Petroleum hydrocarbons chronic effects

In studies of the fate of hydrocarbons in terrestrial animals, considerable attention is directed toward relations between aromatic hydrocarbon metabolism, interactions of metabolites with macromolecules (e.g., DNA), and the formation of neoplastic lesions (] ). A broad perspective exists in studies with marine organisms. In the aquatic forms, exposure to pollutants that are rich in aromatic hydrocarbons, such as petroleum, leads to a wide variety of acute and chronic effects (2J. Attempts to delineate these effects require an understanding of the accumulation of the xenobiotics in tissues and an assessment of metabolite formation and retention. The important additional problem of the interaction of metabolites with genetic materials has not been studied to an appreciable degree in marine life. 

In addition to large oil spills, petroleum hydrocarbons are released into the aquatic environments from natural seeps as well as non-point-source urban runoffs. Acute impacts from massive one-time spills are obvious and substantial. The impacts from small spills and chronic releases are the subject of much speculation and continued research. Clearly, these inputs of petroleum hydrocarbons have the potential for significant environmental impacts, but the effects of chronic low-level discharges can be minimized by the net assimilative capacities of many ecosystems, resulting in little detectable environmental harm. 

Health effects data also are available for some petroleum fractions or process streams that are less heterogeneous. These materials are more representative of the fractions that may partition in the environment and are more useful for assessing health effects of intermediate and chronic exposure to petroleum hydrocarbons. These products are discussed further in Section 6.2. Additional discussion of these and also the more heterogeneous products is presented in Section 6.3. 

Properties Amber liq. taint petroleum hydrocarbon odor sol. < 0.1% in water sp.gr. 0.828 flash pt. 110 F pH 1.70 100% volatile Toxicoiogy Acute overexposure bums to sbn or eyes, respiratory tract initatbn, headaches, dizziness, anesthesia, CNS effects chronic overexposure skin irritation, dermatitis... 

Specific aliphatic and aromatic hydrocarbons found in petroleum products are known to be metabolized via cytochrome P-450 pathways to reactive metabolic intermediates that are thought to cause non-cancer and cancer effects from chronic exposure (e.g., peripheral neuropathy from 2,5-hexadione, a metabolite of hexane, and cancer effects from various intermediary metabolites of benzene and carcinogenic PAHs). There are no known clinical methods to interfere with these mechanisms of action. However, current research programs are studying the basis of how the consumption of cruciferous vegetables may protect... 

The worldwide exploration and shipment of crude oil and petroleum products have led to a number of catastrophic environmental disasters. A wealth of information exists on these events however, long-term consequences are poorly understood. In addition, the processing and utilization of coal and petroleum fuels invariably lead to low levels of pollution in the terrestrial and marine environment by a variety of molecules including polycyclic aromatic hydrocarbons (PAHs). Pollution occurs at different levels which can either be acute or chronic. TTie effects of the latter are the most difficult to discern. 

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