- Luis Abinader, el presidente dominicano de mano dura con Haití
- Sean "Diddy" Combs pide disculpas tras un video que lo muestra agrediendo a su expareja
- El papa Francisco califica de "locura" las actitudes antimigrantes en la frontera de EEUU
- Lai asume como presidente de Taiwán y pide el fin de la "intimidación" china
- El presidente dominicano es reelegido para un segundo mandato marcado por Haití
- El presidente iraní Raisi muere en un accidente de helicóptero
- Ebrahim Raisi, un presidente iraní ultraconservador
- Medios iraníes anuncian el deceso del presidente Raisi en accidente de helicóptero
- Lai asume como presidente de Taiwán y pide fin de "intimidación" de China
- España llama a consultas a su embajadora en Argentina y exige disculpas a Milei
- "Ninguna señal" de vida en helicóptero accidentado del presidente de Irán
- Presidente dominicano reelecto para un segundo mandato marcado por Haití
- Presidente dominicano lidera elecciones marcadas por la crisis de Haití
- Taiwán inviste a un presidente detestado por China
- Biden enfrenta protesta silenciosa por Gaza y promete a estudiantes trabajar por la paz en Oriente Medio
- Irán continúa su intensa búsqueda del presidente Raisi tras un accidente de helicóptero
- Kevin Costner vuelve al wéstern en Cannes, Serebrennikov a los fantasmas de Rusia
- El estreno de "Lula" de Oliver Stone en Cannes, un acto de adhesión al mandatario brasileño
- Al menos once muertos en bombardeos rusos en la región ucraniana de Járkov
- El barco que destruyó el puente de Baltimore será movilizado el lunes
- Manchester City hace historia, Arsenal vuelve a ser segundo
- Biden promete a estudiantes escuchar protestas por Gaza y trabajar por "paz duradera" en Oriente Medio
- Blue Origin lleva pasajeros al espacio, incluido el astronauta con más edad
- Blue Origin lleva al espacio a pasajeros tras dos años de pausa
- El presidente de Irán, ilocalizable tras un "accidente" de helicóptero
- Irán emprende búsquedas para encontrar el helicóptero del presidente Raisi tras "un accidente"
- Los bombardeos continúan en Gaza, emisario de EEUU en Israel
- Blue Origin lleva al espacio a aventureros tras dos años de pausa
- Manifestación contra el partido gobernante de Taiwán en víspera de la investidura
- Los bombardeos israelíes continúan en Gaza, Israel espera la llegada de un emisario de EEUU
What we know about how 'forever chemicals' affect health
Invisible, omnipresent "forever chemicals" have been linked to a wide range of serious effects on human health, prompting growing calls for them to be banned.
While there is firm evidence that at least one of the more than 4,000 human-made chemicals called PFAS causes cancer, researchers are still attempting to fully understand their broader impact on health.
Here is what we know so far.
- What are PFAS? -
Per- and polyfluoroalkyl substances (PFAS) are synthetic chemicals that were first developed in the 1940s to withstand intense heat and repel water and grease.
They have since been used in a vast range of household and industrial products including food packaging, make-up, stain-proof fabric, non-stick pots and pans and foam used to fight fires.
Because PFAS take an extremely long time to break down -- earning them the nickname "forever chemicals" -- over the years they have seeped into the soil and groundwater, getting into our food chain and drinking water in the process.
These chemicals have now been detected virtually everywhere on Earth, from the top of Mount Everest to inside human blood and brains.
- Two biggest culprits -
The two most researched PFAS compounds have already been banned or restricted in many countries, though they remain detectable throughout the environment.
Perfluorooctanoic acid (PFOA), which was once used to make the non-stick cookware coating Teflon, was in December classified as "carcinogenic to humans" by the International Agency for Research on Cancer (IARC).
The World Health Organization agency said there is "sufficient evidence" that PFOA gave animals cancer during experiments, as well as "limited evidence" of renal cell and testicular cancer in humans.
Perfluorooctane sulfonic acid (PFOS) -- once the key ingredient in the Scotchgard fabric protector -- was meanwhile ruled "possibly carcinogenic to humans".
There was limited proof of cancer in animals but "inadequate evidence regarding cancer in humans", the IARC said.
- Other linked diseases -
More broadly, observational studies have suggested that exposure to PFAS chemicals is associated with an increased rate of cancer, obesity, thyroid, liver and kidney disease, higher cholesterol, low birth weight, infertility and even a lower response to vaccines.
But such observational research cannot prove that the chemicals directly cause these health problems.
And the level of risk can vary greatly depending on the level of PFAS people are exposed to -- almost everyone on Earth is believed to have at least a little PFAS in their bodies.
According to the IARC, most at risk for serious PFAS exposure are people who directly work with the chemicals while making products.
- Question of exposure -
Exactly what level of PFAS exposure is hazardous to health has been a matter of debate.
Previously, guidelines in numerous countries ruled that having less than 100 nanogrammes of PFAS per litre of tap water was enough to protect health.
But the United States has proposed lowering the limit to four nanogrammes of PFOA and PFOS per litre -- and the EU is considering following suit.
Last year, a media investigation found PFAS levels over 100 nanogrammes per litre at 2,100 sites across Europe and the UK.
The level soared over 10,000 nanogrammes at 300 of the sites, according to the investigation carried out by 16 newsrooms.
- 'Chemical whack-a-mole' -
Further complicating the ability of research to comprehend the health effects of PFAS is that new compounds are still being developed.
As manufacturers phase out compounds identified as potentially hazardous, they sometimes simply replace it with another member of the PFAS family that has been studied less, researchers have warned.
Harvard environmental researcher Elsie Sunderland has called this process "chemical whack-a-mole".
- Calls for action -
Environmentalists and health experts across the world have been increasingly sounding the alarm about forever chemicals.
On Thursday, French MP Nicolas Thierry will introduce a bill that -- if passed -- would ban non-essential PFAS in France from 2025.
The European Union is also considering a Europe-wide ban on PFAS from as early as 2026.
- What can you do? -
For people at home, it is nearly impossible to avoid consuming miniscule amounts of PFAS.
But experts recommend reducing contact with non-stick cookware and grease-proof food packaging such as fast food wrappers.
Drinking filtered or bottled water and storing leftovers in glass -- not plastic -- containers could also help.
J.Horn--BTB