Effects of Exposure to JP-8 in Experimental Animals

This section describes experimental-animal studies that have assessed the neurotoxic potential ofJP-8 and related fuels. The studies are summarized in Table 5-2. 

Baldwin et al. (2001) exposed 6-month-old Fischer 344 rats to room air or JP-8 aerosols alone or to JP-8 and then aerosolized substance P, which has been shown to attenuate the effects of JP-8-induced pulmonary dysfunction and immunotoxicity in animals. Inhalation exposures were nose-only and performed 1 hr/day, 5 days/wk for 28 days. Aerosolized JP-8 with a mass mean aerodynamic diameter (MMAD) of 1.7-1.9 pm (M. Witten, University of Arizona, personal communication, 2002) was administered to the rats at 

Fuel Type Species Exposure Concentration Exposure Duration Effects Reference 

JP-8 (aerosol) F344 rats 1,059 mg/m3 for first 25 days, 2,491 mg/m3 for final 3 days 1 hr/day, 5 days/wk for 28 days Neurologic measures were assessed with functional observation battery exposed rats had significant differences in spontaneous activity and CNS excitability from controls exposed rats exhibited greater velocity of swimming in Morris swimming task Baldwin et al. 2001 

5 days/wk for Animals were evaluated immediately after Koschier 

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Because findings from several studies indicate the potential for adverse health effects from exposure to JP-8 aerosols at concentrations below the interim PEL of 350 mg/m3 and because the JP-8 vapor concentrations tested were approximately 1,000 mg/m3 (that is, less than three times the interim PEL), the subcommittee strongly recommends that a battery of inhalation-toxicity tests in experimental animals be conducted with JP-8 vapors and mixtures of vapors and aerosols. The animal studies should include evalua-... 

The Subcommittee on Permissible Exposure Levels for Military Fuels judged that, on the basis of available data, DOD s PEL of 350 mg/m3 for the fuel vapors is adequate to protect the health of naval personnel exposed to them occupationally (NRC 1996). However, because of uncertainties in the database, the PEL should still be considered interim until further research has been completed. The subcommittee recommended that data be obtained on exposures during operational procedures, including exposure to respirable aerosols of unburned fuels that studies be conducted on the possible effects of high-level acute and low-level chronic exposure to fuel vapors on the central nervous system and that research be conducted on the effect of fuel vapors on hepatotoxicity in experimental animals to help to identify a no-observed-adverse-effect level for JP-8 with greater confidence. 

No studies of humans or experimental animals have been done to assess reproductive performance after exposure to JP-8. There are human data that demonstrate that exposure to jet fuel (mostly JP-4) at below 6 ppm did not affect semen quality for aircraft maintenance personnel (Lemasters et al. 1999b). Ancillary studies in rats and mice (USAF 1978b Mattie et al. 1995) did not suggest an adverse effect on reproductive organs or reproductive performance. The testicular atrophy reported in mice exposed to JP-4 (Bruner et al. 1993) might have been secondary to the debilitating effect of chronic skin disease. 

In this chapter, the subcommittee reviews studies in humans and experimental animals that examined potential respiratory tract effects of jet-propulsion fuel 8 (JP-8), related fuels, and kerosene. The subcommittee uses that information to assess the potential respiratory toxicity of JP-8 in humans. The National Research Council report Permissible Exposure Levels for Selected Military Fuel Vapors (NRC 1996) did not include a review of the effects of JP-8 on the respiratory tract. 

Several investigators have studied the effects of subchronic exposure to military fuel vapors on the liver in experimental animals. No liver histopatho-logical changes were found in three inhalation studies in which animals were exposed intermittently (occupational-type exposure) to fuel vapors. In one study, rats exposed to JP-5 vapors at concentrations of 1,000 or 1,600 mg/m3 for 6 hr per day, 5 days per week for 6 weeks showed no evidence of adverse effects on the liver. In the second study, rats, mice, dogs, and monkeys exposed to JP-4 vapors at 2,500 or 5,000 mg/m3 for 6 hr per day, 5 days per week for 8 months showed no evidence of exposure-related effects except a slight increase in liver weight in the female rats. In the third study, rats and mice exposed to JP-4 vapors at 1,000 or 5,000 mg/m3 for 6 hr per day, 5 days per week for 12 months showed no liver toxicity. N o clear evidence of hepatic neoplasia in rats or mice was found. Based on this study, the subcommittee identified a no-observed-adverse-effect level (NOAEL) of 5,000 mg/m3,... 

This chapter summarizes the findings on potential neurotoxicity from exposure to jet-propulsion fuel 8 (JP-8) presented in the National Research Council report Permissible Exposure levels forSekctedMiUtary Fuel Vapors (NRC 1996) and reviews additional studies, most of which were completed after the 1996 report was published. Since the 1996 report was released, additional epidemiologic studies associated with occupational JP-8 exposure and experimental animal studies examining the neurotoxic potential of kerosene-based jet fuels, including JP-8, and kerosene via the dermal and inhalation routes have been conducted. The subcommittee used the available information on JP-8 to assess the potential for toxic effects of JP-8 on the nervous system in humans. 

In addition to the studies summarized above, experimental-animal studies have been conducted to examine the effects of JP-8 exposure on renal function they are described below and summarized in Table 8-2. 

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