Triclosan (TCS) is a broad spectrum antibacterial agent present as an active ingredient in some personal care products such as soaps, toothpastes and sterilizers. It is an endocrine disrupting compound and its increasing presence in water resources as well as in biosolid-amended soils used in farming, its potential for bioaccumulation in fatty tissues and toxicity in aquatic organisms are a cause for concern to human and environmental health. TCS has also been detected in blood, breast milk, urine and nails of humans. The significance of this is not precisely understood. Data on its bioaccumulation in humans are also lacking. Cell based studies however showed that TCS is a pro-oxidant and may be cytotoxic via a number of mechanisms. Uncoupling of oxidative phosphorylation appears to be prevailing as a toxicity mechanism though the compound's role in apoptosis has been cited. TCS is not known to be carcinogenic per se in vitro but has been reported to promote tumourigenesis in the presence of a carcinogen, in mice. Recent laboratory reports appear to support the view that TCS oestrogenicity as well as its anti-oestrogenicity play significant role in cancer progression. Results from epidemiological studies on the effect of TCS on human health have implicated the compound as responsible for certain allergies and reproductive defects. Its presence in chlorinated water also raises toxicity concern for humans as carcinogenic metabolites such as chlorophenols may be generated in the presence of the residual chlorine. In this paper, we carried out a detailed overview of TCS pollution and the implications for human and environmental health (1).
There was also an association between human exposure to parabens and triclosan and birth results with measurements of weight, body length, head size and gestational age of birth. All these measures were negatively affected (2).
Ongoing laboratory studies provide strong evidence for the effects of Triclosan that alter the endocrine system, particularly reproductive hormones (3).
Regarding the aquatic toxicity eight biocidal preservatives, among which Triclosan, have shown considerable toxicity in the studied biological assays, but with a marked difference in power (4).
Triclosan has been used around the world for about 40 years and many studies have reported the wide exposure of Triclosan both in the natural environment and in the human body.
References_________________________________________
(1) Triclosan in water, implications for human and environmental health.
Olaniyan LW, Mkwetshana N, Okoh AI.
Springerplus. 2016 Sep 21;5(1):1639.
(2) Association of birth outcomes with fetal exposure to parabens, triclosan and triclocarban in an immigrant population in Brooklyn, New York.
Geer LA, Pycke BF, Waxenbaum J, Sherer DM, Abulafia O, Halden RU.
J Hazard Mater. 2017 Feb 5;323(Pt A):177-183. doi: 10.1016/j.jhazmat.2016.03.028.
(3) Reproductive endocrine-disrupting effects of triclosan: Population exposure, present evidence and potential mechanisms.
Wang CF, Tian Y.
Environ Pollut. 2015 Nov;206:195-201. doi: 10.1016/j.envpol.2015.07.001.
(4) Personal care product preservatives: risk assessment and mixture toxicities with an industrial wastewater.
Carbajo JB, Perdigón-Melón JA, Petre AL, Rosal R, Letón P, García-Calvo E.
Water Res. 2015 Apr 1;72:174-85. doi: 10.1016/j.watres.2014.12.040.
Triclosan 
2,4,4-trichloro-2-hydroxydiphenyl ether
