How does the human body metabolize gasoline?

Question

A Chinese man has been drinking gasoline to relieve his pain for 25 years. How does the human body metabolize gasoline? Also, what are the side-affects to gasoline?

Answer 1

Gasoline toxicity through ingestions seems to be a topic where there's not a great deal of in-depth information available. I don't know how this works for chronic use, as most literature refers to acute scenarios. Either way, orally ingested, 30-50g is said to be toxic to humans while 350g can be fatal.[3].

So...

Gasoline's Constituents

A lot of components that make up gasoline are toxic to humans. This includes for example, benzene, toluene, xylene and butadiene. It's a mixture of more than 500 hydrocarbons and additives made up of:

• 60–70% alkanes (paraffins)
• 25–30% aromatics
• 6–9% alkenes (olefins).[2].

If you really want to know specifics about metabolism of gasoline, you can probably check out how some of the constituents are metabolised (processed) and their effects. This is because different components have varying metabolic pathways.

If you want to check this out, see Reese, et al at http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1520023/pdf/envhper00383-0118.pdf.[3].

Ingestion and Toxicity

Apparently, most reported cases of toxicity from gasoline occur from inhalation or absorption through the skin (intravenous use has also been reported). Even though ingestion is a frequent occurrence, there's not much data on outcomes after oral ingestion.[1],[2]. Gasoline can however be well absorbed through the gastrointestinal tract[2].

The main target organ of gasoline toxicity is the nervous system and at high doses, this effect can cause death within minutes.[3]. However, generally, the primary cause of mortality seems to be related to gasoline's toxicity to the lungs. There are severe effects on the pulmonary system. Other effects of ingestion hasn't been as well documented.[1],[2].

It's suggested that these compounds have a direct effect on lung tissue and disrupts gas exchange and causes fluid buildup in the lungs (pulmonary edema). This in turn causes the oxygen levels in the body to drop (hypoxemia).[2]. There are many other toxic effects on the lungs as well.

Additionally, liver damage, kidney damage, damage to blood cells, gastric ulcers and toxicity in the heart can occur.[2],[3]. Again, this is discussed in Reese, et al.

Hope that helps!

1. Rahman I. Gasoline ingestion: a rare cause of pancytopenia. Am J Med Sci. 2009. 338(5):433-4.
2. Domej W. Successful outcome after intravenous gasoline injection. J Med Toxicol. 2007. 3(4):173-7.
3. Reese, et al. Acute Toxicity of Gasoline and Some Additives. Environmental Health Perspectives. 1993. 115-131.

Answer 2

Just to add an answer to the 'how does the body process gasoline?' portion of the question, the liver and kidney would be doing most of the work of removing the stuff from the system once it was absorbed in the digestive tract.

The liver does most of the processing of toxins and their removal from the blood and would tend to do the most work in removing hydrocarbons from gasoline. It has enzymes that oxygenate toxins (adds oxygens) which make them more soluable in the blood, usually less toxic, and also removable from the body by the liver or the kidney. In the case of gasoline the compounds are likely to be just as toxic.

The kidney works by actively filtering out excess water and mostly water soluable wastes like oxygenated hydrocarbons. Kidney damage occurs when gasoline is ingested in excess. This may be due to the toxicity of the gasoline, but also due to the compounds the liver is producing.

Gasoline will tend to be fat soluable too, so it will leave the system more slowly, even after being processed by the liver (benzene and toluene in gasoline will tend to become phenols which are quite toxic and fat soluable).

http://www.ncbi.nlm.nih.gov/pubmed/3379185

Answer 3

Prolonged exposure to high concentrations of n-hexane (>1,000 ppm) has resulted in decreased sperm count and degenerative changes in the testes of rats but not those of mice. Acute Data: Gasoline: Dermal LD50>5 ml/kg (Rabbit) LC50> 4500 ppm (Rat) Oral LD50= 18.75 ml/kg. (Rat)

Carcinogenicity: Two year inhalation studies of wholly vaporized unleaded gasoline produced increased incidences of kidney tumors in male rats and liver tumors in female mice. Follow-up studies suggest that occurrence of the kidney tumors may be linked to alpha-2-u-globulin nephropathy, and most likely unique to the male rat. Epidemiology data collected from a study of more than 18,000 petroleum marketing and distribution workers showed no increased risk of leukemia, multiple myeloma, or kidney cancer from gasoline exposure. Unleaded gasoline has been identified as a possible carcinogen by IARC.

Because solvent extracts of gasoline exhaust particulates caused skin cancer in laboratory animals, IARC has categorized gasoline engine exhaust as a possible human cancer hazard. Target Organ(s): A two year inhalation study of wholly vaporized unleaded gasoline producednephropathy in male rats, characterized by the accumulation of alpha-2-u- globulin in epithelial cells ofthe proximal tubules, and necrosis and hyperplasia of surrounding cells. Follow-up studies havedemonstrated that these changes are unique to the male rat. Although prolonged exposure to n-hexane, a component of gasoline, has resulted in adverse male reproductive effects in experimental animal studies, no adverse male reproductive effects were found in studies conducted with gasoline.

Developmental: No evidence of developmental toxicity was found in pregnant laboratory animals(rats and mice) exposed to up to 9,000 ppm vapor of unleaded gasoline via inhalation.

All data taken from the Material Safety Data Sheet (MSDS) from Petroleum Products Corp. See this link for more information.