These microplastics are pervading the world’s water sources, invisible to the naked eye, but fully present in more than 83% of cups of drinking water around the world, according to a study conducted by Orb Media that surveyed dozens of countries.
Plastics slowly degrade into microplastic particles. Chemicals added to plastics to improve their properties leach (escape) into the water as this happens. Leached chemicals attach to microplastic particles by a process called sorption.
Some of the leached and sorbed chemicals are listed below. They are thought to be dangerous for us, but this may be true only when they are sufficiently concentrated.
PCBs (polychlorinated biphenyls) are synthetic chemicals that are no longer made in the United States. They used to be added to plastics and are still present in the environment, however. They can produce a number of harmful health effects and are classified as a probable carcinogen (cancer causer).
PAHs (polycyclic aromatic hydrocarbons) are persistant chemicals that don't break down easily, like PCBs. They are added to some plastics. They are a possible carcinogen and can also produce other effects.
Flame retardants, chemicals that act as hormone disrupters, and pesticides are also carried by microplastic particles. Each of these can produce a range of harmful effects, which depend on the identity of the chemical.