This article is about heavily fluorinated organic compounds -- molecules with a carbon skeleton and all or most of the hydrogen atoms replaced by fluorine. These are not the ionic fluorine compounds that protect teeth against decay (and that cause acute toxicity in case of over-consumption).
Why are these compounds hazardous?
- Harmful biological effects in the human body, like hormone-mimic activity.
- Low molecular polarity leads to bio-magnification in fats and oils up through the food chain, and persistence in human fat.
- The high strength of the carbon-fluorine bonds greatly reduces the rate at which typical environmental degradation mechanisms (hydrolysis, photolysis, atmospheric oxidation, enzymatic breakdown in cells...) act on these compounds, compared to their hydrocarbon counterparts.
Why are these compounds used?
The same properties that make them hazards once dispersed -- strong carbon-fluorine bonds that resist breakdown, low polarity -- make them desirable in applications where people want water-repellant surfaces or materials that resist high temperatures and/or chemical attack.
Why weren't the risks better known before?
It's a lot easier to test for acute hazards than for chronic ones. By acute toxicity metrics, like feeding a bunch of rats these compounds until the dose is high enough to kill half, these materials are generally less toxic than substances like potassium fluoride. It turns out that for low level chronic exposure, perfluorinated compounds are more hazardous than simple ionic fluorides due to persistence and accumulation.
The link between stability and persistence makes up a recurring theme in environmental toxicology: materials with lower acute hazards are often worse hazards in the long term. The very lack of reactivity that makes molecules less acutely hazardous in case of e.g. a fire or a worker accidentally splashing some on skin makes them more likely to be long term problems, because the same basic properties impair how quickly environmental sinks can break them down. Pure methanol ignites more easily than diesel fuel and has worse acute toxicity risks if a worker gets drenched in a spill. But diesel contamination from a leaking storage tank is more persistent.
Maybe I should have headed that "why weren't the risks obvious at the beginning?". According to the lawsuit DuPont had discovered the risks of perfluorooctanoic acid exposure by 1961. Industrial production of perfluorooctanoic acid began in 1947. Had it been a simple acutely hazardous chemical that killed rats hours after you fed them a few milligrams, the risks wouldn't have taken a decade+ to surface. I'm not trying to excuse DuPont's duplicity after they did discover problems, rather explaining why these sorts of chronic hazards are not necessarily known the first time somebody writes up a Material Safety Data Sheet.
maybe it has more to do with an institutionalized focus on short-term financial gain, disregard for future generations, and either an unawareness of, or an unwillingness to observe, the precautionary principle.
This is analogous to why scientists and policymakers focus so much on CO2 when worrying about global warming.
Other compounds, like water vapor or methane, trap more heat than CO2. But they leave the atmosphere much more quickly: water rains out after a week or two, and methane breaks down in about a decade. But CO2 persists for many decades, perhaps even longer depending on the state of the biosphere.
So despite that fact that CO2 is harmless to human health at atmospheric concentrations, and actually beneficial to plants and some animals, the systemic harm due to its longevity can be huge.
The article doesn't mention whether or not these compounds are removed by using a filter (like a Brita filter).
I know Brita filters don't remove fluoride normally, but these compounds sound organic, which activated carbon usually does remove. Any idea whether standard filters remove this?
----------------
Can PFOA and/or PFOS be boiled out of my water?
No; PFOA and PFOS cannot be removed by heating or boiling water. However, there are steps you and your drinking water system can take to limit your exposure.In some cases, drinking water systems may be able to reduce concentrations of perfluoroalkyl substances, including PFOA and PFOS, by closing contaminated wells or changing rates of blending of water sources. Alternatively, public water systems can treat source water with activated carbon or high pressure membrane systems (e.g., reverse osmosis) to remove PFOA and PFOS from drinking water. These treatment systems are used by some public water systems today, but should be carefully designed and maintained to ensure that they are effective for treating PFOA and PFOS. In some communities, entities have provided bottled water to consumers while steps to reduce or remove PFOS or PFOA from drinking water or to establish a new water supply are completed.
Home drinking water treatment units are typically certified by independent third party organizations against ANSI (American National Standards Institute) standards to verify their contaminant removal claims. Some home filters remove impurities using activated carbon and reverse osmosis, which are the same technologies utilized by public water supply systems to remove PFOA and PFOS. However, there currently are no ANSI protocols for testing home treatment systems to verify that these devices effectively remove PFOA and PFOS or how frequently the filters should be changed in order to maintain removal efficiency. NSF International is currently developing such protocols.
There are no official treatment recommendations for PFNA, PFOA, PFOS that I know of but they can be treated with activated carbon, RO membranes or some combination. GAC seems to be pretty effective and you could feel pretty safe with a Brita filter, a multi-stage undersink system or a large whole house filter.
The issue with chemicals like these and treatment is that without extensive testing there isn't much information about breakthrough rate and contact time and the relationship, so repeated testing is really the only way to know when you need to change media.
Manufacture cartridge change recommendations generally are pegged to chlorine removal only, so a filter may deplete it's PFOA removal potential in a 1/10 the recommended change interval.
Activated carbon can remove some, but not all [0].
> part from the commonly studied perfluoroocta
noic acid (PFOA or C8) and perfluorooctane
sulfonate (PFOS), eight additiona
l PFASs were evaluated: perfl
uorobutanoic acid (C4), perfluoro-
pentanoic acid (C5), perfluorohexanoic
acid (C6), perfluoroheptanoic acid (C7),
perfluorononanoic acid (C9), perfluorodecanoic
acid (C10), perfluorobutane sulfonate (PFBS),
and perfluorohexane sulfonate (PFHS).
> Regardless of the test
ed (S-)PAC, C4 removal was
negligible, while PFOS removal was essentially complete. PFAS removal increased with
increasing perfluorinated carbon chain length, and
for a given perfluorinated carbon chain length,
sulfonates were more adsorbable than carboxylat
es.
tl;dr: long-chain PFAS are removed, while short-chain PFAS are hardly removed at all
> This article is about heavily fluorinated organic compounds -- molecules with a carbon skeleton and all or most of the hydrogen atoms replaced by fluorine.
Yes, though Teflon itself is of such high molecular weight that it's not a hazard that way. Some chemical intermediates and additives associated with Teflon manufacturing and/or application are hazardous though, like perfluorooctanoic acid:
> Why are these compounds hazardous?
> - Harmful biological effects in the human body, like hormone-mimic activity.
Can you provide some evidence for that claim? I know that perfluoro compounds degrade very slowly and accumulate in fatty tissue, but I haven't seen a supported claim about harmful effects. From the misleading links in the article, I suspect more than a few people confuse PFAS and PCBs.
Very true. I've been to some of the anti-fluoride talks and read a lot on both sides.
From what I gather, there simply isn't enough fluoride added to water to really make a difference. Add enough and you start getting dental floursis.
The people against municipal fluoride use a lot of the same bad maths to link fluoride to a plethora of ailments. Their evidence doesn't really add up either. Overall it looks like it's a wash.
I err on the side of it not being in water. It doesn't really help teeth unless applied topically in high concentrations, so we're better off spending money to give kids free toothpaste/brushes/education.
There's the question as to whether or not it can lead to things like osteoporosis, and honestly that question can't be answered easily. Long term toxicity buildup over 30~40+ years in humans is very difficult to test and control for. You can't put humans in a cage and have one group only drink water with fluoride and the other not. Our primate counterparts simply don't live long enough. People move around too much and drink too many different types of drinks to accurately survey exposure.
Of course this article is not about fluoride in water, so this is kinda a rabbit trail comment anyway.
Floride in water is really meant for the people who aren't going to use mouthwash, or floss, or brush their teeth as much as they should anyway. It brings up the dental health of the group with the worst dental health.
You said 'seems', which seems to leave the topic open to discussion in your mind. (:
What's the downside to adding appropriate amounts of fluoride to municipal water sources?
EDIT: after I posted this, I did some quick Googling, and man this is an all over the map topic. There APPEARS to be reasonable evidence on both sides of the debate, but honestly, I'm not personally vested in this enough to dig any more.
And they vote in shockingly large numbers, for example enough to get anti-vaxxers (who I think of as having a lot of overlap with fluoride conspiracy people) seriously considered for cabinet-level positions in the US.
They'll succeed at banning WiFi and other things if we don't obstruct this nonsense. Hell, they'll succeed at banning refrigeration if they have their way.
"A foreign substance is introduced into our precious bodily fluids without the knowledge of the individual. Certainly without any choice. That's the way your hard-core Commie works." - Dr Strangelove
Your comment would hold a lot more weight if EPA or some other massive government agency found it possible to help people in Flint, MI, which did not have drinkable water for years now, and still don't have it.
The EPA and other regulators have been hamstrung by republicans since their inception and then when they don't do everything perfectly republicans love to show how the EPA, SEC or whoever aren't doing their job. Republicans sabotage these regulators and don't provide adequate funding. It's sabotage. "The Republicans are the party that says government doesn't work and then they get elected and prove it." - P. J. O'Rourke
FYI, the EPA is comprised of 15000 employees, and its annual budet is $8.14B. That's $543K per head. A lot of money for sitting on their hands and making excuses that they're "hamstrung".
It's all about how you want to manipulate the stats--$8billion for 320,000,000 Americans is $25/person. Don't you think $8billion is a relatively small budget/price to pay for protecting human health and regulating environment protections in a $16.7 trillion economy with 3.797 million square miles of territory? I sure do.
Nonetheless, people in Flint didn't have drinkable water for years. If the agency is so toothless with a highly politicized case like this, you can only imagine how toothless it is when it comes to the less publicized cases. So don't tell me how awesome the EPA currently is. Maybe it could, in fact, benefit from a swift kick in the ass.
It's been proven that policy decisions & budgeting issues at the state level(and more specifically the governors office) propagated the issues potable water issues Flint has been encountering.
If only there was a conscientious regulator at the state of Michigan....
I'm not sure the logical response to the failings in Flint is to throw out the EPA and other "massive" government agencies. I haven't followed the situation closely but my understanding is that multiple levels of government failed the people of Flint (and continue to fail people in other areas with similar water quality issues) due to politics, funding, and the complex nature of the crisis.
Replacing aging infrastructure needs to be a national priority and will take many decades. Until that is complete we need a strong agency that monitors hazards and enforces compliance regulations - access to clean drinking water (and clean air) should not be a partisan issue. Instead we have a President who appears to believe that the solution to "Democrats didn't do anything to help Flint" (my fake news alarm bells are ringing....) is to gut the EPA and pass ridiculous laws like "for every new regulation we need to remove two".
Not to diminish the Flint Michigan situation, as republicans did when they shuttered the investigative bodies that were looking into it. But how dafuq can the EPA be doing nothing if flint is the rare exception to the rule? If they are to lose credibility for not catching one thing, how much credibility do they get for all the stories we DONT read?
Being EPA is like running IT in a company. You can only lose. If things don't go well you get the blame. If things go well you are asked "what are all these people doing?"
Let me make sure I understand your argument; The EPA was not able to prevent a State's local budgetary decisions regarding drinking water. Therefore it would be more effective if we cut funding to the EPA?
Just goes to show that "regulations" isn't all that needs to happen. We've known for years there are problems in various areas, some of the most drastic of which have been widely publicized due to Flint. What's also been publicized by Flint is that the US government can't find $60M in their multi trillion dollar budget (EPA budget alone is $8.1 _billion_) to fix the situation, yet there's $210M to send abroad at the last minute as Obama is heading out the door, none of which, I might add has any chance of reaching the people who need it there either.
Regulations are not enough. Someone needs to actually go in and fix the shit that doesn't meet the regulations. For that to happen, someone needs to make it a priority to actually fix things right here in this country, rather than just tell us regulations aren't met, and writing up new ones all the time.
While drinking water is generally extremely safe in the US, especially compared to many other countries of the world. I still install three stage, under the counter filtration systems for any kitchen tap water. Minimal costs, and at the very least prevents the water from tasting like a pool.
Exactly! Everyone's always so worried about fluoride in drinking water, with little justification and without giving a thought to all the chlorine which is often present in far greater concentrations and, in certain conditions, can react with other organic and inorganic compounds to form all sorts of nasties.
Get a good filter for your drinking water and most of these concerns vanish. Plus you'll save a fortune on bottled water.
Free chlorine will indeed break down over time, but an hour in the fridge probably won't be sufficient - the half life of free chlorine in water is much longer than an hour! (In sunlight or UV, however, it'll break down much faster).
Secondly, Chloramine is now often used instead (or in addition to) free chlorine. Chloramine is more stable and won't break down by putting it in the fridge.
And the potential health issue isn't so much with chlorine itself anyway, but with other chemical products that can be formed by reactions with chlorine, possibly before the water even reaches your tap.
Not as true as it used to be. Increasingly municipalities are using Chloramine, which I seem to recall does not disperse. While it doesn't affect the safety, it does mean that letting the water sit won't necessarily get rid of the taste.
The article seems to play extremely fast and loose with watershed vs waste treatment plant sludge vs drinking water all being the same. Which is it?
I'm particularly interested because I live in a community marked blue and I'm sure our industrially polluted river tested positive, yet our drinking water comes from 800 foot deep wells and is extremely hard although otherwise extremely clean.
So are we contaminated because somehow the deep wells are contaminated with just this unusual pollutant, or is our industrially polluted river (or some old industrial EPA superfund site, who knows) verified as being polluted, or is our waste treatment plant essentially failing us? (Or of course a combination)
In an era of infotainment and clickbait and fake news its sad to see harvard in the domain name, but its the current year, its not the authors fault that someone is profiting off scientific research, etc.
Its surprisingly difficult to figure out the percentage of people who drink deep municipal well water vs groundwater vs near-ground-water (shallow wells often private and contaminated). Therefore I don't know if my situation of drinking deep well water (presumably safe) but living in a contaminated area is unusual or typical.
My understanding is that just because you live in a blue area of the map doesn't mean you have contaminated water.
Also, note that this paper only looks at public water supply testing data, not private well water.
From the linked article:
"From the authors of the study: We have mapped watersheds in the United States that have potentially high concentrations of PFASs based on U.S. EPA data. This does not mean that all drinking water supplies within the highlighted regions contain high PFAS concentrations, but that at least one sample from at least one water supply was reported to be at or above levels considered safe by the U.S. EPA between 2013 and 2015. However, no measurements have been made in many water supplies across the country. We recommend increased monitoring of these contaminants in our drinking water. For more information, please contact the EPA: Cathy Milbourn, Milbourn.cathy@Epa.gov, or Monica Lee, Lee.monica@Epa.gov."
I'll follow up with my colleague to see if she has any thoughts.
I have another request. (You didn't limit us to one)
The article very carefully avoids discussing actual hazard level or a comparison, merely a measured number exceeded a beancounter's number.
Its irresponsible to make policy decisions without knowing the actual risk level... so inform us?
I realize its difficult to compare ochem toxicity between compounds, famously there are obscure reactions where nothing interesting happens to anyone except pregnant women or unborn children, obscure herbicides that slaughter fish but are otherwise mostly harmless, obscure herbicides that selectively kill broadleaf plants, etc.
None the less ... would it be possible to put the risk in a form people (perhaps incorrectly) think they can understand and manage? Something like fill in the blank: "The risk of drinking unfiltered tapwater at the EPA limit on a normal daily basis is roughly as dangerous to your health as consuming X ounces of 100 proof ethanol per day"
I'm curious if EPA defined contaminated tapwater is as risky as drinking four bottles of wine per day WRT cancer risk or if its more like sniffing an open bottle of N.A. beer.
I tried to find some data on that, but it appears that there is no data available showing definite health hazards of these compounds.
Getting such data can be difficult. Animal models can often be wrong: the toxicity may be specific to humans, or the damage may require exposure over time frames than the animals' life span, or it only manifests under rare circumstances (i. e. interactions with drugs).
The best data you can get may be from people who were exposed to the compounds unusually high degrees, usually because they worked with them. But that group of people may be too small, or not diverse enough (we've long avoided exposing pregnant women to industrial chemicals), or the nature of their work exposed them to different chemicals muddling any results.
You say "Its irresponsible to make policy decisions without knowing the actual risk level", but I'd say that you can't not make a decision: taking the view that a chemical is safe until proven otherwise is as much a decision as the opposite. The EU has started to assume new compounds to be dangerous until proven otherwise – I believe the US may still be doing the opposite.
Ethanol (i. e. alcohol) is also a particularly bad unit of measurement, considering its effects on human health are not just somewhat disputed, but apparently highly unusual. There is quite a lot of evidence for beneficial effects of alcohol, possibly even at rather high dosages (although the effects on cancer, which you mention specifically, are probably closer to a standard linear dose-response relationship,)
We had a big debate in Portland about whether we should add fluoride to our water (we voted it down). As far as I can tell, fluoride in the water is beneficial to people who don't brush their teeth with fluoride toothpaste, but for the majority of us who do, it's not particularly helpful.
I think people should generally have a right not to ingest substances that they don't want to, especially when said substances aren't doing anything useful and might be marginally harmful to some.
There's also an argument that all that fluoride eventually ends up accumulating in the environment, and there may be long term negative effects from that. There's no benefit from watering our lawns or flushing our toilets with fluoridated water.
So, I don't really think this is so much of a science versus anti-science debate as a question of how you should weight the costs and benefits of a policy that people can't realistically opt out of if they don't approve of it.
The best way to prevent this, in my opinion, is to be clear that the research has nothing to do with fluoridated water.
From my colleague:
"The highly fluorinated chemicals that we discussed are organic compounds, meaning that they contain carbon atoms. They are called highly fluorinated or per- and polyfluoro alkyl substances because they have many fluorine atoms, and the carbon atoms are entirely or often bound to fluorine (There may be highly fluorinated chemicals that aren't strictly PFASs, but that's a minor point). These highly fluorinated chemicals have unique chemical properties that give them their characteristic grease and water resistance (typically one end of the molecule is more soluble in oil, and the other end is more soluble in water, similar to other surfactants). The concerns about PFAS toxicity stem from the properties of the whole molecule and not just because they contain fluorine."
Yeah, but people just hear "flouride" and think "OMG That's what they're putting in the water!" Just like they hear about mercury in vaccines and assume they cause nerve damage.
The masses understand at the soundbite level only. I don't know what to do about this.
As an "anti-fluoride person", I just want to go on the record to state that it's ridiculous to be more concerned with riling up a particular group than having safe drinking water.
In fact, counter to common opinion, we have a solidly science-based view on this issue--I'm not sure how we got grouped in with anti-vaxxers and others.
There simply isn't good evidence that adding fluoride to drinking water is a justifiable public health method to reduce cavities, which is why 97% of Western Europe doesn't do it[0]. And because there's no opt-out, it may be dangerous for bottle-fed babies [1].
I'm not saying it's the world's biggest problem right now (by a long shot), but dispensing medicine in water is not good policy.
If I understand correctly, I'd rather have cavities than cancer.
That is: Flouride is supposed to help prevent tooth decay. This stuff, on the other hand, "has been linked to" cancer (how strongly, I'm not sure). But if warning about a cancer-causer kills flouridation as collateral damage, well, I prefer that to the other way around (not doing anything about the cancer-causer to protect people's teeth).
This is extremely non-scientific, but I am an american living outside of the us - and I often wonder 'what's wrong with us' when I meet Americans. Maybe we just have it too easy, maybe we don't have to open up our minds to other cultures (we are the dominant one). But I've met enough people that just make me think c'mon man! That said, we're the dominant culture for a reason - we have some super talented people. At the end of the day, 'flouride' probably isn't the root-cause of our 'unique'-ness.
"The contamination of drinking water in Hoosick Falls is an example of the shortcomings of the UCMR3 program. As part of the UCMR program, all large public water supplies that serve over 10,000 residents, and a small percent of smaller public water supplies, are required to conduct water testing. Most smaller public water supplies and private wells are not required to conduct water testing as part of the UCMR program. The public water supply in Hoosick Falls serves less than 10,000 residents, so it was not required to conduct testing for PFOA as part of the UCMR program, nor were residents in the area who relied on private wells."
I can add that we're also following several other communities with PFAS contamination issues, like Newburgh, NY; Bennington, VT; and Pease, NH.
Not really related, but even as a scientist I really don't understand how ng/L == parts-per-trillion. I know that's a correct conversion, but it doesn't doesn't make much sense. I guess that's why part-per notation are called pseudo-units.
A more substantive comment:
Some of these are particularly scary, especially if you have a job where you're potentially exposed. For example, for benzene has a pretty strong odor, but 5000 ng/L is supposedly 1000 times below what you're able to smell. And it's a carcinogen...
The L part is assumed to have density of 1 (kg/L) and therefore be 1kg mass (mostly water). 1 kg = 1 trillion ng. Because the vast majority of the sample is water the number of nanograms of the substance per nanograms of water is approximately the number of parts per trillion. As you get into higher concentrations of solute you have to consider density of the solute and water as separate parts. In the ng/L or ug/L range you can hand wave the L as 1 trillion parts (by mass) and the ng as the parts out of a trillion in the full volume of sample.
This is because water has a nice correlation of units in SI. 1g water = 1 cubic cm = 1 mL, and takes 1 calorie of heat to raise by 1 degree Celsius. (all at atmospheric pressure). See:
The natural concentration of the weird high molecular weight fluorine compounds is exactly zero, whereas cyanide compounds are natural and show up in small amounts in many fruit seeds, a couple nuts, some root vegetables.
Its not physically possible to eat enough apple seeds to get sick, but if you industrially concentrate cyanide by a factor of a hundred thousand or so because its so nifty at plating metals and stuff, then that purified form will kill you.
Its kinda like ethanol, your liver knows exactly what to do with it in small rare amounts, and out in the wilderness its extremely hard to die of ethanol poisoning from eating too many over ripe berries, or at least you'd have to try really hard for a long time, but given some industrial processing assistance its been possible for humans to die of ethanol poisoning for the last couple thousand years. Very few alcoholics drank themselves to death in 50000 BC, likewise no human died of cyanide poisoning until the 1800s AFAIK.
Unlike cyanides your liver has no idea what to do with the fluorine compounds given that a human liver had never seen one until 1930s, so naturally a little can really mess you up.
I see where you're going, but I'm not sure long-term prior exposure to toxins necessarily dictates just how toxic they are. There are too many confounding variables.
There are plenty of never-been-made-before chemicals that are completely non-toxic and plenty of been-around-forever chemicals that are super toxic (ricin, botulism toxin, etc).
> likewise no human died of cyanide poisoning until the 1800s AFAIK
Cassava roots (tapioca) have been killing and otherwise causing problems for humans for millennia through cyanide poisoning. Bitter almonds have been causing trouble for almost as long.
Nice, an article that links to sources in the prrimary scientific literature! Let's see, the link text says "potent immunotoxicants", that's probably a study about the effects of PFAS on the immune system. But no, it's actually some meaningless bullshit about evolution and doesn't even mention the word "fluor" once.
Given that, the term "toxic" is unjustified (it appears that if PFOA is toxic, then so are fatty acids), and so is the claim of "unsafe levels". This is sensationalist bullshit.
Your misunderstanding starts where you're considering the linked article a "primary source". Even though it's at harvard.edu, it's not a peer-reviewed "primary source".
Given that the absence of evidence does not constitute evidence of absence, the conclusion and causation you imply with "given that" is wrong.
You're also awfully quick to call stuff you don't understand "bullshit".
What, are you saying they didn't link to a scientific source at all?! I'm shocked, shocked, I tell you!
The point was that this is bullshit precisely because it pretends to link to a scientific source, but doesn't. Sure, it's still possible that every single word in the article is correct even in the absence of actual research---but is it likely?
The study found that PFASs were detectable at the minimum reporting levels required by the EPA in 194 out of 4,864 water supplies in 33 states across the United States.
So, about 4% of water supplies had something at the minimum reporting levels; which must be above the detection limits, but may not be at action levels. I'd probably be more worried about heavy metals and organics in some of those locations than fire-fighting foam, but I drink groundwater, not surface-based treatment plant water.
My father was a Ph.D. organic chemist who worked for DuPont at the Experimental Station in Wilmington, DE. We admired and even loved DuPont while I was growing up there in the 1950's and 60's (the "Better Living Through Chemistry" era).
Now I am learning the sad truth about DuPont (and many other industrial chemical manufacturers). Despite the many great achievements of their employees, DuPont was a diabolically evil company. The history of their GM partnership and their promotion of tetraethyl lead in gasoline alone is justification for this statement.
I'm not really strong in stats, but it seems like many of the non-contaminated counties have very low sample sizes that may not be statistically significant. Example: in Marin County, 0 of 11 samples were found to be contaminated. In Alameda, 2 of 73 samples were contaminated.
Why isn't the state of our water supply a national emergency? In the long term this will affect far more people than whatever terrorist scare Trump is currently worried about.
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