration
but also any oxygen that is taken up will readily oxidize the
sulfides to free sulfur.
The sample is preserved by pipetting 2 ml of 2N zinc acetate
solution into the bottle, replacing the stopper, and shaking
well. This precipitates the sulfides as inert zinc sulfide,
which not only prevents oxidation of sulfides but also
prevents further sulfide generation.
2. Apparatus
2.1 Distillation apparatus, all glass. For large samples, a
suitable assembly consists of a 1-liter pyrex distilling flask
with Graham condenser as used for the analysis of phenols.
-------
Total Sulfide in Bottom Sediments
A section of glass tubing should be connected to the tip of the
condenser so that it reaches the bottom of the collection tube,
2.2 Distillate collection tubes. Short form Nessler tubes.
graduated at 50 and 100 ml.
2.3 Spectrophotometer, for use at 650 mu and providing a light
path of 1 inch or greater.
3. Reagents
3,1 Nitrogen, water-pumped.
3.2 Zinc acetate, 2N. Dissolve 220 g of Zn O^H^^^I^O in
distilled water and dilute to 1 liter.
3«3 Zinc acetate, 0.2N. Add several drops of acetic acid to 100 ml
of 2M zinc acetate solution and dilute to 1 liter.
3»U Sulfuric acid solution, 1:1. Add, cautiously, 500 ml of cone.
H2soli to £°° ^ °? distilled water in a 1-liter flask. Mix
continuously and cool under running water while combining
reagents. Cool solution before using.
3«5 Dilute sulfuric acid solution, approx. 0.1N: Dilute 5 ml of
1:1 H2SO^ to 1 liter with distilled water.
3.6 Stock amine solution: Dissolve 2.7 g of N,N-Dimethyl-p-
phenylenediamine sulfate and dilute to 100 ml with 1:1 H^SOi
solution. This solution is stable for approximately one
week.
3.7 Working amine solution. Dilute 2 ml of stock amine solution
to 100 ml with 1:1 fSO solution. Prepare fresh daily.
3.8 Ferric chloride solution: Dissolve 100 g of FeCl-.6H20 in
hot distilled water and dilute to 100 ml. Cool before use.
3.9 Standard potassium biniodate solution, 0.025N. Accurately
weigh out 0.8l2li g KH(lOo)2 and dissolve in distilled water.
Dilute to 1-liter.
3.10 Standard sodium thiosulfate titrant, 0.025N. Dissolve 6.205 g
N2S2°3'^H2° i*1 distilled water and dilute to 1 liter.
Preserve with 5 ml chloroform. Standardize against standard
potassium biniodate using starch as an indicator.
-------
Total Salf lie in Bottom Sediments 89
3.11 Potassium iodide solution. Dissolve £ g of KI in distilled
water and dilute to 100 ml.
3.12 Treated h7drochloric acid. Place one or two strips of aluminum
in a small beaker of concentrated HC1. After violent reaction,
the acid is poured off and is ready to use.
3»13 Oxygen-free dilution water. Pass nitrogen gas through a suf-
ficient quantity of distilled water for dilution requirements.
A minimum of 10 minutes is required to displace oxygen in
the water.
3»lU Sodium sulfide, Reagent, crystal.
It. Procedur-e
iul Standardization: Sulfide solutions are extremely unstable
and must be prepared fresh and used immediately. Stability
is increased by using nitrogen-saturated water for dilution,
etc.
Prepare 0.01N sulfide solution as follows: Weight out ap-
proximately 1.2 g of large crystal Na2S.?H20. Wash the
crystals several times with distilled water. Discard the
washings and add the washed crystals to 975 ml of nitrogen-
saturated distilled water. Dilute to 1 liter. The exact
concentration of this stock solution is determined by
reacting the sulfide with an excess of iodine to give free
sulfur and titrating the unreacted iodine with sodium thio-
sul fate.
Pipet 20.00 ml of stock sulfide solution into ICO ml of
oxygen-free water. Add {? ml of KI solution, 20.00 ml of
O.O2SM KH (103)2 solution, and 10 ml of O.BI I^SO^. Titrate
with 0.025>M Ite^SjO-j solution using starch as an end point
indicator. Carry a blank through the procedure and calculate
the amount of reacted iodine from the difference between the
blank and standard titrations. Since 1 ml of 0.025>N KHClO-,^
is equivalent to O.UOO mg of sulfide ion, calculate the
sulfide concentration in the stock solution. Calculate the
ml of stock solution equivalent to 2 mg sulfide and add this
amount to 9CO ml of oxygen-free water and dilute to 1 liter.
This is the working standard containing 2 u.g sulfide per ml
of solution.
Prepare a standard curve using the working sulfide solution
in the range from 2 to $0 ng sulfide, as follows: Pipet
2O ml of Oe2N Zn (CgH-jOg^ into a series of 50 ml nessler
tubes. Add the required amounts of sulfide solution to each
-------
90
Total Sulfide in Bottom Sediments
tube and dilute to 50 ml with oxygen-free water. Develop
the color as outlined in section U.3 and read the optical
density at 650 m(a.
Prepare a standard curve for distilled samples "by running
consecutive amounts of the working standard through the distil
lation procedure in section U.2. Determine the sulfida concen
tration of each standard run through this procedure by adding
an identical amount of working standard to 20 ml of zinc
acetate, diluting to 5>0 nil, developing the color and comparing
the optical density with the standard curve. This step is
necessary since the sulfide concentration in the working
standard decreases with time.
U.2 Distillation Procedure. Set up the distillation apparatus.
The transfer tuba frcm the condenser should reach to the
bottom of the distillate collection tube. The condenser
should be attached in such a manner that it can be easily
moved up or dorrn when diluting the distillate or adding
reagents .
Pipet 20 ml of 002N Zn^HoOg^ into a 100 ml nessler tube
and lower the condenser so that the transfer tubing reaches
below the level of the liquid. Attach a distilling flask
and pass nitrogen gas through the system for at least 10
minutes. Md an aliquot of the bottom sediment sample contain-
ing not more tiiaQ 50 ng °f sulfide. Bubble nitrogen gas through
the sample to remove any oxygen dissolved in the sample. A small
amount of sulfide may be driven over by the gas, so be sure that the
010.7- exit is through the zinc acetate solution in the collecting
tube. Discontinue nitrogen evolution and add rapidly several
boiling stones ; 2 drops of methyl orange indicator, and enough
treated HC1 to change the color from orange to red. Stopper
as quickly as possible and heat slowly The slower the heating
rate the greater the contact time between the evolved I^S and
Zn(C2H^02)2 and the less chance of sulfide loss. Distill the
solution until approximately 20 ml of distillate have been col-
lected (roughly 5-8 minutes after the solution commences to
boil). Turn off heat and remove the stopper in the distil-
lation flask to ksep the distillate from being sucked back
up the condenser. Raise the transfer tube above the 50 ml
mark on the r;ollection container and dilute the solution to
50 mis, Return the transfer tube bo the solution and proceed
with color development,
-------
91
Total Sulfide in Bottom Sediments
4.3 Color Development. Since some zinc sulfide adheres to the
transfer tube, it should be in the solution while the color
reaction is taking place. Furthermore, since this reaction
is sensitive to temperature, the solution should be immersed
in a vater bath at 23-25°C while reagents are being added.
Md 2 ml of dilute amine solution to the 50 *&• of distillate,
mix and add 5 drops of FeClo solution. Mix again and set
aside for 10 minutes while the color develops. Measure the
absorbance at 650 mji-
5. Calculation
5.1 Wet basis:
mg/kg » mg in 5td, a P.P. Sample x 1000
O.D. Std. (grams Sample
,.__,. in aliquot)
5.2 Dry basis:
, mg /kg wet basis
^kg* % Solids (decimal fraction)
6. References
6.1 Photometric Determination of Sulfide and Reducable Sulfur
in Alkalies, M. Budd, H. Bewick, Anal. Chem. 24, 1536 (1952).
6.2 Standard Methods for the Examination of Water and Wastewater,
12th ed., APHA, Inc., N.Y., 1965, 426-432.
6.3 A Revised Method for the Determination of Total Sulfide in
Water and Bottom Sediments. T. 0. Meiggs, Lake Michigan
Basin Office, Chicago, 111. (1966).
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92
SILICA IN BOTTOM SEDIMENTS
1. General Discussion
Although silicon constitutes approximately 26% of the lithosphere,
it is never found in the native state. As the silicate, it occurs
extensively as a constituent of igneous rocks, quartz and sand.
The silica content may serve to differentiate sediment due to
erosion from that of industrial and municipal origin.
The classical gravimetric procedure is videly used for determining
silica in minerals and other materials e.g., portland cement, glass,
etc. which are high in silica content, (j.l, 7 A, 7.5.)
This method includes:
1. Sodium carbonate fusion to decompose refractory silica
and other such materials.
2. Double evaporation - dehydration to isolate silica as
its insoluble anhydride.
3- Ignition of the residue to constant weight.
U. Volatilisation of silica as silicon tetrafluoride.
5. Calculation of the amount of silica from the weight lost
or volatilization.
Highly accurate results can be obtained using this method;
however, it suffers the following disadvantages: (a) it is
quite lengthy and (b) requires the use of expensive platinum
equipment. This extreme accuracy is not required when
monitoring the silica composition of a large number of sediments.
A modified gravimetric procedure is here proposed for the deter-
mination of "uncorrected silica'(7»2) in sediments. Pure or
corrected silica caji be reported only after the residue has
been subjected to the hydrofluoric acid volatilization procedure.
"Uncorrected silica" is hereafter referred to as "silica."
2. Apparatus
2.1 Porcelain evaporating dishes.
2.2 Porcelain crucibles and covers.
2.3 Watch glasses, to fit evaporating dishes.
2.h Pestle, large.
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93
Silica in Bottom Sediments
2.5 Hot plates, large.
2.6 Glass stirring rods.
2.7 Filter paper.
2.8 Filtering funnels and rack.
2.9 Beakers, kOO ml capacity.
2.10 Hot water wash bottles.
2.11 Drying oven, 110°C.
2.12 Fisher burners.
2.13 Ring stand and rings.
2.lh Clay triangles.
3. Reagents
3.1 Hydrochloric acid concentrated.
3.2 Hydrochloric acid, 10$.
3-3 Nitric acid, concentrated.
h. Procedure
Start with the residue from the determination of volatile solids,
contained in a porcelain evaporating dish.
k.I Add 30 ml of concentrated HC1 to the residue.
k-.2 Pulverize with a pestle, taking care not to lose any
sample in the process.
U.3 Wash the pestle with distilled water using a rubber
policeman to dislodge adhering particles.
k.k Add 1 ml of concentrated HNO_ to each sample.
U.5 Place the evaporating dish on a hot plate, cover with a
watch glass and evaporate to dryness.
4.6 Transfer the evaporating dish from the hot plate to a
drying oven and bake at 110°C for 1 hour.
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Silica in Bottom Sediments
4.7 Set baked residue back on the hot plate, add 15 ml
concentrated HC1 and heat to dissolve the difficult
soluble salts.
4.8 Wash any adhering material off the watch glass into the
evaporating dish with about 25 ml of distilled water.
4.9 Continue heating until all soluble salts are dissolved,
filter while hot through an ashless filter paper into
a 400 ml beaker (save this filtrate for subsequent
analysis).
4.10 Wash any residue remaining in the evaporating dish onto
the filter paper using a rubber policeman to aid in the
removal of adhering particles.
if.11 Wash the residue retained on the filter paper free of
soluble salts with hot 10% HC1 (about 10 times).
4.12 Transfer the filter paper containing all the residue to
a tared porcelain crucible.
4.13 Dry and ignite to constant weight at the hottest
temperature attainable with a bunsen burner.
4.l4 Cool with cover on, weigh and calculate the % SiO.
5. Calculations
* sio? = gSiOpxioo +
2 g dry sample wt.
6. Discussion of Method
The modified gravimetric method for the determination of silica
in sediments utilizes the residue from the determination of
volatile solids. It is convenient to use this residue since
ignition at 600°C has destroyed interfering organic matter.
Furthermore, ignition has served to prepare the sample for
analysis, by converting certain insoluble silicates to calcium
silicate, which is acid soluble: (7.2)
Equation (7«l)
Si02 + CaCO 600 "C 2 / CaSiO
This conversion is highly probable when sediments are ignited
since they contain substantial amounts of calcium carbonate.
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95
Silica in Bottom Sediments
The sodium carbonate fusion serves a like function.
Equation (2)
Since ignition is noted to serve the same function as fusion,
the latter step was excluded from the modified procedure.
The modified procedure also suggests that porcelain vare be used
in lieu of platinum. The literature noted that strong hydro-
chloric and nitric acids, used to decompose the sample, might
dissolve some silicates from the porcelain evaporating dish. (7*3)
However, it is further noted that, any silicates thus gained hope-
fully will be negated by adsorption losses when the dehydrated
silica is removed from the dish (silica being tenaciously adsorbed
by porcelain).
The most time consuming step in the classical gravimetric silica
procedure is the one which involves the double evaporation-
dehydration of the sample. A reference to the literature indicates
that a single evaporation-dehydration step would recover 97-99$ of
the total silica present in a sample. (7«3)
Investigation has confirmed this recovery rate (See Table l).
A single evaporation-dehydration is used in the modified procedure,
since in surveillance work the relative change over a period of time
rather than exact amount is most important.
It is expedient to utilize the filtrate from the silica procedure
for subsequent determinations of iron and manganese, since inter-
fering organic matter and silica have been removed. (See iron and
manganese analysis).
Finally, as noted in the General Discussion (Section l), silica as
determined by the modified procedure is "uncorrected", since the
residue was not subjected to a hydrofluoric acid volatilization.
7- References
7»1 Snell, F.D., & Biff en, P.M., Commercial Methods of Analysis,
New York: McGraw Hill, ISkh, pp 176-191
7-2 Ayres, G.H., Quantitative Chemical Analysis, New York:
Harper Bros., 1958,
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96
Silica in Bottom Sediments
7.3 Kolthoff, I.M. & Sandell, E.B., Textbook of Quantitative
Inorganic Analysis, New York: MacMillan Co., 1946, p.402-403,
7.4 Standard Methods for the Examination of Water and Wastewater,
12th ed., APHA, Inc., N.Y., 1965 258-260.
7.5 "Methods for Collection & Analysis of Water Samples,"
Geological Survey Water Supply Paper, 1454, I960, pp 259-263.
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97
SILICA RECOVERY -
TABLS 1
SINGLE VS DOUBLE EVAPORATION
Saaple
Ko.
1
2
3
k
5
6
7
8
9
10
11
12
13
14
15
16
17
1.8
19
20
A
Wt. of Residue
Fran Single
Evap.-Eehy.
2.9732
3.2149
1.3853
1.3932
2.5408
1.0645
2.VT57
1.9985
l.W5^
3.58^5
^.6ij-03
1.07^6
1.1986
5.1323
1.&29
2.1838
1.3859
3.711^
1.5161
1.0811
B
tit. of Residus
Froa Second
Evap.-Dshy
0.0032
0.0022
O.OOJj-0
0.0015
0.0015
0.0008
0.0003
0.00^0
0.0016
0.0110
O.OKA.
0.0017
0.0037
0.0089
0.0063
0.0008
O.OOS4
0.0007
0.0021
O.COOlt
Total
Residue
A + B
2.976^
3.2171
1.3893
1.39VT
2.5^23
1.0653
2.ij-76o
2.0025
1.4870
3.5955
^.6507
1.0763
1.2023
5.1*02
1.6^92
2.1846
1.39^3
3.7121
1.5182
1.0815
^ Silica
Recovery By
Single Svap.
99.89
99.93
99.71
99.89
99.9^
99.92
99.98
99.80
99.89
99.69
99.77
99.84
99.69
99.82
99.61
99.96
99.39
99.98
99.86
99.96
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98
MANGANESE IN BOTTOM SEDIMENTS
1. General Discussion
1.1 Principle: Manganese is readily determined in small concen-
trations by oxidizing it in acidic solution to the intensely
colored permanganate ion and measuring the absorbance of the
resulting solution at a wavelength of 525 np.
After the sample has been digested with acid to oxidize
organic matter and to volatilize chlorides as HC1, phosphoric
acid is added to form a colorless complex with ferric ion.
Oxidation with persulfate ion is carried out in hot acidic
solution in the presence of silver as a catalyst. The color
is stable for 2k hours.
1.2 Interferences: The most important interferences are organic
matter, chloride ion and other reducing substances. These are
taken care of in the ashing steg. Other colored ions,
notably ferric iron, copper, nickel and chromate contribute to
the color. The interference of iron is overcome by the addition
of phosphoric acid. That of the other ions is compensated for
using a portion of the sample from which the permanganate color
has been bleached for a blank.
1.3 Minimum detectable concentration: If the volume of the sample
is 100 ml, the minimum detectable concentration using a 1 inch
cell is 0.01 mg/1.
2. Apparatus
Spectrophotometer equipped with absorption cells providing a light
path of 1 inch or longer, for use at 525 mu.
3. Reagents
3.1 Stock manganese solution: Dissolve 1.8g potassium permanganate
in about ^50 ml distilled water in a liter flask and heat U-5
hours at 70°-8dt! protecting the mouth of the flask from dust.
Within 2k hours standardize oxidimetrically against sodium
oxalate.
3.2 Standard manganese solution: The volume of stock solution
required to prepare a liter of solution containing 50 mg/1 Mn
is k.55 divided by the normality of KMnO^. Transfer exactly
this volume to a pyrex 1-liter volumetric flask. Add 5 ml
cone. HoSO^ and then NaHSO- dropwise with stirring until the
pink color disappears. Boll gently for a few minutes to remove
excess S0o« Cool and dilute to volume with distilled water.
1 ml - 0.05 mg Mn.
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QO
Manganese in Bottom Sediments 'y
3.3 Sulfuric acid, cone.
3.U Special reagent: Dissolve 18.7500 g of mercuric sulfate in
100 ml cone. HNO_ and 200 ml distilled water. Add 200 ml
85 percent phosphoric acid and 0.85 g silver nitrate and
dilute the cooled solution to 1 liter.
3.5 Ammonium perfiulfate, reagent grade.
3.6 Sodium "bisulfite solution: Dissolve lOg HaHSO^ in 90 ml
distilled water.
3.7 Sodium oxalate, primary standard, Ma2C20^. (0.2 — 0.^ g
anhydrous Ha2C2Oi<. weighed to nearest 0.1 sag.)
Procedure
4.1 Take an aliquot of the filtrate from the determination of
silica containing not more than 2.0 mg of Mn.
k.2 Transfer this aliquot to a 400 ml beaker, add 5.0 ml con-
centrated H2SOj^. Cover loosely with a watch glass and
evaporate on a hot plate to the copious evolution of SOo
fumes.
4.3 Transfer the residue to a 250 ml Erlenmeyer flask, using a
minimum amount of water, and again bring to fumes .
k.k Cool, add approximately 75 ml of distilled water and boil
to dissolve the soluble salts.
4.5 Allow to cool, add 20 ml of the special reagent and 1 g of
ammonium persulfate, (NH4)2S20g (use a 1 g Hach measuring
spoon for this addition).
U.6 Quickly heat to boiling and continue to boil for 2 minutes.
4.7 Remove the solution from the hot plate, add 0.2 g persulfate
(use a 0.2 g Hach measuring spoon) and allow to stand for
1 minute before transferring to an ice bath for further cooling.
U.8 Adjust the volume of solution in each flask to 100 ml with
distilled water.
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100
Manganese in Bottom Sediments
U.9 Read the absorbance of each solution versus a blank in a
spectrophotometer set at a wavelength of 525 HVI •
4.10 Prepare calibration curve covering the range 0-5 mg/1.
5« Calculation
5.1 Wet Basis
/, mg Std. OP Sample ,-._„
rag/kg r ,% o-uj x 7 - o - =r" x 100°
^" ^ OD Std. (grams Sample
in aliquot)
5.2 Dry Basis
mg/kg vet basis
"
% Solids (decimal fraction)
6. Reference
Standard Methods for the Examination of Water and Wastevater,
12th ed., APHA, Inc., N.Y., 1965,
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101
OXIDAITON-REDUCTION POTENTIAL MEASUREMENTS
The oxidation-reduction (redox or Eh) potential is defined as the
electromotive force developed by a platinum electrode immersed in the
vater or bottom sediment, referred to the standard hydrogen electrode.
This is a measure of the oxygen potential of the bottom sediments.
When Eh is positive, this indicates the presence of oxygen or the material
is in the oxidized state and when it is negative the absence of oxygen is
indicated or the material is in the reduced state. .An %
measurement would give a good indication whether the iron was in the ferric
state or the ferrous state.
To measure the potential, a Beckman Zeromatic pH Meter or a Beckman
Model N is used in connection with a calomel (saturated KCL solution
used) and platinum electrode system. Instructions are followed for the
specific meter to obtain MV readings. Eh is measured by inserting the
electrodes just into the surface of the undisturbed sediment (about 1/2").
The oxidation-reduction potential of the sample in millivolts referred
to the hydrogen scale is calculated as follows:
Oxidation-reduction potential, Mv s E - C where:
E - electromotive force, in millivolts of the cell
C - potential, in millivolts of the saturated calomel
electrode referred to the hydrogen scale.
Note: There should not be any electrical interferences in the immediate
locale.
Reference
Manual on Industrial Water, Second Ed., 1966 Printing,
No. 148-1, pages 578-582.
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