Occupational Exposure to Carbon Nanotubes and Nanofibers

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Table A–4. Benchmark dose estimates * and associated human working lifetime airborne concentrations—dichotomous responsedata in rats or mice exposed to SWCNT by intratracheal instillation (dose metric: administered lung dose)Rodent HumanHuman working lifetimeairborne concentration(µg/m 3 ) †Rodent study, CNT type, and responseBMD ‡, §(µg/lung)BMDL(µg/lung)BMD(mg/lung)BMDL(mg/lung) BMC BMCLLam et al. [2004]— SWCNT (2% Fe)Granuloma (at 90 d) in mice45 7.6 84 14 10 1.7* Benchmark response level—10% excess (added) risk in exposed animal [US EPA 2010].† 8-hr time weighted average (TWA) concentration associated with the human-equivalent BMD(L)s. BMC: maximum likelihood estimate of the benchmark concentration.BMCL: 95% lower confidence limit of BMC.‡ BMD: estimated benchmark dose (maximum likelihood estimate). BMDL: estimated 95% lower confidence limit of the BMD; multistage (polynomial degree 2) model[US EPA 2010].§ P value: 1.0112 NIOSH CIB 65 • Carbon Nanotubes and Nanofibers
Table A–5. Benchmark dose estimates and associated working lifetime airborne concentrations—grade 1 or higher severity oflung responses in rats after subchronic inhalation of MWCNT (dose metric: estimated deposited or retained dose in lungs)Human working lifetimeairborne concentration ‡(µg/m 3 )Rodent HumanBMD †BMDLBMDRodent study and response * (µg/lung) (µg/lung) (mg/lung)BMDL(mg/lung) BMC BMCLDeposited lung dose (assuming no clearance)Ma-Hock et al. [2009]Granulomatous inflammation21 8.1 5.4 2.1 0.51 0.19Pauluhn [2010a]Alveolar septal thickening28 14 7.2 3.5 0.77 0.38Retained lung dose (assuming normal clearance)Ma-Hock et al. [2009]Granulomatous inflammation11 3.8 2.7 0.97 2.7 1.0Pauluhn [2010a]Alveolar septal thickening14 6.5 3.6 1.7 4.2 1.9* Histopathology grade 1 (minimal) or higher severity. Benchmark response level—10% excess (added) risk in exposed animals.† BMD: estimated benchmark dose (maximum likelihood estimate). BMDL: estimated 95% lower confidence limit of the BMD; multistage (polynomial degree 2) [US EPA2010]. P values for the rodent dose-response models: 0.99 for Ma-Hock et al. [2009] and 0.88 for Pauluhn et al. [2010a] (deposited dose); 1.0 for Ma-Hock et al. [2009]and 0.94 for Pauluhn [2010a] (retained dose).‡ 8-hr time weighted average (TWA) concentration associated with the human-equivalent BMD(L)s. BMC: maximum likelihood estimate of the benchmark concentration;BMCL: 95% lower confidence limit of the BMC.NIOSH CIB 65 • Carbon Nanotubes and Nanofibers113
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CURRENT INTELLIGENCE BULLETIN 65Occ
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Current Intelligence Bulletin 65Occ
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ForewordThe Occupational Safety and
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Executive SummaryOverviewCarbon nan
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2009; Pauluhn 2010a; Porter et al.
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neurogenic sig nals from sensory ir
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possible. Until the results from an
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••Follow exposure and hazard as
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Periodic Evaluations••Evaluatio
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ContentsForeword ..................
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A.3.2 Comparison of Short-term and
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ESPFeFMPSFPSSgGMGSDHCLHECHEPAhrISOI
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AcknowledgementsThis Current Intell
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1 IntroductionMany nanomaterial-bas
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2 Potential for ExposureThe novel a
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CNMs, with MWCNT agglomerates obser
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composite materials with local exha
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information on air contaminants. Sa
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3 Evidence for Potential Adverse He
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decreasing agglomerate size increas
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examined up to 60 days post-exposur
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3.3 SWCNT and MWCNTIntraperitoneal
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The same potency sequence was obser
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Table 3-3. Findings from published
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Table 3-7 (Continued). Findings fro
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length, respectively) [Muller et al
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5 CNT Risk Assessment and Recommend
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A-6). Risk estimates derived from o
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Table 5-4. Factors, assumptions, an
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and analytical methods. NIOSH is re
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Table 5-5. Recommended occupational
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deficits in animals or clinically s
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(3) Rat lung dose estimationIn the
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tasks where worker exposures exceed
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As part of the evaluation of worker
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Table 6-1. EC LODs and LOQs for 25-
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6.2 Engineering ControlsOne of the
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Table 6-6 (Continued). Examples of
Page 88 and 89: Table 6-7 (Continued). Engineering
Page 90 and 91: exposure estimates for SWCNT on ind
Page 92 and 93: Table 6-8. Respiratory protection f
Page 94 and 95: ••Workers in areas or in jobs w
Page 97 and 98: 7 Research NeedsAdditional data and
Page 99 and 100: ReferencesACGIH [1984]. Particle si
Page 101 and 102: Bolton RE, Vincent HJ, Jones AD, Ad
Page 103 and 104: eport issued on July 22, 2011. NEDO
Page 105 and 106: Kobayashi N, Naya M, Mizuno K, Yama
Page 107 and 108: Methner M, Hodson L, Geraci C [2010
Page 109 and 110: Human Services, Centers for Disease
Page 111 and 112: Piegorsch WW, Bailer AF [2005]. Qua
Page 113 and 114: AD, Baron PA [2003]. Exposure to ca
Page 115: Varga C, Szendi K [2010]. Carbon na
Page 119 and 120: ContentsA.1 Introduction ..........
Page 121 and 122: A.1 IntroductionThe increasing prod
Page 123 and 124: provide an informal check on the es
Page 125 and 126: these same dose groups; this effect
Page 127 and 128: Table A-1. Rodent study information
Page 129 and 130: the deposited (no clearance) and th
Page 131 and 132: The other BMDS models failed to con
Page 133 and 134: Figure A-2. Benchmark dose model (m
Page 135 and 136: Figure A-3 (continued). Benchmark d
Page 137: Table A-3. Benchmark dose estimates
Page 141 and 142: histopathology grade 2 or higher lu
Page 143 and 144: Table A-8. Working lifetime percent
Page 145 and 146: developing early-stage adverse lung
Page 147 and 148: Figure A-4. Dose-response relations
Page 149 and 150: cell surface area). However, the wo
Page 151 and 152: purified or unpurified (with differ
Page 153 and 154: Table A-9. Comparison of rat or hum
Page 155 and 156: A.6.1.3 Pulmonary Ventilation RateT
Page 157 and 158: used as the effect levels in evalua
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Page 161 and 162: or overloading, of particle clearan
Page 163 and 164: Table A-13. Human-equivalent retain
Page 165 and 166: A.7.1 Particle CharacteristicsBoth
Page 167 and 168: and density. The following MMAD and
Page 169: Table A-15. CNT lung dose normalize
Page 172 and 173: B.1 Key Terms Related toMedical Sur
Page 175 and 176: APPENDIX CNIOSH Method 5040
Page 177 and 178: filter. In the method evaluation, d
Page 179 and 180: Most of the studies on sampling art
Page 181 and 182: e analyzed to determine the onset o
Page 184: Delivering on the Nation’s promis
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