Chromatography Measures Benzene Exposure at Fuel Stations

Petrol is one of the major fuels used around the globe. Many governments around the world are putting regulations and policies in place to reduce the use of petrol and diesel to power our vehicles. There are obvious drivers like reduced use of fossil fuels and a reduction in greenhouse gas emissions ad pollution from cars and lorries.

People who work closely with fuels like petrol have to take precautions on to limit their exposure to the fuel and its vapour. A recent study in Thailand that has been published in the International Journal of Environmental Research and Public Health has investigated the exposure of workers at petrol station to benzene.

Benzene - a risk of leukaemia

Research data suggests a strong link between benzene exposure and leukaemia. The International Agency of research for Cancer classify benzene as a human carcinogen. It is a colourless flammable and volatile liquid that is formed in natural processes as well as its use as a chemical feedstock. Benzene is a constituent of crude oil and thus finds its way into some of the products of crude oil including petrol.

The main way the people get exposed to benzene is by breathing in the vapour. But it can also be absorbed through the skin during contact with petrol - but as it is volatile and evaporates quickly this is a less common pathway. The amount of benzene allowed in petrol has been reduced in some countries to try and limit the workplace exposure and also the environmental exposure from petrol fumes.

Thailand has a high leukaemia incidence

Thailand has been identified as one of forty countries in the world with a relatively high incidence of leukaemia. The Thailand Bureau of epidemiology has reported that in cases of organic solvent toxicity, benzene was the most common causative agent with the incidence of benzene toxicity cases increasing since 1994. The main cause of the increase was identified as occupational exposure among workers in the chemical industry and on petrol forecourts.

Biomarkers of benzene exposure

A research team looked at the possibility of using biomarkers to detect occupational exposure to benzene. It has previously been reported that trans, trans-muconic acid (tt-MA) could be used as biomarkers of benzene exposure. Both of these metabolites can be detected in the urine of workers making it easy to get samples.

The team sampled the urine and took blood samples of workers and analysed the urine for tt-MA and blood samples for benzene. HPLC was used for the analysis of tt-MA and gas chromatography for the analysis of benzene demonstrating the strength and versatility of chromatography as an analytical technique - a point underlined in the article, SFC/SFE 2019:  Pushing the Limits.

The work carried out by the team found that tt-MA functioned well as a biomarker for benzene exposure. They also found that exposure was highest in workers who had least training and who positioned themselves close to the nozzle when refuelling.