The only thing we humans did an incredible job of leaving behind is plastic. Microplastics, in particular, seem to be everywhere these days: in sea turtles, table salt and even beer. Now, a new study offers evidence that microplastics may be seeping into our groundwater supply as well. Researchers from Illinois have discovered microplastics in wells and two aquifer wells in the state.
This latest study, published in the journal Groundwater last week, claims to be the first to find microplastics in fractured limestone aquifers, which account for about a quarter of the world's potable water supply. Because of their geology, these aquifers are highly porous so they can easily absorb the water from the surface above – and everything that comes with it. Researchers at the Illinois Sustainable Technology Center and Loyola University Chicago collected 11 groundwater samples from one aquifer near St. Louis and six from an aquifer in northwestern Illinois.
Only one sample returned free of microplastics. Researchers speculate that the tiny plastic fibers they found come from domestic septic tanks, perhaps carrying the drain of laundry loads.
Clothes were previously identified as a major source of microplastic pollution, with each wash potentially releasing hundreds of thousands of tiny plastic fibers. In this last study, the highest concentration of plastics found in a sample was about 15 particles per liter.
That does not mean much now. There is not enough data on groundwater microplastics for scientists to tell if this is too much. In addition, we still do not know much about the impacts of microplastics on our bodies, so there is no concentration considered unsafe or illegal.
"Research on this topic is at a very early stage, so I'm not convinced that we have a frame of reference for the expectations or boundaries of the state at low or high levels," said Tim Hoellein, a biology professor at Loyola University . Chicago and co-author of the new study, in a press release. "Our questions are still basic: how much is there and where does it come from?"
These researchers did not discover only microplastics in the water. They also found drugs and household contaminants, supporting the idea that the particles originated in domestic septic systems.
A study conducted earlier this year found some microplastics in groundwater, but not enough to raise any alarm. Last year, a separate study warned that the impacts of microplastics on terrestrial ecosystems, including soils and freshwater, can be as damaging as ocean impacts.
This new study is the latest to remind us that our local water supply may be vulnerable. And if microplastics are getting into our drinking water or our fish, they're coming back to us.