Evaluation of the genetic toxicity of middle distillate fuels

Abstract

Petroleum middle distillate (PMD) fuels are mixtures of hydrocarbons that distill between approximately 170-370 degrees C. Commercial products that fall into this category include kerosine, diesel fuel, jet fuel, and home heating oil. These products contain both saturated (paraffins and cycloparaffins) and aromatic species, but because of the boiling range normally contain very small amounts of the 3-6 ring polycyclic aromatic hydrocarbon (PAH) constituents, which are considered to be carcinogenic. Nevertheless, there is evidence of weak tumorigenic activity when these materials are repeatedly applied to mouse skin. In the current studies representative products were tested in two commonly used, short-term assays for genetic toxicity, the Salmonella/mammalian microsome mutagenicity assay and the mouse bone marrow micronucleus test. All samples were inactive in the micronucleus assay, and three were clearly inactive in the Salmonella test. Of the remaining two, one was marginally active in the Salmonella assay, and one was equivocal. The marginally active sample contained detectable levels of PAH due to the use of catalytically cracked materials as blending stocks. The results indicated that PMDs that do not contain cracked material were not mutagenic. Thus they may produce tumors via nongenotoxic processes. Those products that do contain cracked stocks may have sufficient PAH to be mutagenic in the Salmonella assay, and in those cases the PAH might also contribute to tumor formation.

Characterization of the toxicological hazards of hydrocarbon solvents

“…These studies are supported by data from studies of kerosene (American Petroleum Institute 1984a, Blackburn et al 1987, jet fuel Sterner 2011, McKee et al 1994), and diesel fuel (McKee et al 1994). No in vivo studies of the genotoxic potential of C14-C20 aliphatic ( 2% aromatic) hydrocarbon solvents were identified, but there have been both chromosomal aberration studies and micronucleus tests of kerosene (American Petroleum Institute 1984b), jet fuel (American Petroleum Institute 1980a, Mattie and Sterner 2011) and diesel fuel (McKee et al 1994). As all of these tests produced negative results, C14-C20 aliphatic ( 2% aromatic) hydrocarbon solvents are considered to be non-genotoxic.…”

“…In other studies, jet fuel and kerosene have been reported to be inactive when tested in vitro in Salmonella and under in vivo conditions in tests for micronucleus induction in mouse bone marrow (McKee et al 1994). …”

“…Kerosene is not mutagenic when tested under in vitro and in vivo conditions (American Petroleum Institute 1984a, 1984b, Blackburn et al 1986, McKee et al 1994, Vijayalaxmi et al 2006, and similarly, jet fuels were reported as inactive as shown in summarized information published by Sterner (2011) andMcKee et al (1994).…”

“…The only fetal effects in developmental toxicity studies are developmental delays at maternally toxic levels (American Petroleum Institute 1977, 1979a, 1979b, Cooper and Mattie 1996, Jakobsen et al 1986, Schreiner et al 1997, and, based on studies of related substances, there is no evidence of impairment of fertility Sterner 2011, Schreiner et al 1997). These solvents are not active in tests for mutagenic activity (Amoruso et al 2008, Gochet et al 1984, McKee et al 1994, and there are no reports suggesting that they might be carcinogenic. The principal concern for these solvents relates to the potential for some of the Category 3 solvents, in particular those with primarily C9-C11 aliphatic constituents, to cause chronic neurological effects in humans.…”

The Mammalian Toxicological Hazards of Petroleum-Derived Substances

“…10 In Salmonella tests, gas oils may or may not be mutagenic depending on the types and levels of aromatics that they contain 55 ; but the gas oils do not increase frequencies of micronuclei when tested under in vivo conditions. 53 The gas oil streams that do contain specific aromatic constituents at toxicologically relevant levels can also induce skin tumor formation in mouse skin via a genotoxic process. [55][56][57] The gas oil streams that do not contain high levels of PACs can also induce mouse skin tumors; however, these substances are not tumorinitiating agents and appear to act via a promotional process related to repeated skin irritation.…”