ASTM E884-82(2006)
(Practice)Standard Practice for Sampling Airborne Microorganisms at Municipal Solid-Waste Processing Facilities
Standard Practice for Sampling Airborne Microorganisms at Municipal Solid-Waste Processing Facilities
SIGNIFICANCE AND USE
Bacteria and fungi present in municipal solid wastes (as well as in other forms of waste) may become airborne as dusts during waste processing. Several investigations to determine the health significance of these microbiological aerosols have been hindered by the lack of standardized procedures for sampling airborne bacteria and fungi in an industrial environment and by the absence of standards for assessing their health significance. Because it is difficult to correlate airborne levels of bacteria and fungi with epidemiological data, this standard is designed to permit the formation of a data base to aid in the assessment of the health significance of airborne microorganisms. It is intended that the use of this practice will improve sampling precision and thereby facilitate comparisons between sampling results.
SCOPE
1.1 This practice covers sampling of airborne microorganisms at municipal solid-waste processing facilities, hereafter referred to as facilities. Investigators should consult Practice D 1357 for the general principles of conducting an air-sampling program.
1.2 This practice applies only to sampling airborne bacteria and fungi, not viruses. Since sampling airborne viruses is significantly more difficult than sampling bacteria and fungi, reliable methods of sampling viruses are not yet available.
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Standards Content (Sample)
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Designation: E884 − 82(Reapproved 2006)
Standard Practice for
Sampling Airborne Microorganisms at Municipal Solid-
Waste Processing Facilities
This standard is issued under the fixed designation E884; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 4. Summary of Practice
1.1 This practice covers sampling of airborne microorgan-
4.1 Concentrations of selected airborne bacteria and fungi
isms at municipal solid-waste processing facilities, hereafter
are determined using both liquid impinger and multi-stage
referred to as facilities. Investigators should consult Practice
impactor samplers.
D1357forthegeneralprinciplesofconductinganair-sampling
4.2 Procedures are included for selecting sampling loca-
program.
tions; determining numbers of samples, types of microorgan-
1.2 This practice applies only to sampling airborne bacteria
isms to be sampled, intervals between sample collection and
and fungi, not viruses. Since sampling airborne viruses is
analysis; choosing sampling equipment; preserving samples;
significantly more difficult than sampling bacteria and fungi,
and reporting results.
reliable methods of sampling viruses are not yet available.
5. Significance and Use
2. Referenced Documents
2.1 ASTM Standards:
5.1 Bacteria and fungi present in municipal solid wastes (as
D1356Terminology Relating to Sampling and Analysis of
well as in other forms of waste) may become airborne as dusts
Atmospheres
during waste processing. Several investigations to determine
D1357Practice for Planning the Sampling of the Ambient
the health significance of these microbiological aerosols have
Atmosphere
been hindered by the lack of standardized procedures for
2.2 Other Standards:
sampling airborne bacteria and fungi in an industrial environ-
MicrobiologicalMethods for Monitoring the Environment,
mentandbytheabsenceofstandardsforassessingtheirhealth
Water and Wastes
significance. Because it is difficult to correlate airborne levels
AirSamplingInstrumentsfortheEvaluationofAtmospheric
ofbacteriaandfungiwithepidemiologicaldata,thisstandardis
Contaminants
designed to permit the formation of a data base to aid in the
assessment of the health significance of airborne microorgan-
3. Definitions
isms. It is intended that the use of this practice will improve
3.1 microbiological aerosol—an airborne particle partially
samplingprecisionandtherebyfacilitatecomparisonsbetween
orexclusivelycomposedofmicroorganismsincludingbacteria
sampling results.
and fungi.
3.2 For definitions of other terms used in this practice, refer
6. Apparatus
to Terminology D1356.
6.1 Two types of samplers are used in each sampling
program for microbiological aerosols at waste processing
1 5
This practice is under the jurisdiction of ASTM Committee D34 on Waste
facilities (5).
Management and is the direct responsibility of Subcommittee D34.01.02 on
6.1.1 Multi-Stage Impactor, for collection of airborne mi-
Sampling Techniques.
Current edition approved Feb. 1, 2006. Published March 2006. Originally
crobes on agar plates. It is recommended that an impactor be
approvedin1982.Lastpreviouseditionapprovedin2001asE884-82(2001)DOI:
used for sampling all of the types of bacteria and fungi listed
10.1520/E0884-82R06.
in 10.6.1.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website.
3 5
Available from the National Technical Information Service, 5285 Port Royal Theboldfacenumbersintheparenthesesrefertothelistofreferencesattheend
Road, Springfield, Va. 22161. Request EPA-600/8-78-017. of the method.
4 6
Available from American Conference of Governmental and Industrial The six-stage and two-stage microbiological samplers manufactured byAnder-
Hygienists, 6500 Glenway Avenue, Building D-5, Cincinnati, OH 45211. son Samplers, Inc. have been found to be satisfactory.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E884 − 82 (2006)
6.1.2 All-Glass Impinger, for collection of airborne mi- 8. Precautions
crobesinaliquidmedium.Itisrecommendedthatanimpinger
8.1 Due to the nature of municipal refuse, common sense
be used for sampling fecal coliforms and for determination of
dictates that some precautions should be observed when
total plate count.
sampling dusts at municipal solid-waste processing facilities.
6.2 Air Sampling Pumps, providing approximately 40 Lper Recommended safety practices include wearing hard hats,
safety shoes, safety glasses, gloves, and respirators as well as
min (1.4 CFM) free-flow capacity.
washing hands before eating or smoking.
6.3 Additional equipment such as carts, stands, and tool
boxes are routinely used during dust-sampling programs.
9. Sampling
9.1 Location and Number of Sampling Sites:
7. Reagents and Materials
9.1.1 All sampling shall be carried out during normal plant
7.1 Agars for Use with the Multi-Stage Impactor:
operations.
7.1.1 Littman Oxgall, for total number of fungi present and
9.1.2 Use not less than two sampling locations inside the
for identification of the following species of fungi: (a) Asper-
facilityatworksitesorzoneswhereemployeesaremostlikely
gillus flavus and (b) A. fumigatus.
to be exposed to airborne dust concentrations (7). (Note 2)
7.1.2 Vogel and Johnson, selective for Staphylococcus au-
Among these locations, those where sampling equipment can
reus.
be located without interfering with facility operations shall be
preferred.
NOTE 1—Afungicide such as nystatin should be used with these agars.
NOTE 2—Examples of potential sampling locations are (a) on a tipping
7.1.3 Levine eosin methylene blue, specific for enterics
floor near or on a front end loader; (b) at a hand-picking station along a
including Klebsiella spp. (Note 1)
conveyor belt; and (c ) along catwalks or platforms in frequent use by
7.1.4 Trypticase soy, for total bacteria count. (Note 1)
employees.
7.2 Liquid Media for Use in Impingers:
9.1.3 Outside the facility, locate at least one sampling site
7.2.1 Lactose Broth with Antifoam A, for analysis of fecal
300 m (1000 ft) upwind from the facility and at least one
coliform and total plate count.
sampling site 100 m (330 ft) downwind from the facility.
7.2.2 The exact amount of Antifoam A to be added should
Measure the distances upwind and downwind from the same
be determined prior to field sampling. Sufficient antifoam
point, the point at which the emissions leave the facility or, in
should be added to prevent loss of fluid from the impinger, but
the case of multiple discharge points, from a central point
excess should be avoided.
equidistant from the discharge points.
9.1.4 Carefully measure and record the actual distances of
7.3 Media Preparation:
the sampling sites from the points of emission and wind
7.3.1 Conduct the following according to Microbiological
direction and velocity.
Methods for Monitoring the Environment, Water and Wastes
(14):(a) laboratory quality assurance, (b) selection and use of
9.2 Position of Sampling Inlet—Locatethesamplinginlet(s)
laboratory apparatus, (c ) washing and sterilization, and (d)
1.5 m (5 ft) above the floor level to approximate the breathing
preparation of culture media.
zone of a worker or other person exposed to the dusts. Locate
7.3.2 Preincubate all sampling media to determine if con-
the vacuum pumps where they will not disturb the air flow
tamination has occurred and to dry the agar surface. Excessive
patterns around the sampling inlet(s).
evaporation from the media or excessive contamination of the
9.3 Number of Samples:
exterior surfaces of the petri dishes must be guarded against
9.3.1 Inside the facility, collect not less than 5 replicate
during this preliminary incubation.
samples at each sampling site.
7.3.3 Media level in the sampling container is critical to
9.3.2 Outside the facility, collect not less than 3 replicate
collection efficiency.
samples at the upwind site(s) and not less than 5 replicate
7.3.3.1 Impactor—The petri dishes must be of such a size
samples at the downwind site(s).
thattheagarsurfaceisatthemanufacturer’sspecifieddistance
9.3.3 Wide variations in reported microbiological aerosol
below each stage. The manufacturer of theAndersen impactor
levels within facilities make it unlikely that the collection of
specifies 27 mL of agar per standardAndersen petri dish. The
five samples will yield a tight distribution of results; therefore,
agar surface must be smooth and free of bubbles to ensure an
where economically feasible, it is recommended that the
even air flow.
sample size be increased to more than five.
7.3.3.2 Impinger—For the all glass impinger, 20 mL of
9.4 Air Temperature:
broth is recommended (17). Autoclave impingers, and then
9.4.1 Collect samples when the air temperature at the
aseptically add 20 mL of sterile broth. Mark its level on the
sampling site is above 5°C (40°F).
impinger, and record any significant loss during sampling.
9.4.2 At temperatures below 5°C (40°F), the sampling
After sampling, the volume must be reconstituted to the
medium may crystallize, thus affecting recovery of microor-
original or the actual volume carefully calculated because a
ganisms.
known volume must be used for quantitative work.
10. Procedure
10.1 Record air temperature and relative humidity for each
AirsamplingimpingerNo.7540manufacturedbyAceGlass,Inc.(AGI30)has
been found to be satisfactory. location sampled.
E884 − 82 (2006)
10.2 Label all impingers to denote sampling run and loca- 10.5 Care During Sampling and Transport—Collect, pack,
tion. Label all petri dishes to denote sampling run, location, transport, and manipulate the sample prior to analysis in a
and stage of impactor. manner that safeguards against any change in the microbial
activity in the sample, such as, extreme heat and cold and
10.3 Air-Flow Rates:
radiation, including sunlight. Use the proper media to ensure
10.3.1 Determine the air-flow rate by an in-line flow meter.
preservation of the sample until its identification. If samples
Where this is not possible, calibrate air-flow rate with a
must be shipped prior to analysis, positive controls should be
gas-flow meter according to the procedure described in Ref
included with each shipment. Federal regulations must be
(16).The recommended flow rate for theAndersen impactor is
followed when they apply to these shipments.
28.3L/min.Theoptimumflowratefortheall-glassimpingeris
10.5.1 Care During Sampling with the Impactor:
12.5 L/min.
10.5.1.1 Carry out impactor loading and unloading in an
10.3.2 Maintainaconstantair-flowratethroughthesampler
atmosphere of minimal microbial activity, preferably in a
during the sampling time. Before sampling, allow the vacuum
portable polyethylene glove bag or a similar container. Invert
pumptowarmupfornotlessthan1min.Useclamps,T-shaped
the petri dishes immediately when the sampler is unloaded.
connectors, and in-line membrane filters with 1-mm pore size
Sanitize the impactor with a 70% alcohol solution and dry
topullfilteredairthroughthepumpduringthewarmupwithout
pulling air through the sampler. Select clamps and T-shaped thoroughly between samplings. Do not sanitize in the glove
bag. To provide a control check for contamination, load and
connectors that will not alter the flow rate through the
samplers. unload the impactor without sampling using a set of trypticase
soy agar petri dishes, and then subject these petri dishes to the
10.3.3 Secure all connections to keep the air loss less than
4% of the average sampling rate or less than 0.00057 m /min same processing steps and analytical procedures applied to the
samples.
(0.02 ft /min), whichever is smaller. Measure the leakage-flow
rate with a suitable dry-gas meter connected to the discharge
10.5.1.2 Minimize uneven distribution of colonies on the
side of the vacuum pump while the inlet to the sampling
platesbycenteringtheplatesonthethreepegsineachstageof
apparatus is plugged and a 380-mm (15-in. Hg) vacuum is
theimpactorand,onceloaded,handlingtheimpactorcarefully
drawn. A lower vacuum may be used provided it is not
to maintain this position.
exceeded during sampling.
10.5.2 Care During Sampling with the Impinger:
10.5.2.1 Include a negative (sterile) control with the im-
NOTE3—Manyofthevane-typeairsamplingpumps(includingtheone
furnishedforusewiththeAndersensampler)useaneedlevalvetocontrol
pingers to determine whether the samples become contami-
the air flow through the sampler by bleeding in air that bypasses the
nated while in transit or at the test site.
sampler. The air flow through the pump is therefore constant, and a
10.5.3 Preserve all samples by placing each one in a closed
meaningful measure of the flow through the sampler can only be made at
this location in the sample stream. containerat4 62°Cimmediatelyaftertakingthem.Protectthe
plates from direct contact with the ice to prevent contamina-
10.4 Sampling time—The length of time needed to collect
tion.
each sample is dependent upon the type of sampler used and
theconcentrationofmicrobiologicalaerosolspresentintheair.
NOTE 4—Sealed ice packets have been found to be satisfactory and
Trial sampling runs may be necessary to determine if a
convenient for this purpose.
satisfactoryplateloadingcanbeobtainedwithinthelimitations
10.5.4 Return the samples to the laboratory as soon as
of the equipment used.
possible and not later than 6 h after sampling. Process the
10.4.1 For the all-glass impinger operating at a flow rate of
samples and place in a incubator as soon as possible.
12.5 L/min, the normal sampling time is 20 min.
10.5.5 Forimpingersamples,rinsetheneckoftheimpinger
10.4.2 When using a multistage impactor, choose the sam-
and add this material to the sample. The volume of the rinse
pling time to avoid overloading the impaction plates, that is,
solution must be measured so that the final sample volume is
theloadingonanyoftheplatesshouldnotexceed300colonies
known.
per plate. The sampling time for the multistage impactors will
vary depending on the medium used for sampling collection
10.6 Identification of Colonies:
and the concentration of airborne dust. Suggested initial
10.6.1 Analyze for the types of bacteria and fungi listed in
sampling times for the various media are in Table 1.
10.6.1.1-10.6.1.4. This is a minimum list of bacteria and fungi
recommended for identification and quantification. Individual
investigators may wish to sample for a
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