Benzene Benzene is an organic chemical compound with the molecular formula C6H6. The benzene molecule is composed of six carbon atoms joined in a planar ring with one hydrogen atom attached to each. Because it contains only carbon and hydrogen atoms ...

in soft drinks is of potential concern due to the

carcinogen A carcinogen is any substance, radionuclide, or radiation that promotes carcinogenesis (the formation of cancer). This may be due to the ability to damage the genome or to the disruption of cellular metabolic processes. Several radioactive subs ...

ic nature of the molecule. This contamination is a

public health Public health is "the science and art of preventing disease, prolonging life and promoting health through the organized efforts and informed choices of society, organizations, public and private, communities and individuals". Analyzing the det ...

concern and has caused significant outcry among environmental and health advocates. Benzene levels are regulated in drinking water nationally and internationally, and in

bottled water Bottled water is drinking water (e.g., well water, distilled water, mineral water, or spring water) packaged in plastic or glass water bottles. Bottled water may be carbonated or not. Sizes range from small single serving bottles to lar ...

in the United States, but only informally in soft drinks. The benzene forms from decarboxylation of the

preservative A preservative is a substance or a chemical that is added to products such as food products, beverages, pharmaceutical drugs, paints, biological samples, cosmetics, wood, and many other products to prevent decomposition by microbial growth or by ...

benzoic acid Benzoic acid is a white (or colorless) solid organic compound with the formula , whose structure consists of a benzene ring () with a carboxyl () substituent. It is the simplest aromatic carboxylic acid. The name is derived from gum benzoin, ...

in the presence of ascorbic acid (vitamin C) and metal ions (iron and copper) that act as

catalyst Catalysis () is the process of increasing the rate of a chemical reaction by adding a substance known as a catalyst (). Catalysts are not consumed in the reaction and remain unchanged after it. If the reaction is rapid and the catalyst recyc ...

s, especially under heat and light. Hot peppers naturally contain vitamin C ("nearly as much as in one orange") so the observation about soft drinks applies to pepper sauces containing sodium benzoate, like Texas Pete.

Formation in soft drinks

The major cause of benzene in soft drinks is the decarboxylation of

in the presence of ascorbic acid (vitamin C, E300) or erythorbic acid (a

diastereomer In stereochemistry, diastereomers (sometimes called diastereoisomers) are a type of stereoisomer. Diastereomers are defined as non-mirror image, non-identical stereoisomers. Hence, they occur when two or more stereoisomers of a compound have di ...

of ascorbic acid, E315).

Benzoic acid Benzoic acid is a white (or colorless) solid organic compound with the formula , whose structure consists of a benzene ring () with a carboxyl () substituent. It is the simplest aromatic carboxylic acid. The name is derived from gum benzoin, ...

is often added to drinks as a

in the form of its salts

sodium benzoate Sodium benzoate is the sodium salt of benzoic acid, widely used as a food preservative (with an E number of E211) and a pickling agent. It appears as a white crystalline chemical with the formula C6H5COONa. Production Sodium benzoate is commo ...

(E211),

potassium benzoate Potassium benzoate (E212), the potassium salt of benzoic acid, is a food preservative that inhibits the growth of mold, yeast and some bacteria. It works best in low- pH products, below 4.5, where it exists as benzoic acid. Acidic foods and bev ...

(E 212), or calcium benzoate (E 213).

Citric acid Citric acid is an organic compound with the chemical formula HOC(CO2H)(CH2CO2H)2. It is a colorless weak organic acid. It occurs naturally in citrus fruits. In biochemistry, it is an intermediate in the citric acid cycle, which occurs in ...

is not thought to induce significant benzene production in combination with benzoic acid, but some evidence suggests that in the presence of ascorbic or erythorbic acid and benzoic acid, citric acid may accelerate the production of benzene. The proposed mechanism begins with

hydrogen abstraction In chemistry, a hydrogen atom abstraction or hydrogen atom transfer (HAT) is any chemical reaction in which a hydrogen free radical (neutral hydrogen atom) is abstracted from a substrate according to the general equation: :X^\bullet + H-Y -> X- ...

by the

hydroxyl radical The hydroxyl radical is the diatomic molecule . The hydroxyl radical is very stable as a dilute gas, but it decays very rapidly in the condensed phase. It is pervasive in some situations. Most notably the hydroxyl radicals are produced from the ...

, which itself is produced by the Cu²⁺-catalysed reduction of

dioxygen There are several known allotropes of oxygen. The most familiar is molecular oxygen (O2), present at significant levels in Earth's atmosphere and also known as dioxygen or triplet oxygen. Another is the highly reactive ozone (O3). Others are: * ...

by ascorbic acid: Benzoic acid decarboxylation landscape

Other factors that affect the formation of benzene are heat and light. Storing soft drinks in warm conditions speeds up the formation of benzene. Calcium disodium

EDTA Ethylenediaminetetraacetic acid (EDTA) is an aminopolycarboxylic acid with the formula H2N(CH2CO2H)2sub>2. This white, water-soluble solid is widely used to bind to iron (Fe2+/Fe3+) and calcium ions (Ca2+), forming water-soluble complexes ev ...

and sugars have been shown to inhibit benzene production in soft drinks. The International Council of Beverages Associations (ICBA) has produced advice to prevent or minimize benzene formation.

Limit standards in drinking water

Various authorities have set limits on benzene content in drinking water. The following limits are given in

parts per billion In science and engineering, the parts-per notation is a set of pseudo-units to describe small values of miscellaneous dimensionless quantities, e.g. mole fraction or mass fraction. Since these fractions are quantity-per-quantity measures, they ...

(ppb; μg/kg). *

World Health Organization The World Health Organization (WHO) is a specialized agency of the United Nations responsible for international public health. The WHO Constitution states its main objective as "the attainment by all peoples of the highest possible level of ...

(WHO): 10 ppb (WHO notes that benzene should be avoided whenever technically feasible.) * Republic of Korea (

South Korea South Korea, officially the Republic of Korea (ROK), is a country in East Asia, constituting the southern part of the Korean Peninsula and sharing a land border with North Korea. Its western border is formed by the Yellow Sea, while its eas ...

): 10 ppb"South Korea urges recall of benzene-containing drinks"
*

Canada Canada is a country in North America. Its ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, covering over , making it the world's second-largest country by tot ...

: 5 ppb *

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territori ...

: federal limit: 5 ppb;United States Food and Drug Administration: Questions and Answers on the Occurrence of Benzene in Soft Drinks and Other Beverages
/ref> state limits in

California California is a state in the Western United States, located along the Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the most populous U.S. state and the 3rd largest by area. It is also the m ...

Connecticut Connecticut () is the southernmost state in the New England region of the Northeastern United States. It is bordered by Rhode Island to the east, Massachusetts to the north, New York to the west, and Long Island Sound to the south. Its capita ...

New Jersey New Jersey is a state in the Mid-Atlantic and Northeastern regions of the United States. It is bordered on the north and east by the state of New York; on the east, southeast, and south by the Atlantic Ocean; on the west by the Delaware ...

, and

Florida Florida is a state located in the Southeastern region of the United States. Florida is bordered to the west by the Gulf of Mexico, to the northwest by Alabama, to the north by Georgia, to the east by the Bahamas and Atlantic Ocean, and to ...

: 1 ppb *

European Union The European Union (EU) is a supranational political and economic union of member states that are located primarily in Europe. The union has a total area of and an estimated total population of about 447million. The EU has often been de ...

: 1 ppb The EPA and

have set public health goals for benzene of 0 ppb and 0.15 ppb.

Environmental exposure to benzene

Benzene in soft drinks has to be seen in the context of other environmental exposure. Taking the worst example found to date of a soft drink containing 87.9 ppb benzene, someone drinking a 350 ml (12 oz) can would ingest 31 μg (micrograms) of benzene, almost equivalent to the benzene inhaled by a motorist refilling a fuel tank for three minutes. While there are alternatives to using sodium benzoate as a preservative, the casual consumption of such a drink is unlikely to pose a significant health hazard to a particular individual (see, for example, the EPA IRIS document on benzene). The UK Food Standards Agency has stated that people would need to drink at least 20 litres (5.5 gal) per day of a drink containing benzene at 10 μg to equal the amount of benzene they would breathe from city air every day.New Zealand Food Safety Authority / Te Pou Oranga kai O Aotearo
Benzene in flavoured drinks
Daily personal exposure to benzene is determined by adding exposure from all sources. * Air: A European study found that people breathe in 220 μg of benzene every day due to general atmospheric pollution. A motorist refilling a fuel tank for three minutes would inhale a further 32 μg. Food Standards Agency, March 2006,
of Benzene in Soft Drinks
'' (PDF) The estimated daily exposure from "automobile-related activities" is 49 μg and for driving for one hour is 40 μg. * Smoking: For smokers, cigarette smoking is the main source of exposure to benzene. Estimates are 7900 μg per day (smoking 20 cigarettes per day), 1820 μg/day, and 1800 μg/day. * Passive smoking: Benzene intake from passive smoking is estimated at 63 μg/day (Canada) and 50 μg/day. * Diet and drinking water: 0.2 to 3.1 μg per day.

History

1990s

In 1990, a study reported having found

benzene Benzene is an organic chemical compound with the molecular formula C6H6. The benzene molecule is composed of six carbon atoms joined in a planar ring with one hydrogen atom attached to each. Because it contains only carbon and hydrogen atoms ...

in bottles of

Perrier Perrier ( , also , ) is a French brand of natural bottled water, bottled mineral water obtained at its source in Vergèze, located in the Gard ''département''. Perrier is known for its carbonation and its distinctive green bottle. Perrier w ...

for sale in the United States, resulting in a voluntary product recall. In the early 1990s, the soft drink industry initially approached FDA with concerns about

formation in soft drinks. Following testing, FDA asked manufacturers to voluntarily reformulate. By 1993, FDA determined that most drinks had little

contamination. In 1993, research showed how benzene can form from benzoic acid in the presence of vitamin C. In the summer of 1998, a number of well known soft drinks manufacturers had to withdraw large quantities of their products from sale after benzene contamination in some production plants was discovered.

2005

In November 2005, the FDA received test results conducted by private citizens that benzene was forming at low levels in several types of beverages.FDA. May 19, 2006
"Data on Benzene in Soft Drinks and Other Beverages"
/ref> In December 2005,

Germany Germany,, officially the Federal Republic of Germany, is a country in Central Europe. It is the second most populous country in Europe after Russia, and the most populous member state of the European Union. Germany is situated betwe ...

's Federal Institute for Risk Assessment (''Bundesinstitut für Risikobewertung'') published a review of benzene's possible formation in foods and drinks.

2006

In February 2006, an unnamed former

chemist A chemist (from Greek ''chēm(ía)'' alchemy; replacing ''chymist'' from Medieval Latin ''alchemist'') is a scientist trained in the study of chemistry. Chemists study the composition of matter and its properties. Chemists carefully describe t ...

at the FDA publicly revealed that

may be created as part of a chemical reaction during production of soft drinks, particularly those having an

orange Orange most often refers to: *Orange (fruit), the fruit of the tree species '' Citrus'' × ''sinensis'' ** Orange blossom, its fragrant flower *Orange (colour), from the color of an orange, occurs between red and yellow in the visible spectrum * ...

flavor.Mercer, Chris. ''Food Production Daily'', February 15, 2006
"FDA re-opens probe into benzene contamination of soft drinks"
Full-scale investigations immediately started at the Food Standards Agency ( UK) and in

to reveal exactly which amounts of benzene, if any, were present, with several other organizations awaiting their findings.Mercer, Chris. ''Food Production Daily'', February 20, 2006
"UK, Germany checking soft drinks for benzene"
The

United Kingdom The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Europe, off the north-western coast of the European mainland, continental mainland. It comprises England, Scotlan ...

's Food Standards Agency released results on March 31, 2006 for 150 beverages. Its results showed 43 beverages contained benzene, four of which contained levels above the

drinking water standards (10 ppb). These four were withdrawn from sale. In April 2006, the Korea Food & Drug Administration (KFDA) announced that it had detected benzene in 27 out of 30 (90%) vitamin-enriched drinks on sale in

. It said the detected amount of benzene – ranging from 5.7 to 87.8 ppb – was not harmful to humans but advised manufacturers of beverages containing more than 10 ppb of benzene to voluntarily recall their products. The FDA released preliminary results in May 2006 for 100 beverages showing that many soft drinks contained low levels of benzene (less than 5 ppb, the federal drinking water limit) while four drinks contained amounts above the standard. Two of these drinks contained amounts 15-18 times above the drinking water standard. Many of the products showed large variations in the amount of benzene they contained. The FDA stated that it is working with manufacturers to reformulate products that contain benzene above the federal drinking water standard. These test results are both lower and more accurate than a previous long-term study by the FDA. In the Total Diet Study that FDA conducted from 1996 - 2001 to determine the amounts of

volatile organic compounds Volatile organic compounds (VOCs) are organic compounds that have a high vapour pressure at room temperature. High vapor pressure correlates with a low boiling point, which relates to the number of the sample's molecules in the surrounding air, a t ...

in various foods, FDA used an analytical procedure that caused more benzene to form in the drinks during the test. The FDA emphasized that most beverages contain levels below 5 ppb and pose no risk to consumers. Furthermore, there are no standards for beverages beyond drinking and

. On 9 June 2006, Health Canada released its study results of benzene levels in beverages. Four products out of 118 had levels above the Canadian guideline of five micrograms per liter for benzene in drinking water (average range 6.0 to 23.0 μg/L). The follow up study the next year found only three samples with marginally higher levels and concluded the average levels were quite low. On 24 August 2006, two soft drink manufacturers agreed to settle a

class-action A class action, also known as a class-action lawsuit, class suit, or representative action, is a type of lawsuit where one of the parties is a group of people who are represented collectively by a member or members of that group. The class action ...

lawsuit that had been filed by a group of parents in the

Superior Court of the District of Columbia The Superior Court of the District of Columbia, commonly referred to as DC Superior Court, is the trial court for the District of Columbia, in the United States. It hears cases involving criminal and civil law, as well as family court, landlor ...

. The two companies, Zone Brands Inc., maker of "BellyWashers" products, and TalkingRain Beverage Co., denied that their products were harmful, but agreed to change the ingredients in their drinks.

2008

Coca-Cola Coca-Cola, or Coke, is a carbonated soft drink manufactured by the Coca-Cola Company. Originally marketed as a temperance drink and intended as a patent medicine, it was invented in the late 19th century by John Stith Pemberton in Atlant ...

announced that it would be phasing out sodium benzoate from many of its drinks, but not

Fanta Fanta is an American-owned German brand of fruit-flavored carbonated soft drinks created by Coca-Cola Deutschland under the leadership of German businessman Max Keith. There are more than 200 flavors worldwide. Fanta originated in Germany as ...

and Sprite. As of August 2012, Coca-Cola Zero and

Barq's Barq's is an American brand of root beer created by Edward Barq and bottled since the beginning of the 20th century. It is owned by the Coca-Cola Company. It was known as "Barq's Famous Olde Tyme Root Beer" until 2012. Some of its formulations ...

root beer still contains benzoate (added as potassium salt and sodium salt respectively). A Belgian study found that plastic packaging may play an important role in the formation of benzene in soft drinks.Christof van Poucke et al
Monitoring the Benzene Contents in Soft Drinks Using Headspace Gas Chromatography−Mass Spectrometry: A Survey of the Situation on the Belgian Market
J. Agric. Food Chem., 2008, 56 (12), pp 4504–4510

References

External links

Soft Drinks and Benzene: A Primer
{{Consumer Food Safety Soft drinks Medical controversies Food safety Soft drink