sampling for contaminants of biological origin presented by
TRANSCRIPT
SAMPLING FOR CONTAMINANTS
OF BIOLOGICAL ORIGIN
PRESENTED BY
MOLD IN THE NEWS!
BIOLOGICAL CONTAMINANTS
DEFINING THE ISSUE
BIOLOGICAL CONTAMINATIONAs defined by ACGIH
Aerosols, gases, and vapors of biological origin of a type and concentration likely to cause disease or predispose persons to experience adverse health effects
Inappropriate indoor levels of bioaerosols typically found outdoors
Biological indoor growth of particles that may become airborne and have an adverse effect on exposed individuals
BIOLOGICAL CONTAMINANTS AEROSOLS
Airborne particles of biological origin
bacteria, fungi, pollen, viruses By-products
endotoxins and mycotoxins Other fragments
insect parts and excreta, skin scales, hair
BIOLOGICAL CONTAMINANTS VAPORS
Fungi and bacteria in indoor environments produce microbial volatile organic compounds (MVOCs) as a by-product of their metabolism.
The odors of MVOCs are good indicators of microbial growth even when growth is not visible.
Knowledge is limited. MVOC research will attempt to answer the questions:
What role do MVOCs play in health effects?
Do certain microorganisms produce a typical MVOC fingerprint?
BACTERIA FOUND IN THE WORKPLACE
Legionella bacteria can grow in water systems including cooling towers and air conditioners.
Pseudomonas bacteria can grow in water-based metal working fluids.
Staphylococcus aureus, bacteria including the methicillin-resistant superbug (MRSA), can be transmitted by direct skin-to-skin contact with infected individuals.
BACTERIA BY-PRODUCTS
Gram-negative bacteria may contain harmful substances in their outer membranes called endotoxins.
Endotoxins are referred to as pyrogens because they will induce fever. They will also cause respiratory distress and even death at high levels.
In the workplace, the most common route of endotoxin exposure is through inhalation of aerosolized bacteria including Pseudomonas found in metalworking fluids.
ENDOTOXIN EXPOSURES
WORKPLACECan be found in
sewage treatment
plants, cotton textile
mills, fiberglass
production plants,
poultry/swine facilities,
and in industries using
metal-working fluids
OTHERHave been found in air
conditioning units, spa
water, and swimming
pools. They can also
be found on water
damaged material
following a water
intrusion event
FUNGITHE USUAL SUSPECT IN IAQ
Primary biological contaminant implicated in indoor air complaints
Fungi found most often in the indoor environment include Penicillium, Aspergillus, and Cladosporium.
Described as saprophytic because they can grow on any nonliving organic material if adequate moisture is present.
PRODUCES MYCOTOXINS
Mycotoxins are natural by-products of fungal metabolism.
They are produced by some species of Aspergillus (versicolor), Fusarium (moniliforme), and Stachybotrys (chartarum).
Chemical structures and health effects of mycotoxins are quite diverse.
MYCOTOXIN EXPOSURESWORKPLACE Inhalation of
aerosolized fungal
spores or other fungal
structures in water-
damaged building
materials
OTHER Ingestion of moldy
food products by
animals and people Aflatoxin and
trichothecenes have
been found in mold-
contaminated animal
feed and cereal grains.
BIOLOGICAL CONTAMINANTS
WHO’S EXPOSED
WORKERS POTENTIALLY EXPOSED TO BIOAEROSOLS
Agricultural Workers Grain handlers Tobacco and cotton
handlers Farmers Livestock producersFood Handlers andProcessors Meat packing plants Poultry processors
WORKERS POTENTIALLY EXPOSED TO BIOAEROSOLS
Industrial Workers Pulp and paper mills Textile mills Wastewater and
sewage treatment plants
Machinists Industries with
cooling towers
WORKERS POTENTIALLY EXPOSED TO BIOAERSOLS
Healthcare workers Military personnel Construction and
maintenance personnel
• Remediation workers Office workers in
humidified indoor air
BIOLOGICAL CONTAMINANTS
HEALTH EFFECTS
SKIN INFECTIONS
Staph bacteria, including MRSA, can cause skin infections that look like a pimple or boil. Serious cases can lead to bloodstream infections or pneumonia. Mold may also induce skin infections like ringworm or rashes.
EYE, NOSE, AND THROAT IRRITATION
ACGIH reports that most health complaints in indoor environments are dueto eye, nose, and throat irritation, headache, and fatiguefrom unknown
causes.
Sick Building Syndrome
INHALATION FEVERS
HUMIDIFIER FEVER
Flu-like symptoms that
arise 4 to 8 hours after
exposure and subside
within 24 hours. Possibly
related to endotoxins
PONTIAC FEVER
A self-limited, flu-like
illness caused by
contamination of water
systems with
Legionella bacteria
HYPERSENSITIVITY DISEASES
Result from exposure to specific antigens in the environment that trigger an immunological response
Dust-mite and animalallergens are common causes in residences.
HYPERSENSITIVITY DISEASES IN THE WORKPLACE
Hypersensitivity pneumonitis characterized by acute, recurrent pneumonia with fever, cough, chest tightness, and a progression of symptoms
Building-related asthma characterized by chest tightness, wheezing, coughing, and shortness of breath that is worse on work days and improves on weekends
INFECTIOUS DISEASES
Influenza (H1N1) and SARS - viral illnesses Legionnaires’ Disease - pneumonia caused
by Legionella pneumophila bacteria contaminated water sources
Tuberculosis - lung disease caused by Mycobacterium tuberculosis and spread from person to person
HEALTH EFFECTSFROM MYCOTOXINS
Mycotoxins will reduce the effectiveness of the immune system by interfering with or killing macrophages.• This results in increased susceptibility to
infectious diseases and a reduction in defense against other contaminants.
WIDE-RANGING EFFECTSFROM MYCOTOXINS
VASCULAR SYSTEM• Increased vascular fragility
Hemorrhage
DIGESTIVE SYSTEM• Vomiting• Intestinal hemorrhage• Liver effects
RESPIRATORY SYSTEM• Respiratory distress
Bleeding from lungs
NERVOUS SYSTEM• Tremors
Lack of coordination• Depression• Headache
BIOLOGICAL CONTAMINANTS
CONDUCTING AN INVESTIGATION
ACGIH RECOMMENDS
A STEPWISE APPROACH
1. Gather information through occupant interviews, surveys, and building inspections.
2. Formulate a hypothesis on the cause of the complaints/illness by using the information gathered.
3. Test the hypothesis by collecting samples.4. Make recommendations for controls by
using sampling data and professional judgment.
INFORMATION GATHERINGOCCUPANT INTERVIEWS
Before embarking on a program of air measurements, survey the area and the people involved in the complaint.
Use this time for information gathering.
Look around and listen.
Complaint vs non-complaint areas
Date when problem was first noted
Days or times when problem is noted more and less
Seek input to formulate a hypothesis on the root cause of the complaints.
INFORMATION GATHERINGBUILDING INSPECTION
1. Examine the physical structure, maintenance, and occupancy patterns.
2. Look for potential sources of biological contaminant and evidence of water damage.
BUILDING INSPECTIONMOISTURE INDICATORS
Water marks on ceiling tiles and other surfaces
Visual presence of mold Musty smell of microbial VOCs White, powdery, or crystalline substance on
the surface of concrete, plaster, and masonry, which are soluble salts dissolved from the building materials
BUILDING INSPECTIONMOISTURE METERS
Used to survey moisture in any non-conductive, porous material to which the probes can be applied
Ceiling Tiles Gypsum Board Carpeting Wood Plaster Concrete
MOISTURE METERSFROM SKC
ECONOMY MODEL Operates by measuring the
electrical conductance between two probes inserted into the test material
Useful for construction, renovation projects, or other situations when the test surface can be punctured by the probes SKC Cat. No. 753-006
MOISTURE METERSFROM SKC
PINLESS MODEL Measures resistance
between two low-frequency signals transmitted from conductive pads without the need for insertion into the test material. • Specialty models available
for testing concrete
SKC Cat. Nos. 759-101/102
DATA INTERPRETATIONMOISTURE METERS
Moisture levels can be compared from wall to wall to determine where moisture intrusion is occurring.
Once the location of the moisture is found, an investigation can be made as to the cause and a control strategy can be developed.
DATA INTERPRETATIONMOISTURE METERS
The Western Wood Products Association (WWPA) has prepared a technical guide on preventing and controlling mold in lumber.• See www.wwpa.org/moldff2.htm
WWPA recommends that the moisture content of the wood be kept below 20%.
DATA INTERPRETATIONMOISTURE METERS
Greenguard Environmental Institute (GEI) has received ANSI approval for a standard covering the management of moisture (and mold growth) during building construction.
See www.greenguard.org.
BUILDING INSPECTIONHVAC SYSTEM CHECKS
OUTDOOR AIR SUPPLY Inadequate amounts of outdoor air often
leads to building-related complaints and health-related symptoms.
Ensure outdoor air supply meets ASHRAE or other appropriate standards.
BUILDING INSPECTIONHVAC SYSTEM CHECKS
LOCATION OF AIR INTAKES Air intakes on rooftops can draw in
bioaerosols from cooling towers, sanitary vents, building exhausts and animal waste.
Air intakes at street level can draw in moisture, vehicle emissions, and odors.
BUILDING INSPECTIONHVAC SYSTEM CHECKS
CONDITION OF AIR
FILTERS HVAC filters are not
designed to protect equipment or occupants from heavily contaminated air.
Filters may promote the growth of microorganisms if they become damp.
BUILDING INSPECTIONHVAC SYSTEM CHECKS
SUPPLY AIR Ductwork should not be coated with
excessive debris.• Dirt mixed with moisture can support microbial
growth.
Ensure that cold air leaving a diffuser does not produce condensation and the potential for microbial growth.
CHOOSING A SAMPLING METHOD TO TEST THE
HYPOTHESES
Data Interpretation
Tips
SAMPLING FOR BIOLOGICAL CONTAMINANTS
WHY: To test your hypothesis
on the cause of the problem
To positively confirm the absence/presence of contaminant
To identify the type of microbe• Genus/species
To confirm the effectiveness of decontamination
HOW: Bulk samples Surface samples Air samples
Followed by analysisat a qualified environmental microbiology laboratory
BULK SAMPLING
Portions of materials in the building can be tested for mold or other biological contaminants.
Typical test materials include sections of wallboard/wallpaper, carpet pieces, return-air filters, duct lining, and settled dust.
These are very useful because air sampling may miss some contaminants due to temporal variations.
BULK SAMPLING
Portions of the test material are typically placed in a sealable plastic bag for transport to the lab.
In some cases, sterile jars for dry items or sterile bottles for water or metalworking fluid samples may be required.
Settled dust can be collected using conventional vacuum cleaners and a new vacuum cleaner bag for each sample.
SURFACE SAMPLING
MICROVACUUM CASSETTES Carpeting is an effective reservoir for fungal spores and
sampling this surface can reveal the history of mold in the building.
Sample fungal spores in carpeting using a vacuum-style cassette. • 0.45 µm polycarbonate filter loaded into a 3-piece styrene
cassette with 2-inch tubing nozzle • Sample at flows up to 16 L/min to vacuum a defined area.
Work the inlet tube as deep as possible into the carpeting to collect a good sample of the dust.
CARPET SAMPLING KIT
SKC Cat. No. 225-9540
DATA INTERPRETATIONCARPET SAMPLES
An 2003 AIHCE paper by MidWest
Microbiology gave some numerical guidelines
for fungal spores on surfaces like carpet using
microvacuum cassettes:
Normal - < 5000/1000 cm2
Borderline - 25,000/1000 cm2
Elevated - 75,000/1000 cm2
SURFACE SAMPLING
STERILE WIPES A swab or filter wetted with
sterile water or wash solution is used to wipe a specified area.
The swab is then used to inoculate an agar plate for growth culture.
This technique is often used for MRSA testing.
SKC Cat. No. 225-2402
DATA INTERPRETATIONSWAB SAMPLES
The November 2001 AIHA Synergist
guidelines for fungal spores in swab
samples:
Normal: < 10,000 cfu/in2 or < 1500 cfu/cm2
Probable Contamination: > 10,000 cfu/in2 or > 1500 cfu/cm2
SURFACE SAMPLING
LIFT TAPE Collected by placing clear adhesive, packing tape,
or commercially available sampling strips onto a surface and removing it with slow, steady force
Following collection, the tape is attached to glass slides and examined using light microscopy to view mold spores.
SURFACE SAMPLING
LIFT TAPE ON A SLIDE Flexible plastic
microscopic slides with a sticky adhesive sample area can be used like lift tape.
Press on the test surface, place the slide in the provided mailer, and send to a qualified laboratory.
Stick-to-It Slides
SKC Cat. Nos. 225-9808/9
DATA INTERPRETATIONLIFT TAPE SAMPLES
The November 2001 AIHA Synergist
guidelines for fungal spores in tape
samples:
Normal: No significant fungal material or biomass• 1 to 5% spores
Probable Contamination: 25 to 100% spores
AIR SAMPLING WHY AND HOW
Like with chemical
sampling, air sampling
for biological
contaminants is done
for the purpose of
evaluating actual
human exposures.
Air Sampling for
Bioaerosols
Involves the use of: Impactors Filters Liquid-based
(impinger-type) devices
AIR SAMPLINGSPORE TRAP CASSETTES
Easy, inexpensive screening device Use with a pump at 15 to 30 L/min for up to
10 minutes. Spores impact onto a microscopic slide with a
sticky surface. Slide is stained and analyzed microscopically.
VERSATRAP CASSETTES
SKC Cat. Nos. 225-9820/1
AIR SAMPLING PUMPSFOR USE WITH SPORE TRAPS
Constant flows from
10 to 30 L/min User selectable
sampling times Lithium-ion battery
powered up to 4 hours Indefinite run time from
AC adapter Optional sampling wand
SKC Cat. No. 228-9530
DATA INTERPRETATIONSPORE TRAPS
Spore trap analysis will provide the total number of spores and the genus of the spores found.
Information can be used to compare the complaint area to non-complaint areas of the building and outdoors.
Genus of the spores should be similar inside and outside.
Numbers should be
lower inside.
DATA INTERPRETATIONSPORE TRAPS
November 2001 AIHA Synergist guidelines for Air samples:
Residential Buildings: Normal: < 5000 spores/m3
Probable Contamination: > 10,000 spores/m3
Commercial Buildings:Normal: < 2500 spores/m3
Probable Contamination: > 10,000 spores/m3
AIR SAMPLINGVIABLE CASCADE IMPACTOR
Specified in NIOSH Methods 0800 and 0801
Used with a pump at 28.3 L/min for typical sample times of 2 to 5 minutes
Mold impacts onto growth medium (agar)
Agar plates are shipped to a microbiology laboratory for growth culture
SKC BiostageSKC BiostageCat. Nos. 225-9610/11Cat. Nos. 225-9610/11
SKC BIOSTAGE SAMPLER PREPARATION
SKC BIOSTAGE WITH QUICKTAKE 30 PUMP
Sample Assurance Tip:
Impactor must be cleaned with isopropyl
alcohol before each use
Evaluate blank samples of agar plates
AIR SAMPLINGFILTERS Collection of microorganisms is
achieved by passage of air through a porous medium, typically a membranefilter.
Polycarbonate, mixed cellulose ester, or polyvinyl chloride filters may be used depending upon the application.
Gelatin filters will help to maintain viability by minimizing dehydration of the spores.
GELATIN FILTERS WITH SKC BUTTON SAMPLER
An AIHA Journal article reported that 25-mm filters used with the SKC Button Sampler provided collection efficiencies close to 100% for enumeration of airborne spores.
SKC offers sterile gelatin filters in 25 or 37-mm diameters. (Cat. Nos. 225-9551/2) SKC Cat. No. 225-360
INHALABLE SAMPLING at 4 L/min
VIABLE AIR SAMPLINGFILTERS
Filters, support pads and cassettes should be sterile.
Samples are collected with a portable pump at 1 to 4 L/min for 5 to 30 minutes.
After sampling, the material collected on the filters is inoculated onto agar plates.
AIR SAMPLINGCOLLECTION INTO LIQUID
Pumps are used to pull mold spores into glass impingers filled with a liquid collection medium, typically a dilute buffer solution or mineral oil.
Portions of the collection liquid can be placed onto nutrient agar and incubated or analyzed using other methods. BioSampler
SKC Cat. No. 225-9595
ADVANTAGE: 8-hour sampling
OPERATION OF THE BIOSAMPLER
Particle collection is achieved by drawing the aerosol through3 nozzles directed at an angle toward the inner sampler wall.
The collection liquid swirls upwardon the inner surface and removesthe collected particles.
ANALYSIS OPTIONS
Growth culture Microscopic Bioassay Immunoassay PCR (using water
as collection media)
DATA INTERPRETATIONVIABLE AIR SAMPLES
November 2001 AIHA Synergist guidelines:
Residential Buildings: Normal: < 500 cfu/m3
Probable Contamination: > 1000 cfu/m3
Commercial Buildings:Normal: < 250 cfu/m3
Probable Contamination: > 1000 cfu/m3
AIR SAMPLING FOR MVOCs
Sorbent tubes/pumps
Stainless steel canisters
AIR SAMPLING FOR MVOCs Photoionization
detectors (ppb RAE)
Man’s best friend
Seewww.Mold-dog.com
DATA INTERPRETATION
GENERAL GUIDELINES
WHAT ABOUT OELs?
Few established guidelines/standards for biological contaminants except for wood dust, cotton dust, etc.
ACGIH indicates that a “general exposure limit for concentrations or countable biological agents is not scientifically supportable.”
1. Biological contamination typically is a complex mixture of many types of microorganisms.
2. The health effects for various microorganisms vary greatly between individuals.
3. There is no single sampling method appropriate for all types of biological contamination.
4. There is insufficient scientific evidence to support a dose-response relationship from which an exposure standard could be derived.
ACGIH RECOMMENDS
“Gather the best data possible and use knowledge, experience, expert opinion, logic, and common sense to interpret information, design control, and remediation strategies.”
GENERAL GUIDELINESFOR DATA INTERPRETATION
1. Fungi found in indoor air should be the same species as that found in outdoor air, but the levels should be lower.
2. If there is a dominant fungal species in indoor air that is not present in outdoor air, it is probably growing from biological contamination within the building and is reducing air quality.
GENERAL GUIDELINESFOR DATA INTERPRETATION
3. Comparisons of indoor/outdoor air or problem/non-problem areas should be made at the species level, not just at the genus level.
4. Some species may be considered indicator organisms indicating specific problems such as E. Coli as an indicator of sewage contamination.
GENERAL GUIDELINESFOR DATA INTERPRETATION
5. In order to compare sampling results from indoor/outdoor areas or from different zones, an identical sampling protocol for each zone including the sample media, sampling duration, sampler type, and laboratory analysis is required.
CONTROL AND REMEDIATION
OF MICROBIAL CONTAMINATION
GENERAL CONTROL RECOMMENDATIONS
Within 24 to 48 hours after floods or leaks, dry materials and discard sewage-contaminated materials.
Have an effective drainage plan to prevent penetration of rain, snow, and groundwater through materials.
The relative humidity of an air-conditioned building should not exceed 60%.
GENERAL CONTROL RECOMMENDATIONS
Install appropriate insulation to prevent large temperature differences between air and surfaces.
Maintain and inspect HVAC components such as filters and drain pans to avoid accumulation of water or debris.
Pay close attention to the location of the outside air intake. Air intakes should be as far as possible from cooling towers, standing water, bird droppings, and vehicle emissions.
MOST IMPORTANT ISSUES IN REMEDIATION
Identify the conditions that contributed to microbial growth in the building.
Determine if mold is an allergen or a toxin for appropriate remediation steps.
TO REMOVE EXISTING CONTAMINATION
Vacuum with high-efficiency filters. Discard materials with “extensive” microbial
growth.• Surface areas greater than 3 m2
Wash with a dilute biocide (such as a 1:10 dilution of bleach) and with detergent followed by thorough drying.
TO REMOVE EXISTING CONTAMINATION
Soda Blasting
Similar to sand
blasting, but the soda
material will not
damage building
materials
HOW DO YOU KNOW WHEN YOU HAVE FINISHED REMEDIATION?
1. Water problem is fixed
2. Moldy materials removed
3. Mold similar in type/number inside and outside
4. No new growth or water damage
5. No health problems on re-entry
ESSENTIAL REFERENCES
Field Guide for the Determination of Biological Contaminants in Environmental Samples
By AIHAwww.aiha.org
Bioaerosols: Assessment and Control
By ACGIHwww.acgih.org
THANK YOU FOR YOUR ATTENTION!
YOU ARE NOW AN
OFFICIAL SKC
MOLDBUSTER!
SKC