About 70 years ago, humans invented a whole class  of chemicals that improved things like this and   this and this, but it turns out they're probably  bad for us.

And they can last for ever forever.

Forever chemicals are usually per  and poly floralalkyl substances or   PFAS, which are thousands of chemicals known for  being water, heat, oil, and corrosion resistant,   which makes them really useful in jet engines and  firefighting foams, but also more common things   like fast food wrappers so that that burger  grease doesn't soak all the way through.

Or   microwave popcorn bags so  that they don't catch on fire.

Here's a typical forever chemical called PFOA.

It's a chain of carbons surrounded by fluorine   atoms.

Carbon fluorine bonds are covalent, meaning  the atoms are sharing electrons.

And as far as   bonds go, covalent bonds are pretty strong.

But on  top of that fluorine is the most electronegative   element on the periodic table.

That means that  although it's sharing electrons with carbon   fluorine, will pull those electrons  closer to it, creating partial charges.

That makes the carbon and fluorine even more  attracted to each other and less likely to   react with other molecules like water,  different oils or corrosive compounds,   and less likely to break down  even under extreme temperatures.

So do these chemicals really last  forever?

Depends.

In the environment,   we don't know how long they last.

In our bodies  they seem to hang out for at least a few years,   but some PFAS might hang out for decades, which  is a lot longer than any other chemicals we're   regularly eating or drinking.

They stick around  by binding to proteins in our blood, which is   probably why we're finding them in a bunch of  different tissues, especially tissues that have a   lot of blood vessels like our liver or kidneys.

In  people they've been linked to higher cholesterol,   endocrine and immune system disruption,  and even a higher risk of cancer.

In animal experiment they've caused  reproductive and developmental defects and   tumors, and also messed with liver,  kidney and immune system function.

We're still trying to figure out the chemistry  behind why these compounds seem to be so bad for   us.

So in the meantime, it would make sense  for us to scale back on using them, right?

Here's the thing.

We're super reliant on these  chemicals for kind of good reasons.

They're   useful, convenient, and they can do a lot of  things that most chemicals can't.

Why don't we   just invent new chemicals that don't last forever?

Problem is the chemistry that makes PFAS so useful   is exactly what makes them stick around.

So it's  really hard to create alternatives that won't   last as long, but will still do their job.

Take  GenX, for example, first used in 2009 as a PFOA   alternative, it's a similar structure to PFOA, but  instead of this carbon, there's an ether group.

Small switch was supposed to make GenX less stable  and therefore less likely to stick around in the   environment.

But now it's being found in our  drinking water and animal studies are showing   that it's probably just as bad as PFOA.

And we  still don't know what GenX could do in humans.

It's not like there's been no effort to phase  out PFAS.

It's just been really limited.

In 2006,   EPA and eight major manufacturers agreed to  eliminate PFOA and other related PFAS from   their products by 2015.

But remember there are  still hundreds of other PFAS being used today   and they are everywhere.

I mean, look at this map.

As of January, 2021, over 2300 sites in 49 States   showed PFAS contamination and there's no federal  limit for how much of it can be in our waters.

EPA   has been collecting data on PFAS toxicities and is  hopeful that we're now in a place where some PFAS   regulation might actually happen.

But even if PFAS  are fully phased out and we're no longer using   them, we still have over 70 years worth of PFAS  sitting around in our environment.

So chemists   are trying to figure out how to remove it.

A  recent approach actually has to do with microbes.