Chronic Dermal Studies of Petroleum Streams in Mice

Abstract

The refining processes include, among others, distillation to yield fractions of differing boiling ranges, alkylation to During petroleum refining, a large number of products are genproduce branched-chain saturated hydrocarbons from lowerated which have varying chemical and physical properties. These molecular-weight unsaturated compounds, reforming to proare known in the industry as petroleum streams. In order to charvide aromatic hydrocarbons, catalytic cracking to create acterize their carcinogenic activity, a number of these commercially produced streams were administered to C3H/HeJ mice in more volatile streams from less volatiles ones, hydrotreatchronic dermal bioassays. The bioassays were conducted using one ment to obtain saturated hydrocarbons from unsaturated of two study designs: the first set of test materials was applied for streams, and solvent refining to remove polynuclear aromatic a lifetime and the second set for 24 months. In the lifetime study, hydrocarbons (PNAs) from lubricating base oil streams. The the last mice in the test groups survived for periods of 31 to 32 involvement of the API was preceded by reports of human months. Middle distillates, boiling in the range 115-390ЊC, were cancer, especially scrotal cancer, associated with exposure to found to decrease the lifespan of exposed mice compared to con-''mineral oils' ' (Bell, 1876; Cruickshank and Squire, 1950; trols or streams of higher and lower boiling ranges. These middle Henry, 1946Henry, , 1947 Lione and Denholm, 1959; Volkmann, distillate streams included straight run kerosine, hydrodesulfur-1875; Waterhouse, 1971). Although the most potent of these ized middle distillate, straight run middle distillate, light catalytic mineral oils were derived from coal tar (Kennaway, 1934) cracked distillate, and 90/10% and 70/30% mixtures of the last and shale oil (Leitch, 1922), animal tests (Twort and Twort, two. The middle distillate streams also proved to be active as carcinogens, with tumor incidence ranging from 16 to 67%. Light 1931) confirmed that some petroleum oils were also active. alkylate naphtha, heavy catalytic reformed naphtha, vacuum re-Twort and Twort (1939) identified some of the active comsiduum, and unleaded gasoline did not demonstrate significant pounds in petroleum-derived mineral oils as PNAs of characcarcinogenic potency. Heavy thermal cracked naphtha, heavy cat-teristic molecular weight and structure. Bingham and Horton alytic cracked naphtha, and hydrotreated light naphthenic distil- (1966) demonstrated that processing history is a critical delate were dermal carcinogens of low potency in this study. Admin-terminant of carcinogenic activity in mineral oils and that istration of light catalytic cracked naphtha led to a low incidence those processing steps which might be expected to reduce of very late developing tumors with a mean latency of 118 weeks.or eliminate PNAs also reduced or eliminated carcinogenic Application of the 0.1% solution of catalytic cracked clarified oil activity. Roy et al. (1988) repo...

The cytotoxicity of jet fuel aromatic hydrocarbons and dose-related interleukin-8 release from human epidermal keratinocytes

“…The safety window for each individual hydrocarbon was shown to be narrow, with LD 50 / HNTD ratios mostly within a 5-fold range (Table 2). With rapid dermal absorption and acute toxicity (Broddle et al 1996;Brooke et al 1998) of these compounds, aromatic hydrocarbon components remain a public health concern. Unlike the aliphatic hydrocarbons that are more uniform in structure, the volatile aromatic hydrocarbons have diverse ring and side-chain structures that could significantly, and independently, affect their absorption characteristics and toxicity to the skin.…”

“…Many aromatic hydrocarbons are known carcinogens (Brandt et al 1999;Broddle et al 1996;Freeman et al 1993;Tolbert 1997) with the ability to cause DNA damage (Ingram et al 2000;Rogers et al 2001), immunotoxicity (Harris et al 1997), neurotoxicity (Ritchie et al 2001) and hematopoietosis (Abraham 1996;Hood and Ottley 1985;O'Connor et al 1999). They comprise approximately 18% of the hydrocarbons in jet fuels, second to the aliphatic hydrocarbons (81%) (Committee on Toxicology 1996).…”

Petroleum Mineral Oil Refining and Evaluation of Cancer Hazard

“…The mouse is more sensitive to the development of skin tumors than are other laboratory animal species, (17) and skin cancer is the cancer that has been observed in humans exposed to poorly refined oils. (1,18) The method varies slightly between laboratories, (1,5,14,19) but, in general, 50 mice per dose group are given 2-3 weekly applications of 25-50 µl of undiluted oil on a shaved intrascapular area of the back. Mice are either caged together (approximately 6/cage) or individually housed in wire mesh cages.…”

Effects of JP-8 on Molecular and Histological Parameters Related to Acute Skin Irritation

“…In general, related petroleum middle distillates cause chronic irritation and inflammation with repeated applications (Grasso et al, 1988;Freeman et al, 1990). Petroleum middle distillates have also been shown to increase the incidence of skin cancer in mice treated for 24 months to a lifetime (Freeman et al, 1993;Broddle et al, 1996). Nessel and coworkers (1999) suggest that prolonged irritation is necessary for tumor formation.…”