E. coli level forces advisory on Janesville creek
JANESVILLE — Health officials are warning residents enjoying Palmer Park to stay out of Spring Brook after water testing this week showed high levels of E. coli and nitrates.
Results showed the creek has E. coli levels of 1,414 counts per 100 milliliters.
Any sampling over 1,000 counts results in an immediate closure at licensed beaches or a warning at other sites, said Tim Banwell, environmental health director for the Rock County Health Department.
Staff posted an advisory Wednesday morning in Palmer Park alerting people to avoid contact with the stream, including pets, because they can get sick.
Some varieties of E. coli can cause disease if they get into a human or pet's intestinal tract, Banwell said.
The department Monday sampled surface water for bacteria testing at 26 beaches, lakes, streams and the Rock River around Rock County. Test results Wednesday showed several streams around the county jumped in nitrate levels.
The county nitrates in surface water averaged 9.5 parts per million, up from about 5.5 last year, he said.
“Nitrates in particular aren't really threatening in streams other than promoting algae growth,” Banwell said. “It's just a change we're seeing, probably from a source from people rather than just a natural occurring (change).”
Nitrates can come from manure and fertilizers.
Last year, all but three sample sites had nitrate levels less than 10 parts per million. This year, nine sites were above 10. Only one, Fisher Creek, dropped significantly from about 14 to 8.
There is no standard for nitrate levels in surface water, but the drinking water standard is 10 or less, Banwell said.
All sites are sampled in June and December, with many others sampled on a weekly or monthly basis, “just to get an idea of what is the risk out there,” he said.
Palmer Park's E. coli levels are high ever year, he said, noting results of about 2,500 twice last year in May and mid-July.
Cattle use the Spring Brook “quite a ways” upstream, and county land conservation staff is working with the property owner to keep the cattle out of the stream, he said.
Other sites with higher levels of E. coli were Spring Brook in Carver-Roehl Park near Clinton at 770 parts and Otter Creek north of Milton at 727.
Last updated: 7:51 am Monday, July 29, 2013