Aliphatic hydrocarbons toxicity

Fractionation of mycobacteria resulted in the identification of two cellular immunostimulatory components, namely TDM and MDPs. Both are normally found in association with the mycobacterial cell wall. TDM is composed of a molecule of trehalose (a disaccharide consisting of two molecules of a-D-glucose linked via an a 1-1 glycosidic bond), linked to two molecules of my-colic acid (a long-chain aliphatic hydrocarbon-based acid) found almost exclusively in association with mycobacteria. TDM, although retaining its adjuvanticity, is relatively non-toxic. 

Aliphatic hydrocarbons n-hexane, cyclohexane, and n-heptane Aliphatic hydrocarbons are nonpolar. Their solubility in water is virtually nil. They are less dense than water, and thus would be the top layer in a separatory funnel with a water solution. They are obviously poor solvents for polar compounds, but are very good for extracting traces of nonpolar solutes from water solutions. They are highly flammable and have a low toxicity level. 

Stacey NH. 1989. Toxicity of combinations of chlorinated aliphatic hydrocarbons in vitro and in vivo. In Vitro Toxicol 3 137-143. 

Grant, B.F. Endrin toxicity and distribution in freshwater a review. Bull Environ. Contam. Toxicol, 15 (3) 283-290, 1976. Grathwohl, P. Influence of organic matter from soils and sediments from various origins on the sorption of some chlorinated aliphatic hydrocarbons implications on Koc correlations. Environ. Sci. Technol, 24(11) 1687-1693, 1990. 

The cyclic hydrocarbons, such as cyclohexane, act much in the same manner as the aliphatic hydrocarbons. A significant percentage of quantity inhaled may be metabolized to compounds with a lower order of toxicity. The unsaturated cyclic hydrocarbons generally are more irritating than the saturated forms. 

When exposed to mixtures, chemicals in the exposure medium may affect each other s uptake by humans in a manner that is analogous to some of the bioavailability effects outlined here for environmental species. This was, for instance, shown for the neurotoxicity of EPN (O-ethyl-O-4-nitrophenyl phenylphosphono-thionate), which was enhanced by aliphatic hydrocarbons due in part to increased dermal absorption (Abou-Donia et al. 1985). It was also shown that dietary zinc inhibits some aspects of lead toxicity, which could in part be explained by decreasing dietary lead absorption (Cerklewski and Forbes 1976). Other examples of interactions of chemicals at the uptake phase in humans, which may in part be related to bioavailability interactions, are summarized in Table 1.3. 

Exposure to a single PAH compound seldom occurs in situations of relevance to local law enforcement agencies or defense forces. Often, people are exposed to PAHs in combination with other toxicants such as aliphatic hydrocarbons and/or metals (NRC, 2005). Information on toxicity of chemical mixtures, of which PAHs are a constituent, is lacking. Until such studies are undertaken in animal models, it is difficult to establish whether PAHs have an additive or a synergistic effect in determining neurotoxicity. 

The most suitable solvents for the polymerization by metal chloride-based catalysts are aromatic hydrocarbons, especially toluene. This is due to the following reasons i) they are good solvents for both catalyst and polymer, and ii) they interact only weakly with the active species, and therefore do not reduce its activity. Toluene is preferable to benzene from the viewpoint of toxicity. Though aliphatic hydrocarbons (cyclohexane, hexane, etc.) are also useful, their ability to dissolve catalysts and polymers is lower than that of aromatic hydrocarbons. 

A9.6.4.7 The Nordic Council of Ministers issued a report (Pederson et al, 1995) entitled Environmental Hazard Classification, that includes information on data collection and interpretation, as well as a section (5.2.8) entitled QSAR estimates of water solubility and acute aquatic toxicity . This section also discusses the estimation of physicochemical properties, including log Kow For the sake of classification purposes, estimation methods are recommended for prediction of minimum acute aquatic toxicity, for ...neutral, organic, non-reactive and non-ionizable compounds such as alcohols, ketones, ethers, alkyl, and aryl halides, and can also be used for aromatic hydrocarbons, halogenated aromatic and aliphatic hydrocarbons as well as sulphides and disulphides, as cited in an earlier OECD Guidance Document (OECD, 1995). The Nordic document also includes diskettes for a computerized application of some of these methods. 

Modified methylaluminoxanes exhibit much improved storage stability and several are highly soluble in aliphatic hydrocarbons. (Manufacturers of polyethylene prefer to avoid toluene because of toxicity concerns, especially if resins are destined for food contact.) Most importantly, because yields are higher, modified methylaluminoxane formulations are less costly than MAO. However, since modified methylaluminoxanes contain other types of alkylaluminoxanes, they do not match the performance of conventional methylaluminoxane in some single site catalyst systems. Consequently, modified methylaluminoxanes should be considered niche cocatalysts for single site catalysts. 

Di Paolo, T. (1978a). Molecular Connectivity in Quantitative Structure-Activity Relationship Study of Anesthetic and Toxic Activity of Aliphatic Hydrocarbons, Ethers, and Ketones. J.Pharm.ScL, 67, 566-568. 

Eriksson, L., Jonsson, J. and Berglind, R. (1993a). External Validation of a QSAR for the Acute Toxicity of Halogenated Aliphatic Hydrocarbons. Environ.Toxicol.Chem., 12,1185-1191. 

The mechanism of action for diesel fuels is not well characterized due to the complexity of its petroleum hydrocarbon mixture. The presence of additives that improve fuel combustion or prevent microbial growth may contribute to toxicity. Based on research conducted with individual components of diesel fuels, the primary mechanism of action for central nervous system (CNS) depression from diesel fuel is the reversible, physical interaction of the aromatic and aliphatic hydrocarbons with cell membranes. Renal toxicity is possibly attributed to oxidative metabolites of some of the aromatic constituents. Eye and skin injury are attributable to direct irritant action and the high lipid solubility that may dissolve protective skin oils and allow penetration into the skin tissue. The dermal carcinogenesis observed in rodents subjected to chronic dermal exposure to diesel may be attributed to the genotoxic activity of PAHs and the promoting activity of repeated dermal injury. 

Most of the current toxicological information suggests that heptane is, physiologically speaking, more neurotoxic than other aliphatic hydrocarbons such as pentane, hexane, and octane. However, debilitating peripheral neuropathy, such as that seen on chronic exposure to -hexane, has not been observed in animals or humans. Some cases of polyneuritis, observed in the absence of hexane exposure, might be attributed to the presence of heptane in a solvent mixture. No one to date has discerned a true toxic mechanism for heptane. 

Cleaning products are used regularly in most households These include dishwashing detergents, denture cleaners, toilet bowl cleaners, oven cleaners, drain cleaners, wood and metal cleaners and polishes, tub, tile, and shower cleaners, bleach and pool chemicals. Toxic chemicals contained in household cleaners include glycol ethers, aliphatic hydrocarbons, aromatic hydrocarbons, chlorinated hydrocarbons, surfactants, and heavy metals J32l... 

Deodorizers are used in bathrooms, around pets, on carpets and upholstery, and for aesthetic purposes. Toxic chemicals contained in deodorizers include glycol ethers, quaternary ammonium compounds, aromatic and aliphatic hydrocarbons, alcohols, aldehydes, and esters. 1331... 

Most of the chemicals in Table 11.2 target the respiratory system and CNS. Exposures in arts and crafts use are almost always to mixtures of lipophilic and hydrophilic chemicals. When used in areas with poor air circulation (as is often the case in home use) the result can be unexpected acute toxicity. For example, it has been reported that exposure to formaldehyde and terpene hydrocarbons at very low levels unexpectedly produced dyspnea and other lower-lung symptoms in wood workers. The effects could not be attributed to either the formaldehyde or the terpenes alone at low levels of exposure In another example, it was reported that chronic exposure to a combination of very low concentrations of MEK, ethyl acetate, and aliphatic hydrocarbons in a leather adhesive formulation induced unanticipated CNS effects. Some products that are considered by most... 

Particulates are another source of respiratory irritation when inhaled. In urban environments, diesel exhaust particles and fly ash residue from power plant oil combustion are the main contributors of respirable particulates of less than 10 pm diameter (PM 10). These contain mixtures of lipo-philes and hydrophiles including various metals, acid salts, aliphatic hydrocarbons, PAHs, quinones, nitroaromatic hydrocarbons, andaldehydes. 151 Diesel combustion particulates contain large surface areas that can adsorb large quantities of organic compounds and deliver these to respiratory tract tissue. Other inhaled particulates can adhere to lung surfaces and adsorb and bond other vapors that are inhaled, thereby increasing their toxicities. PM2.5 particulates (those with diameters of less than 2.5 pm) that reach the lower respiratory tract as far as the alveoli are more toxic than PM 10 particulates of the same composition. 16 ... 

Noncarcinogenic Effects. These effects are assessed only if the carcinogenic indicator compounds are not detected or are below regulatory criteria. The following petroleum hydrocarbon fractions, minus the carcinogenic indicator compounds, were selected as representing compounds with similar transport properties. Toxicity values for constituents of the fraction or for a similar mixture were selected to represent the toxicity of the fraction. Aromatic and aliphatic hydrocarbons are considered separately and further subdivided on the basis of equivalent carbon number index (EC). This index is equivalent to the retention time of the compounds on a boiling point GC column (non-polar capillary column), normalized to the //-alkanes. Physical and chemical properties of hydrocarbons that are... 

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