[emanuer]

I am asking this question out of true intellectual curiosity: Could someone please link me a study which shows strong evidence for micro-plastics being harmful to health, that goes beyond finding "potential" harm? – Thank you!

Seriously, I am looking. So far every study I have found — linking micro-plastics to physical harm done to multicellular organisms — had the phrase "potential" (or a derivative) in it.

I dislike plastic as much as the next guy, but I slowly get the feeling: the harmful effects of plastic have the same level of scientific proof as harm caused by radiation of mobile phones — inconclusive to likely _none_.

[radu_floricica]

The question is VERY fair, and I don't want to undermine it. I just want to be the first to say that given the huge potential impact, "potential" is bad enough.

When dealing with probabilities there are two measures that need to be considered independently: probability and effect. Traditional statistics multiplies them into "expected utility" and works just with the aggregated value. But that's tricky, because effect is not a continuous function. Imagine a pebble falling on your head plotted based on its weight - there'll be sharp discontinuities at "hurts", "commotion" and "death".

At society's level there are also similar discontinuities. Something that may cause tens of million of cases of cancer over time should be in a separate category from a medicine that may suddenly kill a few hundred people, even though the latter has a bigger emotional impact.

[Cocktail]

As to why there has been only papers stating potential harm, I believe that is due to the long term study cycle. When can a researcher positively conclude confirmed harm? In humans, that could take a lifetime, maybe two. Other animals must also be studied, but doing that can be much more difficult and resource intensive. Here thinking about marine life primarily. Point being, everything thus far learned points to harm in the long term. Long term studies have only begun in the last 10-20years I believe, and could be that we will be waiting for further still

[L_226]

You may try searching for the components present in certain microplastics that are harmful, e.g. (BPA) bisphenol A [0].

Microplastics that have been generated from plastics containing BPA that are then lodged into the food chain from a very low level will have serious consequences, as BPA is an endocrine disrupter, and shown to negatively affect many physiologial systems including human sperm [1].

[0] https://en.wikipedia.org/wiki/Bisphenol_A [1] https://www.sciencedirect.com/science/article/abs/pii/S08906...

[pgt]

Disrupting any part of a complex system is dangerous to the stability of the system. How can ocean life distinguish between food and small pieces of plastic?

I've seen so many photos of dead fish filled with plastic that it must be a concern to the food supply chain.

And absence of evidence != evidence of absence.

[DoingIsLearning]

https://news.ycombinator.com/item?id=24489565

edit for context:

In practice several plastics compounds are chemically too 'similar' to estrogen (the 'female' hormone).

The plastics with these estrogen like compounds typical either mechanically breakdown (microplastics) or leach due to chemical breakdown (e.g. caused by contact with high temperature liquids or acidic solutions).

Once absorbed it may confuse your body as a 'pseudo estrogen' hormone. This acts as an endocrine disruptor, potentially more so for Males of animal species because of their hormonal profile.

[0xcoffee]

I'm also interested in what happens to the bag labels in hot water. I'm always using these single use tea bags and the label always falls in the cup.

[rorykoehler]

The label has a slit in it so you can avoid this. Wrap the string around the cup handle (or spoon if you don't have a handle) and slot it into the slit to fasten. It will never fall into the water again.

[pritovido]

Most of the time, it is not plastics themselves, but the hundreds of chemical additives that each plastic has, like plastifiers, ph and surface tension modifiers.

The most important is hormone-like compounds like Bisphenol A (BPA) because hormones are chemical compounds that are used as signals and its effect cascade multiplied by billions in the body, so super small amounts can affect you enormously.

They are being replaced, but new compounds also have hormone like response.

Because biology works by "shape is function" lots of chemical compounds can affect your body because they resemble the one we need for our body's normal function, and the body receptors are confused.

This has extensively been proven that happens, what we don't know is what dose could be ok. For example, you can use(without problems) fleece outside clothing if there is not a big part of your skin in contact with the fleece, like what happened with kid's pajamas, that was very problematic.

Probing that on humans is something similar to covid vaccine testing. It is extremely expensive and bureaucratic process and only gives us statistical results. Knowing exactly what happened is extremely difficult or impossible in practice because there are hundreds of chemical compounds, and they interfere with each other creating factorial combinations. But we know it breaks havoc in your body for sure.

You also should avoid heat because it makes chemical diffusion exponentially higher. When you eat your soda can, the PET layer,is at ambient temperature. When you eat coffee or tea, it is hot.

[1ark]

Lots of references to studies on this topic in the book "The Anti-Estrogenic Diet".