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Scientists cut the tolerable intake of PFAs by 99.9% (massivesci.com)
146 points by laurex 19 days ago | hide | past | web | favorite | 112 comments

I think this might be more informative: https://www.doh.wa.gov/CommunityandEnvironment/Contaminants/...

Also the headline overstates the content of the article by two orders of magnitude - article suggests 10x change to safe level while the headline stipulates 1000x.

Don't look now, but PFAs have been "replaced" with a chemical called "GenX." These companies will just shapeshift their toxic sludge every time a major suit is won. Sickening...


This is the problem with our current approach to safety testing; it takes decades of statistical analysis across the population in order to determine whether there are long-term effects from these chemicals. By the time there is evidence to make PFAS illegal, a new alternative will be found. Who knows if this alternative will be turn out to be better or worse that PFAS in 30 years?

This is a hard problem; in general you don't want to shut off all new technological development, and presumably the worse something is for you, the faster the harm will become apparent (e.g. thalidomide). But I'd be interested to see a full-system cost/benefit analysis of e.g. PFAS. If the cost is "with X probability, cause Y QUALYs of harm to the population over 30 years", and the benefit is "improve convenience of cooking by making pans non-stick", what are the maximum values of X and Y that we should be happy to agree to?

It doesn't seem to me that society is currently well equipped to make decisions in this way.

To add to this is the fact that we also have plenty of evidence that industry will do the wrong thing. Lead additives to gasoline is a common example but the story of Diethylstilbestrol (more commonly known as DES) is so much worse.

10 million or more fetuses exposed over 30 years with results ranging from fatal aggressive cancers in young children to birth defects. DES still shows effects two full generations later - in the grandchildren.

During the time DES was in use it was often defended using the “But women have estrogen already and this is exactly the same so obviously it’s fine” sorts of dismissals.

And now, here and again I encounter people dismissing concerns about BPA or PFOA and other endocrine disrupters with hand waving about how if there was really a problem we would have seen it and reacted to it by now so - the reasoning goes - obviously there is not a problem or, if there is one, it’s minor. And then I think of DES.

I wonder if all the 'compostable' bio plastics you see in utentsils and some food packaging have the same problems or are safe.

Most compostable bio plastics are made of Poly-lactic acid (lactic acid is the stuff that gives that burning feeling in your muscles after a workout) from corn.

PLA can compost in industrial sites, but (edit: add a not here) in normal environments, perhaps that is the reason for your quote marks.

So at least the bulk of the material in the bioware is pretty safe, especially when compared against PFA/PFOAs. That's not to say that it's impossible to mix PLA with some other, unsafe chemicals.

IIRC biostarch PLA can be produced from any industrial waste product high in cellulose. In practice this would include for example sugar cane in addition to corn husks. It is often said that they will completely degrade within 14 days in a warm vegetative compost environment. How closely a typical landfill replicates this optimal, aerated environment is questionable. Anyway, they are a lot better to have discarded around the planet than most plastic. The problem is that they are extremely energy inefficient to produce.

Traditional polymers: Oil in, power in, cheap product out, correct disposal and recycling required or planet suffers.

Biostarch polymers: Industrial waste in, huge amount of power in, comparable but more expensive product out (but can be relied on to biodegrade eventually if incorrectly disposed of).

The real solution is better food distribution systems with more efficient and re-usable packaging and cutlery, so that disposal is not required.

Yeah, re-use is always preferable. It often goes against ever-increasing standard of hygiene.

It used to be common to collect used glass bottles and re-use them. That practice still happens in countries like Thailand and Vietnam.

Still happens in America today. I refilled a glass jug at a local brewery today. $5 deposit on a 750ml bottle, can return for the deposit or just leave it in the car and get it refilled at just about any brewery, even some liquor stores, restaurants and grocery stores.

Better food distribution systems would also remove, for example, the need for personal motor vehicles, personal grocery trips, spatially inefficient retail spaces, the non-ideal refrigeration and other concerns deriving from food safety concerns in such spaces, and even individual package labeling.

Yes many of them are made with this junk, a lot of hygiene products have it too like "Oral-B" floss and even things like microwave popcorn bags...

The more people realize the FDA does not care about us and learn to take personal action the better.

Nobody has personal time or money to do the research required. We need some organization to centralize the work and indicate what's safe and what's not safe with enough robustness that unsafe products aren't easily sold to the unwary.

We generally call these things government agencies, but any other body with the same function - private or public - will be susceptible to the same kinds of forces that government agencies are. All we can do is try and build institutions good processes, adversarial audits that ensure processes are followed, and mechanisms to adjust processes when they're found to be lacking.

We generally call the latter mechanisms democracy. It's not great, but it's the best we've come up with.

Well, you'll end up with toxic drinking water with this attitude. I don't know what the right solution is, but saying you don't know enough at this point to throw out your teflon pans and avoid certain products and that you don't want to research things is lazy and ignorant.

Citizen's levying large class-actions suits and making documentaries like "The Devil We Know" are perhaps the best tools we have to stop fascist corruption.

I don't understand what you're responding to in what I wrote, sorry.

For the parents in the audience, carpet is a major exposure path for young children. Anything stain resistant (carpet/appulstry etc) has it (most carpet). Abrasian from ordinary usage causes it to be released in the form of dust. Toddlers, due to their proximity to the ground and propensity to put their hands in their mouths, are particularly susceptible.

Better living through chemistry!

As I understand it, most (all?) nonstick coatings on pans are chemicals in this general category - some variant of fluorine compounds that hold together well. The biggest problem particularly with older ones is that they start to get less stable as heat gets higher - like it may if you leave an empty nonstick pan over a burner, where it can give off fumes that are particularly toxic to pet birds.

Avoiding those compounds likely accounts for at least some of the increased trendiness of cast iron in the past decade or two, including the increase in new "artisanal" cast iron makers like Stargazer, Finex, Butter Pat, Smithey, Field Co and probably a few others (for reviews of a bunch of those, check out Kent Rollins on Youtube). There's also quite a bit of information on improving/smoothing less expensive cast iron.

I looked at some of those brands to see what made them different from Lodge. One had a different handle, while another one had a thicker bottom and thinner sides for better searing, but they're also in the hundreds of dollars. A 12" Lodge skillet is $40, that's at least half the price of the 12" skillets for the other brands. For the price, I don't think that Lodge can be beat.

The primary difference between vintage, “artisanal” and modern cast iron (eg: lodge) is the former is machined and the latter isn’t.

Cast iron, seasoned, is supposed to be slicker than non stick. You should be able to fry an egg in it.

With lodge you have to build up that non stick over the sand casting “bumpies” that are left over from the iron casting process.

They used to machine those out, especially on the cook surface. Until this latest crop of modern cast iron manufacturers, one would typically have to retreat to vintage or perhaps machine your own.

I think most people just look at the sorry state of “lodge” then grab a pfa laden non stick and go home.

+1. I have a lodge cast iron and I prefer a $25 TFal Titanium. Everything sticks to the former, nothing (not even oil!) sticks to the latter. No PFOA in TFal either.

They use reinforced PTFE, versions of which are potentially also toxic, but not banned yet. From Tefal/T-fal's FAQ:

>All non-stick coatings contain PTFE, the abbreviation for polytetrafluorethylene, a plastic polymer. It is a slippery ingredient, made up of molecules of tetra fluoro ethylene that only contain carbon and fluorine.

Tefal/T-fal have been one of the main proponents and suppliers of teflon cookware (hence their name), switching formulas every so often, once the toxicity of the various generations of coating have become an issue.

Everything is "potentially toxic", especially in California. Currently, however, "scientific consensus" suggests PFTE is safe.

I’ll reconsider after a millennium or two of usage.

I got a cheapo Lodge for this reason, but I wonder if the more expensive makes add some postprocessing steps to smooth the casting. I found the rough Lodge finish to be unworkable since food kept sticking, and it was hard to clean. I ended up sanding it down to a glass finish and reseasoning it, and now it works properly.

How do you refinish a lodge skillet? Someone accidentally used the rough side of a sponge on it and there's a shiny metal peeking through now. Also, is it safe to cook with before refinishing with that spot?

I'm a little late to this, but it's called seasoning (or reseasoning) and you can either try to take it down all the way to bare metal or just work on building up additional layers. Plenty of articles available for either, I'm sure I'm leaving things out. Don't get too distracted by fancy processes, remember this is something people have been doing for hundreds of years.

If you want to go bare-metal and have an oven with a self-cleaning cycle, that's probably the simplest way to go - put the cast iron in there open-side down and run that cycle. I'm not sure just how much smoke this will release, but you might not want to do it on a day when you can't open windows. I've also seen notes that this can sometimes cause warping, so buyer beware.

To build up the seasoning, it's basically going to be multiple repetitions of putting on a thin layer of a high-smoke-point food-safe oil, heating and repeating. Darker color generally just indicates more layers.

In some ways it's almost like you're varnishing the cookware with an oil-based varnish, but without some of the other components of varnish. A lot of guides will recommend flaxseed oil for seasoning, it's also known as linseed oil and used to be pretty common in varnishes and wood finishes. For a contrary (and easier and cheaper) view, see https://www.reddit.com/r/castiron/comments/5owtnm/why_i_dont...

(see also https://en.wikipedia.org/wiki/Drying_oil about oil-based varnishes)

Clean it. Put cooking oil on it. Heat it to 170-180°C (depends on oil type, and I use infrared thermometer to check). Keep it at that temerature for 30min or so. It's non-sticky again. That's what I do with my cast iron pan.

Alternatively you can put it into oven and bake it at that temperature.

Interesting. How much oil should I use for a 9" pan? Looks like 170-180 is below the smoking point of any oils I'd potentially use, but does the actual oil matter? Is vegetable, canola, or peanut totally fine?

Very very little oil (no poodles). I use a paper towel to spread it thin. You can even bake the pan upside down to ensure no poodles can form if you have non-level bottom of the pan. Use some refined oil or lard.

Goal is to keep it below smoking point.

It works to reseason the pan after minor damage (not yet rusted, but lacking non-sticky surface). I use the pan almost every day, so I don't have experience with fixing heavier damage.

If the pan gets sticky to the finger afterwards (it shouldn't if you avoid poodles of oil), don't worry. It will resolve itself after a few cooking cycles.

I think that's the go-to process with any new Lodge product. I did it too with similar results. I hear that Lodge actually gives their pans a rough finish precisely to make it harder to clean - and thus more likely to retain oils used in cooking - for the benefit of normal people who don't know that you need to season cast iron.

How did you sand iron? (sorry if this is a naive question)

Same way you sand anything, as long as the grit is harder than what your sanding it works just fine. Iron is only 4 on the Mohs Scale which is below glass, so many types of sandpaper work fine.

Check assorted youtube videos. Abrasive disks of various sorts are easy to come by, though you're likely going to want a plug-in drill or angle grinder - maybe an 18v 6AH battery would give you the oompf you'd need, but I wouldn't count on it.

The key things I'm going to highly highly highly recommend are a good filter mask, good ventilation (or excellent ventilation and a big shop fan blowing past if you have a beard) and a way to securely hold the piece you're working on. I don't have a link, but I like what one guy put together with a heavy duty board - a hook at one end through a hole, and a hook at the other through a slot that could be adjusted to fit the piece. Don't tighten down hard at all unless you want to risk breaking things, just enough to keep what you're working on from shifting around as you sand.

I tried by hand first, but it was going too slow so I used an angle grinder with a sandpaper wheel.

I’ve been to the Lodge factory in rural South Pittsburg Tennessee and I don’t understand what makes “artisanal” cast iron any different from Lodge. It’s pretty much just a marketing hook to convince hipsters to spend hundreds more. The folks that make Lodge are just as “artisanal” as the fancy-pants brands. Lodge has been doing this for over a hundred years. They were “artisanal” before anyone ever used that work. I agree, Lodge can’t be beat. Their iron isn’t any better or worse than the more expensive brands, they just don’t have some bearded “skillet master” in their marketing department convicting people about how good their products are.

Others have covered this as well, but I believe they're all significantly lighter than the comparable Lodge products, and some of the handles apparently actually work pretty well - although the review I've seen of whichever one has that coil handle wasn't very impressed. I have a couple of Lodges that I use weekly, and neither has a handle that's impressed me.

They're also all machined to a smooth finish after molding, where the Lodges are cleaned, possibly sanded a bit to get rid of any lingering material from the mold, then seasoned. Part of the reasoning I've heard for the rougher finish on Lodge pans is that it makes that initial factory seasoning much easier to get on there. If you look around in the cast iron arena you'll come across a fair amount of information on how to do your own machining at home with drills, abrasive pads, hand sanders, etc.

Beyond that, some of them have different configurations of spouts, secondary handles, etc. - they're all somewhat different.

Also, cast iron is known to cure anemia in women, and it has been tested for thousands of years and is well understood. It is not experimental. Also, really, how hard is it to put some oil in a pan and let that coat the pan before you start cooking? My friends complain that their food burns in an iron pan, which I think is a surprising complaint. The solution to burning has been known for centuries: just put some oil or butter in the pan, and use a reasonable flame.

It's about saving time and work. Cast iron takes a lot of work compared to even plain old stainless steel plans in prep and cleaning. They are very heavy to handle and can't use such foods as tomatoes because they are too acidic.

An informal survey as to why you would use a cast iron is "it make meat taste better" and it "heats more evenly".

I will say, the only work my cast iron requires is cooking a really fatty food in it once a month.... my stainless pans require scouring if I do some searing (even with a good deglaze) which is a huge hassle. My cast iron, I just wipe out lightly and never scrub. I have never noticed adverse effects from this and it's well seasoned.

I do hear the weight complaint - I'm a big guy so it's not too bad but my girlfriend needs two hands.

Same here - I have a bigger stainless steel skillet that always needs steel wool to get some pesky things out of it after any frying, but my cast iron cleans up much easier. Though, I make liberal use of dish soap and the scouring side of my sponge. Never had a problem with seasoning other than roommates messing it up a bit here and there.

You can cook tomatoes in cast iron. I wouldn't spread tomato paste around the pan and leave it in the sink with water in it for a week, but that's no reason to avoid cooking with tomatoes in cast iron.

It's not because it damages the pan, it's not good for you. A significant amount of iron breaks down from the acid and leaches into your food.

It's not the iron either - it's because if you cook too much with acidic liquids in cast iron you'll get some of the seasoning coming off and it may turn your food blackish and unappealing. If you do a lot of cooking like that or don't have it properly seasoned you'll eventually have problems with going all the way through the seasoning and then you'll get rust.

If you want to use cast iron for soups, stews, braises, chilis, etc. that you're going to be cooking a long time, get an enameled cast iron pan - that'll get you a lot of the heat retention but with a more durable (but not nonstick) finish.

I used to believe that cast iron were more work, but I moved house, got a (cheap, $20) cast iron pan - and it's less work. I t sticks less than non-stick pans. Very notable when frying eggs. I hadn't have an egg stick yet, while I had it all the time in the non-stick. Also, you can be rough with metal tools without worrying about damaging the non stick coating. And can overheat without damaging the pan.

It's also easy to clean, if you get over the impulse to use detergent. Just clean it in hot water and then a towel or paper towel. If one uses detergent, it needs to be oil coated and heated again, which is annoying.

I'll never use anything but cast iron again. It is heavy though.

So the whole you can’t use soap on cast iron is incorrect. It used to be, when soap was made wit lye, but normal dish soap is not nerely strong enough to remove the coating on cast iron.

I have 5 cast iron pots and pans and use a little soap on all and have no issues with removing coating.

I feel like you must cook a very narrow range of food and/or have very little space / money for more pans. Cast iron is lovely and versatile (see my sibling post) but there is a tool for every job and cast iron is not always that tool,

I have very little space AND when I moved house I got super annoyed over sooo many annoying trinkets. I don’t want more stuff.

You can certainly use a little dish soap, but not with anything abrasive. I used to use a stiff-bristled brush on mine, but these days I'm actually using a little square of stainless steel chainmail intended for cleaning cast iron. There are no sharp edges to dig into the finish, but it's hard enough and flexible enough to get a good scrub going.

Ditch the Lodge, don't even think about the artisanal cast iron, and go straight for the DeBuyer Mineral B. It's much cheaper than the crap artisanal things, much more options in pan sizes, and finished better.

More generally - if they don't sell it at a restaurant supply store (or a store catering toward the restaurant business), you are going to be overpaying for it. This is true for almost everything you really need in the kitchen.

They're not the same thing. That De Buyer is thin carbon steel, not cast iron. I have one (an identical Paderno actually) and it's by far my favorite pan for crepes, but it sucks for everything else. It's no good for searing because it lacks the necessary heat capacity, and the thin steel causes hot spots even worse than cast iron.

Deeper carbon steel pans are great for stir frying, but I have yet to find another use for very shallow carbon steel skillets.

Note that Lodge makes skillets that it calls "carbon steel" which are actually just especially thin cast iron, and I love these. They are thick enough to perform like cast iron, but much lighter. I have 10 and 12 inch skillets (Lodge model numbers CRS10 and CRS12), and they're my go-to skillets for almost everything: pancakes, omelets and fried eggs, sauteing, and shallow frying. The only thing I don't use cast iron for is scrambled eggs.


Nope, nevermind, I'm wrong. I just checked my pans, and my Lodge thin cast iron skillets are the same thickness as those Mineral B pans -- 2.5mm. My crepe pan is thinner. So you're right, those De Buyer pans probably are excellent replacements for cast iron -- lighter, cheaper, similar performance.


Damn you batbomb, now I have to go shopping for pans. Restaurant supply store you say? Maybe ebay?

Not to mention carbon steel is what all restaurants use. Cast iron is too heavy.

Consumer ranges put out 1/3 the BTUs of a typical commercial range. Would that impact the success of carbon steel you think?

The lower power of consumer ranges is mitigated somewhat by heavier steel and iron construction with greater heat capacity. A more powerful restaurant range can keep thin metal pans from cooling too much when food is dumped into them.

This only really matters for searing and shallow frying, where temperatures need to stay high and stable. For lower temperature activities like sauteing, evenness of heat is more important. Delicate things like crepes and egg dishes are sort of special cases, requiring both evenness and a surface that releases the food without sticking.

Yes, and anecdotally I can tell you it's quite possible to kill a bird with non-stick cookware even it's not overheated.

It's important to note that birds can easily be injured or killed by all kinds of cooking smoke and fumes, regardless of origin, and all cooking smoke is known to be carcinogenic. But normal cooking fumes are nowhere near as dangerous as the shit that comes out of overheated PTFE.

I switched to ceramic pans because of these concerns. More sticky than teflon but much better than traditional iron or stell pans.

Ceramic pans unfortunately get sticky with age. My Zwilling J. A. Henckels pans [1] were amazing the first year or so, and then they started to get worse. Now I can no longer cook eggs in them -- complete mess. They're fine for plenty of things, like sauces and vegetables, but not eggs, crêpes, omelets or anything that needs a non-stick surface.

This is unfortunate, because the ceramic process doesn't use PFAs like PFOA, and they don't use PTFEs. Some people claim you can preserve ceramics' non-stickiness by not using oil, but I have my doubts. The short lifespan of ceramics is a pretty common complaint. From what I can tell, there's no way to get the non-stick back -- scrubbing the coating only makes it worse.

[1] https://www.crateandbarrel.com/zwilling-j.a.-henckels-vistac...

Ceramic is actually a marketing gimmick referring not to the material used but rather the process of making it. It is still teflon-coated and just as toxic as "non-stick."

Wish I had a source but I'm on mobile.

No, ceramic sol-gel coatings contain no PTFE. Fluorinated chemicals are not involved in any way. There are many ceramic coatings used in cookware: Greblon CK, made by Weilburger, Thermolon/Zwilling Sol; Fusion, made by Whitford; Ceralon and Xeradur made by ILAG; Duraceram made by GMM. You can see specs for all of these at the manufacturers' websites.

Ceramic is no teflon... I accidentally proved this by leaving an empty ceramic pan on the fire. It took take an amazing high temperature with the aluminium underside discolored a bit but otherwise perfectly fine, still use it today.

Sort of. There's ceramic in the coating, but it's a minor component. More specifically, the coating is referred to as sol-gel ceramic.


I think you're confusing ceramic coatings with reinforced PTFE coatings, which may sometimes contain ceramic particles. Actual ceramic coatings for cookware contain no PTFE at all.

For example, premium PTFE coatings such as GMM's Duramax and Whitford's Eclipse are internally reinforced with hard materials of some sort. However these are not marketed as PTFE-free, because obviously they aren't. On the other hand, a ceramic coating that's advertised as PTFE-free, such as Thermolon (which is used in GreenPan) is completely free of fluorinated chemicals.

Could you please give the source when you're not on mobile?

For fellow Europeans who are also wondering if this might affect them too, one of the comments at the bottom of the article seems reassuring but is actually somewhat misleading, because the precautionary principle wasn't a general principle in EU law until late 2006.

That being said, the EFSA is looking into the topic:


For those wondering

PFA/PFOS="poly- and perfluoroalkyl substances"

As an article seeking to get this message out about the PFA court case, perhaps you are justified, however this should have been your starting point:

"The chemicals used as criteria in the suit are called PFASs (pronounced “pee-fass”), and are unregulated at the federal level. [The suit asserts that these chemicals are found in 98% of Americans today].

In June, the Agency for Toxic Substances and Disease Registry (ATSDR), an arm of the Department of Health and Human Services (HHS) issued an updated draft toxicological profile for PFASs.

For drinking water, [the report recommends an] acceptable concentration of 7 parts per trillion of PFOS and 11 parts per trillion for PFOA, according to Laurel Schaider, a research scientist at the Silent Spring Institute. Right now, the EPA’s 2016 guidelines set an acceptable drinking water concentration for PFOA and PFOS at 70 parts per trillion, about ten times higher than the draft report’s thresholds.

... by the standards in the ATSDR report, a PFASs exposure greater than approximately two thousandth (0.002) of a drop [of water] in the average yearly water intake of an American adult could be considered potentially unsafe"

EPA limits (which are usually the federal action limit, not a recommended consumption limit): https://www.cdc.gov/nutrition/data-statistics/plain-water-th...

PFOA/PFAs are also widely used as DWR (Durable Water Repellant) for clothing.

Even Patagonia still uses chemicals in this class (or did as of 2015): https://www.patagonia.com/blog/2015/03/our-dwr-problem/

More reading here: https://www.motherjones.com/environment/2016/02/ski-clothing...

Ceramic nonstick cookware. Heavier, but does the same job. https://chemistry.stackexchange.com/questions/61420/what-is-...

There's better coverage of the lawsuit here: https://www.bloomberg.com/news/articles/2018-11-29/3m-dupont...

Wow, what an interesting coincidence: https://i.imgur.com/IPqwYGQ.jpg

I was just reading about fluorides in ski wax, and all the problems associated with it and the upcoming EU ban, then I browsed HN and found this story on top.

For a (much!) longer read about this stuff, the intercept has a 21-part series here: https://theintercept.com/series/the-teflon-toxin/

I find I have very little patience for breathless articles that include acronyms in their headline and fail to clearly define those acronyms within the first paragraph. This article therefore lands hard in the waste bin.

However, if you're interested, PFA stands for perfluoroalkoxy polymer. Wikipedia has information here: https://en.wikipedia.org/wiki/Perfluoroalkoxy_alkane

This is a much better Wikipedia article on the subject, one that actually explains why it's so dangerous: https://en.wikipedia.org/wiki/Perfluorooctanesulfonic_acid

There are major swaths of the country where PFAS and PFOS doesn't need to be defined: it's common knowledge and the terms see daily use among the general population as they drink filtered water to avoid ingesting it. But spelling out the name doesn't tell you the story, so if you're discounting the information because the name isn't spelled out, you're missing a major disaster slow-rolling the industrial Midwest right now. The long form of the name is the least interesting part of the article.

Any books I can read on non-toxic living? These days I feel like they are a lot of toxic substances in our everyday products that should be substituted for cleaner versions but I am not aware of all of them. Is there a useful book on this subject?

Last year I read about pm2.5 in our air and have gotten some sensors and air purifier to combat this particular problem.

A major source of PFAS contamination is military bases. There are hundreds of U.S. Air Force and Navy installations with fire and crash training sites, where they literally dump thousands of gallons of PFAS-laden fire fighting foam on the ground during exercises. A combination of brain-dead military leadership and intensive lobbying by DuPont, Chemours, and others. The Intercept has done some excellent reporting on this issue:


Hi all,

Quick note: the headline is from a Massive Lab Note (https://massivesci.com/notes/scientists-just-cut-the-tolerab...), while the link above is pulling from an Oct 2018 article related to an ongoing US health study about safe limits of several PFASs.

I skimmed comments below briefly--PFASs are used as processing components to create non-stick cookware. They can be emitted directly from the cookware as Teflon breaks down, becomes scratched, or is overheated. The "legacy" PFASs have been largely phased out, with replacements like GenX taking their place. These replacements offer similar toxicological consequences compared to "original" PFASs.

Do you think it helps to buy spring water for drinking? Our tap water just came out to have near the epa limit of pfas. (And the water company made it sound like a positive thing!)

It depends. Especially if by spring water you mean normal bottled water. Don't assume that their water quality will be water. In many cases, bottled water is worse than local water.

We bought a counter-top distiller 15+ years ago and are never going back. If fact, I think we have worn out 3 now. Highly recommend.

Can you link to it? I guess a distiller gets all chemicals out.

Basically an earlier version of this beastie: https://waterwise.com/?product=waterwise-3200-countertop-dis...

I suspect that this one is identical for all practical purposes.

It seems that a distiller would remove those chemicals whose boiling point is above the boiling point of water.

Low boiling point compounds, like say benzene, would just evaporate and then condense with your water into your final product. Distillers get rid of heavy things that don't boil, like metals and large contaminants like bacteria and their waste products.

A carbon filter would get rid of the organics and low-boiling point things.

So optimal water purification would first use a carbon filter, and then distill the output of that. Make sure to add minerals to the final product though. Pure water is a vicious solvent and will slowly melt your teeth away. It will also become quite acidic after sucking CO2 out of the air, so consider adding some pH balancing salts too.

The distiller I use has carbon filter packs at the output of the distillation chiller (at the top of each carafe where the water enters).

Distilling the water won’t remove the chemical.

And it will remove minerals, making the water unhealthy. Drinking distilled water is a horrible idea.

Does tap water contain the optimal amount of each mineral? How does it compare to spring water? Is solid food devoid of minerals?

It doesn't matter if you're drinking the "optimal" amount of minerals, distilled water has none so it leeches those minerals out of your body as you drink it. Drinking distilled water leaves you with less calcium and iron and etc than you had before you drank it.

So, you think I should be drinking water pumped out of the ground in Silicon Valley? First of all, the amount of naturally occurring mercury is very high. (The Almaden Quicksilver mine was the largest cinnabar strike west of the Mississippi, if not largest in North America.) Then there is 50 years of semiconductor fabrication. I'll take my chances with distilled, thanks.

... do you know what distilled water is? It's very different from filtered or reverse osmosis water. You can get filtered water in a water bottle that's not distilled water. Dasani, Fiji, Aquafina, Smart, etc... that's filtered water. Distilled water is really really bad to drink. It's acidic, has zero minerals, and has no electrolytes so it will not hydrate you.


Got a source for "really bad"? Because that would conflict with the above link. I stand by my comment above: distilled water, passed through a carbon-filter post-distilation, seems like a better bet than drinking water the city pumps out of the ground in Sili Valley.

>distilled water seems like a better bet than drinking ground water

Those are not the only two options. There is a third option that exists, it's called purified water and it leaves the important minerals and salts in the water. Water can be purified without being distilled, and even your own source says distilled water will leach chemicals from the plastic container into the water. Distilled water is what you put into a car's radiator or a home humidifier, not into your body.

There are plenty of sources from actual medical journals and the WHO (not random Internet blogs) on the negative health impacts of distilled water here: https://en.wikipedia.org/wiki/Distilled_water#Health_effects

Yes. Either that, or install a reverse osmosis filter on your tap.

I’ve heard a lot of bad things about reverse osmosis water effects on your body as well.

I assume that you're referring to magnesium deficiency problems, e.g.:

"Magnesium deficiency in tap water in Israel: The desalination era"


So, yes, make sure that you're supplementing magnesium or getting plenty from foods if you switch from plain tap water to RO or distilled water.

Just get a reverse osmosis system which remineralizes the water. Can be found on many good RO systems

I recently saw a local notice about PFAs and their voluminous use in firefighting foams at the nearby military bases and airports. Apparently it was making its way into the drinking water.

The wikipedia page has some information.


PFAs = PFCs. Not sure why they renamed them.

Maybe because PFCs have such a terrible reputation?

Also called PTFE, Teflon, and GenX. You can never get rid of the molecule (so they've found) but I guess you can try to get rid of the name?

You're describing different things. Teflon is a brand name of PTFE, which is a finished polymer. PTFE is considered safe until it has been subject to heat stress and undergoes thermal breakdown (around 200C). This makes use of PTFE as non-stick coating in cookware potentially dangerous.

GenX and PFOA are notionally different chemicals used in the manufacturing of PFTE. They are both used to accelerate the polymerization reaction. It is nominally possible to have finished PTFE products which do not contain relevant (choose your definition) amounts of either family of chemicals. GenX and PFOA are both toxic in themselves, regardless of use - unlike teflon.

Yes, they're all different molecules but have the same essential characteristics which make them dangerous: namely, that they all cause cancers and birth defects and that they all pollute the water supply in a way that cannot be remediated.

Another story about Teflon! Why do these articles always bury the lede? Just say it's Telfon!

There's a great documentary about this that came out last year called, The Devil We Know. The TL;DR is that Dupont (seller of Teflon) and 3M (the inventor) knew early on that Telfon caused birth defects and cancer.

They knew it would poison the water supply and could never be remediated. And they went ahead and sold it, again and again, into thousands of products because Dupont was earning about $1B in profits (on their $23B in revenue) just from Teflon alone.

Because teflon is not by definition a PFA (PerfluoroAlkoxyAlkane). It is C2F4, while PFAs are C2F3O?? (where there is an oxygen cooridinated reactive fluoro group dangling off at the ??)

Teflon is non-reactive and does not have these health issues. However PFAs can be byproducts of the manufacture of teflon, and they can be used in similar ways to teflon (they allow high temperature molding of corrosion resistant materials). The primary contamination issue is with this byproduct, particularly when it was manufactured, sold and used as a fire suppressing foam.

The people who dumped that crap and covered it up deserve jail time, but uninformed fear mongering doesn't serve the public either.

This is not correct. Please watch the documentary film. Teflon absolutely has these health issues. You can move the tail ends of the molecule around all you want to and it still has the same dangers.

Ummm... tail? C2F4 doesn't have one. It will form a polymer, but it doesn't have a tail. As I mentioned sulfates may be a byproduct in some manufacturing (precipitation) processes, but not in cookware where their contamination would be absolutely critical at ppm levels.

Perhaps you mean the coordinating Oxygen in PFA or the Sulfur in PFOA, PFOS (ScotchGuard)? Those chemicals are known to be toxic and contaminated many marine animals and watersheds... some are regulated, some are not, and some companies have ignored the regulation, or the regulators have ignored the pollution. It's bad, but not relevant to teflon PTFE per se.

It seems like you might not have seen the film. I'm not a chemistry expert, but it was quite enlightening. Maybe if you get a chance to watch it you cost post your thoughts...

So I can keep using my bread maker?

Modern (last 10-20 years at least) commercial teflon is so low in PFAs that your exposure is likely dominated by what comes in your water :^\. I'd consider it at least as safe as the acrylamide coating your cast iron skillet.

All of them are much safer than driving, but that frankly isn't very safe... since it's way up there on the list of things likely to kill you.

Oh, but be careful with very high temperatures (500F+) frying, or dry boiling water pans. The teflon can break down and react with oxygen creating some of the same compounds. It has been known to kill birds!

Chemical companies are pretty much never the protagonists. Stories about green revolutions feeding lots of people or whatever are good tries at making the chemical company the good guy. But there will always be something impeachable about whatever it is that DuPont and 3M do.

It sort of doesn't matter what the specifics of the toxicity are, which people will litigate here endlessly. So for once, consider that talking about the specifics of the toxicity is, fundamentally, co-opted by the antagonists of this scenario, because it sows confusion. Making it a science problem is attractive, but that line of problem solving is certainly perceived by the public to have long been hijacked by moneyed interests.

Because if PFAs really caused cancer, or vaccines really caused autism, or pornography really caused massive amounts of violence against women or whatever--if it was really a hair on fire problem, we'd know. Air pollution really causes lung cancer, and it's seemingly invisible, but the hair on fire problem does exist there: visit Delhi. There, it's visible.

In the United States, a lot of low hanging fruit has been addressed. So the kind of faucets-on-fire urgency that we saw with fracking is actually very rare nowadays. Yet we have a legacy environmental movement oriented too strongly around finding issues like that, that are capable of communicating only about issues like that. Ecoterrorism, class action lawsuits, big urban protests, reactionary political campaigns--it's great for getting rid of air pollution and visible disasters like that, but it's ineffective for stuff that's just a bunch of boring science.

We'll eventually figure out how to litigate environmental problems. It won't at all resemble this preposterous adversarial trial and torts system. Goodnight to environmental lawyers, on both sides, despite their intentions. To keep this on topic for this forum, the person who figures out how to save the environment will definitely not be some grad student or $500k/year 50 y.o. industry MEng trying to make patentable inventions to get funded by VCs. People chasing the dollars are the environmental problem, after all.

The people caught up in details of economics, law and scientific toxicity will just go away (i.e. technocrats) from this problem. We kind of already know that DuPont and 3M are guilty parties in something here. It won't be important to normal people what precisely corporate polluters are guilty of, because a normal person will never be on the wrong side of that justice equation.

>because a normal person will never be on the wrong side of that justice equation.

If someone uses a hammer to kill their spouse, the hammer manufacturer definitely is not on the wrong side of the justice equation and the person is.

The torts system is almost certainly co-opting the criminal justice system, not the other way around.

It's precisely because of some law needing to be fair to hammer manufacturers, who literally no one cares about, that gun manufacturers, which pretty much everyone does care about, can do shitty things in this country. You're thinking in terms of law, and I'm talking about a court of public opinion.

And even if you litter (pretty much the worst a normal person can do in the court of public opinion re: pollution), we don't need years to litigate that in a court of law.

And yet, it took five years to litigate the BP Horizon spill, even though there's camera footage showing oil coming out of their derrick in real time. What was there to litigate there? Who really cares whether it's $18.7 billion, or $187 billion, or $1.8 billion, other than the BP chairman? Who really cares what they think, in the court of public opinion?

No normal person is ever going to have $18.7 billion to lose, nor will ever have the capability of doing the kind of environmental damage BP's bad oil platform did. So why allow environmental law to even adjudicate the matter, over years, which has never once, ever, delivered maximum justice to the public?

Why compromise on our values and the environment, constantly, to protect some essentially unproven economic logic that BP, or DuPoint, or whoever, generate more value for some community somewhere in "jobs" or whatever than the damage they did by polluting?

The primary normative question in that case: Should we just shut down BP? We didn't need 5 years of negotiations to resolve that, we didn't need any more evidence or calculations. Someone in the justice department, in an afternoon, made the determination that BP won't be closed, and then a complex legal strategy was pursued, by both sides, for five years, to generate the illusion of justice to execute on that determination.

Pollution cases act like criminal cases, and they shouldn't be! The whole problem is reductive, slow, storied, legalistic reasoning, and reductive, unproven economic aphorisms.

> Should we just shut down BP?

By what legal process? What happens to the assets, the investors and staff? Does it matter that the British Petroleum is, in fact, a British company?

I personally don't believe that pornography is a major driver of violence against women, but I'd argue that we already do have a hair-on-fire problem in the US. A third of women have experienced physical violence from their partners, one in ten have been raped by their partner.

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