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FIBERS AND CLEAVAGE FRAGMENTS
COMMENTS PERTINENT TO THE NIOSH DOCUMENT “ASBESTOS AND OTHER MINERAL FIBERS:A ROADMAP FOR
SCIENTIFIC RESEARCH”
GRAHAM WILLIAM GIBBS MSc PhD MRSC ROHSafety Health Environment International Consultants Corp.
Suite 101, 38, Athabasca Avenue,Devon, Alberta, Canada
GRAHAM W. GIBBSGRAHAM W. GIBBS
President Safety Health Environment International President Safety Health Environment International Consultants Corp.Consultants Corp.Adjunct Full Professor at University of Alberta.Adjunct Full Professor at University of Alberta.BScBSc Chemistry and Geology (London)Chemistry and Geology (London)MScMSc Geological Sciences (McGill)Geological Sciences (McGill)PhD Epidemiology (McGill)PhD Epidemiology (McGill)ROH Occupational HygieneROH Occupational HygieneMRSC (Member Royal Society of Chemistry).MRSC (Member Royal Society of Chemistry).
OCCUPATIONAL HYGIENE OCCUPATIONAL HYGIENE AND EPIDEMIOLOGYAND EPIDEMIOLOGY
RESEARCHRESEARCH-- ASBESTOSASBESTOS-- FIBERSFIBERS-- OCCUPATIONAL OCCUPATIONAL CANCERCANCER
-- OCCUPATIONAL OCCUPATIONAL DISEASESDISEASES
PURPOSE OF PRESENTATIONPURPOSE OF PRESENTATION
1.1. Share results of the study:Share results of the study:
““An evaluation of the Risks of Lung Cancer and An evaluation of the Risks of Lung Cancer and MesotheliomaMesothelioma from Exposure to Amphibole Cleavage from Exposure to Amphibole Cleavage FragmentsFragments””
by John F Gamble (IERF) and Graham W Gibbs by John F Gamble (IERF) and Graham W Gibbs (SHEI). (The paper is currently in press).(SHEI). (The paper is currently in press).
2.2. Comment on the Comment on the mesotheliomamesothelioma in Minnesota.in Minnesota.
APPROACHAPPROACH
Compare the lung cancer and Compare the lung cancer and mesotheliomamesotheliomaexperience of workers exposed to cleavage experience of workers exposed to cleavage fragments with experience of workers exposed fragments with experience of workers exposed to to asbestiformasbestiform equivalents.equivalents.
Workers Workers exposedexposed to amphibole cleavage to amphibole cleavage fragments.fragments.
Epidemiological studies have been conducted:Epidemiological studies have been conducted:
-- Gold mine South Dakota Gold mine South Dakota ((GruneriteGrunerite--cummingtonitecummingtonite exposure)exposure)
-- Taconite mines in Minnesota Taconite mines in Minnesota ((GruneriteGrunerite and and other nonother non--asbestiformasbestiform amphiboles)amphiboles)
Workers Workers exposedexposed to amphibole cleavage to amphibole cleavage fragments.fragments.
-- Talc mine in St Lawrence County, New York Talc mine in St Lawrence County, New York State (transition minerals, nonState (transition minerals, non--asbestiformasbestiformanthophylliteanthophyllite and and tremolitetremolite). ).
Workers exposed to Workers exposed to asbestiformasbestiformamphibolesamphiboles
AmositeAmosite asbestos mines, mills and asbestos mines, mills and manufacturing facilitiesmanufacturing facilities
Workers exposed to Workers exposed to asbestiformasbestiformamphibolesamphiboles
AnthophylliteAnthophyllite asbestos mines and millsasbestos mines and mills
AsbestiformAsbestiform TremoliteTremolite* in vermiculite mines * in vermiculite mines
**TremoliteTremolite term is used as this term has been used in term is used as this term has been used in medical literature concerning this facility to describe medical literature concerning this facility to describe amphibole fiber exposures. Amphiboles in the mine amphibole fiber exposures. Amphiboles in the mine appear to include appear to include tremolitetremolite, , winchitewinchite and and richteriterichterite..
C1 C2 C3 . .. UG AG , ' A1 A2 A3 A4
SMR
s (9
5% c
onfid
ence
inte
rval
s) fo
r lun
g ca
ncer
and
% fo
r mes
othe
liom
a
0
1
2
3
4
5
6
7
lung cancer SMRs% m eso (n cases/total deaths = PMR) No effect level for lung cancer (SMR=1)% m esotheliom a, asbestos cohortslung cancer SMRs, Asbestos cohorts
C1 = Steenland and Brown (1996)C2 = Higgins et al (1983)C3 = Cooper et al (1992)
UG, AG = underground and aboveground Hem atite (Lawler et al (1985)
A1 = Acheson et al (1984, am osite insulation m fgA2 = Seidm an et al (1986) am osite insulation factoryA3 = Lev in et al (1998) am osite insulation pipe m fg plantA4 = Sluis-Crem er et al (1992) chrysotile/am osite insulation
Nonasbestiformgrunerite
Hematite(no amphiboles)
Am osite (asbestiform grunerite)cohorts
Homestakegold mine
Taconite
Cumulative Exposure in fibers/cc-years
0 50 100 150 200 250 300
Stan
dard
ized
mor
talit
y ra
tio (S
MR
)
0
2
4
6
8
10
12
Hom estake Cohort (Steenland, 1995) Seidm an Am osite AsbestosNo increased risk (SMR=1.0)f/m l-yrs vs Hom estake pneum oconiosis
Am osite Insulationworkers
Seidman et al (1986)Hom estake Non-asbestiform grunerite
(Steenland and Brown, 1995)
lung cancer
pneumoconiosis
lung cancer
Cumulative Exposure (mg/m3-years)Original units in mg/m3-days converted to yrs dividing by 250 d/yr
0 10 20 30 40 50
Rel
ativ
e R
isk
(95%
con
fiden
ce in
terv
als)
0
1
2
3
4
5
6
7
8
9
10
11
12
Lung Cancer Other NMRD Fibrosis Increased risk >1.0, decreased risk <1.0
Lung Fibrosis
Other NMRD
Lung Cancer
FIGURE 3Exposure-response of lung cancer, other non-malignant respiratorydisease (other NMRD) and lung fibrosis by cumulative exposure (mg/m3-years)Honda et al (2002)
Cumulative Exposure = fibers/ml-years
0 100 200 300 400 500 600
Rel
ativ
e R
isk
(SM
R o
r OR
)
-1
0
1
2
3
4
5
6
7
8
9
10
lung cancer SMRs-SCpneumoconiosis regression-Libby Lung Cancer regression analysis-LibbyMesothelioma regression analysis-LibbyIncreased Risk >1 above line, reduced risk <1 bLC SMR by exposure category Libby 1986
Lung CancerLibby
Pneumoconiosis
Mesothelioma
lung cancerS.C
Cumulative Exposure (mg/m3-years)
0 200 400 600 800 1000
Odd
s R
atio
s
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
2.0
2.2
2.4
2.6
Lung Cancer NMRD regression pneumoconiosis regressionOR <1.0 = no effect
Lung Cancer
NMRD
Pneumoconiosis
ExposureExposure--response trends for lung cancerresponse trends for lung cancerNonNon--malignant respiratory disease (NMRD) and malignant respiratory disease (NMRD) and
Pneumoconiosis by cumulative exposure (mg/m3Pneumoconiosis by cumulative exposure (mg/m3--years)years)To Talc not containing amphibolesTo Talc not containing amphiboles
Among French/Austrian Talc WorkersAmong French/Austrian Talc WorkersWild et al (2002)Wild et al (2002)
Lung cancer and Lung cancer and mesotheliomamesothelioma mortality in workers exposed to mortality in workers exposed to Talc containing Talc containing nonasbestiformnonasbestiform amphiboles in New York and Norwayamphiboles in New York and Norway
(Honda et al, 2002; (Honda et al, 2002; WergelandWergeland et al (1990)et al (1990)Talc without amphiboles (Vermont, Italy, France/Austria)Talc without amphiboles (Vermont, Italy, France/Austria)SelevanSelevan et al (1979), et al (1979), CoggiolaCoggiola et al (2003), Wild et al, (2002)et al (2003), Wild et al, (2002)
andandVermiculite containing Vermiculite containing tremolitetremolite asbestos (McDonald et al (1986asbestos (McDonald et al (1986
Anthophyllite Asbestos (Karjalainen et al, 1994;Meurman et al, 1Anthophyllite Asbestos (Karjalainen et al, 1994;Meurman et al, 1994)994)
GTC Norway Vermont Italy FranceAustria S.C. MN Finland
SM
R (9
5% c
onfid
ence
inte
rval
) for
lung
can
cer
PM
R (%
) for
mes
othe
liom
a
0
1
2
3
4
5
Lung Cancer SMRs
PMRs for mesothelioma
Talc amphibole cleavage
fragments
Talcwithout amphiboles
Tremolite asbestosanthophyllite asbestos
COMPARISON GRUNERITE (ASBESTOS) (Mining SA, COMPARISON GRUNERITE (ASBESTOS) (Mining SA, Manufacturing UK, US, US)VS NONManufacturing UK, US, US)VS NON--ASBESTIFORM ASBESTIFORM
EXPERIENCE. (EXPERIENCE. (HomestakeHomestake, Reserve, Erie), Reserve, Erie)
PopulationPopulation No in cohortNo in cohort% Dead% Dead
No. No. MesoMeso%%
SMRSMR--LUNG LUNG CANCERCANCER
AsbestiformAsbestiformgruneritegrunerite ((AmositeAmosite))
9607 (18.7%)9607 (18.7%) 21/1796=1.2%21/1796=1.2% 224/81=2.77224/81=2.77
NonNon--AsbestiformAsbestiformgruneritegrunerite
12510 (23.2%)12510 (23.2%) 0 /2907 = 00 /2907 = 0 192/2119=0.91192/2119=0.91
Comparison NonComparison Non--AsbestiformAsbestiform GruneriteGrunerite ((SteenlandSteenland & Brown & Brown 1995) 1995) –– AsbestiformAsbestiform GruneriteGrunerite ((SeidmanSeidman et al 1986) (Assumes 1 et al 1986) (Assumes 1
MPPCF= 0.146 f/mlMPPCF= 0.146 f/ml
f/mlf/ml--yrsyrs
<4.8<4.8
<6<6
4.84.8--19.519.5
66--11.911.9
19.519.5--29.229.2
1212--24.924.9
>29.>29.
2525--44.944.9 5050--99.999.9 100100--149.9149.9
150150--249.0249.0 250+250+
SMRNSMRNonAsbonAsb
1.171.17 1.011.01 0.970.97 1.311.31
SMRAsSMRAsbb
2.642.64 4.154.15 4.424.42 4.424.42 7.147.14 6.046.04 9.099.09 11.711.7
MINNESOTA MINNESOTA --TACONITETACONITE
EXCESS OF MESOTHELIOMAEXCESS OF MESOTHELIOMALINKED TO MINING?LINKED TO MINING?
NEEDS: WELL CONDUCTEDNEEDS: WELL CONDUCTEDEPIDEMIOLOGICAL STUDY OFEPIDEMIOLOGICAL STUDY OFMESOTHELIOMA WITH APPROPRIATEMESOTHELIOMA WITH APPROPRIATECONTROLS AND TISSUECONTROLS AND TISSUEANALYSES.ANALYSES.
COMMENTS & THOUGHTSCOMMENTS & THOUGHTSThoracic fraction?Thoracic fraction?-- CautionCaution--EpidemiologyEpidemiology--Conversion?Conversion?-- Already the current Already the current fibrefibre counting ignores effect of counting ignores effect of diameters (diameters (EgEg: more : more amositeamosite fibers; Fewer fibers; Fewer crocidolitecrocidolitefibers seen). Validity of fiber exposure and risk fibers seen). Validity of fiber exposure and risk comparisons?comparisons?
Need method to distinguish cleavage fragments from Need method to distinguish cleavage fragments from real fibers.real fibers.-- Consider Aerosol spectrometer Consider Aerosol spectrometer -- TimbrellTimbrell-- Consider magnetic alignment Consider magnetic alignment –– TimbrellTimbrell-- Horizontal Horizontal eleutriationeleutriation –– separates diametersseparates diameters-- NanoNano--technology surface expertise?technology surface expertise?