By David Liu, PHD

Sunday Oct 21, 2012 (foodconsumer.org) -- Benzene is a carcinogen and it can cause leukemia among other things.  A recent study published in Ig Sanita Pubbl. has found all soft drinks contained trace levels of this toxic chemical.

The presence of benzene in soft drinks is no news.  But a study confirms that not all beverage producers have taken any measure to reduce the contaminant in soft drinks and all soft drinks tested contained more or less trace amounts of benzene.

G. Bonaccorsi at Dipartimento di Sanità Pubblica, Università degli Studi di Firenze and colleagues tested 28 soft drinks for benzoic acid, sorbic acid, ascorbic acid (vitamin C) and benzene and found benzene in all analysed beverages with a mean concentration of 0.45 ug/L ranging from 0.15 to 2.36 ug/L.

The concentration of benzene varied widely by the preservative used and higher concentrations were found in soft drinks containing both ascorbic acid and sodium benzoate, both of which react to release benzene.

Benzene in two soft drinks with citrus fruit, which also contained both vitamin C and sodium benzoate, exceeded the European limit for benzene in drinking water, that is, 1 ug/L.

The authors say that "not all soft drink producers have taken steps to eliminate benzoic acid from their soft drinks and thereby reduce the risk of formation of benzene, as recommended by the European Commission."

They also speculated "the presence of benzene in trace amounts in all beverages suggests that migration of constituents of plastic packaging materials or air-borne contamination may be occurring."

Benzene in soft drinks is known to be produced by the reaction between ascorbic acid and sodium benzoate.  Ascorbic acid is often used as a fortifier or antioxidant and sodium benzoate is often used as a preservative.

The U.S. Environmental Protection Agency is aware of the presence of benzene in some soft drinks at a dose above the legal limit for drinking water, which is 5 ppb, but the Food and Drug Administration denies it, according to Ryan Bernhardt at Marian College.

In May 1993, Lalita K. Gardner and Glen D. Lawrence suggested in Journal of Agricultural and Food Chemistry that benzene is formed through a chemical process called decarboxylation of benzoic acid when vitamin c or ascorbic acid and a transitional metal catalyst are present.