3 ms·

EDIT: OK, what I said is quite wrong or at least misleading, see forum_ghost's comment for discussion of importance of catalytic and enzyme inhibitor/activator

EDIT: OK, what I said is quite wrong or at least misleading, see forum_ghost's comment for discussion of importance of catalytic and enzyme inhibitor/activator activity of such compounds. --- ...generally a chemical that doesn't degrade is chemically inert so it has less chances than any other more degradable compounds to cause harm (btw, how much research did we put into the multiple pathways of degradation for the currently fashinable "biodegradable" stuff? how many of those possible intermediary degradation compounds are not in fact quite toxical). (Bio)degradable also means reactive, so things are more complicated than it seems. But yeah, any non-degradable fluid is probably a very bad idea because it's gonna spill and get everywhere, so even minor probability of toxic effect could have insanely large consequences...

mtsr 4y ago
What about bioaccumulation, though? Doesn’t inertness also make it more likely to stick around somewhere in the foodchain?
forum_ghost 4y ago
That's not how any of this works. Metabolism (reactivity by proxy) and enzymatic/inhibitory activity are orthogonal. One of the least reactive metals, Platinum, is an excellent catalyst in numerous reactions, but often found entirely unreacted in nature: https://en.wikipedia.org/wiki/Platinum https://en.wikipedia.org/wiki/Platinum a stable chemical can have catastrophic consequences for various species, if it is a potent agonist/antagonist in a critical signalling pathway, or an enzyme/inhibitor of some process. Often these effects are clinically relevant in nanomolar concentrations. The stable chemical DDT is so stable, it actually bioaccumulates, with biological half-life in decades. It's also a known carcinogen that elevates risks of cancer 4-5x simply from historical exposure decades ago. As for "biodegradable", that's often basically fraud. PLA (polylactic acid), one of the most common greenwashing plastics, does not biodegrade at all under common conditions, outside of very specific composting process, not usually (maybe even never?) found in nature. Luckily PLA isn't very toxic.
adrianN 4y ago
That is of course a good rule of thumb, but as the example in the article shows it is not generally true.

mtsr 4y ago

What about bioaccumulation, though? Doesn’t inertness also make it more likely to stick around somewhere in the foodchain?

forum_ghost 4y ago

That's not how any of this works. Metabolism (reactivity by proxy) and enzymatic/inhibitory activity are orthogonal. One of the least reactive metals, Platinum, is an excellent catalyst in numerous reactions, but often found entirely unreacted in nature: https://en.wikipedia.org/wiki/Platinum https://en.wikipedia.org/wiki/Platinum a stable chemical can have catastrophic consequences for various species, if it is a potent agonist/antagonist in a critical signalling pathway, or an enzyme/inhibitor of some process. Often these effects are clinically relevant in nanomolar concentrations. The stable chemical DDT is so stable, it actually bioaccumulates, with biological half-life in decades. It's also a known carcinogen that elevates risks of cancer 4-5x simply from historical exposure decades ago. As for "biodegradable", that's often basically fraud. PLA (polylactic acid), one of the most common greenwashing plastics, does not biodegrade at all under common conditions, outside of very specific composting process, not usually (maybe even never?) found in nature. Luckily PLA isn't very toxic.

adrianN 4y ago

That is of course a good rule of thumb, but as the example in the article shows it is not generally true.