Microplastics (these nasty entropy-increasing substances) have a way of making it into anything - they even have a way of making it into fruits/vegetables and human placenta. We can expect concentrations in the environment may only be expected to increase over time. That they increase over time means that we should get more concerned over time, and that previous studies hinting at lack of health risk may be invalidated as bodies may accumulate more microplastics than they have several decades ago (even though it appears that their net effect on health/inflammation is lower than that of air pollution, which has been gradually decreasing). These particles may be expected to only bioaccumulate, given that the cell is not great at getting rid of them. We know that even carbon nanotubes can impose oxidative stress on the cell due to disrupting its external structure - microplastics follow a distribution of size vs volume and the smaller microplastics might be similar to air pollution and nanoparticles in how smaller sizes are more easily absorbed by the cell (OR the cell nucleus) and more likely to disrupt the cell structure. The neurological effects of them (The plastic brain: neurotoxicity of micro- and nanoplastics | Particle and Fibre Toxicology | Full Text) may be the most worrisome effects of all.
Despite these limitations and the often observed absence of a clear dose-dependence of the effects (in particular for gene expression studies), there seem to be several consistent effects. Several studies reported the accumulation of micro- and nanoplastics in brain tissue of fish and indications that micro- and nanoplastics can cross the blood-brain barrier [22, 79, 80, 86]. This is confirmed by additional literature observing blood-brain barrier permeability for polystyrene nanoparticles in vivo  and internalization in neuronal cells in vitro [97, 98, 111, 112]. Overall, these findings highlight that (human) exposure to micro- and nanoplastics can result in systemic uptake and/or accumulation in the brain.
AVOID GETTING INTO SITUATIONS THAT GET YOU INTO NEEDING BLOOD/PLASMA TRANSFUSIONS.
They may also be causing systematic demasculinzation/feminization of organisms in all environments, which may be an indirect cause of population decline seen in many animal populations (especially amphibians).
Traditionally, many have said that certain plastics are safer than others (eg they advise you to look at the packaging and stay away from plastics labeled type 3, 4, or 5). This was done based on research from way before 2010 (based on suspicions about endocrine disruptors and styrene’s notable toxicity on cells). Now it appears that microplastics of all kinds can bioaccumulate in the cell - even the more inert kinds that were previously considered benign (polyethylene or polypropylene), and it may be better for us to avoid all sources of plastic exposure altogether.
What’s more, we’re in an era where bioplastics (such as polylactic acid) may now be more manufacturable than ever. Do what you can to accelerate development into bioplastics to make it safer for all of us to switch to plastics sooner rather than later… (creating or starting a startup to create alternatives to microplastics may be THE thing to do). Get or fund an analytical chemist to fund the measurement of these microplastics in common food containers (like they did for plastic water bottles)
BRING THIS TO THE ATTENTION OF RAY DALIO/JEFF BEZOS/BALAJI AND MAKE THEM WANT TO FUND ALTERNATIVES TO PLASTICS (I suspect these 3 more than many others)
Some SF grocery bags are “decomposable/biodegradable” but it is unknown if the plastics contained in these are less harmful than the plastics found in humans.
Human body burdens of microplastics through table salt, drinking water, and inhalation were estimated to be (0–7.3)×10^4, (0–4.7)×10^3, and (0–3.0)×10^7 items per person per year, respectively
Some 80-20 tips on reducing microplastic exposure: Especially STAY AWAY FROM bottled water (Bottled Water Drinkers Could Consume Up to 640,000 Microplastics a Year), get an air purifier, wear N95/N99 masks when possible, wear cotton/lint clothing (plastics from clothing can outgas), avoid eating marine creatures like mussels and fish (even sea salt and seaweed have microplastic contamination, though at lower levels than higher up in the food chain), wash food that has been inside plastic containers, especially stay away from styrofoam (of all microplastics, polystyrene uniquely imposes the most damage), use aggressive water filters (eg reverse osmosis water filters if possible), only use coffee makers where hot water does not come in contact with plastic. Stay away from food packaged in plastic containers for long periods of time (esp food surrounded by water) - the amount of microplastics that leech into food from storage containers can only increase over time.
Avoid sea salt (or salt in general) if you can - it seems especially prone to microplastic contamination.
don’t use eyedrops too much (microplastics can more easily migrate into the brain that way)
Sturdier plastics leach less than “flexible” plastics (this is why plastic water bottles are so uniquely bad)
Canned food is complicated - even bisphenol-A-free containers may have resin that has been contaminated by BPS or polyvinyl.
PFAS might not be a microplastic, but have detrimental effects and you should stay away from them by not using oral-glide-B floss. They may also be found in water pollution so look up water pollution tables of your state.
Furniture and carpets are a major source (so hard to avoid). Wood floors are better, also run air purifiers near overly fibrous furniture
Some brands of almond milk may be coated in tetrapaks made of polyethylene based microplastics) - try to pick almond milk that isn’t packaged in tetrapaks (whole foods almond milk isn’t, for instance)
Microplastics found in all human organs: Microplastic particles now discoverable in human organs | Plastics | The Guardian
Most microplastic exposure from the air: https://pubs.acs.org/doi/10.1021/acs.est.9b04535
Estimating total lifetime microplastic exposure: Estimating lifetime microplastic exposure -- ScienceDaily
""Widely used plasticizers with endocrine disrupting properties, e.g. dibutyl phthalate, dimethyl phthalate, butyl benzyl phthalate, or plastic monomers such as Bisphenol A (BPA), can affect both development and reproduction in marine species: effect concentrations of plasticizers in laboratory experiments in some sensitive species such as molluscs, crustaceans and amphibians (including disturbance in spermatogenesis in fish) coincide with measured environmental concentrations in the low nanogram/litre to microgram/litre range. It should be remarked that there are still basic knowledge gaps, including the long-term exposures to environmentally relevant concentrations and their ecotoxicity when part of complex mixtures . Other EDCs, such as alkylphenols, have the capacity to derail male reproductive development leading to feminisation or demasculinization of the male form in fish and altered sex in molluscs. Others, such as tin-containing plastic stabilisers, elicit immunological disorders in fishes and induce imposex in gastropods .""
Areas of microplastic research: analytical chemistry of microplastics, microplastic quantification and trendlines (eg https://www.nature.com/articles/s41467-020-17932-9 )