Toxicologic Assessment of Jet-Propulsion Fuel 8 (2003) / Chapter Skim
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2 Dosimetry and Exposure Assessment of Jet-Propulsion Fuel 8
2 Dosimetry and Exposure Assessment of Jet-Propulsion Fuel 8
Pages 16-28
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From page 16... ...
The chapter begins with a description of various scenarios under which military personnel are exposed to JP-8, followed by a brief discussion of the challenges of quantifying human exposure to this distillate fuel. The next section contains a summary of data from studies that have measured concentrations of several components of JP-8 in ambient air at Air Force aircraft maintenance sites.
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From page 17... ...
Occupational exposure of military and civilian personnel toJP-8 may occur in the following settings (see Table 2-1~: transportation and storage of JP-8 fuel; aircraft fueling and Refueling; maintenance of aircrafts; cold engine starts and performance testing; and operation and maintenance of other Air Force equipment and machinery. Air Force personnel working in aircraft fuel-cell maintenance shops and fuels-specialty and fuels-transportation shops are probably at the greatest risk for exposure to JP-8 (ATSDR 1998; R
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From page 18... ...
Fuel tanks with cross ventilation had much lower concentrations of JP-8 than fuel tanks with poor ventilation. In an Australian study, JP-8 vapor concentrations were found to reach 2,823 mg/m3 inside wet B747 aircraft fuel tanks (Yeung et al.
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From page 19... ...
Fuel tanks with appropriate cross ventilation have much lower interior air concentrations of JP-8. Estimates of Dermal Exposure Skin can be an important route of JP-8 exposure.
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From page 20... ...
The use of surrogate markers representing a few hydrocarbons is at most a qualitative assessment of dermal exposure to JP-8 fuels. MEASUREMENT OF BODY BURDEN OF JP-8 Environmental monitoring of JP-8 is crude and can lead to incorrect information about body burdens ofJP-8 constituents.
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From page 21... ...
The ranges of postexposure values overlapped substantially between exposed and unexposed subjects. It is often difficult to distinguish between exposed and unexposed workers on the basis of the JP-8 fingerprint, and simple division into highly exposed, moderately exposed, and unexposed workers appears to be an inadequate way to correlate adverse health effects withJP-8 body burden.
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From page 22... ...
The data showed that NQ-Ab may be a marker of long-term exposure toJP-8; however, an estimate of exposure over several days is necessary to validate the use of this marker for chronic exposure to JP-8. FACTORS THAT MODIFY INTERNAL DOSE OF JP-8 Dermal Absorption Because JP-8 is a complex mixture of hydrocarbons of widely varying vapor pressure and lipophilicity, uptake by the dermal route is highly affected by the physicochemical properties of the mixture.
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From page 23... ...
However, overall systemic absorption may be greater over long periods of continuous dermal contact because of a persistent dermal retention. Inhalation Exposure Air Force personnel are most likely to be exposed to JP-8 vapors, although mixed vapor and aerosol exposures may occur during aircraft cold starts or specialized situations such as when the fuel is sprayed as a dust suppressant (CDC 1999~.
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From page 24... ...
The sites of respiratory tract deposition willvary depending on aerosol particle size and whether oral or nasal breathing occurs. For example, for an aerosol particle with a mass median aerodynamic diameter of 3 mm, approximately 60% will deposit in the nose and 10-15% in the pulmonary region in a nasal breathing human.
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From page 25... ...
Another method of atmosphere generation involves bubbling air or nitrogen through the fuel and transporting the resulting atmosphere to the exposure chamber. Both of these systems require care to ensure that the final chamber atmosphere does not contain aerosols created by vigorous agitation of the liquid fuel or condensation of the vapors after cooling of the atmosphere.
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From page 26... ...
Because fuel tanks with cross ventilation have much lower concentrations of JP-8 than fuel tanks with poor ventilation, the subcommittee recommends that the Air Force properly cross-ventilate fuel tanks when personnel are working in them. The subcommittee concludes that in addition to inhalation exposure, We potential exists for a substantial contribution to overallJP-8 exposure by the dermal route, including mucous membranes and the eyes, either by contact with vapors and aerosols or by direct skin contact win JP-8.
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From page 27... ...
2001. Chemical composition of aerosol from kerosene heaters burning jet fuels.
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From page 28... ...
1 9 97. S afe working in aircraft fuel tanks: An Australian experience.
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