The scale of global microplastic contamination is only starting to become clear. There are two principal concerns: very small plastic particles and the chemicals or pathogens that microplastics can harbour. In the nanometre range they can penetrate a cell which means they can penetrate organs. Microplastics can attract bacteria found in sewage. Some studies have shown there are more harmful pathogens on microplastics downstream of wastewater treatment plants. Microplastic contamination has been found in tap water in countries around the world. guardian