airborne contaminants lab
Post on 02-Jan-2016
Embed Size (px)
DESCRIPTIONAirborne Contaminants Lab. Topics. Overview of workplace health and its regulation Particulates and microscopy Gases and vapors Monitoring Real time Noise. Format. Lecture with break Break Hands-on. Practical Application. The terms “Environmental Engineering” “Environmental work - PowerPoint PPT Presentation
Airborne Contaminants Lab
TopicsOverview of workplace health and its regulationParticulates and microscopyGases and vaporsMonitoringReal timeNoise
FormatLecture with breakBreakHands-on
Practical ApplicationThe termsEnvironmental Engineering Environmental workOften extend to analyzing the workplace environment for contaminantshence offering opinions on human healthfirms often practice in this area.
Alphabet SoupOSHA, Occupational Safety and Health AdministrationNIOSH, National Institute of Occupational Safety and HealthAIHA, American Industrial Hygiene AssociationACGIH, American Conference of Governmental Industrial Hygienists.
OSHA and NIOSHCreated in 1970s by same act of congressMSHA was earlier, OSHALaw enforcementDepartment of LaborNIOSHScienceCenter for Disease Control in PHS.
AIHA and ACGIHIndustrial hygiene = science of workplace healthAIHA accredits laboratoriesACGIH produces TLVssafe values
Occupational StandardsOSHA, PELs(CFR , Code of Federal Regulations, on line) PELs ACGIH, TLVsNIOSH, RELsDFK, MAKs
TLVsOf the approximately 450 standards15% have human or otherwise well tested25% have some animal testing60% Based on analogy, supposed, or traditional.
OSHAOSHA main site OSHA 1910 Subpart Z1910.1000History of TablesANSI listlawsuits
Asbestos is usefulAsbestos used since ancient timesFireproofWW II ship buildingInsulation1950s SchoolsSound proofing, Many materialsStrength of fibers, chemical resistant
Asbestos killsAbout 10,000 persons die each year from asbestos related disease1,000 from mesothelioma4,000 from asbestosis5,000 from lung cancer(correlated with cigarette smoking)20 to 40 year latency periodAirborne fibers, not parent material
Asbestos is regulatedOSHA regulates workplace exposuresEPA regulates schoolsEPA regulates disposal process
Asbestos MineralsAsbestos is a commercial termPolysilicate minerals
10 u +/-
AmphibolesAmosite (Mg, Fe)Actinolite (Ca, Mg, Fe)Anthophyllite (Mg, Fe)Crocidolite (Na, Fe+++, Fe++)Tremolite (Ca, Mg)
lisa m applebee:structure
Respiratory TractAnatomyPhysiologyNotes on the asbestos diseases
AsbestosisFibrotic lung diseaseLungs fill with scar tissuerestrictive lung disease, stiffoxygen transport reducedbreathing labored
GalleryBoston University School of Public HealthBreath Taken: The Landscape & Biography of asbestoshttp://www/busph.bu.edu/Gallery
Asbestos, clubbing of fingers
Hairdresser, combed from hair
MesotheliomaCancer of the lining of the abdominal cavityOr thoracic cavityFatal
childhood exposure father worked in plant and died of asbestosis note tumor on right side, fills with fluid
Mesothelioma is a rare cancer 2 deaths per million populations But in a study of asbestos insulation workers there were 175 deaths from mesothelioma.
Lung Cancer32 of 41 studies indicated statistically significant increase in lung cancer of asbestos workersNon-smokers were 5-fold higher than non-exposedSmoking asbestos workers were much higher 50- to 90-fold
Toxicology, Fiber typeSome studies indicate chrysotile can cause mesotheliomaMost indicate amphiboles, especially crocidoliteSome authors have concluded amphiboles are 100 times more potent than chrysotile in inducing mesothelioma.
Clearance and fiber sizeResidents of cities breath several hundred grams of particles over a lifetimeOnly a few grams at autopsyMost are cleared from lungSorting in the airways by aerodynamic diameterThin fibers penetrate much deeper than round particles of similar diameter
Clearance mechanism by location of depositionNasal clearance: in from of ciliated, by sneezing or blowingfurther back swept down and swallowedTracheobronchial: cleared via ciliamucociliary escalatorAlveolarmacrophage
MacrophagesDigest particlesCarry towards ciliated airwayCan wind up in lymph nodes and elsewhereespecially is surface route is overwhelmedRobins pg. 757
Clearance Fibers less than 1 micron cleared half-life of 10 daysFibers longer than 16 micron, half-life over 100 daysMaximum fiber length of one macrophage about 16-17 microns
Disease vs. fiber lengthAnimal studies Dust rich in f < 5 less lung cancerDust rich in f > 5 more lung cancerAsbestosis associated f > 2 Lung cancer f > 5 Mesothelioma f > 10
Dose-ResponseMeasured in fibers per ccf/ccUsually states longer than 5 u.EPA uses structures for some purposesbutDisease incidence is proportional to exposure.
Dose-Response10 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 19715 f/cc in 19722 f/cc in the early 1980s 0.2 f/cc in 1986 Now 0.1 f/cc.
Dose-Response, EpidemiologyLowest dose that produced tumors16 of 19 studies lowest dose was > 10 f/cc yr14 of 19 studies lowest dose was > 20 f/cc yr3 studies lowest dose was < 10 f/cc yr
Dose-Response, estimatedFor 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 yr0.1 f/cc for 15 yrs0.05 f/cc for 30 yrsOSHA uses 1 / 1000 for significance, sometimes.
ACGIH TLVsAmosite0.5 f/cc, A1Chrysotile2.0 f/cc, A1Crocidolite0.2 f/cc, A1Other forms2.0 f/cc, A1(New TLVs do not distinguish fiber type)
Toxicity, SummaryAirborne asbestos fibers are a significant health hazard0.1 f/cc (OSHA PEL) for mixed fiber types is reasonableChrysotile is less toxic than amphibolesFibers less than 5 microns long are less toxic than fibers over 16 microns
MicroscopyPCM Phase Contrast Microscopyand more PCMNIOSH 7400 workhorse Cheap, done on jobcount all fibers longer than 5 micronsDoes not distinguish asbestos from non-asbestos
PCM of Fiber Bundle
MicroscopyTEM transmission electron microscopycan distinguish asbestos fibers and their mineral typeexpensive (10-15 times PCM)can count small fibersBeam of electrons from bottomjust like PCM
TEM of virus
SEMScanning Electron MicroscopyShines the electrons in from the topScansShows surface features.
MicroscopyPLM polarized light microscopycan distinguish asbestos from non-asbestosnot used for air samplesyields percentage of asbestos fibers in bulk
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 sampleIt 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.
PLM of fibers
MicroscopyNIOSH 7400/7402uses TEM to determine % of asbestos in PCMstandard method (OSHA hybrid similar)EPA Level IITEMmeasures small fibers (< 5 microns) as well as larger
Summary of MicroscopesPCM, Phase Contrast Microscope400 X, transparentPLM, Polarized Light400 X, mineral identificationBinocular400 X, dissection and gross identificationTEMvery powerful, expensive, identificationSEMvivid pictures
QuartzSilicon 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 moganiteSome more toxic than others
Inhalation of Quartzsilicosis, kills 200 300 each yearpulmonary 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
SilicosisSilicosis is similar to asbestosis and emphysema, a scarring and hardening of the lungsMediated by auto-immune problemsCan kill relatively quickly in sensitive individuals, 2 to 5 years of exposuresandblasters (sand no longer used in US.)
Monitoring SilicaParticles sizeCrystal structure Use special techniquesXRD Spectrometry IR Spectrometry Colorimetric Spectrophotometry
How to collect samplesDraw known amount of air over a filter.Filter traps particlesDissolve filter for PCMmaterial must permit For silica, use cyclone to separate respirable particlesFor dust, must weight filter before and afterUse PVC filterMore on air volume a little later.
How about gasesHundreds on list(s)What are we monitoringAnd Why?
What ChemicalDo we know?LiquidGasParticle
Chemical PropertiesMajor divisionHydrophobic vs. hydrophilicReactive or FlammableExplosiveOther chemicals present
Process characteristicsSudden releasesAmbientHistory
Receptor characteristicsMost highly exposed workerAll workersAreaWork tasksexertionsclothing