Tags: antibacterial hand soaps, chemicals, environment, pubmed search, soap, triclosan
Triclosan or soap and water?
What is triclosan and why is it used?
Initially used in products for its anti-bacterial and anti-mold properties, triclosan is a chemical substance (5-chloro-2-(2,4-dichlorophenoxy)phenol, CAS 3380-34-5) added to many common products. It is most associated with toothpaste, mouthwash, hand-sanitizer, soap and dish-washing detergent; however, it also crops up in toys, mattresses, clothes, medical devices and kitchen utensils. It works by blocking fatty acid synthesis in bacteria, preventing reproduction and building of cell membranes. Since humans do not have the corresponding enzyme, any toxicity has to occur via other mechanisms.
Its marketing appeal lies in its purported ability to protect people from bacterial infection and poisoning (after all, who does not want protection from bacteria?) has led to very widespread use, to the point where while US Centers for Disease Control and Prevention biomonitoring data show that while 75% of Americans have detectable levels of triclosan in their blood (CDC 2009), potential restrictions on triclosan pose a significant risk to the makers of antimicrobial and antibacterial hand soaps, a market said to be worth about $375 million (NYT 2011).
Research into hazards and effectiveness of triclosan
Despite its widespread use, only a relatively small amount of research into the potential health effects of triclosan has been published. Much of the evidence for potential harm from triclosan comes from in vivo amphibian and fish studies and in vitro mammalian studies. A recent review of the available data found little evidence of carcinogenicity, mutagenicity or developmental toxicity, though there are indications that triclosan may disrupt thyroid hormone homeostasis and possibly the reproductive axis (Dann & Hontela 2011).
A PubMed search for effects of triclosan on the thyroid system (search string: “triclosan thyroid”) yields only 27 results, of which only 12 are human research (“triclosan thyroid human”). Overall there are only 58 papers on human toxicity of triclosan in PubMed (“triclosan toxicity human”) compared with 162 for the stain-repellent PFOA (“PFOA toxicity human”) and 368 for the phthalate DEHP (“DEHP toxicity human”).
Results from among the 12 human thyroid function studies are conflicting. While a recent epidemiological study observed “a positive association between triclosan and total triiodothyronine (T3) concentrations in adolescents” suggesting that “triclosan exposures may be associated with altered thyroid hormone levels in humans” (Koeppe et al. 2013), a rare placebo-controlled clinical trial has found no association between use of toothpaste containing triclosan with changes in thyroid function (Cullinan et al. 2012).
There does seem to be more research into allergenicity of triclosan than any other potential health effect (a search for “triclosan allergy” in PubMed yielding 46 results), suggesting that triclosan exposure increases allergic sensitisation, with higher urinary concentrations of triclosan especially related to inhalant and seasonal allergens (Bertelsen et al. 2013, Savage et al. 2012).
There are also concerns that triclosan may contribute to antibiotic resistance, although evidence is again limited here, and may even be something of a red herring: if triclosan is useful in healthcare for preventing infection, then this should not be compromised by the unnecessary use of triclosan in consumer products, regardless of whether or not it produces resistance to antibiotics and other antimicrobials.
The lack of research into risks posed by triclosan seems to be mirrored by a lack of evidence for its effectiveness. Although Colgate has FDA approval to use triclosan in its Total toothpaste because of its ability to fight gingivitis, the FDA has also said that it “does not have evidence that triclosan in antibacterial soaps and body washes provides any benefit over washing with regular soap and water.” For other consumer products the FDA “has not received evidence that the triclosan provides an extra benefit to health”. (FDA 2012)
What to do?
In Europe and the US, products containing triclosan have to be labelled as such, so it is relatively easy to avoid buying it if one is so inclined. However, depending on labelling instead of regulation to protect people and the environment from exposure to triclosan is unlikely to be successful, as it makes a reduction in environmental exposure contingent on people’s buying choices. These are much more tightly linked to what people know about a product (for triclosan, this may not be much), and the availability and desirability of alternatives, than to the risks posed by the use of the agent.
A UK medical Hygienist Panel has stated that “the uses of triclosan with demonstrable health benefits, as in some medical applications (such as antimicrobial sutures), need to be distinguished from those where there is no proven benefit, such as its use in certain consumer products. The addition of triclosan to a product must be substantiated in any claim of preventive or therapeutic health benefit.” (Leaper et al. 2011)
The high-street chemist Boots has prohibited triclosan from use in plastic articles, clothing and similar types of goods, stating that while they “do not believe that triclosan presents a direct risk to health from its use in consumer products […] that indiscriminate use of triclosan may have put an undue strain on the environment.” Triclosan can continue to be used in cosmetic and toiletry products sold by Boots, but only where it “offers the consumer a clear benefit” (Boots 2005). Johnson & Johnson have announced plans to go further, the company saying it will phase out triclosan by 2015 (AP 2012).
Actio Corporation, a software company providing data management tools to solve supply-chain problems of material disclosure and compliance with conflicting environmental regulations found in a global supply chain, are blunt that “manufacturers see triclosan as a marketing bonus.” (Actio 2012)
Actio’s advice is to “prepare to purge the chemical from product plans”, because “when a chemical like triclosan permeates the product development and/or marketing plans of a business, substantial profits stand to be lost if that chemical turns up on a popular or agency blacklist.”
A note of caution on substituting triclosan for other biocides
Triclosan concerns are encouraging chemical substitution. Reckitt Benckiser, manufacturers of Vanish, Finish and Dettol has removed triclosan from three face washes. Colgate-Palmolive has replaced triclosan with lactic acid in Palmolive Antibacterial Dish Liquid, and its Softsoap liquid hand soap has been reformulated without the chemical.
Bearing in mind, however, the Canadian Government statement that: “In most cases antibacterial soap is not necessary for safe, effective hand hygiene. Alcohol-based hand cleansers are useful when soap and water are not available,” (Health Canada 2012) one could ask if any substitution of triclosan with an alternative biocide is in fact necessary.
The reason being, if triclosan has not contributed to antibiotic or antimicrobial resistance in bacteria, after being used for decades prior to this being investigated, then perhaps we should be counting ourselves lucky. And if we did get lucky with triclosan, why would we want to repeat the gamble with a new range of biocides which are less well-tested than the one they are replacing – especially in an age when antibiotic resistant bacteria are running out of control?
Outside the healthcare environment, the idea that extra anti-microbial ingredients might protect us from germs might be reassuring but there is little reason to think it is true, while there is at least some evidence (bearing in mind this article has not even touched on the ecotoxicity of triclosan) to think it at best constitutes an unknown but potentially serious environmental health risk with no safety pay-off. So what reason is there to use anything other than traditional soap and water?
Study Suggests Long-Term Decline in French Sperm Quality. A new study findings suggest widespread declines in sperm quality in French men between 1989 and 2005, with average sperm counts falling while percentages of abnormally formed sperm rose. These findings are a “serious public health warning,” the authors wrote. Although the average estimated sperm count is still well above the level deemed normal by the World Health Organization, this may increase the proportion of men with fertility problems in the overall population.
Triclosan: Anti-bacterial soaps called useless, potentially dangerous. ”Triclosan is what we call a stupid use of a chemical,” said Dr. Sarah Janssen, a physician and senior scientist with the Natural Resources Defense Council, an environmental advocacy group. “It doesn’t work, it’s not safe and it is not being regulated.”
Everyday chemicals ‘pose threat to health’. Excellent NHS Direct coverage of media responses to the WHO EDC report, covering in detail the concerns correctly highlighted (though in a somewhat sensationalist manner) by the Daily Mail, who reported: “Chemicals found in every home may cause breast cancer, asthma, infertility and birth defects, global health chiefs have said.”
Architect describes how US Green Building Council is being attacked to protect interests of a small group of manufacturers of “toxic and obsolete” chemicals. “The war over toxic chemicals and human health is spilling over into places we live and work: our buildings,” says Robin Guenther. “The American Chemical Council (ACC) has launched an expensive and focused attack on the U.S. Green Building Council (USGBC) to protect the status quo of a small set of bad-actor manufacturers of toxic and obsolete chemicals. But innovative companies across the building industries and human health advocates are fighting back.”
Breast cancer among young women increasing. In 1976, 1.53 out of every 100,000 American women 25 to 39 years old was diagnosed with advanced breast cancer, the study found. By 2009, the rate had almost doubled to 2.9 per 100,000 women in that age group — a difference too large to be a chance result. This news comes at the same time as a report faults priorities in breast cancer research, stating that too little of the money the federal government spends on breast cancer research goes toward finding environmental causes of the disease and ways to prevent it.
Persistent Environmental Pollutants and Couple Fecundity: The LIFE Study. This couple-based prospective cohort study with preconception enrollment and quantification of exposures in both female and male partners observed that a subset of persistent environmental chemicals were associated with reduced fecundity.
In Utero and Childhood Polybrominated Diphenyl Ether (PBDE) Exposures and Neurodevelopment in the CHAMACOS Study. Both prenatal and childhood PBDE exposures were associated with poorer attention, fine motor coordination, and cognition in the CHAMACOS cohort of school-age children. This study, the largest to date, contributes to growing evidence suggesting that PBDEs have adverse impacts on child neurobehavioral development. EHP provides a plain-English summary of findings.
Epigenetics and pesticides. In spite of the current limitations, available evidence supports the concept that epigenetics holds substantial potential for furthering our understanding of the molecular mechanisms of pesticides health effects, as well as for predicting health-related risks due to conditions of environmental exposure and individual susceptibility.
Effect of low dose bisphenol A on the early differentiation of human embryonic stem cells into mammary epithelial cells. This in vitro study provides insight into the effects of low doses of BPA on mammary epithelial cells during early stages of differentiation, suggesting that exposure to BPA may make breast cells more likely to become cancerous later in life.
Potential Sources of Bisphenol A in the Neonatal Intensive Care Unit. The authors describe nasal oxygen administration and continuous positive airway pressure as individual sources of higher exposure to BPA. In these circumstances, BPA would pass into circulation in the blood without undergoing first-pass metabolism in the liver, resulting in higher exposure to free, active BPA than if the same amount were to be ingested.
Tags: chemicals, environment, ragnar löfstedt, risk assessment, risk vs hazard, science
Should chemical regulation be based on the intrinsic potential for a substance to cause harm, or should further account be taken of the probability that they will actually cause harm? This is a question of increasing importance in European chemical regulation, as disputes about the safety of chemicals heat up and regulators seek to reassure the general public that what they are exposed to is safe, or if not safe, that chemical hazards are at least an issue which is under control.
However, as Dr Ragnar Löfstedt, of the Kings Centre for Risk Management at King’s College London, writes: “In Europe there has been a rather long and at times acrimonious discussion, as to the merits of risk assessments for regulatory purposes especially with regard to chemical substances. There is no European consensus of when to use risk assessments and when to use hazard classifications.” (Löfstedt 2011)
This seems particularly pertinent in, for example, the case of BPA, which has been risk-assessed by the European Food Safety Authority (EFSA) and found safe at current levels of exposure, recommended for restriction by French food safety agency ANSES, banned in baby bottles by the EU, banned even in receipts by Sweden, and generally held in suspicion by environmental groups and the public at large. Approvals accord with the current risk assessment advice; bans tend to be based on a preference for regulating on the hazard presented by BPA. At least, that is the story as Löfstedt presents it.
Before we get into why BPA is variously banned or accepted, it is worth reminding ourselves of the difference between risk- and hazard-based approaches to regulating chemicals. This is important, because “risk” and “hazard” have specific, technical meanings in the context of chemical safety assessment which tend to be conflated in everyday use (indeed, the Oxford English Dictionary defines risk as “a possibility of harm” and hazard as “a danger or risk”).
David Ropeik, a consultant in risk perception and management, describes hazard as concerning “whether or not the chemical in question presents an environmental or health hazard (is it potentially harmful?); the level of hazard it presents (such as the dose at which it is toxic, and the effects of the toxic dose); and the people or environmental elements to which it poses a hazard.”
Of risk, he says that: “Risk assessment takes this information and goes one step further, to evaluate the likelihood that the hazard is likely to result in actual harm, asking questions around: in what ways are we exposed to the chemical? How often? To what degree and at what age? (Ropeik 2013)
The contention is the extra information used in risk assessment allows the risk assessor to quantify the exposure level at which a chemical is likely to be harmful, make a judgment on who is going to be exposed to that level, and propose risk management measures on that basis.
If a risk assessment is reliable, then there can be a minimum number of restrictions on chemical use, allowing the maximum advantage to be gained from the entire pool of available compounds, rather than unnecessarily restricting society to using just those which cannot pose a risk because they pose no hazard.
As Löfstedt observes, different EU Member States place different degrees of weight on the hazard and risk elements of evaluating chemical safety in making a regulatory decision. Sweden, with its early action on BPA in infant proposals and its ban on BPA in receipt papers, tends to operate at the hazard end of the scale.
The UK takes quite the opposite approach: its double-checking of EFSA’s risk assessment of neonicotinoids to see if there really is adequate degree of risk to warrant a ban (Independent 6.2.13), and its promotion of a risk-based approach to the regulatory definition of “endocrine disruptor” (DE/UK 2011, see this H&E article for a full discussion) are both testament to this.
Löfstedt characterises risk assessment as a “science-based tool” and warns that “a hazard-based approach takes away the scientific rigour of risk assessments.” (Löfstedt 2011) The implication being that hazard-based approaches to chemical regulation are less scientific.
Hazard assessments are not pulled out of a hat. They are based on the same toxicological and epidemiological research as risk assessment (obviously, since risk assessment is the next step after hazard assessment). Presumably Löfstedt does not mean they are less scientific in that sense; he must mean that the extra data used in risk assessment means it is more scientific.
Risk assessment uses an extra set of data, but whether or not that makes it “more science-based” must surely depend on the quality of the science behind the extra data. More science is not the same thing as more scientific, because adding data only makes a decision more scientific if the data is any good: an extra volume of data does not necessarily improve the management of risk from a compound, if risk is underestimated because of an absence of data or because the exposure is simply too complex to model.
Löfstedt characterises the perceptions which drive hazard- and risk-based approaches as follows: “Those favouring hazard-based regulations argue that risk assessments are complex, non-scientific, costly and based on different methodologies that can produce different outcomes,” while advocates of risk-based approaches see hazard-based decisions as “based on assumptions rather than testing”.
It is not clear if the observation does not work both ways: a sceptic about the effectiveness of risk assessment could argue that risk-based decisions are based on at least as many assumptions as hazard-based decisions. As new evidence emerges about the possibility of low-dose effects, cumulative toxicity of mixtures, endocrine disruption and so forth – all new developments unanticipated by risk assessment practices in the past – the accuracy of risk assessment in the face of knowledge gaps could start to appear questionable.
These knowledge gaps make even the hazard identification stage of risk assessment difficult enough; to then add more information about routes of exposure, environmental impacts etc. introduces so many additional assumptions and reliance on further uncertain data, that it does not in fact improve our ability to protect ourselves from harm.
As is implicit in the latest edition of Late Lessons from Early Warnings (European Environment Agency 2013), if anything, risk-based approaches make us over-confident in our ability to anticipate harm and lowers our ability to respond sufficiently quickly: it is inherently risk to rely on risk assessment. It could be argued that a hazard-based approach is a pragmatic choice to nullify the risk of getting the risk assessment wrong, by eliminating hazard as much as possible.
Risk-based approaches are obviously consistent with the economic imperatives of governments and industry, as it maximizes opportunity for commercial enterprise. But are hazard-based approaches necessarily uneconomical?
Opposition to hazard-based approaches often comes from the argument that unnecessary restrictions on chemicals pose a large economic threat. Companies such as Hewlett Packard see this very differently: scientific uncertainty about the safety of individual compounds, in which new research can rapidly change understanding of the risk posed by an individual compound leading to its being banned, produces a very risky business environment into which to introduce a compound.
See this video for HP’s presentation of its hazard-based approach to chemicals management.
Do companies like HP need risk assessment to deal with these challenges? They argue that they do not. Retailers and product managers sell and design products with electrical flexes, circuit boards, heated surfaces, chewable parts, etc. Since each of these elements is used in the same way, exposure must be more-or-less constant across each product class.
If exposure is constant, to reduce risk the only thing the retailer needs to control for is the intrinsic hazard of the chemicals used in each product class; any decision about substitution can therefore be based on hazard profile. To put it another way: exposure is constant across product class, therefore manufacturers can dispense with exposure and risk assessment, and make substitution decisions based purely on hazard.
This is obviously not an argument which will suit primary manufacturers who are tooled-up for producing any of the chemicals which are restricted on the basis of their hazard profile. The notion, however, that a hazard-based approach might in some way be intrinsically anti-business or unscientific does not seem to stand up to scrutiny when one considers the entire range of companies involved in producing and selling consumer products.