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E. coli Monitoring in Utah's Waters: Advisories
Davis County Health Department issued an E. coli related health advisory on July 7, 2017 for Clinton Pond located in Clinton, Utah. Davis County Health Department will continue to monitoring E. coli concentrations throughout the summer.
The Utah County Health Department posted signs on July 14, 2017 at Sandy Beach on Utah Lake due to elevated levels of E. coli bacteria in water samples collected in July 10th and July 13th.
- Utah Lake E. coli Sampling Data (June 8, 2016 – Present)
Updates: July 2017Utah DWQ continues to monitor E. coli at several beach areas on Utah Lake once per month. The E. coli related advisory remains in place at Lindon Marina.
Updates:October 14, 2016
Utah DWQ has been collecting data in and around the Lindon Marina since the initial closure in order to assess if E. coli levels warrant removal of the water quality advisory. Results for the sampling are provided in the above data file. While levels of E. coli appear to be diminishing, there are still high levels of E. coli identified in a tributary to the Lake that DWQ is currently investigating.
News Release: Temporary Advisory Issued at Lindon Marina Due to E.coli (09/29/16)
Samples collected from the Lindon Marina on September 23, 2016, by the Division of Water Quality (DWQ) indicated an exceedance of the Escherichia coli (E.coli ) indicator for Utah Lake of 668 MPN (most probable number) per 100 milliliter as outlined in Utah State Code R 317-2.
UCHD has posted caution signs at Lindon Marina advising people not to swim or wade in the area or ingest the water. Health officials suggest that people wash their hands with clean water after handling fish or touching the lake.
In 2009, technicians from the National Park Service measured E. coli levels above the numeric criteria established for the North Fork of the Virgin River upstream of the Zion Narrows. Since 2010, the National Park Service has issued warnings to anyone issued a permit to hike the Zion Narrows. Subsequent monitoring has revealed that multiple irrigation return flows are likely the driver of downstream E. coli exceedances.
- Clinton Pond, 2015
An E. coli advisory was issued by Davis County Health Department for Clinton City Pond on May 22, 2015 following 2 consecutive samples over the maximum E. coli criteria for waters with a 2B beneficial use. Signs were posted at the site and remained in place until 5 consecutive samples yielded results below the numeric criteria. The advisory was removed on November 24, 2015.
- Maybey Pond, 2015
Davis County Health Department issued an E. coli advisory for Maybey Pond between October 1, 2015 and November 2, 2015 due to high levels of E. coli.
- Salem Lake, 2010
In 2010, several sets of E. coli samples collected at Salem Lake exceeded the maximum water quality criteria for 2A waters. An advisory was issued following DWQ’s E. coli Advisory Protocol. The advisory remained in place until 5 consecutive samples were found to be below the water maximum quality criteria for Salem Lake at which time the advisory was removed.
What is my risk if there is an advisory?
While E. coli is an indicator of fecal contamination and may not be a direct cause of illness, the threshold of 409 most-probable number of density counts per 100mL of water sample (MPN) for adopted to issue a swimming advisory relates to a risk factor of 8 illnesses per 1,000 swimmers. As the value of the MPN increases above 409 MPN, the risk of illness if exposed to contaminated waters also increases.
Different waterbodies have different numeric criteria based on their beneficial use as outlined in Utah State Code R 317-2. All waters of the State are protected for contact recreation (Class 2A and 2B), and some waters are classified as drinking water sources (Class 1C). Class 2A waters are protected for frequent primary contact, while Class 2B waters are protected for infrequent primary contact.
To remove an advisory, there must be five consecutive samples under the numeric criteria for the beneficial use class, and the long term average of all the samples must be below the 30-day numeric criteria. This lower value is more protective of long term exposure. These values have been adopted from the US EPA.
How is an Advisory Issued and removed?
Priority lakes and reservoirs are routinely monitored for E. coli. When a sample is found to be greater than the water quality criteria according to R317-2, a crew is assembled to resample the site within 24 hours or as soon as possible after the first sample. If the consecutive sample is greater than the water quality criteria, then DWQ and the local health department may issue a joint advisory. The site is routinely monitored during the advisory and will remain in place until five consecutive samples are below the water quality criteria for the site. See DWQ’s E. coli Advisory Protocol for more information.
Where is an Advisory posted?
E. coli advisories are issued by the local health department following guidance from DWQ. If an advisory is in place, signs will be posted at the lake/reservoir. Contact your local health department or visit DWQ’s E. coli advisory page for more information.
Can fish from the lake be contaminated because of E. coli?
Probably not. Because fish are not warm-blooded, E. coli cannot live in the fillets. However, the water covering the fish could contain E. coli, as well as the guts of the fish. Uncooked fish may well have E. coli contamination. Wash and cook the fish, and wash your hands after handling fish and lake water to reduce your risk.