Airborne Contaminants Lab

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Airborne Contaminants Lab
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Topics

• Overview of workplace health and its regulation
• Particulates and microscopy
• Gases and vapors
• Monitoring
• Real time
• Noise

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Format

• Lecture with break
• Break
• Hands-on, with Sheila M Simmons
• Environmental Health, Safety, and Risk Management
• http//www.uaf.edu/safety/

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Practical Application

• The terms
• Environmental Engineering
• Environmental work
• Often extend to analyzing the workplace
  environment for contaminants
• hence offering opinions on human health
• firms often practice in this area.

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Alphabet Soup

• EPA
• OSHA
• NIOSH
• AIHA
• ACGIH

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Alphabet Soup

• OSHA, Occupational Safety and Health
  Administration
• NIOSH, National Institute of Occupational Safety
  and Health
• AIHA, American Industrial Hygiene Association
• ACGIH, American Conference of Governmental
  Industrial Hygienists.

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OSHA and NIOSH

• Created in 1970s by same act of congress
• MSHA was earlier,
• OSHA
• Law enforcement
• Department of Labor
• NIOSH
• Science
• Center for Disease Control in PHS.

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AIHA and ACGIH

• Industrial hygiene science of workplace health
• AIHA accredits laboratories
• ACGIH produces TLVs
• safe values

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Occupational Standards

• OSHA, PELs
• (CFR, code of federal regulations, on line)
• PELs
• ACGIH, TLVs
• NIOSH, RELs
• DFK, MAKs

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TLVs

• Of the approximately 450 standards
• 15 have human or otherwise well tested
• 25 have some animal testing
• 60 Based on analogy, supposed, or
  traditional.

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OSHA

• OSHA main site OSHA
• 1910 Subpart Z
• 1910.1000
• History of Tables
• ANSI list
• lawsuits

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Contaminant Particulates

• Asbestos
• Quartz
• Dust

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Asbestos is useful

• Asbestos used since ancient times
• Fireproof
• WW II ship building
• Insulation
• 1950s Schools
• Sound proofing,
• Many materials
• Strength of fibers, chemical resistant

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Asbestos kills

• About 10,000 persons die each year from asbestos
  related disease
• 1,000 from mesothelioma
• 4,000 from asbestosis
• 5,000 from lung cancer
• (correlated with cigarette smoking)
• 20 to 40 year latency period
• Airborne fibers, not parent material

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Asbestos is regulated

• OSHA regulates workplace exposures
• EPA regulates schools
• EPA regulates disposal process

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Asbestos Minerals
Insert SiO4

• Asbestos is a commercial term
• Polysilicate minerals

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10 u /-
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Amphiboles
lisa m applebee structure

• Amosite (Mg, Fe)
• Actinolite (Ca, Mg, Fe)
• Anthophyllite (Mg, Fe)
• Crocidolite (Na, Fe, Fe)
• Tremolite (Ca, Mg)

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Serpentine

• Chrysotile (Mg)

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Respiratory Tract

• Anatomy
• Physiology
• Notes on the asbestos diseases

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Asbestosis

• Fibrotic lung disease
• Lungs fill with scar tissue
• restrictive lung disease, stiff
• oxygen transport reduced
• breathing labored

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Gallery

• Boston University School of Public Health
• Breath Taken The Landscape Biography of
  asbestos
• http//www/busph.bu.edu/Gallery

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Normal Lung
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Honeycombing
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Asbesosis
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Asbestos, clubbing of fingers
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Hairdresser, combed from hair
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Mesothelioma

• Cancer of the lining of the abdominal cavity
• Or thoracic cavity
• Fatal

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childhood exposure father worked in plant and
died of asbestosis note tumor on right side,
fills with fluid
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• Mesothelioma is a rare cancer
• 2 deaths per million populations
• But in a study of asbestos insulation workers
  there were 175 deaths from mesothelioma.

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Lung Cancer

• 32 of 41 studies indicated statistically
  significant increase in lung cancer of asbestos
  workers
• Non-smokers were 5-fold higher than non-exposed
• Smoking asbestos workers were much higher 50- to
  90-fold

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Toxicology, Fiber type

• Some studies indicate chrysotile can cause
  mesothelioma
• Most indicate amphiboles, especially crocidolite
• Some authors have concluded amphiboles are 100
  times more potent than chrysotile in inducing
  mesothelioma.

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particle
fiber
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Clearance and fiber size

• Residents of cities breath several hundred grams
  of particles over a lifetime
• Only a few grams at autopsy
• Most are cleared from lung
• Sorting in the airways by aerodynamic diameter
• Thin fibers penetrate much deeper than round
  particles of similar diameter

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Clearance mechanism by location of deposition

• Nasal clearance
• in from of ciliated, by sneezing or blowing
• further back swept down and swallowed
• Tracheobronchial cleared via cilia
• mucociliary escalator
• Alveolar
• macrophage

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Macrophages
Robins pg. 757

• Digest particles
• Carry towards ciliated airway
• Can wind up in lymph nodes and elsewhere
• especially is surface route is overwhelmed

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Macrophage
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Macrophage
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Clearance

• Fibers less than 1 micron cleared half-life of 10
  days
• Fibers longer than 16 micron, half-life over 100
  days
• Maximum fiber length of one macrophage about
  16-17 microns

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Disease vs. fiber length

• Animal studies
• Dust rich in f lt 5 ? less lung cancer
• Dust rich in f gt 5 ? more lung cancer
• Asbestosis associated f gt 2 ?
• Lung cancer f gt 5 ?
• Mesothelioma f gt 10 ?

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Dose-Response

• Measured in fibers per cc
• f/cc
• Usually states longer than 5 u.
• EPA uses structures for some purposes
• but
• Disease incidence is proportional to exposure.

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Dose-Response

• 10 f/cc-yr has been suggests as threshold for
  asbestosis. (0.2 f/cc for 50 years)
• OSHA PELs (over 5 microns)
• 12 f/cc in 1971
• 5 f/cc in 1972
• 2 f/cc in the early 1980s
• 0.2 f/cc in 1986
• Now 0.1 f/cc.

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Dose-Response, Epidemiology

• Lowest dose that produced tumors
• 16 of 19 studies lowest dose was
  gt 10 f/cc yr
• 14 of 19 studies lowest dose was
  gt 20 f/cc yr
• 3 studies lowest dose was lt 10 f/cc yr

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Dose-Response, estimated

• For 1 excess lung cancer / 10,000 ATSDR
• For environmental (24 hrs, 365 days)
• 0.35 f/cc yr (non-smokers)
• For workers (40 hrs, 50 weeks)
• 1.5 f/cc yr
• 0.1 f/cc for 15 yrs
• 0.05 f/cc for 30 yrs
• OSHA uses 1 / 1000 for significance, sometimes.

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ACGIH TLVs

• Amosite 0.5 f/cc, A1
• Chrysotile 2.0 f/cc, A1
• Crocidolite 0.2 f/cc, A1
• Other forms 2.0 f/cc, A1
• (New TLVs do not distinguish fiber type

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Toxicity, Summary

• Airborne asbestos fibers are a significant health
  hazard
• 0.1 f/cc (OSHA PEL) for mixed fiber types is
  reasonable
• Chrysotile is less toxic than amphiboles
• Fibers less than 5 microns long are less toxic
  than fibers over 16 microns

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Microscopy

• PCM phase contrast microscopy
• and more PCM
• NIOSH 7400
• workhorse
• Cheap, done on job
• count all fibers longer than 5 microns
• Does not distinguish asbestos from non-asbestos

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PCM of Fiber Bundle
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Microscopy

• TEM transmission electron microscopy
• can distinguish asbestos fibers and their mineral
  type
• expensive (10-15 times PCM)
• can count small fibers
• Beam of electrons from bottom
• just like PCM

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TEM of virus
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SEM

• Scanning Electron Microscopy
• Shines the electrons in from the top
• Scans
• Shows surface features.

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SEM
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Microscopy

• PLM polarized light microscopy
• can distinguish asbestos from non-asbestos
• not used for air samples
• yields percentage of asbestos fibers in bulk

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• Most minerals are translucent (i.e., if the
  mineral grain is thin enough then the light will
  pass through).
• Analyst examines light that passes through a
  given sample
• It has interacted with the internal structure of
  the mineral grains.
• The light emerges from the sample it has been
  altered due to interactions within the mineral
  grains.
• Each mineral is unique in its composition and/or
  structure so each mineral has a unique affect on
  light when it passes through it.
• Thus interpreting the emergent light allows a
  geologist to identify minerals with great
  accuracy.

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PLM of fibers
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Microscopy

• NIOSH 7400/7402
• uses TEM to determine of asbestos in PCM
• standard method (OSHA hybrid similar)
• EPA Level II
• TEM
• measures small fibers (lt 5 microns) as well as
  larger

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Summary of Microscopes

• PCM, Phase Contrast Microscope
• 400 X, transparent
• PLM, Polarized Light
• 400 X, mineral identification
• Binocular
• 400 X, dissection and gross identification
• TEM
• very powerful, expensive, identification
• SEM
• vivid pictures

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Quartz
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Quartz

• Silicon dioxide (SiO2)
• Occurs in a crystalline or noncrystalline
  (amorphous) form.
• Crystalline silica may be found in more than one
  form (polymorphism).
• The polymorphic forms of crystalline silica are
  alpha quartz, beta quartz, tridymite,
  cristobalite, keatite, coesite, stishovite, and
  moganite
• Some more toxic than others

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Inhalation of Quartz

• silicosis, kills 200 300 each year
• pulmonary tuberculosis (TB), lung cancer, and
  scleroderma.
• A rare multisystem disorder characterized by
  inflammatory, vascular, and fibrotic changes
  usually involving the skin, blood vessels,
  joints, and skeletal muscle

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Silicosis

• Silicosis is similar to asbestosis and emphysema,
  a scarring and hardening of the lungs
• Mediated by auto-immune problems
• Can kill relatively quickly in sensitive
  individuals,
• 2 to 5 years of exposure
• sandblasters (sand no longer used in US.)

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Monitoring Silica

• Particles size
• Crystal structure
• Use special techniques
• XRD Spectrometry
• IR Spectrometry
• Colorimetric Spectrophotometry

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Dust

• Nuisance Dust

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How to collect samples

• Draw known amount of air over a filter.
• Filter traps particles
• Dissolve filter for PCM
• material must permit
• For silica, use cyclone to separate respirable
  particles
• For dust, must weight filter before and after
• Use PVC filter
• More on air volume a little later.

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How about gases

• Hundreds on list(s)
• What are we monitoring
• And Why?

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What Chemical

• Do we know?
• Liquid
• Gas
• Particle

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Chemical Properties

• Major division
• Hydrophobic vs. hydrophilic
• Reactive or
• Flammable
• Explosive
• Other chemicals present

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Process characteristics

• Sudden releases
• Ambient
• History

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Receptor characteristics

• Most highly exposed worker
• All workers
• Area
• Work tasks
• exertions
• clothing

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Exposure route

• Inhalation
• Dermal
• Ingestion

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Air contaminant terms

• Gas
• gas at NTP
• Vapor
• fume
• aerosol
• fog
• smog

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Health Hazards

• Asphyxiation
• Narcosis
• Chronic toxicity
• Acutely toxic

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Once you know where you are going

• Regulations may specify
• Manufactures and suppliers literature
• Industrial hygiene professional(CIH)

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Two main divisions

• Air sampling
• Take a sample and analyze elsewhere
• Direct reading
• real time

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Explosive

• Sampling or Direct?

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Sampling Objective

• Documenting exposures
• Regulation compliance
• Pinpointing sources

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Acute Hazard

• Alarms

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Chronic hazard

• Usually health

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Summary of sampling method criteria

• Sampling Objective
• Physical and chemical characteristics of chemical
• Presence of other chemicals
• Required accuracy and precision
• Regulatory requirements

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Summary of sampling method criteria, cont.

• Portability and ease of operation
• Cost
• Reliability
• Type area, personal, grab, integrated, etc.
• Duration of sampling and program.

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Air sampling devices

• Collect and take to laboratory

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SKC

• SKC

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Breathing zone
6-9
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Sampling Train
Collection device
Air inlet orifice
Flow rate control
Airflow meter
Suction pump
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Grab vs. Integrated

• Vacuum bottles
• Bags
• http//www.skcinc.com/prod/tsb.html

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Integrated

• Absorption
• Adsorption
• Filters
• Cyclones
• Electrostatic
• Inertial
• Impinger
• Elutriators

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Absorption

• Highly soluble and non-reactive
• Reactive
• Similar
• Gas wash
• spiral
• fritted glass
• glass beads

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Gas Washing
http//www.skcinc.com/prod/impinger.html
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Adsorption

• http//www.skcinc.com/abosor.html
• Passive http//www.skcinc.com/passamp.html

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Filters

• http//www.skcinc.com/prod/filters.html (good
  intro)
• Respirable dust and selective filtration
• http//www.skcinc.com/prod/ACyclone.html

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Calibration

• Mass of chemical determined in laboratory

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Primary vs. Secondary

• Secondary
• Gas meters
• Rotameters
• http//www.skcinc.com/prod/frott.html
• Primary
• http//www.skcinc.com/prod/sfflow.html

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Direct Reading

• Colormetric
• Length of stain
• Draeger
• Tubes
• /- 25 is an oft quoted reliability
• Advantages
• cheap
• fast

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Direct Reading, electronic

• Most use Wheatstone Bridge

Variable R
R
M
R
R
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Sensor changes conductivity

• Change with temperature
• LEL/UEL
• Change with gas
• O2, etc.

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Calibration

• Gas supply

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NFPA

• National Fire Protection Association
• Standards setting body
• Flammable Liquid
• Combustible Liquid

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Flash Point

• The flash point is a Temperature.
• It is lowest temperature at which the liquid
  gives off enough vapor to form an ignitable
  mixture with the air above the mixture.
• Determined by closed-cup and a variety of test
  methods.

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Flammable Liquid

• Flammable has flash point below 100 F (37.8 C)

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Combustible Liquid

• Flash point above 100 F.

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Flammable RangeAKA Explosive Range

• LEL, Lower Explosive Limit. Minimum
  concentration of vapors, below which propagation
  of flame does not take place. The mix is too
  lean.
• UEL, Upper Explosive Limit. Maximum
  concentration of vapors, above which propagation
  of flame does not take place. The mix is too
  rich.

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LEL-UEL

• Typically expressed as vapor of atmosphere.
• For many liquids (or gases), the LEL is 6 to 12
  
• Table in book lists some in 1 to 2 range
• Contrast with TLV. Most TLVs are 100s or 1000s
  PPM, while 1 is 10,000 PPM. So if vapor is less
  than TLV, much less than LEL.

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If you dont remember anything else

• Cannot use combustion gas meters to check if low
  oxygen

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Environmental vs. Workplace
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Chemical EPA(mg/m3) OSHA (mg/m3) Carbon
10.4 58 555 monoxide Styrene 1
425 42500 Carbon 0.7 62 8850
disulfide
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MSDS

• Material Safety Data Sheet
• Manufactures and Suppliers of chemicals must
  supply.
• Heres a site, Safety
• Always start with MSDS
• Available
• Simple
• One place
• Dont rely on, dimethylmercury

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Summary

• Must know what you are sampling for
• Why you are sampling
• Must calibrate
• Must keep records
• Talk to the lab.