DOWNTOWN — What lies in the murky depths of the mysterious Chicago River?
Scientists aim to get a more complete answer under a new study of the waterway being launched this year.
The study by the federal Argonne National Laboratory and the Metropolitan Water Reclamation District is expected to last seven years.
"The river has become substantially cleaner over the past several decades, thanks to many interventions, but we still don't have a thorough understanding of what lives there," Argonne environmental microbiologist Jack Gilbert said in a statement.
Researchers will take samples monthly between March and November through 2019.
Federal regulations currently require water testing but "they just look for E. coli or a few other known pathogens," Gilbert said of the Environmental Protection Agency.
All bacteria and viruses, pathogenic or not, will be examined in the new study in order to "sort through who is there and what they are doing," Gilbert said. The scientists aren't just interested in what microbes are in the river but how they interact with each other, which could help them prevent unwanted developments such as blooms of bad bacteria, he said.
Argonne environmental scientist Christina Negri said the river's microbial population changes frequently, depending on such factors as temperature and sewage overflows.
The river was reversed in 1900 to stop its flow into Lake Michigan, the source of the city's water supply, having been treated as an open sewer for decades. Its full microbial contents are unknown but a question of increasing importance as the city tries to develop the river for recreational use.
The new study comes as the MWRD prepares to begin disinfecting the effluent it puts back into the local waterways and the city continues to expand ways to use the river, with new boathouses and a Great Chicago Fire Festival.
In 2011, the federal government ordered that the river be cleaned up enough to allow swimming. Currently, the EPA recommends that people who go onto the river cover open wounds, avoid swallowing any river water and wash their hands before eating.
Last summer, the Friends of the Chicago River and Openlands released a study that projected that a clean river could be a "multi-billion dollar economic driver for Chicago and the surrounding region."
"Investing in the Chicago River is good for the river and good for the region," Friends of the Chicago River executive director Margaret Frisbie said in May.