Furan Profile

Furan Profile

QUICK SUMMARY

  • Furan is an organic compound used in chemical manufacturing, and is sometimes found in low levels in some heat-treated beverages and foods such as coffee, and canned or jarred foods
  • Associated cancer: Linked to liver cancer, bile-duct cancer, leukemia, and adrenal-gland tumors in animals (limited evidence)
  • Most important route of exposure: Heat-treated beverages and foods such as coffee, and canned or jarred food (baby food, tomato sauces, canned soups)
  • Occupational exposures: Workers may be exposed in some industrial manufacturing and processing jobs
  • Environmental exposures: Via diet, with higher exposure for infants (due to baby food) and adults (due to coffee). Minor exposures may occur from cigarette smoke, wood smoke, and exhaust from both gasoline and diesel engines
  • Fast fact: Drip coffee tends to have lower levels of furan than espresso or coffee pods

General Information

Furan is a clear, colourless, and volatile organic compound with an ethereal odor.[1,2,3] It is extremely flammable and can even become explosive in some circumstances.[1] The general public can be exposed to furan on a daily basis through the gas phase components related to cigarette smoke, wood smoke, along with both gasoline and diesel exhaust.[4,5] Furan is used in some chemical manufacturing and is also present in low levels in heat treated foods such as canned or jarred foods.[3] It is important to note that furan is not the same as “furans”, which refers to polychlorinated dibenzofurans, which are often considered together with the chemically similar dioxins.[3] Dioxins and furans have much different chemical structures compared to furan.[3]

Furan has been classified by the International Agency for Research on Cancer (IARC) as Group 2B, possibly carcinogenic to humans.[5] While no studies have examined the relationship between exposure to furan and cancer risk in humans, a link between furan and liver tumors has been reported in both rats and mice.[6] Other animal studies have also found a relationship between furan exposure and bile-duct cancer, as well as mononuclear cell leukemia in rats.[7]

Regulations and Guidelines

Furan was not included in the Canadian government environmental guidelines reviewed.[8,9,10,11,12,13,14,15]

Main Uses

Manufacturing
Furan is used to manufacture the chemicals tetrahydrofuran, pyrrole, and thiophene. Furan is also used to make some lacquers, as a solvent for resins, and to produce pharmaceuticals, agricultural chemicals, and stabilizers.[16,17]

Foods
Information on how furan arises in food and beverages is somewhat limited to date. It is not an additive, but believed to enter food sources through thermal degradation of carbohydrates.[18] Health Canada stated that furan is formed by the oxidation of polyunsaturated fatty acids, which happens while heating certain foods.[3] Hypotheses put forward by a number of agencies and scientists center around furan being formed from the heating and subsequent breakdown of components of food and beverages.[19]

Canadian Production and Trade

No information was available on the production and trade of furan.[20]

Environmental Exposures Overview

Air
Furan exposure can be detected in cigarette smoke, wood smoke, and exhausts from automobile engines. Furan is also present in oils isolated from distilling pine wood containing resin,[21] and in volatile emissions from sorb trees (which do not grow in Canada).[22]

Diet
Prior to 2004, furan in food was thought of as a very limited issue. However, in the spring of 2004, scientists discovered that furan was present in canned and jarred foods such as soups, stews, and baby foods, along with low moisture foods such as crackers, potato chips, and tortilla chips.[23] According to studies in the United States and Europe, higher furan concentrations are reported in roasted coffee and foods that were heated in sealed containers, such as canned and jarred foods, and in toasted bread.[8] How coffee is brewed also influences furan levels; espresso has higher levels (88 µg/L) compared to standard drip coffee (18 µg/L).[9] Jarred baby foods also contain higher concentrations of furan (average 24-28 µg/kg), while furan has not been detected in self-prepared baby foods.[10,11,12]

Health Canada estimated mean furan exposures for children (aged 1-3) of 0.32 µg/kg of body weight per day, while adults (18 and older) only receive 0.18 µg/kg of body weight per day.[3] Children typically eat a higher amount of food per body weight which is why their exposure is assumed to be higher. Furthermore, the presence in baby food also increases the intake for children. While no current guidelines exist regarding furan intake and potential health risks, ongoing research by Health Canada and other health organizations from around the world will continue to investigate any potential dose-response relationships regarding toxicity and human health.[3]

Furan is not listed in the National Pollutant Release Inventory (NPRI) dataset.

Occupational Exposures Overview

Furan can be absorbed through the skin and through the respiratory tract.[24] Occupational exposure to furan is likely limited as it is typically handled in closed systems during industrial processes.[25]

Sources

1. National Toxicology Program, Department of Health and Human Services. 14th Report on Carcinogens (2016) (PDF)
2. National Library of Medicine. Hazardous Substances Data Bank (2009)
4. Budavari S, O’Neil MJ, Smith A, Heckelman PE. Furan. In: The Merck Index: An Encyclopedia of Chemicals, Drugs, and Biologicals, 11th Ed. (1989) Rahway, NJ: Merck.
5. International Agency for Research on Cancer (IARC). Monographs on the Evaluation of Carcinogenic Risks to Humans (1995) (PDF)
6. Bakhiya N, Appel KE. “Toxicity and carcinogenicity of furan in human diet.” Arch Toxicol 2010;84:563-578.
11. Health Canada. Cosmetic Ingredient Hotlist (2014)
12. The Canadian Legal Information Institute (CanLII). Ontario Drinking Water Quality Standards, O Reg 169/03 (2017)
13. The Canadian Legal Information Institute (CanLII). Regulation respecting the quality of drinking water, CQLR c Q-2, r 40 (2014)
14. Ontario Ministry of the Environment and Climate Change. Ontario’s Ambient Air Quality Criteria (2016)
15. Alberta Environment and Parks. Ambient Air Quality Objectives (2017)
16. McKillip WJ, Sherman E. Furan derivatives. ln: Encyclopedia of Chemical Technology, 3rd Ed. (1980) New York, New York: John Wiley & Sons.
17. McKillip WJ, Collin G, Höke H. Furan and derivatives. ln: Ullmann ‘s Encyclopedia of Industrial Chemistry, 5th rev. Ed. (1989) New York, New York: VCH Publishers.
18. Perez LC, Yaylayan VA. “Origin and mechanistic pathways of formation of the parent furan – A food toxicant.” J Agricul Food Chem 2004;52:6830-6836. DOI:10.1021/jf0490403
19. Becalski A, Forsyth D, Casey V, Lau BP, Pepper K, Seaman S. “Development and validation of a headspace method for determination of furan in food.” Food Addit Contam 2005;22:535-540.
20. International Trade Centre. TradeMap (Free subscription required)
21. Budavari S. The Merck Index: Furan (1989) Rahway, NJ: Merck & Co.
22. Isidorov VA, Zenkevich IG, loffe BV. “Volatile organic compounds in the atmosphere of forests.” Atmos Environ 1985;19:1-8.
24. Sax NI. Dangerous properties of industrial materials. (1984) New York, New York: Van Nostrand Reinhold Press.
25. National research council. Acute exposure guideline levels for selected airborne chemicals. (2010) Washington DC: The National Academies Press.

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