7040

7040 FACILITIES*
7040 A. Counting Room
The design and construction of a counting room may vary
widely from one laboratory to another. Provide a room free of
dust and fumes to protect the electrical stability of the instru-
mentation; however, a “clean room” with specific controlled
access is not required. Stabilize and reduce background radiation
as much as possible by careful choice of building materials for
walls, floor, and ceiling as well as by assuring that samples
containing appreciable activity are located distant from the in-
strument area. Construct floors and counter tops of a material
that is easy to clean in the event of contamination.
Provide air-conditioning and/or humidity control as necessary
to avoid instrument instability. Follow as closely as possible the
instrument manufacturer’s recommendations for operating tem-
perature and humidity. Most counting instruments are supplied
with voltage-regulating circuitry suitable for controlling minor
fluctuations in line voltage. For unusual fluctuations use an
auxiliary voltage regulator/transformer. Finally, locate the count-
ing room in an area of minimal traffic flow.
A modern chemical laboratory can be used to process routine
environmental samples for radiochemical analyses. Preferably
segregate nonenvironmental levels of radioactivity to preclude
cross-contamination and health concerns. Provide adequate
space between instruments to allow necessary access for re-
quired periodic maintenance.
7040 B. Radiochemistry Laboratory
The prime consideration in the design of a radiochemistry
laboratory is contamination control. Radioactivity concentration
levels found in environmental samples would not normally pro-
duce cross-contamination problems if good laboratory practices
are followed. In areas where radioactive standards are being
prepared, take care to minimize contamination of surfaces, other
samples, and personnel. Either bench surfaces of an impervious
material covered with adsorbent paper or trays (stainless steel,
plastic, or fiberglass) lined with adsorbent paper are acceptable.
1. Chemical Reagents and Reagent-Grade Water
Most reagents contain some radioactivity and other impurities
that may result in a systematic error if not accounted for. Quan-
tify the contribution of reagents by analyzing reagent blanks. A
reagent blank is a sample having all of the constituents of the
unknown except those being determined. Do not use reagents
having a radioactivity level high enough to interfere. It is rec-
ommended that about 5% of every analysis batch be a reagent
blank. In most phases of radiochemistry, it is necessary to use
high-purity reagents. In such cases, use reagent-grade chemicals.
For example, if barium is to be used as a carrier for radium, it is
necessary to determine the radium content of the barium salt used
for the analysis. Rare-earth carriers, such as yttrium or cerium, can
be contaminated with thorium from the original rare-earth ores.
Distilled or deionized water is used in analytical laboratories
for dilution, preparation of reagents, and final rinsing of glass-
ware. Ordinary distilled water usually is not of sufficient purity
to be used for certain applications in the environmental radio-
chemistry laboratory. These applications include background
blanks for gamma spectroscopy and liquid scintillation counting.
Impurities commonly present in distilled water include radon
and tritium. Remove radon by aerating with aged (30 d) air or
other inert gases, or aging the distilled water for 30 d to allow the
radon and daughters to decay. Tritium presence, which is normal
in surface water, can be avoided by using water from deep wells.
Deep well water is normally old enough so that the tritium has
decayed completely or at least to an acceptable level.
2. Apparatus and Glassware
The same considerations apply to the use and care of glass-
ware in the radiochemistry laboratory as in any analytical labo-
ratory. An excellent discussion is given elsewhere of the kinds of
glassware available, the use of volumetric ware, and various
cleaning requirements.
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Certain aspects of glassware usage are
peculiar to radiochemistry. Consider glassware and apparatus
used in the preparation of standards or for higher-level samples
as contaminated; discard or segregate for further use with sam-
ples of comparable activity. (A useful rule of thumb is to not
analyze samples side by side if it is known that they differ in
activity level by three orders of magnitude, i.e., pCi vs. nCi.) As
available, preferably use single planchets and auxiliary supplies.
3. Reference
1. U.S. ENVIRONMENTAL PROTECTION AGENCY. 1979. Handbook for Analyt-
ical Quality Control in Water and Wastewater Laboratories. Chap. 4. EPA-
600/4-79-019, U.S. Environmental Protection Agency, Cincinnati, Ohio.
* Approved by Standard Methods Committee, 2005.
Joint Task Group: 20th Edition—James W. Mullins (chair).
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7040 C. Laboratory Safety
While specific safety criteria are beyond the scope of this discus-
sion, apply general and customary safety practices as a part of good
laboratory procedure. Each laboratory should have a safety plan as
part of standard operating procedure. Where safety practices are
included in an approved method, follow them strictly.
Regard each chemical used as a potential health hazard and
maintain exposure as low as reasonably achievable. Each labo-
ratory is responsible for maintaining a current awareness file of
applicable regulations regarding the safe handling of the chem-
icals specified in the methods for radiochemical analysis. Make
available a reference file of material data handling sheets to all
personnel involved. Use fume hoods when necessary, wear
safety glasses or a shield for eye protection, and wear protective
clothing at all times.
7040 D. Pollution Prevention
1. Management Techniques
Pollution prevention encompasses any technique that reduces
or eliminates the quantity or toxicity of waste at the point of
generation. Numerous opportunities for pollution prevention ex-
ist. The EPA has established a preferred hierarchy of environ-
mental management techniques that places pollution prevention
as the management option of first choice. Whenever feasible, use
pollution prevention techniques to address waste generation.
When wastes cannot be reduced at the source, the next recom-
mended option is recycling. Further information about pollution
prevention that may be applicable to laboratories and research
institutions is available.
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2. Reference
1. AMERICAN CHEMICAL SOCIETY. 1985. Less is Better: Laboratory Chem-
ical Management for Waste Reduction. American Chemical Soc.,
Washington, D.C.
7040 E. Waste Management
1. Management Techniques
Establish laboratory waste management practices consistent
with all applicable rules and regulations. Protect air, water, and
land by minimizing and controlling all releases from hoods and
bench operations, complying with the letter and spirit of any
sewer discharge permits and regulations, and by complying with
all solid and hazardous waste regulations, particularly the haz-
ardous waste identification rules and land disposal restrictions.
Further information on waste management is available.
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2. Reference
1. AMERICAN CHEMICAL SOCIETY. 1990. The Waste Management Manual
for Laboratory Personnel. American Chemical Soc., Washington, D.C.
FACILITIES (7040)/Waste Management
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FACILITIES (7040)/Waste Management