Wastewater and the Environment:
Triclosan is marketed as an antimicrobial agent that adds value to various hygiene and other consumer products [Perencevich, 2001]. Unfortunately, its increased prevalence in a variety of products means that increasing amounts are ending up down the drains, into the wastewater treatment plants [Shelver, 2007; Tatarazako, 2004; Dann, 2011] and ultimately into the environment. While some triclosan gets removed in the water treatment process significant amounts still make it out into the environment when biosolids from the wastewater treatment process are used as crop fertilizers. [Sabaliunas, 2003; Bock, 2010]. Once in the environment triclosan is very good at killing certain types of algae [Tatarazako, 2004]. Since environmental algae are primary producers, decreases in their abundance lead to subsequent decreases in the zooplankton that feed on the algae; in so doing propagate the effects of triclosan further up the food web. At very high concentrations, this could have a dramatic effect on the trophic balance of the ecosystems we all depend on. At more dilute concentrations, we might expect to see long-term rebalancing of trophic levels and in ways that are difficult to predict and whose significance to human health are unknown.
Human and Animal Effects:
Triclosan has also been shown to bioaccumulate in animals and have serious effects on their hormones during development. [Fair, 2009; Raut, 2009]. It has been shown to get absorbed into the human body through the salivary glands and exits through the urinary tract [Calafat, 2008]. In addition, triclosan has been shown to be an endocrine disruptor[Crofton, 2007; Zorrilla, 2009; Paul, 2010; Raut, 2009; Stoker, 2010]. Some animal studies have shown that triclosan alters important hormone levels, which could result in neurotoxicity, decreased thyroid function and the growth of breast cancer cells[Gee, 2008; James, 2010; Fair, 2009]. Finally, triclosan has been found in 97% of american mothers’ breast milk and fetal cord blood; while its health effects are not completely known this observation that together with its known influence on important cell signalling pathways raises further questions about why it is used so prevalently[Allymyr, 2006; Adolfsson-Erici, 2002; Peters, 2005].
Antimicrobial resistance:
The use of antimicrobial compounds has accelerated rapidly across a wide variety of sectors
(from healthcare to agriculture to consumer goods) since the discovery of penicillin in 1928 [Ligon, 2004]. However, the overuse of antimicrobials has been starting to show its negative effects. For example, bacteria resistant to antibiotics is directly responsible for 15 times as many deaths in Europe every year than AIDS[González-Zorn, 2012]. In the case of triclosan, certain resistant strains of Staphylococcus aureus have already been discovered[Suller, 2000; Fan, 2002]. This is quite alarming since resistance seems to be due to a single point mutation. Given the seemingly low evolutionary barrier for resistance to triclosan, it’s beneficial use in hospital settings, and its ever growing environmental footprint, it seems that concern over its seemingly unregulated use is warranted[Shelver, 2007; Tatarazako, 2004; Dann, 2011]. While the concentrations used in consumer products is too high to select for resistance in the products themselves, the residues from the cosmetics and other products left on countertops may have the right concentrations needed for resistance selection[Levy, 2002; Yazdankhah, 2006].
While antimicrobials have always been present in the natural environment – there are ways that plants and fungi naturally defend themselves from invading bacterium[González-Zorn, 2012] – human exploitation of these natural resources and overuse are causing a decrease in their efficacy. Through public awareness, control and proper human practice, the use of antimicrobials like triclosan can be decreased help minimize their impact on the environment and to help maintain their efficacy in the places their use is warranted.
Sources:
Adolfsson-Erici M, Pettersson M, Parkkonen J, Sturve J. 2002. Triclosan, a commonly used bactericide found in human milk and in the aquatic environment in Sweden. Chemosphere. 2002; 46: 14851489.
Ahn KC, Zhao B, Chen J. In vitro biological activities of the antimicrobial triclocarban, its analogues, and triclosan in bioassay screens: receptor-based bioassay screens. Environmental Health Perspectives. 2008 May.
Allymyr M, Adolfsson-Erici M, McLachlan MS, Sandborgh-Englund G. Triclosan in Plasma and Milk from Swedish Nursing Mothers and Their Exposure Via Personal Care Products. Science of the Total Environment. 2006; 372(1) 87-93.
Bock M., Lyndall J., Barber T., Fuchsman P., Perruchon E., Capdevielle M. Probabilistic application of a fugacity model to predict triclosan fate during wastewater treatment. Integr. Environ. Assess Manag.2010;6:393–404. doi: 10.1897/IEAM_2009-070.1.
Calafat AM, Ye X, Wong LY, Reidy JA, Needham LL. Urinary Concentrations of Triclosan in the U.S.
Population: 2003-2004. Environmental Health Perspectives. 2008; 116(3), 303-07.
Centers for Disease Control. Fourth National Report on Human Exposure to Environmental Chemicals. 2009. 38-20.
Crofton KM, Paul KB, DeVito MJ, Hedge JM. Short-term in vivo exposure to the water contaminant triclosan: evidence for disruption of thyroxine. Environmental Toxicology and Pharmacology. 2007; 24: 194-197.
Dann, A. B., & Hontela, A. (2011). Triclosan: environmental exposure, toxicity and mechanisms of action. Journal of Applied Toxicology, 31(4), 285.
Dhillon GS, Kaur S, Pulicharla R, et al. Triclosan: Current Status, Occurrence, Environmental Risks and Bioaccumulation Potential. Tchounwou PB, ed.International Journal of Environmental Research and Public Health. 2015;12(5):5657-5684. doi:10.3390/ijerph120505657.
Diamanti-Kandarakis E, Bourguignon JP, Giudice LC, Hauser R, Prins GS, Soto AM, Zoeller RT, Gore AC. Endocrine-disrupting chemicals: an endocrine society scientific statement. Endocrine Reviews. 2009 June; 30(4): 293–342.
Fair PA, Lee HB, Adams J, Darling C, Pacepavicius G, Alaee M, Bossart GD, Henry N, Muir D. Occurrence of triclosan in plasma of wild Atlantic bottlenose dolphins (tursops truncates) and in their environment. Environmental Pollution. 2009 Aug-Sept; 157(8-9): 2248-54.
Fan, F., Yan, K., Wallis, N. G., Reed, S., Moore, T. D., Rittenhouse, S. F., … & Payne, D. J. (2002).
Defining and combating the mechanisms of triclosan resistance in clinical isolates of
Staphylococcus aureus. Antimicrobial agents and chemotherapy, 46(11), 3343-3347.
Fernando, D. M., Xu, W., Loewen, P. C., Zhanel, G. G., & Kumar, A. (2014). Triclosan can select for an AdeIJK-overexpressing mutant of Acinetobacter baumannii ATCC 17978 that displays reduced susceptibility to multiple antibiotics. Antimicrobial agents and chemotherapy, 58(11), 6424-6431.
Gee RH, Charles A, Taylor N, Darbre PD. Oestrogenic and androgenic activity of triclosan in breast cancer cells. Journal of Applied Technology. 2008: 38: 78-91.
González-Zorn, B., & Escudero, J. A. (2012). Ecology of antimicrobial resistance: humans, animals, food and environment. International Microbiology,15(3), 101-109.
James MO, et al. Triclosan is a potent inhibitor of estradiol and estrone sulfonation in sheep placenta. Environment International. 2010 Nov; 36(8): 942-9.
Kumar V, Chakraborty A, Kural M, Roy P. Alteration of testicular steroidogenesis and histopathology of reproductive system in male rats treated with triclosan. Reproductive Toxicology. 2009 April; 27(2): 177-185.
Levy, S. B. (2002). Antimicrobial consumer products: where’s the benefit? What’s the risk?. Archives of Dermatology, 138(8), 1087-1088.
Ligon, B. L. (2004, January). Penicillin: its discovery and early development. InSeminars in pediatric infectious diseases (Vol. 15, No. 1, pp. 52-57). WB Saunders.
Paul KB, Hedge JM, DeVito MJ, Crofton KM. Short-term exposure to triclosan decreases thyroxine in vivo via upregulation of hepatic catabolism in you long-evans rats. Toxicological Sciences. 2010 Feb; 113(2): 367-79.
Perencevich EN, Wong MT, Harris AD. National and regional assessment if the antibacterial soap market: a step toward determining the impact of prevalent antibacterial soaps. American Journal of Infection Control. 2001 Oct; 29(5):281-283.
Peters RJB. Man-made chemicals in maternal and cord blood. TNO Built Environment and Geosciences-Report. 2005.
Raut SA, Angus RA. Triclosan has endocrine-disrupting effects in male western mosquitofish, gambusia affinis. Environmental Toxicology and Chemistry. 2009 Dec; 29(6): 1287-1291.
Sabaliunas D., Webb S.F., Hauk A., Jacob M., Eckhoff W.S. Environmental fate of triclosan in the River Aire Basin, UK. Water Res. 2003;37:3145–3154. doi: 10.1016/S0043-1354(03)00164-7.
Shelver, W. L., Kamp, L. M., Church, J. L., & Rubio, F. M. (2007). Measurement of triclosan in water using a magnetic particle enzyme immunoassay. Journal of agricultural and food chemistry, 55(10), 3758-3763.
Stoker TE, Gibson EK, Zorrilla LM. Triclosan exposure modulates estrogen-dependent Responses in the female wistar rat. Toxicological Sciences. 2010 June; 117(1): 45-53.
Suller, M. T. E., & Russell, A. D. (2000). Triclosan and antibiotic resistance in Staphylococcus aureus. Journal of Antimicrobial Chemotherapy, 46(1), 11-18.
Tatarazako, N., Ishibashi, H., Teshima, K., Kishi, K., & Arizono, K. (2004). Effects of triclosan on various aquatic organisms. Environmental sciences: an international journal of environmental physiology and toxicology, (11), 133-40.
Wilding B, Curtis K, Welker-Hood K. Hazardous chemicals in health care: a snapshot of chemicals in doctors and nurses. Physicians for Social Responsibility. 2009 Oct.RN
Yazdankhah, S. P., Scheie, A. A., Høiby, E. A., Lunestad, B. T., Heir, E., Fotland, T. Ø., … & Kruse, H.
(2006). Triclosan and antimicrobial resistance in bacteria: an overview. Microbial drug resistance, 12(2), 83-90.
Zorrilla LM, Gibson EK, Jeffay SC, Crofton KM, Setzer WR, Cooper RL, Stoker TE. The effects of triclosan in puberty and thyroid hormones in male wistar rats. Toxicological Sciences. 2009 Jan; 107(1): 56-64.