Biomonitoring Summary

Triclosan

CAS No. 3380-34-5

General Information

Triclosan, a phenolic diphenyl ether used for over 30 years as a preservative and antiseptic agent, acts by inhibiting bacterial fatty acid synthesis. Triclosan has been added to soaps, toothpastes, mouthwashes, acne medications, deodorants, and wound disinfection solutions, and has also been impregnated into some kitchen utensils, toys, and medical devices. Triclosan enters the aquatic environment mainly through residential wastewaters. It can be photochemically and biologically degraded, a process that can result in the formation of small amounts of 2,8-dichlorodibenzo-p-dioxin (Aranami et al., 2007; Mezcua et al., 2004). In 1999-2000, triclosan was found in 57.6% of 139 U.S. streams sampled in 30 states (Kolpin et al., 2002). Triclosan has a low bioaccumulation potential in fish. There is some concern that widespread use of triclosan and other biocides can alter antibiotic resistance in bacteria (Aiello et al., 2007).

General population exposure results from dermal and oral use of products containing triclosan. Triclosan can remain present in the oral saliva for several hours after the use of toothpaste containing triclosan (Gilbert et al., 1987). Triclosan can be absorbed across skin into the blood stream. In the body it is conjugated to glucuronides and sulfates (Bodey et al., 1976; Moss et al, 2000). In animal and human studies, it is excreted over several days in the feces and urine as primarily as unchanged triclosan (Kanetoshi et al., 1988; (Sandborgh-Englund et al., 2006).

Human health effects from triclosan at low environmental doses or at biomonitored levels from low environmental exposures are unknown. Triclosan formulations may rarely cause skin irritation. In animal studies, it has low acute toxicity. Some reports show endocrine effects are observed in amphibians and fish (Foran et al., 2000; Matsumura et al., 2005; Veldhoen et al., 2007). Triclosan is not considered teratogenic at maternally toxic doses, and has not been considered mutagenic or carcinogenic (Bhargava and Leonard, 1996; Lyman and Furia, 1969). IARC and NTP do not have ratings with respect to human carcinogenicity.

Biomonitoring Information

Urinary triclosan levels reflect recent exposure. In a U.S. representative subsample of NHANES 2003-2004, Calafat et al., 2008 found higher levels during the third decade of life and among people with the highest household income, but not by race/ethnicity and sex. In a study of 90 U.S. young girls, the median urinary triclosan level of 7.2 µg/L was comparable to the median level (8.2 µg/L) of children 6-11 years of age who participated in NHANES 2003-2004 (Wolff et al., 2007; Calafat et al., 2008). Over the NHANES 2003-2010 survey periods, urinary triclosan levels appear to be generally similar across the age, sex, and racial/ethnic demographic groups (CDC, 2012).

Finding measurable amounts of triclosan in the urine does not imply that the levels of triclosan cause an adverse health effect. Biomonitoring studies on levels of triclosan provide physicians and public health officials with a reference values so that they can determine whether people have been exposed to higher levels of triclosan than are found in the general population. Biomonitoring data can also help scientists plan and conduct research on exposure and health effects.

References

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Aranami K, Readman JW. Photolytic degradation of triclosan in freshwater and seawater. Chemosphere 2007;66:1052-1056.

Bhargava HN, Leonard PA.. Triclosan: applications and safety. Am J Infect Control 1996;24(3):209-218.

Bodey GP, Ebersole R, Hong HC. Randomized trial of a hexachlorophene preparation and P-300 bacteriostatic soaps. J Invest Dermatol 1976;67(4):532-537.

Calafat AM, Ye X, Wong LY, Reidy JA, Needham LL. Urinary concentrations of triclosan in the U.S. population: 2003-2004. Environ Health Perspect 2008;116(3):303-307.

Centers for Disease Control and Prevention (CDC). Fourth National Report on Human Exposure to Environmental Chemicals. Updated Tables. September 2012. [online] Available at URL: https://www.cdc.gov/exposurereport/. 2/1/13

Foran CM, Bennett ER, Benson WH. Developmental evaluation of a potential non-steroidal estrogen: triclosan. Mar Environ Res 2000;50(1-5):153-156.

Gilbert RJ, Williams PE. The oral retention and antiplaque efficacy of triclosan in human volunteers. Br J Clin Pharmacol 1987;23(5):579-583.

Kanetoshi A, Ogawa H, Katsura E, Okui T, Kaneshima H. Disposition and excretion of Irgasan DP300 and its chlorinated derivatives in mice. Arch Environ Contam Toxicol 1988;17(5):637-644.

Kolpin DW, Furlong ET, Meyer MT, Thurman EM, Zaugg SD, Barber LB, et al. Pharmaceuticals, hormones, and other organic wastewater contaminants in U.S. streams, 1999-2000: a national reconnaissance. Environ Sci Technol 2002;36(6):1202-1211.

Lyman FL, Furia T. Toxicology of 2, 4, 4'-trichloro-2'-hydroxy-diphenyl ether. IMS Ind Med Surg 1969;38(2):64-71.

Matsumura N, Ishibashi H, Hirano M, Nagao Y, Watanabe N, Shiratsuchi H, et al. Effects of nonylphenol and triclosan on production of plasma vitellogenin and testosterone in male South African clawed frogs (Xenopus laevis). Biol Pharm Bull 2005;28(9):1748-1751.

Mezcua M, Gomez MJ, Ferrer I, Aguera A, Hernando MD, Fernandez-Alba AR. Evidence of 2,7/2,8-dibenzodichloro-p-dioxin as a photodegradation product of triclosan in water and wastewater samples. Anal Chim Acta 1004;524:241-247.

Moss T, Howes D, Williams FM. Percutaneous penetration and dermal metabolism of triclosan (2,4,4'-trichloro-2'-hydroxydiphenyl ether). Food Chem Toxicol 2000;38(4):361-370.

Sandborgh-Englund G, Adolfsson-Erici M, Odham G, Ekstrand J. Pharmacokinetics of triclosan following oral ingestion in humans. J Toxicol Environ Health A 2006;69(20):1861-1873.

Veldhoen N, Skirrow RC, Osachoff H, Wigmore H, Clapson DJ, Gunderson MP, et al. The bactericidal agent triclosan modulates thyroid hormone-associated gene expression and disrupts postembryonic anuran development. Aquat Toxicol 2006;80(3):217-227. Erratum in: Aquat Toxicol 2007;83(1):84.

Wolff MS, Teitelbaum SL, Windham G, Pinney SM, Britton JA, Chelimo C, et al. Pilot study of urinary biomarkers of phytoestrogens, phthalates, and phenols in girls. Environ Health Perspect 2007;115:116-121.