Canary Cosmetics Reading Room

From PANUPS: 

Changes in doctors’ diagnoses cannot explain the sevenfold increase in autism since 1990, a new study shows. Rather, “It’s time to start looking for the environmental culprits responsible for the remarkable increase in the rate of autism in California,” said Irva Hertz-Picciotto, an epidemiology professor at University of California, Davis who led the study.

In California alone, more than 3,000 new cases of autism were reported in 2006, up from just 205 in 1990. The increase had previously been attributed to a change in diagnoses, but the new study concludes that those factors can’t explain most of the increases, reports Marla Cone of the Environmental Health News.

“Mothers of autistic children were twice as likely to use pet flea shampoos, which contain organophosphates or pyrethroids, according to one study that has not yet been published,” says Hertz-Picciota. “Another new study has found a link between autism and phthalates, which are compounds used in vinyl and cosmetics.

Other household products such as antibacterial soaps also could have ingredients that harm the brain by changing immune systems,” she added.

http://www.bestsyndication.com/?q=20080914_organic_laundry_detergents.htm

By: Janelle Elizabeth

We hear a lot about how toxic emissions need to be reduced if we are to reduce the harm they can cause to people and the environment. The good thing is that we are each in a position to make some changes in our daily lives that will make up for the harm we have already done to the earth.

A lot of these products in our everyday lives have harmful chemical ingredients. In some cases these are listed clearly, but few of us are able to discern the truth from the scientific jargon. In others, the list of ingredients is very unclear.

Either way, some of these chemicals can affect us, our families, and the environment in very negative ways.

Laundry detergent is one such product that often times contains vague information on its list of ingredients. The residues left behind are potentially harmful as well. Even if your clothes may seem very fresh and clean, they may actually just be loaded down with harsh toxins.

A list of ingredients found on a common brand of laundry detergent leaves a consumer with a lot of questions. For instance, such ingredients included a buffering agent, stabilizer, brightening agent, and fragrance. This confusing description raises even more questions.

What causes that lovely fragrance? What cleans them?

When a closer look is taken, the list becomes shocking at the harmful chemicals found in such a common product as laundry detergent. As a consumer, it becomes clear that it may be time to take control and use a safer alternative.

When your detergent claims to offer brighter and whiter clothes, you may want to rethink your decision. The “optical brighteners” found on the label of one detergent are actually synthetic, or man-made chemicals. They work by turning ultraviolet wavelengths into visible light that makes clothes appear whiter, yet does not really make them any cleaner.

Some of their bad effects are that they can cause bacterial mutations and are poisonous to fish.

They can also cause allergic reactions to the skin when they are exposed to the sun.

Another common selling feature of laundry detergents is fragrance. A lot say that they leave your clothes “smelling fresher” or “lemon fresh”. The artificial fragrances found in detergents can often be derived from petrol. They can harm the environment because they are not biodegradable. Research has shown that these artificial fragrances can have toxic effects on fish and mammals. More importantly, they can cause skin and eye irritation and allergies.

These detergents may in fact create whiter and better smelling garments, but the harmful price being paid for your family and on the environment is hardly worth it.

http://www.plentymag.com/events/2008/09/liquid_soap_without_antibacter.php

Antibacterial liquid soaps, spiked with controversial triclosan, are crowding pesticide-free versions off the shelves. True, our return to crowded workplaces and classrooms means we’re bound to get our hands a little dirty, and cold/flu season looms on the far side of halcyon days. But why worry now, and who needs overkill? After all, a little judicious exposure to germs may strengthen immune systems, according to a recent study of 13,524 children. Those who lived on farms had a reduced risk of developing asthma compared with other rural and urban children; this may be due, at least in part, to exposure to “endotoxins” from animal viruses and manure, the study’s lead author said.

As for triclosan, The American Medical Association, U.S. Centers for Disease Control, World Health Organization and many scientists are concerned that it is contributing to the spread of antiobiotic-resistant bacteria, and recommend washing hands and household surfaces with plain soap and water, instead. Despite its presence in half of 259 hand soaps examined by the Environmental Working Group (EWG), triclosan is easy to avoid:  Just read labels and choose products that don’t list is as an active ingredient.

To get your started, some product tips:

Kids and parents can have nontoxic fun with these new products from Kiss My Face: Obsessively Natural Kids self-foaming handwash and bubblewash (bubble bath), which have no triclosan, synthetic fragrance(phthalates) or parabens.Neither do the following liquid hand washes are also free of , according to EWG’s Skin Deep database:  Aubrey Organics, Avalon Organics, Dr Bronner’s (we love their new baby-unscented and rose oil formulas), and Earth Friendly Products with organic lavender. Check out Skin Deep for more products.

If you want something a bit stronger, but without triclosan or alcohol, there’s a new line of all-natural antibacterial hand washes from Cleanwell. Instead, they use a patented mixture of plant essential oils. The active ingredient:  thyme oil. Cleanwell also makes hand sanitizers in gel (including a handy pocket size) and individually-wrapped wipes, which, yes, waste packaging but are good to keep for emergencies. Does it really work? First, anything will work insofar as it rubs or slides germs off your skin. That’s how plain soap & water works.  As for how this works compared with other antibacterial products, only thyme will tell.

http://www.healthnewsdigest.com/news/Family_Health_210/Toxic_Household_Cleaners.shtml

(HealthNewsDigest.com) - While much of the research is mixed or inconclusive, a variety of human and animal studies have linked chemicals common in household cleaning products with a wide range of health risks.

The most offensive common ingredients, according to a 2006 study by the University of California Berkeley and Lawrence Berkeley National Laboratory, are ethylene-based glycol, used commonly as a water-soluble solvent in cleaning agents and classified as a hazardous air pollutant by the U.S. Environmental Protection Agency (EPA), and terpenes, a class of chemicals found in lemon, pine and orange oils that can morph into carcinogenic compounds when they mix with ground-level ozone.

Also, chlorine, often labeled as “sodium hypochlorite” or “hypochlorite,” is almost ubiquitous in household cleaners, unfortunately for the inhabitants of many homes. Breathing in its fumes can irritate the lungs, and as such poses a serious health risk to those with pre-existing heart or respiratory problems.

According to the non-profit Cancer Prevention Coalition, some other problematic chemicals found in many household cleaners include crystalline silica, an irritant to the eyes and lungs and a likely carcinogen, and butyl cellosolve, which has been linked to kidney and liver problems and is reportedly toxic to forming cells. The group lists dozens of other potentially dangerous ingredients in household products on the “Hazardous Ingredients in Household Products” PDF available for free on its website.

Gaiam, a leading purveyor of green household and lifestyle items, reports that the average American household contains between three and 25 gallons of toxic materials, mostly in the form of household cleaners filled with petrochemical solvents designed to dissolve dirt. The company bemoans the fact that no law requires cleaning products manufacturers to list ingredients on their labels or to test their products for safety, leaving it up to consumers to make sure their homes are not only clean, but also non-toxic.

Luckily there are plenty of “greener” alternatives now widely available from manufacturers like Gaiam, Earth Friendly Products, Citra-Solv, Ecover, Mrs. Meyers, Sun and Earth, SimpleGreen, Method, and Seventh Generation, among many others. Even big players are getting in on the act. Clorox recently released a new line of home cleaning products under the Green Works label to attract a greening clientele.

For those so inclined, making your own green cleaning solutions is easy and cheap. According to The Green Guide, consumers can “circumvent the armada of commercial cleaners” by keeping handy an ample supply of eight ingredients for nearly every do-it-yourself cleaning job: baking soda, borax, distilled white vinegar, hydrogen peroxide, lemons, olive oil, vegetable-based (liquid castile) soap, and washing soda.

http://www.uoguelph.ca/news/2008/09/bpa_impairs_syn.html%22

The controversial chemical Bisphenol A commonly found in hard plastic food and drink containers may impair the brain’s ability to learn and remember according to a groundbreaking study conducted by researchers at the University of Guelph and Yale University.
  
The study reveals that continuous low doses of Bisphenol A (BPA) hinders the formation of synapses in the brain, which allow neurons to communicate with one another and are critical to the way we interpret and remember experiences.
  
“It dramatically impairs the formation of synapses in the regions of the brain important to learning,” said biomedical science professor Neil MacLusky. “These findings are worrisome because BPA is one of the most widely-used chemicals in the world.”
  
BPA is used in plastic water bottles and some baby bottles, dental prostheses and sealants, and in the lining inside of food cans. It has been proven that this chemical can leach from these products and be absorbed through human consumption.
  
Although previous research has been done on the harmful effects of BPA, MacLusky’s study, set to be published this week in the Proceedings of the National Academy of Sciences, is the first to mimic continuous environmental exposure levels. 
  
Using the dose level declared safe by the United States Environmental Protection Agency for daily consumption by humans, the researchers exposed African Green monkeys living on the Island of St. Kitts to BPA for a month.
  
Results showed that even at this low dose BPA turns off increases in synapses density in the brain normally induced by estrogen, said MacLusky.
  
“Estrogen is more than just a female reproductive hormone. It enhances the rate at which some types of synapses are formed and is vital in maintaining normal neuronal structure in regions of the brain that control learning, memory and mood state. When we have BPA in our systems, it seriously impairs this process.”
  
Although further research is needed, these results support the possibility that BPA may be involved in human neurological conditions such as Alzheimer’s disease, depression and schizophrenia, which all feature aberrant synapse formation and are also sensitive to sex hormone levels, he said. 
 
This study was funded by the United States National Institute of Health and the Natural Sciences and Engineering Research Council of Canada.

Last Updated: Monday, August 25, 2008 | 
CBC News 
http://www.cbc.ca/health/story/2008/08/25/incense-cancer.html 
 
Inhaling incense fumes over long periods increases the risk of developing cancers of the respiratory tract, a finding that applies to Asian populations worldwide, researchers warn. 

Burning incense — a mix of plant materials and oils — is an integral part of daily life in large parts of Asia, as well as in North Africa and among Inuit populations.

Incense releases large amounts of smoke containing particulate matter that gets caught in the lungs, as well as possible carcinogens such as polyaromatic hydrocarbons (PAHs), carbonyls and benzene.

Indoor concentrations of particulate matter from burning incense has been found to far exceed outdoor air quality standards, and can potentially produce more particulate matter than second-hand tobacco smoke, previous studies have shown.

Burning incense almost doubled the risk of squamous cell carcinomas in the upper respiratory tract, such as the nose and sinuses, tongue, mouth and larynx, said the researchers led by Dr. Jeppe Friborg of the epidemiology department at Statens Serum Institut in Copenhagen, Denmark. 

Their findings are published in the Oct. 1 issue of the journal Cancer.

‘Given the widespread and sometimes involuntary exposure to smoke of burning incense, these findings carry significant public health implications,’ the study’s authors concluded.

‘Besides initiatives to reduce incense smoke exposure, future studies should be undertaken to identify the least harmful types of incense.’

While a cause-and-effect relationship could not be established in this type of study, experts suggest burning incense less often and improving ventilation to minimize the long-term risks.

The risk increased in both smokers and non-smokers, the study of more than 61,000 Singaporean Chinese found. The intensity and duration of incense use were also both linked to the levels of risk, Friborg’s team found.
 
The overall risk of lung cancer did not appear to increase with incense use, but the study did suggest a link to increased risk of a specific type of disease, squamous cell carcinoma of the lung.

Participants were aged 45 to 74 and were free of cancer when they were first interviewed in 1993-1998. They were followed until 2005. 

Over that time, a total of 325 upper respiratory tract cancers (including nasal/sinus, tongue, mouth, laryngeal and other cancers) and 821 lung cancers were found.

http://www.guardian.co.uk/world/2008/jul/30/health 

Worship is generally not a life-threatening pursuit. But devotees across Asia could be taking their life into their hands every time they go to a temple to pray, according to a study by a Thai doctor.

Burning joss sticks lit as an offering in shrines and temples fill the air with cancer-causing toxins that are every bit as deadly as traffic fumes and cigarette smoke, says Dr Manoon Leechawengwong.

Dr Manoon, who has just completed a two-year study of temple workers tasked with clearing the smouldering sticks, found the cocktail of chemicals in the smoke put them at risk of leukaemia, lung, blood and bladder cancers.

“One joss stick creates the same amount of cancer-causing chemicals at one cigarette,” said Dr Manoon, who led the research. “I knew there would be some carcinogens, but I was surprised by the levels.”

Joss sticks are a type of incense used in worship in many Asian countries. In Buddhism they are believed to aid spiritual communication and serve as an offering.

Dr Manoon’s study was conducted among 40 workers in three temples at Ayutthaya, Chachoengsao and Samut Prakan, sites chosen deliberately far from Bangkok’s traffic pollution. The findings were compared with another 25 people living in a joss-stick free environment.

Temple workers were exposed to high levels of benzene, also known as petroleum ether, related to leukaemia; butadiene involved in blood cancer; and benzo[a]pyrene that can cause lung, bladder and skin cancers.

The level of benzene in the temple workers was four times higher than normal, butadiene was 260 times higher, and benzo[a]pyrene - the most dangerous carcinogen - 63 times greater.

Analysis of the temple workers blood and urine samples discovered damage to their DNA, with a correspondingly lower capacity of their bodies to repair that damage.

“We know from our study that there’s DNA damage,” said Dr Manoon. “But what we don’t know is if they will develop cancer. Certainly they have a greater risk. It’s like smoking. Not all smokers get cancer, it’s about 20% .”

But Dr Manoon urges worshippers to reduce the risks by extinguishing the scented joss stick immediately after use, rather than leaving it standing pots of sand as it burns down. Manufacturers could also produce sticks that burn for a minute or less.

“It’s not necessary as part of the ritual for these traditional joss sticks to burn down,” he said. “By putting them out after a minute or so the air pollution would be cut by 30 to 40 times.”

http://www.medpagetoday.com/PublicHealthPolicy/EnvironmentalHealth/tb/10269

By Emily P. Walker, Washington Correspondent, MedPage Today
Published: July 25, 2008

Reviewed by Dori F. Zaleznik, MD; Associate Clinical Professor of Medicine, Harvard Medical School, Boston.

WASHINGTON — An environmental activist group believes that triclosan, an antimicrobial agent added to hundreds of everyday products, offers no  demonstrable benefits while threatening human health.

Best known as the active ingredient in antimicrobial hand soaps, triclosan is also used as an antibacterial agent in toothpaste, deodorants, laundry  detergent, facial tissues, antiseptics for wounds, and medical devices.

It is used as a material preservative to ward off bacteria, fungus, mildew, and odors in household items like toys, paints, mattresses, clothing, toilet  bowls, and furniture fabric.

Now the Environmental Working Group has called triclosan a toxic pesticide, with ominous hints of carcinogenicity, and has demanded that federal  agencies ban it from consumer goods.

“A toxic pesticide linked to serious health problems should not be in our soap or toothpastes,” contends EWG scientist Rebecca Sutton, Ph.D. “It’s  time to ban triclosan from all personal care and household products.” Scattered research supports some of EWG’s claims. Over the years, even the  American Medical Association has declared that antibacterial soap offers no  cleansing benefit over regular soap, and it cited the risk of antibiotic  resistance developing.

In 2005, an FDA advisory panel concluded that mass-marketed antiseptics are no more effective at preventing infections than washing hands with regular  soap.

But there has been little agreement with the claim that triclosan might foster cancer in humans.

“The facts and the science don’t back up their recommendations,” said a spokesperson for the Soap and Detergent Association, the trade group for  cleaning products. “It’s all hype and headlines, which is what we’ve come to  expect from them.”

The EWG is the same group that recently declared most sunscreen brands to be ineffective and said a common suncreen ingredient — oxybenzene — could be  harmful to humans. The EWG is funded by private conservation organizations  and most of its resources go toward work on purportedly toxic chemicals and  public health.

The Environmental Protection Agency, which shares triclosan regulation with the FDA, is conducting a review of the antimicrobial agent and recently  released its early findings. They dispute the EWG’s claims that triclosan  may cause cancer in humans. The EPA found, however, that triclosan’s  presence in streams and lakes has a harmful effect on marine plants.

The EWG denies being alarmist about triclosan. “Triclosan persists in the environment, breaks down into substances highly toxic to wildlife, pollutes  the human body, and poses health risks that are barely studied and poorly  understood,” the EWG asserted.

A review by epidemiologist Allison Aiello, Ph.D., of the University of Michigan School of Public Health, backed the contention that antibacterial  soap to wash one’s hands is no better than using regular soap and water. The  Michigan review also found that antibacterial soap can cause selective  antimicrobial resistance, at least in a laboratory setting.

The 2007 literature review of 27 antibacterial hand soap studies published in Clinical Infectious Diseases confirmed that regular handwashing in the  home is just as effective. That review determined that using antibacterial  soap did not reduce the amount of bacteria on a person’s hands, nor did it  prevent illness symptoms like cough, diarrhea or skin infections.

One of the studies reviewed found a reduction in hand bacteria levels when the participants used soaps containing triclosan, but that was only after 18  separate 30-second hand washes during five consecutive days.

Eleven of the studies Dr. Aiello reviewed found triclosan-tolerant species and cross-resistant to clinical antibiotics, suggesting that — at least at  the laboratory level — cleaning with triclosan products can lead to  antibacterial resistance.

But when the researchers examined four community-based studies to look for antimicrobial resistance associated with triclosan, it found none.

The Michigan researchers concluded that “further research is clearly needed to assess whether the emergence of antibiotic resistance in the community  setting is associated with the growing use of soaps containing triclosan.”

Triclosan was approved by the FDA in 1969 as a topical antimicrobial. However, until the past 15 years, its use was mostly confined to a hospital  setting.

“The recent entry of products containing antibacterial agents into healthy households has escalated from a few dozen products in the mid-1990s to more  than 700 today,” said Stuart Levy, M.D., of Tufts at a CDC Emerging  Infectious Disease Conference in 2000.

The EPA is examining claims of toxicity and carcinogenicity as part of a scheduled investigation into older pesticides on the market — including  triclosan — to make sure they meet current standards. Although the FDA  governs the non-pesticide used of triclosan — such as in soaps and  cosmetics — the EPA included those uses in its risk assessment. The agency won’t release its “Reregistration Eligibility Decision” until  September, but it issued a preliminary report that looked at various  residential and industrial risks of triclosan exposure.

Using available animal studies, the agency examined the risk of skin exposure as a result of wearing clothes treated with triclosan as well as  the effects of breathing it. The EPA also used data from National Health and  Nutrition Surveys, which looked at the effects that normal use of triclosan  products, such as toothpaste and soap, have on humans. It concluded that  household exposures are “not of concern.” Commercial risks are mostly  nonexistent, except for those who work around paper pulp as a material  preservative, like commercial painters.

To examine the carcinogenic effects of triclosan, the EPA’s Cancer Assessment Review Committee culled existing animal studies and found no link  between triclosan and cancer in mice or hamsters, but it detected an  increased risk for adenomas and carcinomas in rats (P<0.005).

“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,” triclosan manufacturer CIBA said in a public comment to the EPA.

But Anila Jacob, M.D., a senior scientist at EWG said the animal studies are still plenty of cause for concern.

“Do we know that it correlates to people?” she asked. “No, we don’t know that for sure, but why should we expose ourselves? We think there is enough  evidence out there to start phasing [it] out.”

In its letter to the EPA, the EWG criticized the agency’s preliminary report for completely omitting any assessment of the risk of children being exposed  to triclosan through breast milk and toys, as well as an assessment of  triclosan on endocrine system.

As for triclosan’s environmental impact, the EPA concluded that there are not enough acceptable studies addressing the toxicity of triclosan on  freshwater animals, but it did find triclosan in 36 U.S. streams, most  likely from trickle-down filtration, sewage overflow, or from sludge  wastewater from treatment plans. The presence of the antimicrobial in open  waters was found to pose a slight risk to aquatic plants.

http://www.physorg.com/news136035644.html

A University of Washington study of top-selling laundry products and air fresheners found the products emitted dozens of different chemicals. All six products tested gave off at least one chemical regulated as toxic or hazardous under federal laws, but none of those chemicals was listed on the product labels.

“I first got interested in this topic because people were telling me that the air fresheners in public restrooms and the scent from laundry products vented outdoors were making them sick,” said Anne Steinemann, a UW professor of civil and environmental engineering and of public affairs. “And I wanted to know, ‘What’s in these products that is causing these effects?’”
She analyzed the products to discover the chemicals’ identity.

“I was surprised by both the number and the potential toxicity of the chemicals that were found,” Steinemann said. Chemicals included acetone, the active ingredient in paint thinner and nail-polish remover; limonene, a molecule with a citrus scent; and acetaldehyde, chloromethane and 1,4-dioxane.

“Nearly 100 volatile organic compounds were emitted from these six products, and none were listed on any product label. Plus, five of the six products emitted one or more carcinogenic ‘hazardous air pollutants,’ which are considered by the Environmental Protection Agency to have no safe exposure level,” Steinemann said.

Her study was published online today by the journal Environmental Impact Assessment Review. Steinemann chose not to disclose the brand names of the six products she tested. In a larger study of 25 cleaners, personal care products, air fresheners and laundry products, now submitted for publication, she found that many other brands contained similar chemicals.
Because manufacturers of consumer products are not required to disclose the ingredients, Steinemann analyzed the products to discover their contents. She studied three common air fresheners (a solid deodorizer disk, a liquid spray and a plug-in oil) and three laundry products (a dryer sheet, fabric softener and a detergent), selecting a top seller in each category. She bought household items at a grocery store and asked companies for samples of industrial products.

In the laboratory, each product was placed in an isolated space at room temperature and the surrounding air was analyzed for volatile organic compounds, small molecules that evaporate from the product’s surface into the air.

Results showed 58 different volatile organic compounds above a concentration of 300 micrograms per cubic meter, many of which were present in more than one of the six products. For instance, a plug-in air freshener contained more than 20 different volatile organic compounds. Of these, seven are regulated as toxic or hazardous under federal laws. The product label lists no ingredients, and information on the Material Safety Data Sheet, required for workplace handling of chemicals, lists the contents as “mixture of perfume oils.”

This study does not address links between exposure to chemicals and health effects. However, two national surveys published by Steinemann and a colleague in 2004 and 2005 found that about 20 percent of the population reported adverse health effects from air fresheners, and about 10 percent complained of adverse effects from laundry products vented to the outdoors. Among asthmatics such complaints were roughly twice as common.

Manufacturers are not required to list the ingredients used in laundry products and air fresheners. Personal-care products and cleaners often contain similar fragrance chemicals, Steinemann said. And although cosmetics are required by the Food and Drug Administration to list ingredients, no law requires products of any kind to list chemicals used in fragrances.

“Fragrance chemicals are of particular interest because of the potential for involuntary exposure, or second-hand scents,” Steinemann said.

“Be careful if you buy products with fragrance, because you really don’t know what’s in them,” she added. “I’d like to see better labeling. In the meantime, I’d recommend that instead of air fresheners people use ventilation, and with laundry products, choose fragrance-free versions.”

The European Union recently enacted legislation requiring products to list 26 fragrance chemicals when they are present above a certain concentration in cosmetic products and detergents. No similar laws exist in the United States.

“I hope this study will raise public awareness, and reduce exposures to potentially hazardous chemicals,” said Steinemann.

Source: University of Washington

http://www.medicalnewstoday.com/articles/114795.php

A new study by UC Davis researchers calls into question the widespread use of two active ingredients — triclocarban and triclosan — in personal hygiene products, including anti-bacterial bar and liquid soaps. Using human and animal cell lines, researchers found that triclocarban disrupts reproductive hormone activity and triclosan interferes a type of cell signaling that occurs in brain, heart and other cells.

“Americans spend nearly one billion dollars a year on these products even though recent studies show that they are no better than regular soap and water at reducing the spread of illness. Now we have added evidence that, in some cases, the benefits may not be worth the risks,” said Dan Chang, professor emeritus of civil and environmental engineering.

“Manufacturers of products containing triclosan and triclocarban should consider providing cautionary labels. There are new health-related data on these chemicals that consumers should know about, even if the research is in its early stages,” Chang said.

The current study was published online in Environmental Health Perspectives , a publication of the National Institute of Environmental Health Sciences, in May.

The authors of the study are part of the UC Davis Superfund Basic Research Program. The group, part of a national network, is charged with assessing and understanding the effects that exposure to environmental substances have on human health.

“We decided to take a look at triclocarban and triclosan because these compounds appeared to be building up in the environment,” said Bruce Hammock, an Superfund Basic Research Program investigator and professor of entomology. The compounds are also increasingly being detected in human breast milk and urine, he said.

Triclosan and triclocarban were first introduced for use by surgeons and other operating room personnel to prevent bacterial infections. Today they are inexpensive and readily available, in part because the patents on them have expired. “We are not concerned about limited use in settings with clearly edvident high-value such as in surgical settings. It’s the widespread use that is of concern,” Hammock said.

Superfund researchers use bioassays to measure the kind of effects a substance might have on living organisms, using animal or human cell lines as proxies for human exposure. The four assays in this study looked at the effects of triclocarban and triclosan. One assay tests a second messenger system broadly used by cells in the peripheral and central nervous systems, a second examines another pathway important in protein synthesis and two assays evaluate the activity of male and female sex hormones (androgens and estrogens).

The first assay involved observing the impact of the chemicals on ryanodine receptors, proteins that serve to keep calcium levels in balance. Calcium is needed for proper cell signaling, especially in brain, heart and muscle cells where these receptors are found. Disrupting these levels could lead to alterations in cell function. Triclosan significantly increased resting calcium levels in the mouse cells used in the assay.

The second assay looked at the impact on aryl hydrocarbon receptors (AhR). Normally, this cell-surface receptor binds a protein that leads to changes in gene expression, the process by which information encoded in the DNA is translated into proteins. Binding of this receptor by the environmental toxin dioxin has been shown to cause everything from birth defects to tumor production. Triclosan exhibited weak activity in the AhR bioassay. Triclocarban exhibited no activity.

Triclocarban had been previously implicated as a new kind of endocrine disruptor in a paper published in December 2007 in Endocrinology by co-author Bill Lasley, professor of obstetrics and gynecology. Lasley’s group concluded that, unlike classical endocrine disrupters that bind to cell receptors, triclocarban amplifies the response of naturally occurring sex hormones.

Because of feedback loops in the body, amplification of these hormones could have the effect of depressing natural estrogen and androgen production, potentially impacting fertility and other hormone-dependent processes. In the current study, besides carrying out the AhR assays, co-author Michael Denison repeated Lasley’s experiments using a different human cell line. Denison, a professor of environmental toxicology, observed a similar amplification effect.

Given these results, the question for regulators is whether these compounds should be restricted until further testing can be done. To help answer that question, the National Institute of Environmental Health Sciences and the Environmental Protection Agency are sponsoring a scientific meeting for researchers, regulators and industry representatives in October at UC Davis. “We’re all getting together to explore where to go from here,” Chang said.

Chang said he feels strongly that consumers be provided information about potential hazards, though he is quick to point out that those who are not in high-risk groups may decide to continue their use of triclosan- and triclocarban-containing products. “I have not stopped using my gingivitis-fighting toothpaste. However, if I were a pregnant woman or the parent of a small child, I might check the labels of the products that I use and stop using any that contain those chemicals until we can work this out,” Chang said.

Other study authors, all of whom are at UC Davis, include Ki Chang Ahn, of the Departments of Entomology and Cancer Research Center; Bin Zhao, of the Department of Environmental Toxicology; Jiangang Chen, of the Department of Environmental Health; Gennady Cherednichenko, of the Department of Molecular Biosciences and Center for Children’s Environmental Health and Disease Prevention; Enio Sanmart, of the Department of Animal Science; Michael S. Denison of the Department of Environmental Toxicology; Bill Lasley, of the Department of Environmental Health; Isaac N. Pessah, of the Center for Children’s Environmental Health and Disease Prevention; Dietmar Kültz of the Department of Animal Science; Daniel P. Y. Chang, of the Department of Civil and Environmental Engineering; and Shirley J. Gee1 and Bruce D. Hammock, of the Departments of Entomology and Cancer Research Center.

Funding for the research was provided by the NIEHS Superfund Basic Research Program, the NIEHS Center for Environmental Health Sciences, the UC Davis Center for Children’s Environmental Health and Disease Prevention, the U.S. Environmental Protection Agency through the Science to Achieve Results (STAR) program, and the Natinal Institute for Occupational Safety and Health Center for Agricultural Disease and Research, Education and Prevention.

The Superfund Basic Research Program is a national network of university groups charged with finding solutions to the complex health and environmental problems associated with the nation’s hazardous waste sites. The research conducted by the SBRP is a coordinated effort with the Environmental Protection Agency.

UC Davis, which celebrates its centennial this year, is one of the nation’s top public research universities, with a tradition of service to the region, the nation and the world. UC Davis is a pioneer in interdisciplinary problem-solving, and its four colleges, five professional schools, more than 100 academic majors and 86 graduate programs provide a comprehensive, rigorous and research-based learning environment for students, faculty and researchers. The 30,000-student university has its main campus in the Sacramento Valley, near the state capital and San Francisco Bay Area. The UC Davis School of Medicine and UC Davis Medical Center are located on the Sacramento campus near downtown.

UC Davis Health System
www.ucdmc.ucdavis.edu