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Benzene in flavoured drinks

Most people are exposed to a small amount of benzene on a daily basis including in some beverages. Benzene is thought to be carcinogenic if people are exposed to it daily in high levels over many years.

Why benzene is found in some beverages

Benzene can be formed at very low levels in beverages that contain both ascorbic acid (vitamin C) and sodium benzoate (a preservative). The reaction between the ascorbic acid and sodium benzoate in beverages can create a very small amount of benzene.

Both vitamin C and sodium benzoate are regulated chemicals permitted in food. Sodium benzoate (additive number 211) is added to reduce the activity of pathogens (harmful bacteria) and extend the shelf life of the product. Vitamin C (additive 300) occurs naturally in fruit and fruit juices and is used as an antioxidant or vitamin. Use of these additives is specified in the products ingredient list.

Testing for benzene in non-alcoholic drinks

Independent testing of non-alcoholic beverages in several countries found that levels of benzene were occasionally up to five times higher than World Health Organization (WHO) guidelines for water quality. Quality drinking water should have less than 10 parts of benzene per billion parts of water (ppb), or 10 micrograms (10 μg) per litre. This is also the mandatory standard for New Zealand drinking water. 

Food Standards Australia New Zealand (FSANZ) undertook an investigation in 2006 to determine levels of benzene in a range of non-alcoholic drinks sold in New Zealand and Australia.

FSANZ sampled 68 flavoured beverages in March/April 2006. These were purchased from typical retail outlets and analysed for benzene by a qualified independent laboratory. The survey targeted flavoured beverages most likely to have benzene formation and included:

• cola and non cola soft drinks

• flavoured mineral waters

• cordial

• fruit juice

• fruit drinks

• energy drinks

• flavoured/sports water.

In the results, most of the samples had levels of benzene below the WHO guidelines recommended for drinking water (10 μg). Five samples (7%) had levels of benzene higher than 10 μg per litre. The levels detected ranged up to 40 μg per litre.

What is benzene and what is it used for?

Benzene (C₆H₆) is a colourless and flammable liquid hydrocarbon with a pleasant, sweet smell. It is a closed hexagon shape made up of six carbon atoms with arms of hydrogen. It is often drawn as a hexagon with a circle inside it.

Benzene is found in nature and also synthetically produced for industry. It is used to manufacture some types of:

• plastics

• resins

• nylon and synthetic fibres

• rubbers

• lubricants

• dyes

• detergents

• drugs

• pesticides.

Natural production of benzene comes from volcanoes and forest fires. It is also produced by combustion of crude oil and gasoline, and is found in cigarette smoke.

How the benzene level in drinks compares with other sources

Most people are exposed to a small amount of benzene on a daily basis, both indoors in the workplace, and in the environment. Exposure to benzene is mainly through breathing air that contains benzene. Sources of benzene in air include:

• cigarette smoke (active or passive smoking)

• automobile service stations

• exhaust from motor vehicles (benzene is present at 1-2% in most petrol blends)

• industrial emissions.

Vapours (or gases) from products that contain benzene, such as glues, paints, furniture wax and detergents can also be a source of exposure. For non-smokers, much of their exposure comes from vehicle-related activities such as driving and refuelling.

Exposure to benzene in New Zealand is thought to be similar to overseas (see the table below).

Source of exposure	Estimated exposure	Source of information
Air - Inhalation exposure - Refilling car petrol tank - Automobile-related activities - Driving for one hour	220 μg (micrograms)/day 32 μg during refilling (3 mins) 49 μg/day 40 μg/day	European Union European Union Canada Agency For Toxic Substances and Disease Registry
Diet - Food and drink products - Food - Water and food	0.2 - 3.1 μg/day 1.4 μg/day 1.4 µg/day	European Union Canada International Programme on Chemical Safety
Cigarette smoking	7900 μg/day 1820 μg/day 1800 µg/day	European Union Canada International Programme on Chemical Safety
Passive smoking	63 μg/day 50 µg/day	Canada International Programme on Chemical Safety

Table 1: Sources of daily exposure to benzene for the general world population

Exposure to benzene from beverages therefore represents a minor contribution compared to the total benzene exposure, especially for smokers. The UK Food Standards Agency has stated that people would need to drink at least 20 litres per day of a drink containing benzene at 10 μg to equal the amount of benzene you would breathe from city air every day.

The action food regulators are taking

The Food Standards Australia New Zealand (FSANZ) survey showed that although some drinks occasionally contained trace amounts of benzene, the amount is low compared to other daily sources of exposure and therefore safety concerns about consuming beverages with low levels of benzene are minimal. Nonetheless, FSANZ and NZFSA recommend manufacturers keep the levels of preservatives (and benzene formation) as low as can be achieved, while still ensuring the microbiological safety of these products.

The International Council of Beverages Associations (ICBA) has approved a Guidance Document to minimise the potential for benzene formation in beverages. This may help some manufacturers reduce the levels of benzene formation in their products.

ICBA’s guidance document to minimise benzene formation in beverages [Australian Beverage Council]

Some beverage manufacturers in New Zealand have already reformulated their products to use different preservatives, but under certain chemical conditions, the only effective preservative is sodium benzoate. This has prompted industry to initiate some benzene testing of their own, with favourable results. Levels of benzene in the products tested ranged from none to four micrograms, well below the recommended levels for New Zealand drinking water. As the issue becomes more widely understood, industry and NZFSA may take further action as required.