Washing synthetics in your washing machine creates a number of fibres to be released, and these microplastics can get in to the water supply and can't be removed. Once in the water supply they can end up in our food, and animals across the world.
Solution: the Guppy Washing Bag.
Put all your synthetic fabric washing in to this bag and wash as normal. The clothes come out clean as normal, and all microplastics get caught in the bag. Eventually you can see them gather in the bag lining and you can remove them from the bag and put them in the bin.