Fluorine formed in stars and our Sun

The Sun by the Atmospheric Imaging Assembly of NASA's Solar Dynamics Observatory. Credit: NASA

The fluorine that is found in products such as toothpaste was likely formed billions of years ago in now dead stars of the same type as our sun.

This has been shown by astronomers at Lund University in Sweden, together with colleagues from Ireland and the USA.

Fluorine can be found in everyday products such as toothpaste and fluorine chewing gum.

However, the origins of the chemical element have been somewhat of a mystery.

There have been three main theories about where it was created. The findings now presented support the theory that fluorine is formed in stars similar to the sun but heavier, towards the end of their existence.

The sun and the planets in our solar system have then been formed out of material from these dead stars.

Nils Ryde

"So, the fluorine in our toothpaste originates from the sun's dead ancestors", said Nils Ryde, a reader in astronomy at Lund University.

With doctoral student Henrik Jönsson and colleagues from Ireland and the US, he has studied stars formed at different points in the history of the universe to see if the amount of fluorine they contain agrees with the predictions of the theory.

By analysing the light emitted by a star, it is possible to calculate how much of different elements it contains. Light of a certain wavelength indicates a certain element.

In the present study, the researchers used a telescope on Hawaii and a new type of instrument that is sensitive to light with a wavelength in the middle of the infrared spectrum. It is in this area that the signal is found in this case.

"Constructing instruments that can measure infrared light with high resolution is very complicated and they have only recently become available", said Nils Ryde.

Different chemical elements are formed at high pressure and temperature inside a star.

Henrik Jönsson

Fluorine is formed towards the end of the star's life, when it has expanded to become what is known as a red giant. The fluorine then moves to the outer parts of the star.

After that, the star casts off the outer parts and forms a planetary nebula. The fluorine that is thrown out in this process mixes with the gas that surrounds the stars, known as the interstellar medium.

New stars and planets are then formed from the interstellar medium. When the new stars die, the interstellar medium is enriched once again.

The researchers are now also turning their attention to other types of stars.

Among other things, they will try to find out whether fluorine could have been produced in the early universe, before the first red giants had formed.

They will also use the same method to study environments in the universe that are different from the environment surrounding the sun, such as close to the supermassive black hole at the centre of the Milky Way.

There, the cycle of stars dying and new ones being born goes considerably faster than around the sun.

"By looking at the level of fluorine in the stars there, we can say whether the processes that form it are different", said Nils Ryde.

Triclosan and Ubiquitous Antibiotics freely used in Personal Care Products

Earlier this month, the Food and Drug Administration (FDA) issued a press release about triclosan - an ubiquitous antibiotic found in tons of personal care products, including deodorant, toothpaste, hand and facial cleansers, mouthwash, and other household cleaners.

It can't be good for our environment to be flushing lots of antibiotics down the drain. In the press release, the FDA stated that:

For some consumer products, there is clear evidence that triclosan provides a benefit. For other consumer products, FDA has not received evidence that the triclosan provides an extra benefit to health. At this time, the agency does not have evidence that triclosan in antibacterial soaps and body washes provides any benefit over washing with regular soap and water.

After reading the press release, I am sure you are curious what kinds of research have been done on the safety of triclosan, as well as the utility of antibiotics in common household products. Go to the primary literature sources so you can see for yourself what scientists have been researching, and if their research is published in reputable peer-reviewed journals, and first investigate the safety aspects of triclosan.

It isn't hard to find a number of papers that implicated triclosan as problematic in animal studies. One paper (The bactericidal agent triclosan modulates thyroid hormone-associated gene expression and disrupts postembryonic anuran development) found that when bullfrog tadpoles were exposed the levels of triclosan that are typically found in our environment, the tadpoles did not develop normally.

Another paper (Short-term in vivo exposure to the water contaminant triclosan: Evidence for disruption of thyroxine) studying rats found that very low levels of triclosan disrupted thyroid hormone regulation. This has long been a concern about triclosan, as the structure of triclosan is very similar to that of thyroid hormones.

If there is a serious positive influence on our daily lives through the use of triclosan containing products, to some it may be worth the environmental cost. However, this arguement quickly falls apart when looking for evidence to support the claim that triclosan makes our lives better.

In a comprehensive review of the scientific literature published in 2007 (Consumer antibacterial soaps: effective or just risky?). Quoting from their abstract, it says it all:

Soaps containing triclosan within the range of concentrations commonly used in the community setting (0.1%-0.45% wt/vol) were no more effective than plain soap at preventing infectious illness symptoms and reducing bacterial levels on the hands.

So, if you want to avoid contaminating the environment without sacrificing personal hygiene, please check the labels of any household products before you purchase them to see if they contain triclosan (which also is marketed as Microban, Irgasan DP-300, Lexol 300, Ster-Zac, Cloxifenolum, or Biofresh ref).

Not only is this product unnecessary in most circumstances, but it looks like it could have a very negative impact in our environment. So, if it's not really helping you, you might as well find an alternative product that doesn't contain triclosan.