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wagwang

What the fuck... what's stopping this from poisoning our water supply?

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The absolute miniscule volume

Pfas are measured in ppb or even ppt

And water supply is measured in km^3

so 1 liter of eye drop per 1ppt of km^3

That would be 1 liter of the active ingredient, not 1 liter of the eye drop. Also I don't believe that 1 ppt of this stuff is harmful when people are putting it directly in their eyes without severe harm.

There's only a single ingredient, these eyedrops are 100% pure PFAS

And people put asbestos on their christmas trees back in the day - I don't think "obvious harm" is a high enough standard.

I think obvious harm at 1 trillion parts per trillion is a pretty good standard to meet if you want to claim harm at 1 part per trillion.

It's most definitely going to accumulate inside the body, although slowly.

Yes, but too slowly to matter. Average person consumes 1.5 liters per day of water, so if you live to 100 that's 55000 liters. At 1 ppt that's 1 ng / liter, or 55 ug over a lifetime. That's multiple orders of magnitude less than one drop of the stuff to your eye.

We will know after the drops have been out for over a decade, and actual real-world safety data studies get published.

Meanwhile, Restasis (cyclosporine A) (or a generic) works well, and doesn't have to be applied all day long, just two or three times a day. It does burn the eye initially, but it's not harmful, and the burning goes slowly away over time. It does take a few months to start working.

Maybe, maybe not, maybe like teflon, the real poison is an intermediate ingredient, but I think its bullshit that we're just creating chemicals that linger in our water supply for eternity. You literally cannot find anyone in America without traces of the dangerous variant of the PFAS in their blood stream. Like every sip of water is some ridiculous dupont cocktail and we have to tolerate it because people have dry eyes and want non stick pans. Why cant you just use theratears?

> You literally cannot find anyone in America without traces of the dangerous variant of the PFAS in their blood stream.

You also can't find anybody in the world without traces of lead, arsenic, uranium, radium, and other chemical elements in their blood.

> Why cant you just use theratears?

Because they don't work.

Good thing there are 3*10^21 atoms of H2O in a water drop

PFAS are expressed as a mass fraction, not mole fraction.

Ok and there are around that many atoms of pfas per tear drop?

How many gallons of Miebo/Evotears do you think are manufactured every year?

Multiply that by the t in ppt. How many trillions of gallons of water do you think an average city uses every year?

Is all the Miebo/Evotears that’s manufactured being dumped directly into the drinking water supply?

Where do you think it goes after it gets to your eyes? The valid choices are:

A. Absorbed into your body forever.

B. Becomes a part of the water cycle.

C. Is broken down.

And even choice A eventually becomes choice B, ideally after significant time though.

One thing you can be sure of is that the vats of PFAS being produced year after year for this drug aren't going away anytime soon. They're called "forever chemicals" for a reason.

Being dispersed in the environment is not the same as being concentrated into our drinking water supply with each measure resulting in 1ppt contamination of a trillion measures of water.

I suggest that you read about food chains and water cycles.

How do you think pfas got into the water supply in the first place.

Largely firefighting foams, industrial and manufacturing, and landfill sources, but it's still an interesting problem. They don't really break down (that's why they're so useful both in a materials science sense and as a medication) which implies they'll stick around for an extremely long time.

Teflon is also PFAS. The whole PFAS scare is overblown.

> The whole PFAS scare is overblown.

You have absolutely no idea of what you're talking about. If you actually think the scare is overblown, I dare you to drink the whole bottle of that eyedrop.

> You have absolutely no idea of what you're talking about.

I do.

1. "PFAS" is a technically incorrect term. 2. It's ridiculously broad. Teflon is PFAS, sevoflurane is PFAS, and so on.

> If you actually think the scare is overblown, I dare you to drink the whole bottle of that eyedrop.

They literally use the same liquid to FILL THE EYEBALLS after retinal surgery. It's been approved for 25 years. A bottle of eyedrops has 4 milliliters of it, and it would do essentially nothing if swallowed.

The only relevant subdivision of PFAS is by chain length: small, medium, large. Even so, they all accumulate in the environment. Just because you with your short term selfish interest doesn't take any responsibility for the world at large, willing to totally destroy it for small personal gain, does not mean that others don't either. All PFAS are very harmful in the environment because it's like paperclips that keep being made but not ever being unmade. Medium and long chain are also harmful in the human body due to significant accumulation.

Teflon does not get a free pass. It is a toxin. The last I recall, it causes brain damage in children. There is a reason why sane people avoid nonstick cookware.

> The only relevant subdivision of PFAS is by chain length: small, medium, large.

PFOA and PFOS have 8-member fluorinated chains. And they are dangerous, with clear dose-dependent effects.

PFHO has a 6-member fluorinated chain, and it has no known toxic effects.

> Even so, they all accumulate in the environment.

So does silicon oxide. Or a lot of other "terminal" compounds. The questions that need to be asked are:

1. Are they dangerous by themselves?

2. Do they bioaccumulate?

3. Do they stay mobile in the environment (i.e. don't get sequestered)?

In case of PFHO, it's not dangerous. It does not bioaccumulate because of its poor absorption. And it's also not mobile.

> The last I recall, it causes brain damage in children.

No, it doesn't.

Don't confuse silicon oxide with a PFAS. It is quite the negligent and hazardous fallacy to put them in the same bucket. One has been around for billions of years. The other hardly has any research, and will take at least a decade more of data and research before we know what's it is capable of.

You are in no way smart enough to understand and consider all the pathways, uptake mechanisms, and consequences that are affected by the PFAS compound across all of biological life. Knowing just one or two over just a few years does not make you competent in it or qualified to make a broad safety comment.

The same argument applies to literally everything, including doing nothing.

PFAS is to my knowledge the only human-created unnatural class of compounds that does not deteriorate in the environment. So no, the argument applies exclusively to PFAS.

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