PROGRAMS AND PLANS--Guidelines for sampling and analysis of water-quality constituents associated with solids
June 22, 1971
QUALITY OF WATER BRANCH TECHNICAL MEMORANDUM NO. 71.09
Subject: PROGRAMS AND PLANS--Guidelines for sampling and
analysis of water-quality constituents associated
with solids
Quality of Water Branch Technical Memorandum 71.05 described
the largely self-evident basis for sampling and analyzing the
suspended solids phase when investigating water-quality
constituents that are known to be associated with suspended
solids. Reference was made also to guidelines that would be
provided to field offices for use in planning investigations
that include these constituents.
At a recent meeting of the Branch staff with other Division
water quality specialists, constituents of interest were
classified geochemically, and recommended interim procedures
and methods for the investigation of those constituents were
outlined. Decisions made at this meeting reflect the
collective knowleoge and opinion of a large cross section of
Division research and operations personnel. They also reflect
what is believed to be a reasonable balance between the
desire for technical exactness and the necessity of
practicality in field operations.
At the meeting, it was concluded that adequate data for
making certain important decisions are not presently
available, but possibly can be obtained within the next few
months, in time for dissemination of final instructions to be
effective at the beginning of the 1972 water year. Pending
release of final instructions, the following interim
instructions are provided as a basis for conducting
investigations of the elements of interest.
I. Classification of minor elements or compounds associated
with solids:
A. Organics, pesticides
B. Organics, all others
C. Nitrogen and phosphorus
D. Inorganic anions
1. Weakly sorbed--selenium (Se), tellurium (Te), boron
(B), halogens (Br, I, F).
2. Moderately sorbed--molybdenum (Mo), vanaclium (V),
chromium (Cr), arsenic (As), uranium (U).
E. Inorganic cations
1. Moderately sorbed--lithium (Li), radium (Ra), strontium
(Sr).
2. Strongly sorbed--cesium (Cs), rubidium (Rb), iron (Fe),
manganese (Mn), copper (Cu), lead (Pb), zinc (Zn),
cadmium (Cd) cobalt (Co), mercury (Hg), silver (Ag),
gold (Au), aluminum (Al), nickel (Ni), beryllium (Be).
II. Types of investigations:
A. Reconnaissance--short one-time evaluation; can provide
definition of problems.
B. Monitoring--repetitive, continuing measurements; can
define variations and trends.
C. General resource appraisal--a moderately long-term
monitoring program, but with a defined duration; typical of
many WRD basin studies .
D. Detailed study, topical or areal--an intensive
investigation of limited duration.
III. Phases which should be studied in WRD investigations:
Minor elements or compounds in water can occur in two
phases--dissolved, and associated with solids. The solids
can, of course, be suspended or on the bed. The phases to be
investigated for each of the classes of minor elements or
compounds and for each type of investigation are listed
below:
A. Dissolved or sorbed on suspended solids:
1. Reconnaissance
a. Inorganic cations and anions--study both the material
in solution and the material sorbed on suspended solids
b. Nitrogen and phosphorus--study both phases
c. Organics--
Dissolved organic carbon (DOC)--study only the
dissolved phase
Suspended organic carbon and all other organics--study
both phases.
2. Monitoring--same as reconnaissance.
3. General resource appraisal--same as reconnaissance.
4. Detailed study--same as reconnaissance.
B. Sorbed on bottom material:
Bottom material, especially the fine fraction, serves as an
integrator of chemical and biological processes that occur in
the stream, and commonly is a useful indicator of the nature
of the solids that will be carried by the stream during the
early stages of the next significant runoff event. Thus, it
should be sampled at lease once at any study site, especially
if samples of suspended material cannot be obtained during
the early stages of runoff events, Because a new supply of
fine material is deposited after each runoff event, a
reasonable period of time is required to allow the
integration process to take place before sampling. Prediction
of the quantity of an element transported with the bedload on
the basis of the size distribution of bed-material samples is
questionable at present.
1. Reconnaissance--at least one sample of bed material should
be collected in the reach studied if suspended-solids samples
are not obtained during the early part of a stream rise.
2. Monitoring--bed-material samples not required if
suspended solids are adequately sampled; otherwise take at
least one sample.
3. General resource appraisal--sample bed material.
4. Detailed study--sample bed material.
IV. Analytical techniques:
A. Size of filter pore opening--for the present, continue to
use 0. 45 um pore size for separating dissolved (liquid)
phase from solids phase.
B. When to filter a sample--filtering immediately after
collection is recommended. Samples must be filtered within
24 hours after collection.
C. Recoverable (partial extraction) vs. total destruction--
measurement of the recoverable portion of inorganic
constituents is highly recommended. See attached procedure
for a description of the analytical technique currently
favored to extract and measure the recoverable fraction.
Extraction techniques for bed material samples will be
provided at a later date.
D. Type of filter to be used for separation of dissolved
phase from solids phases, and type of sample used for
analysis of solids phase:
Constituents to Filter To leach from solids,
be determined type extract from
___________________________________________________________
Organics-carbon Silver 1/ whole-water sample 1/
Organics-all others Silver whole-water sample
Nitrogen & Phosphorus Membrane whole-water sample
Inorganic anions Membrane 1/ whole-water sample 1/
Inorganic cations Membrane 1/ whole-water sample 1/
___________________________________________________________
1/ Whole-water sample to be used at least through 1971 water
year. Extraction techniques for analyzing material retained
on the filter pad will be developed and tested. After
comparison with whole-water extraction, decision may be
revised. A whole-water sample is defined as a representative
sample of the water-suspended solids mixture in the cross
section of a flowing stream, or in a vertical (or portion of
a vertical) of a lake or reservoir. Content of constituent in
solids phase must be calculated by difference (content in
whole-water sample minus content in dissolved phase).
E. A separate sample will be required for determination of
the concentration of suspended solids in the whole-water
sample.
F. The extraction procedures for recoverable inorganic
constituents (attached) is applicable to all minor-element
inorganic anions and cations that are listed under I., D and
E, above. Extraction procedures for pesticides and nutrients
(nitrogen and phosphorus) are already in use.
V. Sampling
A. Generally, sorption capacity per unit weight of solids
decreases with increasing particle size. However, due to
coatings on coarse grains (coarser than about 0. 5 mm) and
aggregation of fine material, the content of the constituents
of interest in the coarser size fractions cannot be ignored;
the only exception might be in the analysis of bed-material
samples for reconnaissance studies (see V., B).
B. For reconnaissance bed-material sample, analyze only
material finer than 20 ,um (except for organic analysis,
separate in field by timed multiple decantations--
instructions will be provided upon request). Samples for
organic analysis should not be separated in the field.
C. For special purposes, sample benthic organisms and analyze
for minor-element content.
D. If only the dissolved phase is to be determined and
reported, sediment-sampling equipment may not be required.
Nevertheless, the sample should be representative of the
entire stream cross section or lake vertical. Established
chemical-quality sampling procedures should be used.
E. When sampling for the suspended-solids phase (whole-water
sample), sediment sampling techniques must be used.
Procedures outlined in Interagency Committee on Water
Resources, Subcommittee on Sedimentation Report 14, and TWRI
Book 3, Chapter C2, Field Methods for Measurement of Fluvial
Sediment, must be followed.
F. Teflon nozzles for sediment samplers are mandatory when
collecting samples for the determination of inorganic minor
elements, and are acceptable when sampling for the
determination of organic constituents. Nozzles will be
supplied by this office upon request. We have nozzles for the
D-48, DH-59, D-49, and P-61 samplers.
G. The black rubber gasket in sediment samplers must be
replaced with a silicone-rubber gasket when collecting
samples for the determination of minor elements and organics.
Silicone-rubber gaskets for the samplers listed above will be
supplied by this office upon request.
H. One liter is the minimum sample volume required for the
determination of minor elements associated with suspended
solids.
I. Presently used pint milk bottles are satisfactory for the
interim for collecting whole-water samples, but the samples
should be quantitatively transferred in the field (except
when sampling for organics) to an approved screw-top bottle.
Samples collected for organic determinations should receive a
minimum amount of handling in the field.
J. A handscoop made from a cut-out plastic bottle or other
straightsided plastic container may be used for
reconnaissance sampling of bottom sediments when the stream
can be waded. Samples collected should be iced in the field.
When sampling bottom sediments with the BM-54 and BMH-60 bed-
material samplers, the buckets on the samplers must be
thoroughly cleaned before each use, and the rubber gaskets
must be replaced by silicone rubber gaskets. Requests for
these gaskets should be made through this office.
K. The valve mechanism in the P-61 and 63 point samplers may
pose a serious contamination problem. Use of point samplers
for sampling minor elements should be avoided unless notifed
otherwise .
The above instructions indicate, in effect, that if a
quantitative analysis of constituents associated with
suspended solids is to be made, it must be made using a
sample that is representative of both the suspended solids
and the liquid phase in the cross section sampled. If the
required sampling effort cannot be justified, it is better to
filter the sample and analyze for the dissolved constituents
only.
The Quality of Water Branch will be interested in receiving
written comments from the field pertaining to the interim
guidelines given above. Further guidelines will be
forthcoming.
W. H. Durum
Attachment
WRD Distribution A, B, S, FO, PO.