Scientists are beginning to explore the presence of microplastic contamination in groundwater systems. A new study of University of Illinois at Urbana-Champaign is the first to uncover the discovery of microplastics in fractured limestone aquifers, an underground freshwater source that supplies 25% of the world's drinking water.
In two aquifer systems in Illinois, the team found microplastic fibers and a variety of medications and household contaminants.
"Plastic in the environment breaks down into microscopic particles that can end up in the guts and gills of marine life, exposing animals to chemicals in plastic," said study co-author John Scott, a researcher at the Illinois Sustainable Technology Center. "As plastics break down, they act like sponges that absorb contaminants and microbes and can finally reach our food supply."
According to Scott, groundwater flows through cracks in limestone, potentially carrying sewage and runoff from roads, landfills and agricultural areas to the aquifers below.
The research team collected 17 groundwater samples from wells and springs, including 11 samples from a highly fractured limestone aquifer near St. Louis and six from an aquifer that had much smaller fractures in northwest Illinois.
Overall, 16 of the 17 samples contained microplastic particles. The highest concentration, which was 15.2 particles per liter, was collected from a source in the St. Louis region. Scott said it is difficult to understand what this concentration implies because there are no published risk assessment studies or safety standards.
Lead study investigator Samuel V. Panno, a researcher at the Illinois State Geological Institute, said field area concentrations were comparable to the surface water concentrations found in the Chicago rivers and streams.
"Research on this topic is at a very early stage so I am not convinced that we have a frame of reference to declare expectations or limits on what is considered low or high," said co-author Tim Hoellein, a professor at the University of Loyola. . "Our questions are still basic – how much is there and where does it come from?"
Scott explained that much work remains to be done, and he hopes that microplastic contamination will continue to be a problem for many years.
"Even if we stop making cold turkey plastics today, we will still deal with that issue for years because the plastic never goes away," Scott said. "It is estimated that 6.3 billion tons of plastic waste have been produced since the 1940s, and 79% of them are now in landfills or in the natural environment. To me, it's such a strange concept that these materials are meant for single use, but they are designed to last forever. "
The study is published in the journal Groundwater.
Per Chrissy Sexton, Earth.com Employee writer