Julia Poska| May 3, 2019
Luther College biologists have found disease-causing bacteria and parasites in Winneshiek County water, in some cases at disease-causing concentrations, according to Iowa Public Radio.
Over half of the 48 surface water samples Jodi Enos-Berlage and Eric Baack took at streams and springs tested positive for cryptosporidium, a parasitic protist that can cause digestive distress for weeks. Half of the 22 private wells tested showed cryptosporidium, too, but at significantly lower levels, the researchers said.
Twenty percent of the surface waters tested positive for the Shiga toxin, as well, which is produced by the pathogenic strain of E. coli. At some sites, the concentration of the toxin in just one cup of water would be high enough to cause fever and digestive distress if consumed.
The biologists also tested for indicators of human and animal feces, which could have carried those pathogens into the water via farm runoff or aging septic systems. Baack told IPR he was surprised to find low-level fecal contamination widespread in surface waters. The researchers found less fecal contamination in wells.