There aren't any in polypropylene plastic, polyethylene plastic or polycarbonates.
I'm sympathetic, less plastic is probably good - it does have to be a well thought through change. If the change reduces safety, or if it gets manufacturers to switch to a worse risk profile product, we could be net worse off.
Plastics — including those listed — act as chemical sponges, soaking up and concentrating toxins present in the ambient environment. For example in a household the airborne dust absorbs brominated fire retardants and formaldehydes. The total quantity of toxins in these tiny particles can exceed the gaseous concentration in the air by thousands of times, so microplastics act like a billion tiny Trojan horses for toxins to enter the body.
So when modelling these risks, it could be less about the equilibrium amount of microplastics in the body at any one time (the stock), so much as the constant re-introduction of new microplastics into the body (the flow).
https://www.sciencedirect.com/science/article/abs/pii/S02697...
https://www.motherjones.com/politics/2013/01/plastics-and-ch...