(Press-News.org) PerFluoroAlkyl Substances (PFASs) and precursor compounds have been used in a wide variety of commercial and industrial products over the past six decades. Applications include water and oil repellent coatings, e.g. for textiles, paper products, carpets and food packaging, pharmaceuticals and surfactants in cleaning products and fire-fighting foams. PFASs are highly resistant to chemical, thermal and biological degradation.
PFASs and their precursor compounds have shown a dramatic increase and dispersal around the world over the past four decades. An increasing amount of information is becoming available on the toxicity of these compounds. Hence, studies have documented the toxicity of PFASs on wildlife and human health, including carcinogenesis, genotoxicity and epigenetic effects as well as reproductive and developmental toxicities, neurotoxicity, effects on the endocrine system and immunotoxicity.
Bioaccumulative PFASs enter all parts of the brain
Despite the fact that the liver is considered the major repository in the body for most PFASs, some shorter chain compounds from this grouping have previously been reported in the brain of chicken embryos, suggesting that they are able to cross the blood–brain barrier.
Previous studies have shown a dramatic biomagnification of several PFASs, and particularly one known as perfluorooctane sulfonate (PFOS) as well as several compounds of the perfluorinated carboxylate (PFCAs) grouping, in polar bears. PFOS have been shown to be at concentrations in the liver that are 100 fold higher than the ringed seals on which they are predating. In a new study Arctic researchers from Carleton University in Canada and Aarhus University in Denmark have used the polar bear as a sentinel species for humans and other predators in the top of the food chain. The researchers demonstrated accumulation of PFOS and several PFCAs in eight brain regions of polar bears collected from Scoresby Sound, East Greenland. Dr. Robert Letcher, Carleton University, explains:
"We know that fat soluble contaminants are able to cross the brain-blood barrier, but is it quite worrying that the PFOS and PFCAs, which are more associated with proteins in the body, were present in all the brain regions we analyzed."
Professor Rune Dietz, Aarhus University, is also worried about the results:
"If PFOS and PFCAs can cross the blood-brain barrier in polar bears, it will also be the case in humans. The brain is one of the most essential parts of the body, where anthropogenic chemicals can have a severe impact. However, we are beginning to see the effect of the efforts to minimize the dispersal of this group of contaminants."
Select environmentally labeled products
The eight carbon chain PFOS and perfluorooctane carboxylate (PFOA) are PFASs have been phased out and are no longer produced in the western world. However, production in China, today the only known production source of PFOS and PFOA, has increased by roughly a factor of 10, since it was phased out in the USA. Unfortunately, no emission inventory is so far available from this region. Furthermore, replacements for PFOS and PFOA are now marketed and produced in e.g. the U.S.A. and China, which generally have perfluorinated carbon chains that are shorter or branched.
Another recent study from Aarhus University documents that PFOS concentrations in Greenlandic polar bears and ringed seals started to decline after 2006. Other wildlife populations closer to the sources in Europe and North America have shown a decline prior to the Greenlandic animals. Rune Dietz comments:
"It is promising to see that the PFAS are on the decline. This development should be encouraged by the authorities globally.
In the meantime my best advice to the consumers is to go for environmentally labeled products. But avoiding products is difficult, because PFASs are so widespread in many kind of products and they are rarely declared."
INFORMATION:
FACTS
With fluorine in the tail
Perfluoroalkyl substances (PFASs) constitute a group of compounds where one end of the molecule consists of a carbon chain in which all the hydrogen atoms are replaced by fluorine atoms. This so-called perfluoroalkyl "tail" can be short or long, but the strong C-F bonds make the tail more or less impossible to degrade, compared to the more well known CFC-bonds. The best known PFAS is PFOS with an eight-chained perfluoroalkyl tail.
Further information:
Dr. Robert Letcher
Carleton University
Department of Chemistry
tel.+011-613-998-6696
mobile: +011-613-291-3563
robert.letcher@ec.gc.ca
Professor DSc.Rune Dietz
Aarhus University
Department of Bioscience and Arctic Research Centre
tel. +45-8715 8690
mobile: +45 21254035 rdi@dmu.dk
Literature:
Greaves, A.K., R.J. Letcher, C. Sonne, R. Dietz. 2013. Brain region distribution and patterns of bioaccumulative perfluoroalkyl carboxylic and sulfonic acids in highly exposed East Greenland polar bears (Ursus maritimus). Environ. Toxicol. Chem. 32:713-722. DOI: 10.1002/etc. 2107
http://www.ncbi.nlm.nih.gov/pubmed/23280712
Rigét, F., R. Bossi, C. Sonne, K. Vorkamp, R. Dietz (submitted). Trends of perfluorochemicals in Greenland ringed seals and polar bears: indications of shifts to decreasing trends. Chemosphere
Environmental toxins enter the brain tissue of polar bears
Perfluoroalkyl substances, PFASs, are crossing the blood brain barrier of polar bears
2013-07-23
ELSE PRESS RELEASES FROM THIS DATE:
Going through the motions improves dance performance
2013-07-23
Expert ballet dancers seem to glide effortlessly across the stage, but learning the steps is both physically and mentally demanding. New research suggests that dance marking — loosely practicing a routine by "going through the motions" — may improve the quality of dance performance by reducing the mental strain needed to perfect the movements.
The new findings, published in Psychological Science, a journal of the Association for Psychological Science, suggest that marking may alleviate the conflict between the cognitive and physical aspects of dance practice, allowing ...
Electroacupuncture is effective for post-stroke detrusor overactivity
2013-07-22
Detrusor overactivity is common after stroke, and is characterized by frequent micturition and urinary incontinence. However, the optimal treatment for post-stroke detrusor overactivity remains unclear. According to a study reported in the Neural Regeneration Research (Vol. 8, No. 18, 2013), patients with post-stroke detrusor overactivity from the Department of Neurology, Fourth Hospital of Harbin Medical University, China, received electroacupuncture at points Baliao [including bilateral Shangliao (BL31), bilateral Ciliao (BL32), bilateral Zhongliao (BL33), and bilateral ...
Chinese herbal medicines are safe and effective for vascular dementia
2013-07-22
Chinese herbal medicine, which has been used for thousands of years in China, has long been considered an effective treatment for vascular dementia. There are already meta-analyses of the effects of herbal extracts (ginkgo biloba and huperzine A) on vascular dementia. However, there has been no systematic review of the efficacy and safety of Chinese herbal medicines for vascular dementia, despite its wide use in clinical practice. A recent study published in the Neural Regeneration Research (Vol. 8, No. 18, 2013) evaluated the efficacy and safety of Chinese herbal medicines ...
Lentivirus carrying target genes infects normal rat cochlea
2013-07-22
A recent study published in the Neural Regeneration Research (Vol. 8, No. 17, 2013) injected recombinant lentivirus carrying enhanced green fluorescent protein and the target gene Atoh1 into the cochlea of normal rats using a postauricular approach via the round window membrane. After 30 days, recombinant lentivirus was shown to have no impact on the hair cell numbers and auditory functions, infect hair and supporting cells, and promote supporting cells to transdifferentiate into hair cells. Researchers believed that it may be a new approach for gene therapy in the treatment ...
2 in 1 solution for low cost polymer LEDs and solar cells
2013-07-22
Considerable improvement in device performance of polymer-based optoelectronic devices is reported today by researchers from Ulsan National Institute of Science and Technology (UNIST), South Korea. The new plasmonic material, can be applied to both polymer light-emitting diodes (PLEDs) and polymer solar cells (PSCs), with world-record high performance, through a simple and cheap process.
The contrary demands of these devices mean that there are few metal nanoparticles that can enhance performance in PLEDs and PSCs at the same time.
Most semiconducting optoelectronic ...
Iberian lynx threatened by climate change
2013-07-22
Climate change could drive the Iberian lynx ‒ the world's most threatened cat – to extinction within 50 years, despite substantial ongoing conservation efforts, a new international study has found.
Published today in Nature Climate Change, the research team says the impact of climate change must be incorporated in strategies to reintroduce the Iberian lynx to new habitats if the species is to be saved.
"We show that climate change could lead to a rapid and severe decrease in lynx abundance in coming decades, and probably lead to its extinction in the wild within ...
How to manage concussions
2013-07-22
Concussions, the most common traumatic brain injury, can have serious long-term health effects; therefore, diagnosis and management of these injuries are important. A primer published in CMAJ (Canadian Medical Association Journal) provides physicians with current approaches to diagnosing and managing concussions in patients.
"The importance of accurate and timely recognition and management stems from the consequences of misdiagnosis or faulty management that can lead to major disability or death, in both the short and long term," writes Dr. Charles Tator, Division of ...
Study lays groundwork for norovirus anti-viral treatments
2013-07-22
ANN ARBOR, Mich. – An animal model of the human norovirus created at the University of Michigan Health System lays the groundwork for understanding the biology of the pesky virus and developing antiviral drug treatment.
Well-known as the virus that impacts cruise ship vacations, norovirus leads to misery on land too. The virus spreads quickly from person to person in any closed-in space, such as schools, nursing homes, or day-care centers.
"The first virus in this group was discovered in 1972 following a disease outbreak at a school in Norwalk, Ohio in 1968. Since then ...
Researchers make droplets dance
2013-07-22
Researchers from Aalto University and Paris Tech have placed water droplets containing magnetic nanoparticles on strong water repellent surfaces and have made them align in various static and dynamic structures using periodically oscillating magnetic fields. This is the first time researchers have demonstrated reversible switching between static and dynamic self-assembly.
'We are conducting this line of research because it opens up a way to create new responsive and intelligent systems and materials,' said Dr. Robin Ras of Aalto University, Finland.
Self-assembly is ...
New hope for hormone resistant breast cancer
2013-07-22
A new finding provides fresh hope for the millions of women worldwide with oestrogen receptor positive breast cancer. Australian scientists have shown that a specific change, which occurs when tumours become resistant to anti-oestrogen therapy, might make the cancers susceptible to treatment with chemotherapy drugs.
Seventy percent of breast cancer patients have oestrogen receptor positive cancer, and most patients respond well to anti-oestrogen therapies, for a few years at least. Within 15 years, however, 50% will relapse and eventually die from the disease.
Dr Andrew ...
LAST 30 PRESS RELEASES:
Breathable yet protective: Next-gen medical textiles with micro/nano networks
Frequency-engineered MXene supercapacitors enable efficient pulse charging in TENG–SC hybrid systems
Developed an AI-based classification system for facial pigmented lesions
Achieving 20% efficiency in halogen-free organic solar cells via isomeric additive-mediated sequential processing
New book Terraglossia reclaims language, Country and culture
The most effective diabetes drugs don't reach enough patients yet
Breast cancer risk in younger women may be influenced by hormone therapy
Strategies for staying smoke-free after rehab
Commentary questions the potential benefit of levothyroxine treatment of mild hypothyroidism during pregnancy
Study projects over 14 million preventable deaths by 2030 if USAID defunding continues
New study reveals 33% gap in transplant access for UK’s poorest children
Dysregulated epigenetic memory in early embryos offers new clues to the inheritance of polycystic ovary syndrome (PCOS)
IVF and IUI pregnancy rates remain stable across Europe, despite an increasing uptake of single embryo transfer
It takes a village: Chimpanzee babies do better when their moms have social connections
From lab to market: how renewable polymers could transform medicine
Striking increase in obesity observed among youth between 2011 and 2023
No evidence that medications trigger microscopic colitis in older adults
NYUAD researchers find link between brain growth and mental health disorders
Aging-related inflammation is not universal across human populations, new study finds
University of Oregon to create national children’s mental health center with $11 million federal grant
Rare achievement: UTA undergrad publishes research
Fact or fiction? The ADHD info dilemma
Genetic ancestry linked to risk of severe dengue
Genomes reveal the Norwegian lemming as one of the youngest mammal species
Early birds get the burn: Monash study finds early bedtimes associated with more physical activity
Groundbreaking analysis provides day-by-day insight into prehistoric plankton’s capacity for change
Southern Ocean saltier, hotter and losing ice fast as decades-long trend unexpectedly reverses
Human fishing reshaped Caribbean reef food webs, 7000-year old exposed fossilized reefs reveal
Killer whales, kind gestures: Orcas offer food to humans in the wild
Hurricane ecology research reveals critical vulnerabilities of coastal ecosystems
[Press-News.org] Environmental toxins enter the brain tissue of polar bearsPerfluoroalkyl substances, PFASs, are crossing the blood brain barrier of polar bears