Plastic is a synthetic material derived from organic products such as `hydrocarbon fuels`_ (coal_, `natural gas`_, `crude oil`_, salt, and_, and other possible constituents.

Most plastics are created in one of two major processes: polymerization or polycondensation. In both cases, petroleum distillates are combined with specific catalysts to create novel, typically larger, molecules.

1   Health

The concerns with plastics that break up into many smaller pieces and enter the body and wider ecosystem are different (and potentially worse) than the concerns of the impacts of a single macro piece.

This is the big question. I think people around the world have been ingesting microplastic for 30 years or longer, yet there's no reported case of any direct toxic effects. So I guess microplastic doesn't have immediately effects on health, but I won't be surprised if future studies find longterm effects, such as increasing the risk of cancer, damage to the circulatory system or the brain.

Overall, I think we must take actions immediately for solutions, but I won't particularly worry about this problem and I'll continue buying bottled water. It's not unlike the air pollution in the 20th century, one has to live with it.

Nevertheless, "microplastic is going to kill all of us" surely is going to be the trope of the next decade.

See also:

The good thing, if you can call it that, is PET and nylon (what these silk teabags are made of) are some of the least reactive and most human-safe plastics you can put in your body.

Researching this it seems like PLA is also common. "Plastic" is a super vague term, and it seems like non-petroleum plastics are the norm for this application. One benefit is that these types of plastics readily biodegrade into lactic acid (which naturally occurs in many foods). From a health standpoint it seems like they could be safer than some petroleum based plastics. Would be interested to learn more from someone who knows this area better.

Commentary published in Environmental Health Perspectives in April 2010 suggested that PET might yield endocrine disruptors under conditions of common use and recommended research on this topic.[26]