A new University of Illinois study documents concentrations of mercury in fish in two state waterways between 1900 and 2007.
Researchers at the Prairie Research Institute found that mercury concentrations in small fish have declined but still persist, even in rural areas far from mercury sources.
Researchers in 2006 and 2007 collected small fish from Panther Creek in Jasper County and Saline Branch ditch in Champaign County.
Panther Creek fish showed higher mercury concentrations, which researchers say may be due to coal-fired power plants in the region
They also tested minnows collected from Panther Creek in 1900 and 1961. They found that mercury concentrations dropped by 64 percent from 1900 to 1961, but increased slightly between 1961 and 2006.
The findings were published in the journal Environmental Monitoring and Assessment.