Tag Archives: chemicals of concern

New stain repellent chemical doubling in blood every 6 years.

Nov 26, 2012

Glynn, A, U Berger, A Bignert, S Ullah, M Aune, S Lignell and PO Darnerud. 2012. Perfluorinated alkyl acids in blood serum from primiparous women in Sweden: Serial sampling during pregnancy and nursing, and temporal trends 1996-2010. Environmental Science and Technology http://dx.doi.org/10.1021/es301168c.


Synopsis by Craig Butt and Wendy Hessler
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erikschmidt/flickr

 

As the phased-out stain repellent PFOS steadily decreases in people, its replacement is rising rapidly at levels that are doubling every six years, a Swedish study shows. Levels of perfluorobutane sulfonate (PFBS) in the women’s blood rose 11 percent per year between 1996 and 2010. Whether there are any potential health effects of these exposures — which are still far lower than PFOS levels — is unknown.

 

Context

Polyfluorinated and perfluorinated chemicals (PFASs) are applied to clothing, furniture, carpeting, cookware and food packaging to make the products stain repellent. PFASs – commonly referred to as PFCs – are a large group of chemicals that are unique because they repel both grease and water.

The PFAS chemicals used in commercial products fall into two main categories: the large fluorinated polymers that are used in clothing, furniture and carpet treatments and the phosphate surfactants that are used to coat paper.

Commercial products often contain the parent PFAS chemicals used to make the polymers and phosphate surfactants – called precursors – as impurities. PFASs break down in the atmosphere and in our bodies to form very long-lived perfluorinated alkyl acids (PFAAs).

People are exposed to PFAAs and their precursors mainly through food, air and water. Studies suggest the chemicals may contribute to kidney damage, and prenatal exposures have been linked to low birth weight.

Two of the most well-known and well-studied PFAA varieties are perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA). In addition to forming as breakdown products, small amounts of PFOS and PFOA were directly produced for specialized products. PFOS was used in fire-fighting foams as well as in the semiconductor industry. PFOA was used in the production of Teflon, but is typically not detected in the final products.

In 2002, the 3M Company – a leading manufacturer of PFOS and PFOA – voluntarily stopped manufacturing both PFOS and the chemicals that degrade to form PFOS because they were accumulating in humans globally and in animals – such as polar bears – that live in remote areas (Hansen et al. 2001; Giesy and Kannan 2001; Butt et al. 2010).

The company has substituted PFOS-based chemicals with another PFAA variety that is based on perfluorobutane sulfonate (PFBS). PFBS has four carbons whereas PFOS has eight. Otherwise, their molecular makeup is identical.

The smaller PFBS clears from the human body much faster than PFOS. PFOS has a half-life in people of 4 – 5 years, but PFBS’s half-life is only 26 days (Olsen et al. 2009).

After 3M stopped making PFOS-based compounds, production of other compounds made by another manufacturing process rapidly increased. These are called fluorotelomer-based chemicals. The fluorotelomer compounds are used for the same purpose as the PFOS-based compounds were: to make fluorinated polymers and surfactants. However, these chemicals degrade to form perfluorinated carboxylates (PFCAs), including PFOA.

Due to the increasing concern about PFOA, the eight major manufacturers have committed to eliminate PFOA emissions by 2015.

 

What did they do?

The research is part of a larger study that examined time trends of persistent organic pollutants in the blood and breast milk of pregnant and nursing women in Uppsala County, Sweden.

Blood samples were collected from first-time mothers, aged 19 – 41 years, three weeks after delivery. Samples were collected each year between 1996 and 2010, except in 2003 and 2005. For each year, several individual blood samples were pooled together for analysis. In general, three pooled samples per year were analyzed.

The study investigated levels of 13 PFAAs, including PFBS and PFOS. The study also measured perfluorooctane sulfonamide (FOSA), which is known to degrade to PFOS.

A unique aspect of this study was the ability to measure PFBS levels at very low levels.  It was this improved analytical capability that allowed the researchers to detect the PFBS  trends over time.

In addition to examining time trends, the study also investigated PFAA trends at different stages during pregnancy and after delivery.

 

What did they find?

The study showed that PFBS blood concentrations in the Swedish women increased by 11 percent per year between 1996 and 2010. The levels doubled every 6.3 years. This is the first study to show increasing PFBS levels in humans.

However, during the same time period, PFOS levels decreased by 8.4 percent per year. The study also showed decreasing levels of perfluorodecane sulfonate (PFDS), PFOA and FOSA.

In contrast, blood levels of two PFCAs – perfluorononanoate (PFNA) and perfluorodecanoate (PFDA) – increased by 4.3 percent and 3.8 percent, respectively, from 1996 to 2010.

The study also looked for longer-chain length PFCAs: perfluorododecanoate (PFDoA), perfluorotridecanoate (PFTrA) and perfluorotetradecanoate (PFTA).  But these PFCAs were not found in the women’s blood.

 

What does it mean?

Perfluorobutane sulfonate or PFBS – the chemical that replaced the PFOS-based fluorinated chemicals used as stain repellents – is building up in human blood with levels doubling every six years. This is the first study to show increasing PFBS levels in humans.

The study showed that PFBS levels in Swedish women are rapidly increasing. This means that humans are widely exposed to PFBS and its precursors. Exposure to these chemicals has increased dramatically from 1996 to 2010.

These findings were surprising because it was thought that PFBS would not accumulate in humans due to its very short half-life (26 days). But the new research shows that PFBS is building up at an alarming rate.

However, PFBS levels are still about 75 times lower than PFOS.

The study did not investigate whether there were any health effects associated with the increasing PFBS levels. There have been few toxicology studies on PFBS, and the toxic effects are generally less than PFOS and PFOA (Lieder et al. 2009).

PFBS-based chemicals were introduced as replacements for PFOS-based chemicals after 3M stopped their manufacture in 2002. In the current study, PFBS levels did not start increasing until 2002. Presumably, this increase in PFBS blood levels is a reflection of increased use of PFBS precursors in commercial products and their release into the environment after 2002.

The new study also showed that PFOS and FOSA levels are decreasing in Swedish women’s blood. FOSA is formed when PFOS precursors are metabolized in the body.

These results show that 3M’s PFOS ban in 2002 had a rapid effect on PFOS blood levels. Studies from the United States (Kato et al. 2011; Olsen et al. 2012) and Norway (Haug et al. 2009) have also shown decreasing PFOS blood levels after the 3M ban.

In contrast, PFNA and PFDA levels were shown to increase in the Swedish women. These chemicals are breakdown products of fluorotelomer-based compounds that are used in some polymers and surfactants. They have similar uses as the PFOS-related chemicals. In addition, PFNA is used in the production of polyvinylidene fluoride (PVDF) and trace amounts can be detected in the final products. Production of fluorotelomer chemicals increased after the 3M PFOS ban. The increasing blood levels of these chemicals most likely represents the increased use of their precursors in commercial products.

Because the study only monitored Swedish women, it will be necessary to confirm the trends in other regions of the world. This is because fluorinated chemical use varies in different areas of the world. For example, China began producing PFOS-chemicals in 2003. Their production in China may represent a new source of PFOS to the world.

Scientists are concerned when blood levels of a chemical increase in our bodies because it shows that our exposure is increasing. However, it is necessary to determine if the contaminant levels are enough to cause harmful effects in wildlife and people.  Future research is needed to determine if the increasing PFBS levels are affecting human health.

Resources

Buck, RC, J Franklin, U Berger, JM Conder, IT Cousins, P de Voogt, AA Jensen, K Kannan, SA Mabury and SPJ van Leeuwen. 2011. Perfluoroalkyl and polyfluoroalkyl substances in the environment: Terminology, classification, and origins. Integrated Environmental Assessment and Management 7:513-541.

Butt, CM, U Berger, R Bossi and GT Tomy. 2010. Levels and trends of poly- and perfluorinated compounds in the arctic environment. Science of the Total Environment 408:2936-2965.

Giesy, JP and K Kannan. 2001. Distribution of perfluorooctane sulfonate in wildlife. Environmental Science & Technology 35:1339-1342.

Hansen, KJ, LA Clemen, ME Ellefson and HO Johnson. 2001. Compound-specific, quantitative characterization of organic fluorochemicals in biological matrices. Environmental Science & Technology 35:766-770.

Haug, LS, C Thomsen and G Bechert. 2009. Time trends and the influence of age and gender on serum concentrations of perfluorinated compounds in archived human samples. Environmental Science & Technology 43:2131-2136.

Kato, K, LY Wong, LT Jia, Z Kuklenyik and AM Calafat. 2011. Trends in exposure to polyfluoroalkyl chemicals in the U.S. population: 1999-2008. Environmental Science & Technology 45:8037-8045.

Lieder, PH, RG York, DC Hakes, S-C Chang and JL Butenhoff. 2009. A two-generational gavage reproduction study with potassium perfluorobutanesulfonate (K+PFBS) in Sprague Dawley rat. Toxicology 259:33-4.

O’Connor, Mary Catherine. Greenpeace scolds outdoor apparel makers for chemical use. Outside Magazine Nov 12, 2012.

Olsen, GW, SC Chang, PE Noker, GS Gorman, DJ Ehresman, PH Lieder and JL Butenhoff. 2009. A comparison of the pharmacokinetics of perfluorobutanesulfonate (PFBS) in rats, monkeys, and human. Toxicology 256:65-74.

Olsen, GW, CC Lange, ME Ellefson, DC Mair, TR Church, CL Goldberg, RM Herron, Z Medhdizadehkashi, JB Nobiletti, JA Rios, WK Reagen and LR Zobel. 2012. Temporal trends of perfluoroalkyl concentrations in American Red Cross adult blood donors, 2000-2010. Environmental Science & Technology 46:6330-6338.

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“Don’t put that junk on your junk”


I recently said this to my favorite cyclist when discussing that he may not want to apply chamois cream containing parabens (the junk) to his junk. Male cyclists are repeatedly applying (maybe daily, for 5-7 hours at a time) these paraben containing creams to their reproductive parts. Research is showing that maybe they should reconsider.

 

You may see parabens listed as “methylparaben” “propylparaben” or “butylparaben” Etc.  Don’t let that fool you; these compounds are all structurally and functionally similar compounds, each just has an additional carbon group – the methyl, propyl, or butyl.

 

Parabens’ alias is alkyl hydroxy benzoate, not as easily recognizable, but still present on food and cosmetic labels. You can find these parabens in hair products, skin care products, or even your salad dressing! For male cyclists, they are in most creams that are applied to the groin area to alleviate chafing against the saddle of the bike.

 

Studies have shown that parabens can mimic the female sex hormone estrogen (Gomez et al 2005) and in turn can act as endocrine disruptors, inhibiting “testosterone (T)-induced transcriptional activity” (Chen et al 2007). Also, “exposure of post-weaning mammals to butyl paraben adversely affects the secretion of testosterone and the function of the male reproductive system.” Similar effects can be seen with propyl paraben (Oishi 2002).

 

What are other potential effects of this chemical on males? Recent research has shown parabens in association with  breast cancer, though causality has not yet been established (Khanna et al 2012).  This may seem irrelevant for men unless one considers the fact that breast cancer among men is actually on the rise.

 

Additionally, these chemicals may reduce male fertility. Butylparaben was shown in the lab to have an adverse effect on the male mouse reproductive system in that it damaged the late steps of spermatogenesis in the testis (Oishi 2002). Similar effects can be seen for other forms of parabens. They are also suspected of affecting the mitochondria in rat testes, reducing virility (Tavares et al 2008).

 

Male cyclists might want to look for anti-chafe chamois creams that do not contain parabens, such as creams containing lanolin, the oil in sheep’s wool. You can even make lanolin cream in your own home, following this recipe (but make sure the lanolin you use is high quality and pesticide free).

 

Alternatively, one can pay closer attention to the label on chamois cream to ensure that it does not contain parabens.

 

If you are a cyclist, know a cyclist, or love a cyclist, please share this with them.

 

By: Mana Sassanpour

 

Sources:

1. Antiandrogenic properties of parabens and other phenolic containing small molecules in personal care products. J. Chen, K.C. Ahn, N.A. Gee, S.J. Gee, B.D. Hammock, B.L. Lasley. Toxicology and Applied Pharmacology. Volume 221, Issue 3, 278–284, 2007.

 

2. Effects of propyl paraben on the male reproductive system. S. Oishi. Food and Chemical Toxicology. Volume 40, Issue 12, 1807 – 1815, 2002.

 

3. Estrogenic activity of cosmetic components in reporter cell lines: parabens, UV screens, and musks. E. Gomez, A. Pillon, H. Fenet, D. Rosain, M. J. Duchesne, J. C. Nicolas, P. Balaguer, C. Casellas. 
Journal of Toxicology and Environmental Health, Part A 
Vol. 68, Iss. 4, 2005.

 

4. Male breast carcinoma: increased awareness needed. J. White, O. Kearins, D. Dodwell, K. Horgan, A.M. Hanby, V. Speirs. Breast Cancer Research. Volume 13, Issue 5, 219, 2011.

 

5. Organ toxicity and mechanisms: effects of butyl paraben on the male reproductive system in mice. S. Oishi. Archives of Toxicology. Volume 76, Number 7, 423-429, 2002.

 

6. Parabens enable suspension growth of MCF-10A immortalized, non-transformed human breast epithelial cells. S Khanna and P.D. Darbre. Journal of Applied Toxicology. doi: 10.1002/jat.2753, 2012.

 

7. Parabens in male infertility—Is there a mitochondrial connection? R.S. Tavares, F.C. Martins, P.J. Oliveira, J. Ramalho-Santosa, F.P. Peixoto. Reproductive Toxicology. Volume 27, Issue 1, 1-7, 2009.

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EPA cancels $20-million green chemistry grant program, gives no explanation

In an announcement that stunned scientists, the U.S. Environmental Protection Agency has cancelled grant applications for what was supposed to be a $20-million, four-year green chemistry program. The mysterious cancellation comes less than three weeks before the deadline for the proposals. The grants, which were supposed to fund four new centers, would have been a major new source of funding for green chemistry, a field that seeks to design environmentally friendly chemicals and processes that can replace toxic substances. The requests for proposals may be reissued, the EPA said. But the program’s sudden halt and uncertain future — and lack of explanation — have left scientists disheartened. “My reaction is shock that it happened and total dismay that what appeared to be a novel program was cancelled without warning or explanation,” said Eric Beckman, a chemical engineer at the University of Pittsburgh.

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Joshua Vaughn/flickr
Green chemistry’s aim is to design environmentally friendly chemicals and processes that can replace toxic substances currently in use.

By Brett Israel
Senior Editor and Staff Writer
Environmental Health News
April 10, 2012
In an announcement that stunned scientists, the U.S. Environmental Protection Agency has cancelled grant applications for what was supposed to be a $20-million, four-year green chemistry program.

The mysterious cancellation, announced on Friday, came less than three weeks before the April 25 deadline for the grant proposals.

The federal grants, which were supposed to fund four new academic centers, would have been a major new source of funding for green chemistry, a field that seeks to design environmentally friendly chemicals and processes that can replace toxic substances.

The requests for proposals may be reissued, the EPA said Monday. But the program’s sudden halt and uncertain future – and lack of explanation – have left scientists disheartened. Lab researchers had worked for months on their proposals and scientists now fear their hard work will be wasted.

“My reaction is shock that it happened and total dismay that what appeared to be a novel program was cancelled without warning or explanation,” said Eric Beckman, a chemical engineer at the University of Pittsburgh who was working on a proposal.

Terry Collins, a green chemist at Carnegie Mellon University and a pioneer in the field, said the announcement “stunned me.” Collins was on a team of green chemists and other environmental scientists that had been working for months to put together a funding proposal. West Coast institutions, including University of California, Berkeley, also were developing a proposal.

Beckman said he’d never seen such a thing happen before – a government agency pulling the plug on a request for proposals so close to its deadline – in his more than 20 years in academia.

Eric Beckman, a University of Pittsburgh chemical engineer, said he’d never seen such a thing happen before – a government agency pulling the plug on a request for proposals so close to its deadline – in his more than 20 years in academia.The $20 million in funding would be “one of the most significant sources of dedicated support for green chemistry so it is a blow to the community that the call for applications was cancelled without explanation,” said Evan Beach, a green chemist at Yale University. “Everybody was in the home stretch on writing. The preparations took several months.”

The EPA offered no reason for the last-minute cancellation.

 “Given the new and emerging research areas…EPA determined that it was necessary to further explore these research areas and also consider changes to its usual review process,” Kelly Widener, assistant director for research communications at EPA’s National Center for Environmental Research, said in an email response to Environmental Health News.
Widener, who declined to elaborate, said the EPA anticipates re-issuing its requests for proposals in June or July.
Green chemistry, according to the EPA, is “the design of chemical products and processes that reduce or eliminate the use or generation of hazardous substances…across the life cycle of a chemical product, including its design, manufacture, and use.”
The new program – to create Centers for Material Life Cycle Safety and Centers for Sustainable Molecular Design – was announced in late December as a part of the EPA’s Science to Achieve Results (STAR) program.
The green chemistry centers were to draw together scientists from wide-ranging disciplines, including engineering, chemistry, social science and physics, to develop “improved methods for the design of next generation chemicals,” the EPA said when it announced the available funding.
“This holistic approach to design, which considers all the stages of a material’s life cycle, provides an opportunity to produce materials which minimize, and preferably eliminate, any associated potential environmental and human health impacts that may occur during the life cycle,” the original request for proposals said
That funding for such a promising area of science was halted without explanation at the last minute has many researchers scratching their heads.
“For the EPA to treat so wastefully the field that holds most of the keys to a good future for the relationships between chemical products and processes and the environment and health is mystifying to say the least,” Collins said. Read more science at Environmental Health News.

Low doses, big effects: Scientists seek ‘fundamental changes’ in testing, regulation of hormone-like chemicals.

Small doses can have big health effects. That is a main finding of a new report, three years in the making, published Wednesday by a team of 12 scientists who study hormone-altering chemicals. Dozens of substances that can mimic or block hormones are found in the environment, the food supply and consumer products, including plastics, pesticides and cosmetics. One of the biggest controversies is whether the tiny doses that most people are exposed to are harmful. Researchers led by Tufts University’s Laura Vandenberg concluded after examining hundreds of studies that health effects “are remarkably common” when people or animals are exposed to low doses. “Fundamental changes in chemical testing are needed to protect human health,” they wrote.

By Marla Cone

Editor in Chief

Environmental Health News

March 15, 2012

Small doses can have big health effects. 2012-0315labrats

That is a main finding of a report, three years in the making, published Wednesday by a team of 12 scientists who study hormone-altering chemicals.

Dozens of substances that can mimic or block estrogen, testosterone and other hormones are found in the environment, the food supply and consumer products, including plastics, pesticides and cosmetics. One of the biggest, longest-lasting controversies about these chemicals is whether the tiny doses that most people are exposed to are harmful.

In the new report, researchers led by Tufts University’s Laura Vandenberg concluded after examining hundreds of studies that health effects “are remarkably common” when people or animals are exposed to low doses of endocrine-disrupting compounds. As examples, they provide evidence for several controversial chemicals, including bisphenol A, found in polycarbonate plastic, canned foods and paper receipts, and the pesticide atrazine, used in large volumes mainly on corn.

The scientists concluded that scientific evidence “clearly indicates that low doses cannot be ignored.” They cited evidence of a wide range of health effects in people – from fetuses to aging adults – including links to infertility, cardiovascular disease, obesity, cancer and other disorders.

“Whether low doses of endocrine-disrupting compounds influence human disorders is no longer conjecture, as epidemiological studies show that environmental exposures are associated with human diseases and disabilities,” they wrote.

The scientists concluded that scientific evidence “clearly indicates that low doses cannot be ignored.” They cited evidence of a wide range of health effects in people – from fetuses to aging adults – including links to infertility, cardiovascular disease, obesity, cancer and other disorders.In addition, the scientists took on the issue of whether a decades-old strategy for testing most chemicals – exposing lab rodents to high doses then extrapolating down for real-life human exposures – is adequate to protect people.

They concluded that it is not, and so they urged reforms. Some hormone-like chemicals have health effects at low doses that do not occur at high doses.

“Current testing paradigms are missing important, sensitive endpoints” for human health, they said. “The effects of low doses cannot be predicted by the effects observed at high doses. Thus, fundamental changes in chemical testing and safety determination are needed to protect human health.”

The report was published online Wednesday in the scientific journal Endocrine Reviews. Authors include scientists University of Missouri’s Frederick vom Saal, who has linked low doses of bisphenol A to a variety of effects, Theo Colborn, who is credited with first spreading the word about hormone-disrupting chemicals in the late 1980s and University of California, Berkeley’s Tyrone Hayes, who has documented effects of atrazine on frogs.

The senior author is Pete Myers, the founder of Environmental Health News and chief scientist of Environmental Health Sciences.

Linda Birnbaum, director of the National Institute of Environmental Health Sciences, said the new report is valuable “because it pulls a tremendous amount of information together” about endocrine-disrupting compounds. Her agency is the main one that studies health effects of contaminants in the environment.

Linda Birnbaum, director of the National Institute of Environmental Health Sciences, said in many cases, industry is still asking “old questions” about chemical safety even though “science has moved on.” Birnbaum said she agrees with their main finding: All chemicals that can disrupt hormones should be tested in ultra-low doses relevant to real human exposures, she said.

In many cases, chemical manufacturers still are asking “old questions” when they test the safety of chemicals even though “science has moved on,” she said. “Some of the testing paradigms have not advanced with the state of the science.” Birnbaum wrote an editorial on Wednesday referencing the new report.

Nevertheless, for most toxicologists, Birnbaum said the report does not offer a big shift from what they are doing. The NIEHS already conducts low-dose testing of chemicals, including looking for multi-generational effects such as adult diseases that are triggered by fetal exposures.

“Some people keep slamming the toxicologists. But you can’t paint everyone with the same brush,” Birnbaum said.

However, the scientists who wrote the report said that low-dose science “has been disregarded or considered insignificant by many.” They seemed to aim much of their findings at the National Toxicology Program and the U.S. Food and Drug Administration. The FDA in 2008 discounted low-dose studies when it concluded that bisphenol A (BPA) in consumer products was safe. Two years later, the agency shifted its opinion, stating that they now will more closely examine studies showing low-dose effects. The National Toxicology Program in 2008 found that BPA poses “some risks” to human health but rejected other risks because studies were inconsistent.

Several of the report’s authors have been criticized by some other scientists and industry representatives because they have become outspoken advocates for testing, regulating and replacing endocrine-disrupting compounds. The scientists, however, say they feel compelled to speak out because regulatory agencies are slow to act and they are concerned about the health of people, especially infants and children, and wildlife.

Industry representatives say that just because people are exposed to traces of chemicals capable of altering hormones doesn’t mean there are any harmful effects. They say that the studies are often contradictory or inconclusive.

“Based on the evidence, it is concluded that these ‘low dose’ effects have yet to be established [and] that the studies purported to support these cannot be validly extrapolated to humans.” -Michael Kamrin, Michigan State University  In a statement, the American Chemistry Council, which represents chemical companies, said Wednesday that the industry “has committed substantial resources to advancing science to better understand any potential effects of chemical substances on the endocrine system. While we have not had an opportunity to fully review this paper, Michael Kamrin, emeritus professor of Michigan State University, has concluded ‘low dose’ effects have not been proven, and therefore should not be applied to real-world conditions and human exposures.”

“Based on the evidence, it is concluded that these ‘low dose’ effects have yet to be established [and] that the studies purported to support these cannot be validly extrapolated to humans,” Kamrin, a toxicologist, wrote in the International Journal of Toxicology in 2007.

But vom Saal and other scientists have said that tests that do not find low-dose effects of chemicals such as BPA are often industry-funded, and they often have tested the wrong animals or the wrong doses, or don’t expose the animals during the most vulnerable time of fetal growth.

Endocrinologists have long known that infinitesimal amounts of estrogen, testosterone, thyroid hormones and other natural hormones can have big health effects, particularly on fetuses. It comes as no surprise to them that manmade substances with hormonal properties might have big effects, too.

“There truly are no safe doses for chemicals that act like hormones, because the endocrine system is designed to act at very low levels,” Vandenberg, a postdoctoral fellow at Tufts University’s Levin Lab Center for Regenerative and Developmental Biology, told Environmental Health News.

But many toxicologists subscribe to “the dose makes the poison” conventional wisdom. In other words, it takes a certain size dose of something to be toxic. They also are accustomed to seeing an effect from chemicals called “monotonic,” which means the responses of an animal or person go up or down with the dose.

The scientists in the new review said neither of those applies to hormone-like chemicals.

“Accepting these phenomena should lead to paradigm shifts in toxicological studies, and will likely also have lasting effects on regulatory science,” they wrote.

In the report, the scientists were concerned that government has determined ”safe” levels for “a significant number of endocrine-disrupting compounds” that have never been tested at low levels. They urged “greatly expanded and generalized safety testing.”

“Accepting these phenomena should lead to paradigm shifts in toxicological studies, and will likely also have lasting effects on regulatory science,” the scientists wrote.”We suggest setting the lowest dose in the experiment below the range of human exposures, if such a dose is known,” they wrote.

Vandenberg said that there may be no effect or a totally different effect at a high dose of a hormonal substance, while a lower dose may trigger a disease.

The breast cancer drug tamoxifen “provides an excellent example for how high-dose testing cannot be used to predict the effects of low doses,” according to the report. At low doses, it stimulates breast cancer growth. At higher ones, it inhibits it.

“Imagine taking 100 individuals that are representative of the American population and lining them up in order of exposure to an EDC [endocrine-disrupting compound] so that the person on the far left has the least exposure and the person on the far right has the most. For many toxic chemicals, individuals with the highest levels of exposure, at the right end of the line, have the highest incidence of disease. But for some EDCs, studies suggest that people in the middle of the line have the highest risk,” Vandenberg said.

She compared hormones, which bind to receptors in the body to trigger functions such as growth of the brain or reproductive organs, to keys in a lock.
“The more keys that are in the locks, the more of an effect that is seen. But at some point, the locks are overwhelmed and stop responding to the keys. Thus, in the lower range, more keys equals more of an effect, but in the higher range, more keys equals less of an effect,” she said.
Vandenberg predicted the report “will start conversations among academic, regulatory and industry scientists about how risk assessments for EDCs can be improved.”
“The question is no longer whether these phenomena exist, but how to move forward and deal with them.” Read more science at Environmental Health News.

Uneven effort to simplify science.

Posted by Wim Thielemans at Jan 20, 2012 06:00 AM | Permalink

The Montreal Gazette prints 20 key points to help the public interpret chemical science but a scientist specializing in green chemistry explains why not all of them hit the mark.

In an article in the Montreal Gazette, Joe Schwarcz of McGill University lists 20 points he believes are important to address when interpreting chemistry for the public. His ideas – distilled from a year of lecturing to public audiences – touch on some very good points but also lack other key ideas.

In the article, Schwarcz welcomes criticism and comments of his personal views on the subject. My main concerns are with omissions in some of the individual points as well as a contradiction between his points.

• #2 – Everything is comprised of chemicals. Citing examples of common chemicals in nature – such as oxygen, water and kitchen salt – would have bolstered his point.

• #3 – There are no dangerous or safe chemicals. I would argue there are dangerous chemicals. A highly toxic or explosive chemical always has an inherent danger associated with it, irrespective of how it is used. This is one reason industrial processes – when using these chemicals to create other chemicals or products – will make them and then immediately react them to change them into a safer product. An example would be phosgene, a gas well known for its use as a chemical weapon in World War I. Because it reacts every quickly, it is used to produce polycarbonates. These widely used polymers are in glass lenses, for example. So phosgene is made but then directly converted into a safe product by reaction with other chemicals.

• #5 – Animal studies do not necessarily reflect humans. This paints a very limited picture. It is true that animal studies do not reveal everything about how chemicals might affect people. However, they do give some important indications, especially when acute toxicity – short-term toxic effects – is concerned. Brushed over is one of the main problems with current toxicology: adults respond differently than embryos and children at various stages of development. So even within humans, important differences in toxic responses are seen.

#6 – Chemical presence does not equal risk. No, other issues matter, such as dose and those mentioned above: a person or animal and stage of life – embryo, young or adult – that is exposed to the chemical. All may respond differently.

• # 9 – Affirming there are hazardous chemicals appears to contradict point #3: There are no inherently dangerous or safe substances. Indeed, even kitchen salt can kill if taken in too high an amount. I would therefore describe “green chemistry” as replacing current chemicals with less hazardous ones.

• #16 – It is nonsense that the body can heal itself with the right natural substances. This idea should be carefully interpreted. As a scientist, I know we have a limited understanding of the human body. Maybe some day, science will help us better understand if and how naturally occurring chemicals could cure ailments. Scientific progress has a knack for proving the impossible possible.

I applaud the attempt to come up with a top 20 list of chemical science considerations for the public. While not an easy feat – and certainly one that easily draws criticism – it also generates constructive debate about important issues surrounding the public understanding of science. Read more science at Environmental Health News.

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Polymer Clay Jewelry Chemistry

This interview was inspired by my latest infatuation with my etsy shop. My inspiration for starting an ‘store’ on etsy was Inedible Jewelry. They are a polymer clay jewelry business in the lovely city of Charlottesville, making replicas of everyday foods with PVC. The ladies of Inedible Jewelry, Jessica and Susan Partain, are at our local farmer’s market every weekend selling their latest miniature creations.  Taking the opportunity to see their studio and learn more about the chemistry behind polymer clay, I set up an interview with Jessica Partain in her workshop (see picture to left).

I interrupted her in the middle of placing holiday orders, in her studio filled with doll-house sized desserts, drinks, fruits, vegetables, etc. The main material used to make these bit-sized creations is PVC.  I started the interview asking about the chemical concerns with PVC over the past decade. Jessica explained: “While the formulation of PVC itself has not changed, both of the polymer clays that I work with (97% Premo, 3% Sculpey, both manufactured by polyform products) were reformulated in 2008 to be phthalate-free and lead-free.” Phthalates, which are also endocrine disruptors, used to be a concern for the sculptors before the reform because baking the clay would release them, consequently allowing them to be  inhaled by the artist. Jessica also explained: The clay she uses is also ASTM certified, making the product safe. “They’ve run it past medical experts and biochemists looking specifically for potentially harmful interactions between the material and the artist.” This made me proud of my fellow medical experts and biochemists, doing good in the world.

Jessica and Susan have also always used a separate toaster in a well-ventilated room for their polymer baking, making creations such as the cupcake earrings to the right. They use a separate toaster to ensure that they would not combine their cooking with their polymer. One concern that still remains is when the clay is burnt, from baking for too long or from baking at too high a temperature – releasing toxic HCl gas.

As a loyal customer, I asked her: “What do you do with annoying customers like myself, who also ask all these difficult chemistry questions before a purchase.” She answered: “Well, you are one of two people asking me these questions in past 22 years; and the other person who asked did not have much basis for her questioning.” I felt like a major nerd at that moment – 8 years of intense science back ground can do that to you.

Although most customers do not ask about the chemistry behind polymer clay, many worry about the metals used in the jewelry. I then asked “Is this because they are worried about the toxic chemicals in metals?” That was strike two for Nerd Mana. The real reason is because many people are allergic to certain metals. To combat this problem, Inedible Jewelry uses 925 Sterling Silver for their necklaces.925 indicates the silver is 92.5% silver, and 7.5% copper. Jessica explained that the copper allows for 925 Sterling Silver to hold its shape because 100% silver is too malleable. All her metals are nickel free to avoid allergic reactions that lead to inflammation.

AGC loves the work of Inedible Jewelry and is impressed with their knowledge of chemistry and toxicology as it applies to their work. We all have a necklace with a polymer clay pendant. So far our collection includes: a peppermint, a gingerbread man, and a rainbow cake (mine!). The equally festive peach pies are pictures to the left where each miniature peach slice is crafted by hand.

 

Written by Mana Sassanpour

 

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AGC at UVA

On Wednesday November 9, 2011 UVA Green Chemistry hosted AGC’s Mana Sassanpour for a lecture and discussion on “What is Green Chemistry?”

Mana gave an overview of green chemistry, Paul Anastas and John Warner’s 12 principles of green chemistry, followed by a description of Advancing Green Chemistry’s involvement in the field.

Mana: “The discussion that followed after the lecture was phenomenal! Almost everyone who attended the lecture asked a question. I had never seen such an involved group of students!”

We started off discussing endocrine disrupting chemicals, for example: bisphenol A (BPA). What exposure level is safe? Really large amounts are harmful, but so are really tiny amounts  – the correlation is not linear. We proceeded to discuss how we could test compounds for toxicity if the correlation is not linear. This led to a discussion on general methods for testing for toxicity, what the current standards are and how we could do better. We discussed the ethical concerns around animal testing and other tools.

The students were curious to find out what some of the common sources of BPA exposure are, and were surprised to find out that it is found in many disposable water bottles and plastic containers. A concerned student then asked for advice on how to avoid BPA. The response was: don’t use plastic food containers – but if you do, definitely do not microwave food in them because that allows the BPA and other contaminants to leach into your food. Store food in glass jars instead.

The ladies in the crowd then opened a discussion on cosmetics. Like many, they had never considered the chemicals in their beauty products. We talked about how many chapsticks and lip balms have oxybenzone in them – a component that acts as a sunscreen but is also a carcinogen. Most girls in the room immediately reached for their chapsticks to look at ingredients. A hand darted up to ask me “My chapstick has 6% oxybenzone – should I throw it away?” From this topic we went on to discuss how many sunscreen components do not degrade and go into our rivers and affect the reproductive anatomy of frogs and fish. This then led to how effects on amphibians predict effects on humans.

Needless to say, the conversation was great – filled with great facts, questions, and laughs!

Are Flame Retardants Safe? Growing Evidence Says ‘No’.

by Elizabeth Grossman: originally published 29 Sep 2011 in Yale360

Over the past 40 years, a class of chemicals with the tongue-twisting name of halogenated flame retardants has permeated the lives of people throughout the industrialized world. These synthetic chemicals — used in electronics, upholstery, carpets, textiles, insulation, vehicle and airplane parts, children’s clothes and strollers, and many other products — have proven very effective at making petroleum-based materials resist fire.

Yet many of these compounds have also turned out to be environmentally mobile and persistent — turning up in food and household dust — and are now so ubiquitous that levels of the chemicals in the blood of North Americans appear to have been doubling every two to five years for the past several decades.

Acting on growing evidence that these flame retardants can accumulate in people and cause adverse health effects — interfering with hormones, reproductive systems, thyroid and metabolic function, and neurological development in infants and children — the federal government and various states have limited or banned the use of some of these chemicals, as have other countries. Several are restricted by the Stockholm Convention on persistent organic pollutants. Many individual companies have voluntarily discontinued production and use of these compounds. Yet despite these restrictions, evidence has emerged in recent months that efforts to curtail the use of such flame retardants — a $4 billion-a-year industry globally — and to limit their impacts on human health may not be succeeding.
This spring and summer, a test of consumer products, as well as a study in Environmental Science & Technology, showed that use of these chemicals continues to be widespread and that compounds thought to be off the market due to health concerns continue to be used in the U.S., including in children’s products such as crib mattresses, changing table pads, nursing pillows, and car seats. Also this summer, new research provided the first strong evidence that maternal exposure to a widely used type of flame retardant, known as PBDEs (polybrominated diphenyl ethers), can alter thyroid function in pregnant women and children, result in low birth weights, and impair neurological development.

“Of most concern are developmental and reproductive effects and early life exposures — in utero, infantile and for children,” Linda Birnbaum, director of the National Institute of Environmental Health Sciences and the National Toxicology Program, said in an interview.

Read full post here.

ABOUT THE AUTHOR
Elizabeth Grossman is the author of Chasing Molecules: Poisonous Products, Human Health, and the Promise of Green Chemistry, High Tech Trash: Digital Devices, Hidden Toxics, and Human Health, and other books. Her work has appeared in Scientific American, Salon, The Washington Post, The Nation, Mother Jones, Grist, and other publications. In earlier articles for Yale e360, she explored how the Fukushima nuclear plant disaster could affect marine life off the Japanese coast and reported on recent studies suggesting a possible link between prenatal exposure to pesticides and the mental abilities of children.
MORE BY THIS AUTHOR

Nano research leads to a greener lubricating oil.

Synopsis by Wim Thielemans, Sep 15, 2011

Majano, G, E-P Ng, L Lakiss and S Mintova, 2011. Nanosized molecular sieves utilized as an environmentally friendly alternative to antioxidants for lubricant oilsGreen Chemistry http://dx.doi.org/10.1039/c1gc15367f.

An environmentally-friendly, sieve-like nanomaterial can reduce the chemical fallout from the breakdown of lubricants better than the chemical additives now used.

Looking to solve an old problem in a new way, green chemists find that a special porous material can better reduce levels of dangerous breakdown byproducts in oil lubricants than the long-used but harmful chemicals now added. The team of researchers report their findings about the material – called zeolites – in a recent issue of Green Chemistry.

Lubricant oils reduce friction between moving parts in machines and motors in every part of society, including factory conveyor belts, cars and sewing machines. Synthetic mineral oils are used most often because they are more stable than other types. About 32 million tons of the lubricant oils leak and enter the environment every year.

To reduce human health impacts and meet new European regulatory standards, chemists are trying to find ways to make the oils both functional and environmentally benign.

One big problem with lubricants is they break down and form byproducts when exposed to oxygen – a process known as oxidation. Oxidation generates water, reactive alcohols and acids that increase corrosion and rust, thicken the lubricant, form sludge and sediment, break down the oil and create foam.

Chemical additives prevent or reduce the oxidative reactions. Unfortunately, most additives are dangerous and can impact human health and the environment. Some also affect the machine’s function, such as deactivating the catalyst converters in cars.

In this work, researchers from France, Belgium and Malaysia tested how a highly porous inorganic nanomaterial called zeolites absorb the initial oxidation products in an effort to reduce the harmful chemical byproducts that form. They did not try to stop oxidation like the current crop of chemical additives do. In theory, since oxidative reactions naturally speed up over time, removing the reaction products would reduce further oxidation, slow the process and create less harmful byproduct.

One of the three zeolites compared in the study worked surprisingly well. The researchers found the zeolite cleans up the process in two ways. First, it slowed the inherent oxidation reactions and reduced the amount of chemical byproduct produced. Second, it also absorbed the byproducts that formed. In the end, very little sludge was produced.

The zeolites used have no known adverse environmental effects and can even work together with existing oxidation-preventing chemical additives. The zeolites – when combined with perhaps a next generation of more benign additives – would then give added protection.

Future laboratory studies will need to test the performance of the numerous other zeolites available. From there, they must be tested and assessed in a real working environment. Even though this is not the final word on the technology, it looks to be very promising.

Read more science at Environmental Health News.

Pollution and predators: a double whammy for tadpoles.

Pollution and predators: a double whammy for tadpoles.

Synopsis by Roxanne Karimi, Aug 16, 2011

Reeves, MK, M Perdue, GD Blakemore, DJ Rinella and M Holyoak. 2011. Twice as easy to catch? A toxicant and a predator cue cause additive reductions in larval amphibian activityEcosphere http://dx.doi.org/10.1890/ES11-00046.1.

Low levels of copper can make tadpoles sluggish, putting them at a disadvantage with predators.

Copper levels in water that are considered safe by regulatory agencies can slow wood frog tadpoles enough to make them easier prey for predators, report researchers in the journal Ecosphere. The slowing combined with the normal quiet triggered when a natural predator approaches can so diminish a tadpole’s movements that it is even more vulnerable to predators that can injure or eat it.

The results of the study highlight how low levels of contaminants can indirectly influence animal fitness in unexpected ways. It also shows the importance of examining toxicity effects in a broader ecological context.

There is considerable concern over the effects of multiple stressors on tadpoles, because worldwide, certain amphibian populations are declining. While experts debate the causes, they generally agree that more than one factor may be at play in their demise, including contaminants, disease and atmospheric changes.

More broadly, frogs, salamanders and other amphibians are important because they act as sentinal creatures that indicate the health of the environment. Their unique absorbent skin and dependence on water at some point in their life cycle means they are highly sensitive to environmental changes.

Copper is a trace metal that enters waterways from road runoff and is also a waste product of hard rock mining. While copper is considered essential for growth and survival, high doses lead to toxic effects in many aquatic organisms.

Previous studies have found that copper can interfere with smell and alter fish behavior by impairing homing ability. Other studies show that tadpoles change their behavior in response to environmental cues, such as chemicals released when a predator eats another tadpole.

This new study looks at what happens to tadpoles when exposure to what is considered safe, low levels of copper in the water is combined with a routine, ecological stress – in this case, the presence of a dragonfly predator.

In an earlier study, the researchers found that copper and predators were associated with limb abnormalities, that smaller frogs were found in sites with high copper levels and that the smaller animals were more likely to have limb abnormalities than larger frogs.

To understand how the combined presence of copper and predators might detrimentally alter tadpole behavior and lead to limb abnormalities, the authors collected tadpoles undergoing hind limb development from multiple sites within the Kenai National Wildlife Refuge. They exposed the tadpoles to a low, nontoxic level of copper (5 micrograms per liter), a predator chemical cue or both. They recorded the number of times the tadpoles moved in two hours.

The tadpoles exposed to copper at this low concentration were half as likely to move compared to tadpoles not exposed to copper at all. Predator cues also reduced tadpole activity, but to a lesser extent than copper. Older tadpoles responded less to predators and were more likely to remain active than younger tadpoles. When combined, copper and predators reduced tadpole activity in an additive way. The change in behavior was particularly strong in less developed tadpoles.

While reduced activity can help avoid predation, the additional slowing from the contaminants can lead to less feeding, which can delay growth and development, increase vulnerablity to predators and decrease survival and reproduction. These results help explain the researchers’ previous study in which they found smaller frogs with more abnormal limbs in copper-laden water. The scientists think that the slower-moving tadpoles are more vulnerable to dragonfly predators, which tend to eat the tadpoles developing hind limbs. In this case, the copper indirectly leads to hind limb abnormalities.

The findings show how low levels of copper, thought to be nontoxic to amphibians, can lead to a change in behavior that is likely to be harmful. However, further studies will need to directly measure the effect of copper on feeding or growth and address whether reduced activity leads to changes in survival or reproduction.

See more science at Environmental Health News.