Toxicity and occupational exposure assessment for Fischer-Tropsch synthetic paraffinic kerosene

Abstract

Fischer-Tropsch (FT) Synthetic Paraffinic Kerosene (SPK) jet fuel is a synthetic organic mixture intended to augment petroleum-derived JP-8 jet fuel use by the U.S. armed forces. The FT SPK testing program goal was to develop a comparative toxicity database with petroleum-derived jet fuels that may be used to calculate an occupational exposure limit (OEL). Toxicity investigations included the dermal irritation test (FT vs. JP-8 vs. 50:50 blend), 2 in vitro genotoxicity tests, acute inhalation study, short-term (2-week) inhalation range finder study with measurement of bone marrow micronuclei, 90-day inhalation toxicity, and sensory irritation assay. Dermal irritation was slight to moderate. All genotoxicity studies were negative. An acute inhalation study with F344 rats exposed at 2000 mg/m for 4 hr resulted in no abnormal clinical observations. Based on a 2-week range-finder, F344 rats were exposed for 6 hr per day, 5 days per week, for 90 days to an aerosol-vapor mixture of FT SPK jet fuel (0, 200, 700 or 2000 mg/m). Effects on the nasal cavities were minimal (700 mg/m) to mild (2000 mg/m); only high exposure produced multifocal inflammatory cell infiltration in rat lungs (both genders). The RD (50% respiratory rate depression) value for the sensory irritation assay, calculated to be 10,939 mg/m indicated the FT SPK fuel is less irritating than JP-8. Based upon the proposed use as a 50:50 blend with JP-8, a FT SPK jet fuel OEL is recommended at 200 mg/m vapor and 5 mg/m aerosol, in concurrence with the current JP-8 OEL.

Conventional and Alternative Aviation Fuels: Occupational Exposure and Health Effects

“…Moreover, while not strictly genotoxic, studies showed definitive cellular toxicity when blood plasma was exposed to JP-8 in laboratory tests, instances of premature death, increased malignancy risks and behavioral disturbances, nervous system effects, and a 2- to 5-fold increase in the risk of hearing loss . Additionally, occupational exposure to JP-8 was associated with an increased incidence of miscarriages in female military aircraft personnel; however, the literature review conducted by the particular authors did not reach definitive conclusions regarding the relationship between exposure to aviation fuels or specific constituents and adverse reproductive health outcomes.…”

“…Naphthalene or bicyclic aromatics produce increased soot, smoke, and thermal radiation, making them also less desirable for aviation fuel usage, and desulfurized or ultralow sulfur diesel fuel has now become a requirement under regulations as a means to minimize corrosion on turbine metal parts . However, although it was claimed that biofuels might be genotoxic, most adverse health effects of alternative fuels were the same if not slightly better compared to the toxicological profile of JP-8 and Jet A-1. ,,,, Below, we discuss a few available studies on the toxicity of alternative fuels and comparisons with conventional aviation fuels.…”

“…A review of the potential of SPK to cause dermal irritation found that SPK and JP-8 cause a similar level of skin irritation on rabbits . Also, Fischer–Tropsch (FT) SPK fuel was tested for dermal irritation, inhalation toxicity, sensory irritation, and genotoxicity in an in vitro experimental study to determine occupational exposure limits . To compare irritants, the authors above conducted the following experiments: (a) in one study, they used two groups of three white rabbits dermally exposed to either neat fuel or blends for 4 h, (b) another experiment acutely exposed five rats of each sex to the inhalation limit dose of 2000 mg/m 3 for 4 h, (c) in a third study conducted for 2 weeks, they exposed five rats to 500, 1000, or 2000 mg/m 3 aerosol/vapor concentrations for 6 h/day, 5 days/week, and (d) in the last study, they exposed 10 rats to aerosol/vapor in levels of 200, 700, or 2000 mg/m 3 for 6 h/day, 5 days per week for a total of 65 days .…”

“…Also, Fischer–Tropsch (FT) SPK fuel was tested for dermal irritation, inhalation toxicity, sensory irritation, and genotoxicity in an in vitro experimental study to determine occupational exposure limits . To compare irritants, the authors above conducted the following experiments: (a) in one study, they used two groups of three white rabbits dermally exposed to either neat fuel or blends for 4 h, (b) another experiment acutely exposed five rats of each sex to the inhalation limit dose of 2000 mg/m 3 for 4 h, (c) in a third study conducted for 2 weeks, they exposed five rats to 500, 1000, or 2000 mg/m 3 aerosol/vapor concentrations for 6 h/day, 5 days/week, and (d) in the last study, they exposed 10 rats to aerosol/vapor in levels of 200, 700, or 2000 mg/m 3 for 6 h/day, 5 days per week for a total of 65 days . The results of the tests suggested that FT-SPK is a mild to moderate dermal irritant, not genotoxic, and shows unremarkable acute inhalation toxicity, minimal subchronic effects, and upper airway sensory irritant characteristics, which are similar to JP-8 fuel toxicity data …”

“…On the other hand, concerns over diminishing oil supplies, price increases, and environmental damage due to emissions have prompted research into alternative renewable fuels such as fuel cells, synthetic fuels, which are known as synthesis gas from mixtures of hydrogen and carbon monoxide, and biofuels, which are biological in origin and are generally produced from inedible oils . For example, biofuel is a complex hydrocarbon mixture derived from biomass, and Fischer–Tropsch synthetic paraffinic kerosene (FT-SPK) is a synthetic jet fuel produced from coal, natural gas, or biomass and is intended to augment JP-8 within the US military …”