[john-radio]

This comment is unhelpful; the person you're replying to clearly is not claiming that "absolutely everything that's harmful in large doses is harmful in small doses."

> Unrealistically high doses imply absolutely nothing about lower doses.

The example they give of nuclear radiation is a clear illustration of how a useful hint can be drawn from the high-level example of harm, a pattern which microplastics might very well follow.

[cowl]

But it's not actually a clear illustration. Quite the opposite of it. We are all (no exception) at all times exposed to radiation (And this is not something recent or man-made, we are exposed to natural radiation all the time). So his Assertion that High-level -> harm means low level -> harm is clearly False without specifying a threshold where this happens.

[sfn42]

If it doesn't apply to everything then we don't know whether it applies to this which is exactly my point.

Ionizing radiation is also a great example of something everything on the planet is exposed to all the time and we're fine. So clearly the fact that you'll die standing next to the molten core in Chernobyl does not imply that you'll die from background radiation.

Similarly, showing that an extreme dose of microplastics is harmful does not imply that a normal dose of microplastics is. It might be, but we don't know because we've only tested extreme dosages, apparently.

We also don't know that it works the same way in the body as it does in a test tube.

[s1artibartfast]

Models can breakdown at huge scales because they introduce other non-representative factors or nonlinear responses.

Sending an astronaut to the center of the Sun and concluding their death is from radiation would be a pretty bad model.

Hitting a person with a car would be a pretty bad model for a fly landing on them.

The first model is bad because the sun is doing more than just exposing them to radiation.

The second model is bad because there's a nonlinear response to force applied to a human body.

[peteradio]

There needs to be an understanding of the mechanism of cell death in the OP. And then the question is, under what circumstances will it occur in the human body? Is it basically impossible because the body is filtering it out? Or is there some long-term accumulation where eventually we will see some parts of the population suffering these ill effects? Unknown, but without studies like OP we aren't on the first rung of the ladder.

[s1artibartfast]

Sure, Data is data. It is the extrapolation and conclusion that are suspect and dishonest