Comment by rmah | Hacker News Reader

Comment by rmah | Hacker News Reader

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The Reuters article is based on an article published by the WWF about a study they commissioned at the U. of Newcastle (Australia). Press release is here (https://wwf.panda.org/wwf_news/press_releases/?348337) and the summary is here (https://www.dropbox.com/s/nxvyl3v5s9d0a1v/PLASTIC%20INGESTIO...). If I'm reading this right, the study itself was a analysis of 50 other studies, not original work. A brief about the methodology is here (https://www.newcastle.edu.au/newsroom/featured/plastic-inges...).

And, given the language "people could be ingesting...", "suggests people are consuming...", I'm a bit suspicious of the numbers given. The study itself is said to be under review for publication and has been for over six months now. Anyone know if that's a long time, normal or short?

Not sure if this matters, but the naive math doesn't really work... they say "about 2000 pieces a week" and that they were "fibers", and "about 5 grams". The pieces are stated to be < 1mm in size. Assuming an average of 1mm x 0.1mm x 0.1mm "fibers" (rather large IMO), that's 20 cu mm or 0.02cc. Given plastic's density that's 0.03g, not 5g. I wonder if someone misplaced a decimal point or confused mg with g.

Further, they claim that the majority of plastic is from drinking water. Call that at least 2.6 grams per week. Say that someone drinks 3 liters of water a day. There should be more than 120 mg in each liter of water. Cover a tall glass of tap water with a cloth and let it evaporate, and there should be a highly visible layer of plastic left at the bottom. Boil a pot of water to dryness, and there should be atrocious smoke from scorching the residual plastic.

Run a faucet with a filter system attached, and in minutes there should be multiple grams of plastic trapped in the filter. You'd expect clogging by plastic to be the lifetime-limiting factor of a faucet filter and of circulating filtered water fountains for pets.

In reality, I have never seen visible plastic residue in evaporation residue or trapped in household water filters.

Many people drink almost exclusively bottled water.

That's easy to test too. Run the boiling-to-dryness test once with tap water and once with bottled water. Try the same with a Brita filter pitcher. I don't think that you will observe any more plastic in the bottled water than in the tap water.

Bottled water is tap water.

https://clark.com/deals-money-saving-advice/pepsi-aquafina-t...

Yes, but tap water isn’t bottled water. It’s been shown that plastic beverage containers leach plastic into their contents.

Where has this been shown? I have never seen this. Are you saying that there's plastic particulates that leach into the water, or some kind of residue?

The person is referring to BPA. And the answer is... maybe.

scientificamerican.com/article/plastic-not-fantastic-with-bisphenol-a/

Not long ago I watched a tv show from Spain that wanted to make some awareness about this topic. They bought some fish and prawns and more seafood that should contain "lots of microplastics".

They took all of it to a laboratory and the laboratory found nothing at all. The presenter told the audience that it was surprising for him, and that they thought that the results were a letdown for the purpose of the documentary but that it was "good news" that we can still enjoy food without microplastics...

I would say that the results will vary vastly depending on the place you obtain the samples, but anyway, we should change our relationship with plastic...

Kudos to the show for still airing the episode anyway (whatever their reasons might have been)

Plot twist: the show was paid for by Big Plastic.

So we eat tons of the stuff every year. Now what? Try searching for "what happens to ingested microplastic". To kill the suspense, most everyone looking to scare you with huge numbers also seem to avoid answering that more interesting question. But from the small amount of information that I could gather, I suspect that the answer is too big of a let down (figuratively and literally) to make interesting news. Happy trails to all looking for answers.

Everything I've heard is microplastics can cause infertility.

https://www.sciencemag.org/news/2014/06/can-plastics-cause-i...

https://environmentjournal.online/articles/microplastic-poll...

https://www.theguardian.com/us-news/2019/may/24/toxic-americ...

None of this is conclusive, but there's more and more evidence that microplastics might be causing serious reproductive issues in humans.

The fact that we don't yet know the ramifications, if any, doesn't mean that it isn't a potential problem. This is true for the complex chemical soup that is our bloodstream these days, making any sort of inferences to specific isolates exceedingly difficult and even off the mark.

Don't read anything into the six month review time: it's perfectly normal.

In fact, we've waited longer than that for a single set of reviews (ugh) and it's rare for anything to be accepted straightaway. Most papers go through the review-revise cycle at least once, even at the journal where they're ultimately accepted. This also doesn't indicate much about the quality of the research. Reviewers can flag serious problems, but they may also just want improvements to the writing (more details/discussion) or complementary experiments.

It's hard to check the numbers from the press release stuff. I swear I saw at <5mm somewhere too. I would bet the underlying studies are a morass of different definitions and methods, and I'd expect that a major contribution of the paper is to find some clever way to combine them.

Or, to put it another way: A study which has not passed peer review made an outlandish claim, one which anyone can verify is false just by boiling their tap water and inspecting the sediment. Flagged, and also I no longer trust Reuters to do simple factual reporting.

If the study just studied YOUR tap water, then yes, a counter-experiment of the sort will refute it.

Else you could be the unscientific outlier, thinking you've shot a study down with a sample of one -- whereas you could e.g. be on one fortunate district with really clean water supply.

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