Center for Drug Evaluation and Research
Food and Drug Administration
Department of Health and Human Services
Regarding: Request for Environmental Impact Data and Information;
Antimicrobial active ingredient triclosan
Docket No. FDA-1992-N-006
Environmental Working Group (EWG) is a non-profit public health and environmental research and advocacy organization based in Washington, DC. We focus much of our research on potential health risks from chemical contamination of food, water, consumer products, and the environment. With this letter, we urge the Food and Drug Administration (FDA) to conduct a thorough assessment of the adverse effects of the antimicrobial chemical triclosan on human and environmental health.
Under the current review of the environmental impact of active ingredients proposed for an Over-the-Counter drug monograph, FDA has an opportunity to make a regulatory decision that would protect human health and the environment from widespread triclosan releases. Due to its potent, broad-spectrum antimicrobial activity, triclosan serves a useful public health function in medical applications. However, for the vast majority of FDA-regulated triclosan products such as antibacterial hand soaps and dishwashing detergents, there is no evidence of greater efficacy compared to plain soap (Aiello 2007; FDA 2010; Levy 2001). This fact alone raises significant questions about consumer use of triclosan.
For the compliance of the proposed FDA action with the National Environmental Policy Act (NEPA), triclosan is clearly ineligible for categorical exclusions from an environmental assessment as defined in the current FDA regulations (21 CFR 25.1). For human-made, synthetic ingredients, FDA typically relies on a calculation that estimates the concentration of a chemical substance in the US waters (FDA 1998), calculated as the annual production volume of the chemical divided by the total quantity of water entering publicly owned water treatment facilities in the US. If the estimated concentration is below 1 part per billion (ppb), a chemical is granted exclusion from an environmental assessment.
Such an exclusion and the estimated concentration on which it would be based, would be utterly inappropriate for triclosan for 2 reasons:
- First, triclosan levels in many individual bodies of water likely exceed 1 ppb, as demonstrated by the tests conducted by the U.S. Geological Survey which found concentrations as high as 2.3 ppb in the pilot group of 85 water samples collected nationally (Kolpin 200). Aquatic life most at risk from triclosan pollution will be that in areas of highest triclosan concentration. An exclusion based on a crude calculation of a national average concentration of triclosan in surface water will leave many water bodies potentially at risk.
- Second, according to research from the Environmental Protection Agency and academic scientists, triclosan selectively partitions into sewage sludge and sediments, which serve as a constant triclosan reservoir and a source of chronic triclosan exposure for aquatic life, agricultural ecosystems and the food chain (Heidler 2009). Again, an exclusion based on the bulk average level of triclosan in all U.S. waters will leave aquatic life in many water bodies at risk, particularly those for which significant amounts of triclosan are bound to sediment.
With this letter, we bring to FDA’s attention three key considerations in triclosan risk assessment:
- Massive amounts of triclosan are released into the environment from down-the-drain disposal of consumer products, making the FDA’s 1 ppb exclusion rule inappropriate for triclosan.
- Triclosan bioaccumulates in aquatic plants and animals and poses multiple ecotoxicity risks.
- A growing body of research points to the endocrine-disrupting potential of triclosan and the likelihood of antimicrobial resistance development.
We urge FDA to conduct a full environmental assessment of triclosan, and to require nationally representative surface water, sediment, and sludge sampling by triclosan manufacturers to determine the full extent of environmental pollution caused by existing, widespread use of this compound.
Details and rationale for our recommendations are listed below.
1. Massive amounts of triclosan are released into the environment from down-the-drain disposal of consumer products, making the FDA’s 1 ppb exclusion rule inappropriate for triclosan.
The use of triclosan in consumer products has resulted in contamination of both people and the environment (Buth 2010; EPA 2008; Focazio 2008). Triclosan tends to accumulate in the fatty tissues of humans and wildlife (Samsøe-Petersen 2003). Researchers at the Centers for Disease Control and Prevention detected triclosan in 75 percent of Americans (Calafat 2007). Triclosan has been also detected in umbilical cord blood and in human breast milk (Adolfsson-Erici 2002; TNO 2005; Allmyr 2006a,b).
While precise statistics are not available, U.S. Environmental Protection Agency (EPA) data from the chemical inventory update reporting indicates that annually an excess of a million pounds of triclosan is released into the environment in the United States, much of it through down-the-drain disposal of consumer products such as hand soaps and detergents (Miller 2008). Due to its hydrophobicity, triclosan primarily partitions into sewage sludge and sediment following wastewater treatment and discharge (Buth 2010; Kinney 2008; Miller 2008; Singer 2002). Together with another antimicrobial chemical, triclocarban, triclosan is the most abundant anthropogenic pollutant in sewage sludge (McClellan 2010). EPA’s latest Targeted National Sewage Sludge Survey found triclosan in 92.4 percent of public wastewater treatment plants tested nationwide (EPA 2009). In some cases, triclosan levels in dried wastewater sludge were as high as 133 milligram/kilogram (133 parts per million or ppm) (EPA 2009). Once triclosan-containing biosolids are applied to agricultural areas, a common disposal practice across the country, they would serve as a constant reservoir for triclosan contamination of soils and local water bodies (Heidler 2007; Heidler 2009).
In light of extensive triclosan discharges both with wastewater effluent and via sewage sludge, it is not surprising that the U.S. Geological Survey scientists (USGS) detected triclosan in 58% of 85 rivers and streams tested (Kolpin 2002). Concentrations up to 2.3 ppb were observed in this pilot USGS study. Clearly, there are water bodies in the United States where local triclosan concentrations exceed the arbitrary 1 ppb rule established by FDA for categorical exclusion of FDA-regulated substances from the NEPA-mandated environmental assessment (FDA 1998). Long-term accumulation of triclosan in sediments and sludge is another reason why this exclusion based on a theoretical calculation would be inappropriate and severely underestimate the risks of triclosan in the environment.
2. Triclosan bioaccumulates in aquatic plants and animals and poses multiple ecotoxicity risks.
Despite decades of triclosan use in commerce, well-documented ecotoxicity (Chalew 2010; Dussault 2008) and ability to form toxic byproducts (Buth 2010; Fiss 2007), so far no U.S. government agency conducted a comprehensive environmental risk assessment for the full range of triclosan-containing consumer products and resultant pollution. EWG urges FDA to address this gap and develop stringent regulations for triclosan release into the environment.
By their very design, antimicrobial pesticides are meant to kill, making them inherently unsafe for aquatic life. When released with effluent from wastewater treatment plants, triclosan accumulates in algae, snails, fish and amphibians that live downstream, frequently at concentrations several orders of magnitude above ambient levels (Balmer 2004; Coogan 2007; Palenske 2010). In addition, stream and river sediments may serve as a constant-release source of triclosan that would adversely impact bottom-dwelling organisms such as worms, mussels and clams, crabs, and some herbivorous fish species (Binelli 2009; Miller 2008). Furthermore, larvae of many aquatic organisms are filter feeding. During the early, most sensitive stage of their life cycle, they may be exposed to levels of triclosan that have been associated with embryonic toxicity, anatomic changes, and developmental delays (Oliveira 2009; Palenske 2010).
Due to its toxicity towards a wide spectrum of microbial and algal species, triclosan may disrupt critical ecological processes performed by beneficial microorganisms in nature (Dokianakis 2004; Johnson 2009; Lawrence 2009; Miller 2008; Neumegen 2005; Waller 2009). Especially worrisome are recent reports that indicate significant presence of antimicrobial pesticides in agricultural soils, associated with soil application of triclosan-containing sludge and biosolids from wastewater treatment plants (Cha 2009). These findings are of great concern because triclosan has been shown to inhibit soil respiration and nitrification processes that are essential for preserving soil fertility (Waller 2009). Additionally, in its risk assessment for triclosan, EPA reported that at the highest concentration of triclosan found in U.S. streams, there is a potential for acute risks to freshwater algal species (EPA 2008), which would have adverse effects on oxygen-producing algal communities in waterways (Lawrence 2009).
3. A growing body of research points to the endocrine-disrupting potential of triclosan and the likelihood of antimicrobial resistance development.
In animal studies, triclosan has been linked to liver damage, adverse developmental defects and a possible risk of cancer. So far, the highest concern has been raised for hormone toxicity of triclosan, including adverse effects on thyroid, estrogen, and testosterone hormone function. Some of the recent findings include:
- In an animal study, low level maternal triclosan exposure lead to health effects in offspring, including irregular skull development and decreased fetal weight, indicating that triclosan may be a developmental toxicant (EPA 2008).
- Studies have shown that triclosan perturbs thyroid hormone signaling (Paul 2010; Veldhoen 2006; Zorrilla 2008). Thyroid hormones are critical for normal brain development, especially for the developing fetus during pregnancy.
- Studies suggest that triclosan and its metabolites may interfere with the normal function of male and female hormones, disrupting androgenic and estrogenic pathways (Foran 2000; Gee 2008; Ishibashi 2004; James 2010; Matsumura 2005). Chemicals with estrogen- or androgen-effects have been linked to an elevated risk of breast and prostate cancer (Diamanti-Kandarakis 2009)
The studies of triclosan hormone toxicity are still ongoing as part of the research conducted by university scientists and by the EPA. The existing data have been sufficient for the EPA to make a decision to re-review triclosan’s eligibility for re-registration in 2013, 10 years ahead of the usual schedule for pesticide re-registration at the Agency (EPA 2010).
Additionally, the presence of triclosan in the environment, in people’s homes and in human beings raises the possibility of antimicrobial resistance development and consequent loss of triclosan’s medical usefulness. Spread of triclosan-tolerant bacterial strains would make this chemical ineffective in its important public health applications. As summarized in a recent review, “of major concern is the possibility that triclosan resistance may contribute to reduced susceptibility to clinically important antimicrobials, due to either cross-resistance or co-resistance mechanisms… Thus, widespread use of triclosan may represent a potential public health risk in regard to development of concomitant resistance to clinically important antimicrobials” (Yazdankhah 2006). Already, triclosan-resistant bacterial strains have been reported in multiple laboratory studies (Birosova 2009; Chen 2009; Cottell 2009; Pycke 2010; Yu 2010; Zhu 2010). These findings show the strong potential for development of clinically relevant triclosan-resistant strains of bacteria, a possibility that could be averted or significantly delayed simply by restricting triclosan use for essential medical applications only (Aiello 2007).
In conclusion, EWG strongly urges FDA to address long-standing, severe gaps in government oversight for triclosan that resulted in widespread and uncontrolled human and environmental exposures, potential risks to human health, and chronic ecosystem toxicity. The presence of triclosan in daily consumer products may well endanger future uses of this chemical in essential, life-saving settings and medical applications. EWG advises FDA to incorporate the broad range of toxicology, exposure, and environmental fate studies for triclosan and to assess the full impact of triclosan from all FDA-regulated, triclosan-containing products, a step that FDA has not as yet conducted despite decades of triclosan use in consumer products. We look forward to working with FDA on the issues of triclosan safety for humans and the environment, and we advise FDA to restrict triclosan uses for primary medical applications where it is truly needed.
With best regards,
Olga V. Naidenko, Ph.D.
Environmental Working Group
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