Microplastics.

Microplastics are omnipresent and pervasive and as their name declares, very very small.  

Primary microplastics are any plastic fragments or particles that are already 5.0 mm in size or less before entering the environment. These include microfibers from clothing, microbeads, and plastic pellets (also known as nurdles or mermaids tears)

Secondary microplastics are microplastics that are created from the degradation of larger plastic products once they enter the environment through natural weathering processes. Such sources of secondary microplastics include water bottles, fishing nets, plastic bags and every piece of single use plastic used in our everyday lives.

There are pieces even tinier than microplastics, nanoplastics. Nanoplastics are pieces of plastic as above that have degraded down to sizes less than 1 μm or less than 100 nm in size, respectively.  

Tiny particles of plastic have been found in the bloodstream of blue mussels and in human faeces. Scientists are now focusing their attention on research to discover the affects of plastic pollution on human health.

Microfibres are being eaten by plankton (check out Plankton Pundit, Dr Richard Kirby on Twitter)  and with plankton being at the very bottom of the food chain, all marine life from the bottom up are eating plastic particles, and then in turn so are humans.