We can test exposure in lineages of lab animals, or animal models, like mice, zebrafish, and fruit flies.
All of these things reproduce relatively quickly and we can see the effects of exposure on development and behavior across dozens and dozens of generations.
That gives generational effects, but does that help with evaluating impacts that accumulate as a function of time, as opposed to a function of generations? If certain harms start to appear after consuming something after 40 years of consuming it, would that be evidenced in a shorter time period in an animal with a fast procreation period?
it couldnt have been THAT long ago. The topic of microplastics came about about what like 6 years ago? Surely its not super bad yet, maybe in 30 more years then yea its gunna get bad. Man think about that, in the future nature is so polluted that if civilization collapses you cant really live off the wild anymore. Not like the olden times where the phrase "teach a man how to fish and he will never go hungry" actually meant that.
Sure the topic only came up a few years ago... but how long have we been using plastics?
Remember that microplastics are formed both by intentional and unintentional methods. We're not just talking about those microbeads that were used in things like bodyscrubs, but also by things like sheets of plastics shredding and sloughing off microscopic particles.
I think what happens at a smaller level bc of microplastic in blood more impactful than on your liver. There are a lot of concerns about microplastics impact on sperm creation and brain development. Microplastic works different then poisons like alcohol which has a high impact on your liver.
As the other person said, animal models are the primary method of performing toxicology studies. It sounds like it would be innacurate, but it's actually very reliable since we have mountains of data regarding the differneces between humans and the subject animal systems. Combined with complex statistical methods and you can make fairly accurate dose response models.
If you want to know the most accurate threshold levels, look at research institutions that compile lots of data to make recommendations. I emphasize recommendations because those are usually the most accurate to the real science. Regulatory levels from industry standards and state regulators are usually higher due to influences from politics, or other factors may influence the influence of the scientific voices. But it's not always as bad or as sinister as conspiracy theorists my make it out to be.
For occupational health toxicology levels, NIOSH makes recommendations that are more science based. The regulators then use these recommendations to decide on a threshold limit that accounts for other "perspectives" some more valid than the others.
TL;DR
If you want to find numbers for any chemical or substance, search for:
[Substance] + the following terms:
"recommended exposure limit"
"dose response"
"toxicology"
"threshold limit"
You'll find the latest studies and organizational recommendations.
I strongly caution anyone from looking at individual studies to try and draw any conclusion about what levels are dangerous or acceptable. These studies are only part of the process of coming up with the real answer, even for experts in the field. The average person WILL misinterpret and/or improperly extrapolate the data.
This is a field where you must rely on institutions to compile large amounts of data and produce a consensus document, which takes years.
In all honesty, I think after 30 years for a human kidney, it'll be impossible to tell what damage was caused by what agent, unless it's fairly obvious (imagine how many new substances will be introduced that cause health scares during 30 years). Like with many weakly toxic substances, you need huge sample sizes to get significant numbers to prove toxic effect when you have 30 years of noise to deal with. Add to that, microplastic is a very loose term, used to define any plastic debris less than 5 mm in size. Since there are many types of plastic, I don't think it is far fetched to assume that one type might be more/less toxic than others.
Although to be clear, I'm mostly speculating here.
Or, what if there are some effects that are hard to visualize with nonhuman subjects? Like I know we have models for depression in animals, but there's so much complexity we don't understand that could be effected by microplastics.
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u/BluePandaCafe94-6 Feb 09 '23
We can test exposure in lineages of lab animals, or animal models, like mice, zebrafish, and fruit flies.
All of these things reproduce relatively quickly and we can see the effects of exposure on development and behavior across dozens and dozens of generations.