Has Ciba conducted environmental safety studies?
In October of 2000, Ciba reviewed data on triclosan with US EPA's Antimicrobials Division and in November of 2000, Ciba submitted existing safety information related to triclosan to the Interagency Testing Committee (ITC), a committee which includes FDA representation. This environmental data included topics such as biodegradation and ecological endpoints. Upon review by ITC, triclosan was determined to satisfy the DEBITS criteria (Degradation Effects Bioconcentration Information Testing Strategies) listed in the 45th ITC Report published in the Federal Register of December 1, 2000. As a result, ITC did not request any additional environmental safety information on triclosan. The relevant text is on page 10303.
What happens to triclosan in Waste Water Treatment Plants (WWTP)?
Typically 90-98% of triclosan in waste water is removed as a result of biodegradation and sorption in waste water treatment plants. Research shows that only small traces are detectable in the effluent water that reaches rivers. The little amount that does leave with effluent is degraded to almost a non-existent state by either biological or photolytic processes.
For additional information on WWTP degradation refer to:
Heidler J and Halden R (2007) Mass balance assessment of triclosan removal during conventional sewage treatment Chemosphere Vol 66 (2): 362-369
Waltman E, Venables B, and Waller W. (2006) Triclosan in a North Texas wastewater treatment plant and the influent and effluent of an experimental constructed wetland Environ. Toxicology & Chemistry Vol. 25(2), 367-372.
Bester, K. (2005). Fate of Triclosan and Triclosan-Methyl in Sewage TreatmentPlants and Surface Waters Environ Contam Toxicol. July Vol. 49(1):9-17
Thompson A, Griffin P, Stuetz R, and Cartmell, E. (2005) The Fate and Removal of Triclosan during Wastewater Treatment Water Environ Res. Vol. 77(1):63-67.
Sabaliunas D, Webb S, Hauk A, Jacob M and Eckhoff, W. (2003) Environmental fate of Triclosan in the River Aire Basin, UK Water Research Vol. 37(13): 3145–3154.
Singer H, Müller S, Tixier C and Pillonel L. (2002) Triclosan: Occurrence and Fate of a Widely Used Biocide in the Aquatic Environment: Field Measurements in Wastewater Treatment Plants, Surface Waters, and Lake Sediments Environ. Sci. Technol. Vol. 36(23): 4998-5004.
Is triclosan released in effluent from WWTP toxic to aquatic organisms?
Studies using accepted modeling protocols to simulate in-river conditions in Europe and the U.S., suggested that risks to sensitive aquatic species are low even under the highest likely exposures which would occur immediately downstream of WWTP discharge points. Actual monitoring data in Europe and the U.S. corroborate the modeled estimates as well as expected reductions in triclosan concentrations with increasing distance downstream of WWTP discharges. In reality, in-stream sorption, biodegradation and photodegradation of triclosan will tend to reduce exposures further. (Capdevielle, M., et al., Consideration of Exposure and Species Sensitivity of Triclosan in the Freshwater Environment, Integr Environ Assess Manag. 2008 Jan; 4(1):15-23 (http://www.ncbi.nlm.nih.gov/pubmed/ enter: 18260205)
Fate of Triclosan in the Environment:
A recent publication reveals that triclosan is adequately and effectively processed by the wastewater treatment systems of the US and that in 2 important natural water bodies triclosan was not found. Archived sediments collected in 1996 from the Grassy Bay section of Jamaica Bay, NY (JB) and collected in July 2005 & July 2006 from eight Back River (a tributary to Chesapeake Bay, MD) (CB) locations were used to assess the long term environmental behavior of triclosan. The sediments were dated using cesium decay calculations and. were determined to be representative of sediment from the years 1955-1995 (JB) and 1970-2006 (CB).
Although there is a significant amount of speculation associated with the potential impact from the presence of triclosan in the environment, the authors did not detect triclosan or the levels were below the limit of quantitation (LOQ) in all of the Chesapeake Bay sediments and with the exception of one sample was not detected above the LOQ in Jamaica Bay sediments in the past 20 years. The one sample with measurable triclosan from the 1980's is associated with a documented raw sewage overflow event in that area.
The authors also measured for heavy metal contamination (lead, copper, and zinc), noting that triclosan was only present in the older JB samples with elevated heavy metals, suggesting that the presence heavy metal contaminants impacts the natural biodegradative processes of the soil microorganisms as CB samples had lower heavy metal concentrations and demonstrated no detectable triclosan from any representative sampling year. The authors further explain the geographical variations between these two sampling sites, clarifying the importance of physicochemical and biological characteristics in sediment. JB is poorly flushed by tidal currents, is deeper and has more water-column stratification, and experiences seasonal bottom water anoxia. These characteristics limit phototransformation and aerobic biological degradation, whereas the well oxygentated CB bottom waters facilitate these degradation processes.
This study gives a retrospective insight into triclosan trends in waterways impacted by high population density and the related high discharge of treated wastewater. The absence of triclosan in measurable concentrations confirms the importance and efficacy of the wastewater treatment infrastructure in the US. These data also show that increased use of triclosan during the past 25 years did not lead to accumulation in key environmental areas.
Fate of Triclosan and Evidence for Reductive Dechlorination of Triclocarban in Estuarine Sediments (2008). Todd R. Miller, Jochen Heidler, Steven N. Chillrud, Amelia DeLaquil, Jerry C. Ritchie, Jana N. Mihalic, Richard Bopp, and Rolf U. Halden. Environ. Sci. Technol. Published on Web 05/13/2008. doi: 10.1021/es702882g
Is there evidence that triclosan is subject to both biodegradation & photodegradation? Does it form 2,8-dichlorobenzo-p-dioxin?
Triclosan has been shown in numerous studies to be biodegradable and photo-instable causing it to breakdown following its release into the aquatic environment.
A series of studies show that photodegradation of triclosan produced 2,4-dichlorophenol and 2,8-dichlorodibenzo-p-dioxin (DCDD). The 2,4-dichlorophenol itself is known to be biodegradable as well as photodegradable (European Commission 2000). For DCDD, one of the non-toxic compounds of the dioxin family, a conversion rate of 1% has been reported and estimated half-lives suggest that it is photolabile as well (Aranami et al. 2007). The formation-decay kinetics of DCDD are also reported by Sanchez-Prado et al. (2006). A transformation to toxic dioxins has never been shown and is highly unlikely since chemical chlorination would have to take place.
For additional information on degradation of triclosan refer to:
Aranami K and Readman J. (2007) Photolytic degradation of triclosan in freshwater and seawater.Chemosphere, Vol. 66(6):1052-1056.
Sanchez-Prado L, Llompart M., Lores M., García-Jares C., Bayona J. and Cela R. (2006) Monitoring the photochemical degradation of triclosan in wastewater by UV light and sunlight using solid-phase microextraction. Chemosphere, Vol 65(8):1338-1347
Morrall D, McAvoy D, Schatowitz B, Inauen J, Jacob M, Hauk A and Eckhoff W. (2004) A field study of triclosan loss rates in river water (Cibolo Creek, TX).Chemosphere, Vol 54(5):653-660.
Bester K. (2003) Triclosan in a sewage treatment process—balances and monitoring data. Water Research, Vol 37(16):3891-3896.
Latch D, Packer J., Arnold J. and McNeill K. (2003) Photochemical conversion of triclosan to 2,8-dichlorodibenzo-p-dioxin in aqueous solution. Journal of Photochemistry and Photobiology A: Chemistry, Vol. 158 (1), 30:63-66
Sabaliunas D, Webb S, Hauk A, Jacob M and Eckhoff, W. (2003) Environmental fate of Triclosan in the River Aire Basin, UK Water Research Vol. 37(13): 3145–3154.
Singer H, Müller S, Tixier C and Pillonel L. (2002) Triclosan: Occurrence and Fate of a Widely Used Biocide in the Aquatic Environment: Field Measurements in Wastewater Treatment Plants, Surface Waters, and Lake Sediments. Environ. Sci. Technol. Vol. 36(23): 4998-5004.
Tixier C, Singer H, Canonica S, and Müller S. (2002) Phototransformation of Triclosan in Surface Waters: A Relevant Elimination Process for This Widely Used Biocide-Laboratory Studies, Field Measurements, and Modeling. Environ Sci Technol. Vol. 36(16):3482-9.
Is it true that sewage sludge containing triclosan is applied to farmland?
Sewage sludge is commonly applied to agricultural land (including pasture and range land), forests, reclamation sites, public contact sites (e.g., parks, turf farms, highway median strips, golf courses), lawns, and home gardens. Depending on the sludge quality and heavy metals content, sludges are either burned, land-filled, or land-applied, where any remaining triclosan is biodegraded without harm to terrestrial organisms.
Taking the mix of WWTP facility-types into account, we conservatively expect around 25,000 kg/year triclosan to reach agricultural soils from the 2.6 million metric tons of sludge applied annually. Each kilogram of sludge is applied to one square meter of land and is typically worked into around 20 cm of topsoil, therefore diluting it by a factor of 300 (weight/weight). A mass balance, based on all current data, safely excludes any risk to humans or wildlife from secondary exposure to triclosan from any environmental route.
As a quick reality check, think of it this way, in order to ingest the same amount of triclosan from sludge that you might ingest from brushing your teeth with an FDA approved triclosan containing toothpaste, you would have to eat almost 1 kg (~2 pounds) of raw undiluted sludge containing triclosan, everyday!
For additional information on Biosolids Generation and Use in the United States refer to the US EPA Biosolids website.
Does triclosan have endocrine and/or anti-androgenic effects?
Generic statements regarding triclosan and the endocrine system have lead to significant misinformation regarding triclosan safety. The human body, and that of animals, is regulated by a complex endocrine system. A hormone is a generic term for one of the body’s many chemical messengers. There are about 15 different hormone systems in the body that make up the endocrine system, each with specific chemical messengers (eg, insulin, testosterone, and melatonin) and receptors (eg. pancreas, testes, and the brain).
Recent research has looked at the effect of triclosan on thyroid hormone receptors in the thyroid gland of bullfrogs (Rana catesbeiana), at blood serum concentrations of the thyroid hormone, thyroxine (T4), in weanling rats and at testosterone induced transcriptional activity in cell culture experiments using mechanistically-derived cell-based assay systems. Based on the species chosen or the methods used in conducting the study, each of these studies raise questions as to the significance of the findings and if there is real world association of the findings to humans and animals.
It is indeed clearly confirmed by a wealth of scientific data including a number of multi-generation reproduction and developmental (teratology) studies that triclosan has no anti-androgenic or androgenic affects whatsoever on living organisms. In addition, study results in whole animal models show no effect on thyroid function from exposure to triclosan. These data, from 14-day exposures to lifetime studies (1 or 2-years) using validated test methods, demonstrate that triclosan does not adversely impact normal endocrine organs or their functions; does not interfere with normal reproduction; does not interfere with normal developmental processes, and support its safe use in oral care, personal care and home care products.
Does triclosan bioaccumulate?
Triclosan has been reported in the bile of fish exposed to waste water treatment plant effluent and in wild living fish from rivers receiving Waste Water Treatment Plant (WWTP) effluent. Analysis of filamentous algae (Cladophora spp) sampled in the vicinity of a WWTP for triclosan bioaccumulation found increasing concentrations downstream of the outfall despite decreasing triclosan levels in water. Recent work in earthworms suggests that bioaccumulation may occur, but the data show a range of possible bioconcentration factors with no clear explanation as to why the variance is so large.
Triclosan does not accumulate in food-chains because it is excreted by animals and man by their metabolism. If a constant inflow occurs a steady concentration will be present in body fluids. These steady state concentrations cannot be interpreted as biomagnification as there is no triclosan remaining some time after cessation of intake (see Triclosan Human Heath and Safety: Common Questions for more details). For zebrafish this clearance time was measured to be around 5 days when exposed in water containing 35-59 µg/L triclosan after 5 days plateauing to steady state concentrations (Schettgen et. al., 1999).
The risk assessment for the aquatic and terrestrial organisms including fish-eating birds clearly showed no concern for these exposure routes. Thus the presence of triclosan in some soils or earthworms is at concentrations that are not causing any noted adverse effects.
Capdevielle, M., Van Egmond R, Whelan M, Versteeg D, Hofmann-Kamensky M, Inauen J, Cunningham V, and Woltering D. (2008) Consideration of Exposure and Species Sensitivity of Triclosan in the Freshwater Environment. Integrated Environmental Assessment and Management, Vol. 4(1):15-23. DOI: 10.1897/IEAM_2007-022.1
Pharmacokinetics of Triclosan Following Oral Ingestion in Humans Sandbourgh-Englund et al, 2006
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