Two city beaches, Bell Park's main beach and Nepahwin Park beach, are the subject of a water quality advisory from the Sudbury and District Health Unit.
Routine water samples taken at the two beaches showed higher levels of bacteria than is acceptable.
"We have enhanced our monitoring and will continue taking water samples at both beaches," Cindy Rocca, a support officer in the health unit's environmental health division, said in a press release.
While the health unit isn't closing the beach, it is strongly recommending against swimming at the site, as E. coli and other bacteria can cause health problems, according to a previous interview with Holly Browne, a manager of the environmental health division at the health unit..
"If they ingest the water, it can cause an upset stomach and it may cause symptoms such as diarrhea. Certainly, there's intestinal problems."
Other problems can include eye, ear and nose infections, and infections in wounds.
While the health unit tests beaches for bacteria, it doesn't test beyond determining what type and how much bacteria is present.
"There's always the potential that the (bacteria) is a harmful bacteria. We don't know that, which is why we put the warnings up."
The beaches will have to have bacteria levels within the acceptable levels for two days in a row before the health unit will remove the signs.
The health unit tests more than 30 frequently-used beaches in the Greater Sudbury and Manitoulin area on a regular basis. The results of these tests can be found on its website at www.sdhu.com.