By DEQ Communications Office
Escherichia coli (E.coli) have been in the news a lot lately. The outbreak in Hildale that claimed the lives of two children, a recent health advisory at Utah Lake’s Sandy Beach, and a boil water order in Lindon City last winter — all attributed to E. coli contamination. And while most large outbreaks of illness can be traced to contaminated food, E. coli can contaminate water as well.
E. coli are a large and diverse type of bacteria commonly found in the intestines and feces of healthy people and warm-blooded animals. While most strains of E. coli are harmless, some varieties can cause diarrhea, urinary-tract infections, and even pneumonia. Infections may be very mild, but some can be severe or even life-threatening.
The Utah Department of Health and local health departments are the front-line responders for illnesses caused by fecal contamination and have the authority to issue health advisories for E. coli, but the Utah Department of Environmental Quality’s (DEQ’s) Division of Water Quality (DWQ) does its part to keep the public safe by monitoring Utah’s high-priority waterbodies for E. coli contamination.
E.coli in Recreational Waters
While the impact of E. coli in waterways doesn’t generally get the press coverage of foodborne illnesses or drinking-water boil orders, these pathogens can pose a risk to people recreating in lakes and streams.
E. coli makes its way into surface water and ground water through human and animal waste. Sources can include improper waste dumping, faulty septic tanks/sewer systems, stormwater runoff, and waste from dogs and livestock. Even large concentrations of waterfowl and other wildlife can cause problems. Recent research, for example, has shown that seagulls are important contributors of fecal contaminants in surface waters, and some gulls have even been found to carry a drug-resistant strain of E. coli. With so many potential sources of E. coli contamination, it can sometimes be difficult to pinpoint a specific source or cause.
DWQ’s statewide monitoring program samples for a wide range of possible contaminants, including E. coli, to determine if waters in the state are meeting water-quality standards. Water-quality data collected by DWQ is used to identify emerging problems, determine whether pollution-control programs are working, and help direct resources and pollution-control efforts to the areas where they are most needed.
E. coli is a good indicator of the presence of fecal contamination, and possible disease-causing bacteria or viruses in water. Health officials use the presence of E. coli to determine if the public needs to be notified of a health risk, since the pathogens that accompany fecal contamination can also make the water unsafe for people.
While it would be ideal to collect E. coli samples on all Utah waters on a weekly basis, limited resources means DWQ must take a tiered approach to monitoring. Each year, DWQ works with local health departments to prioritize highly recreated water bodies across Utah. Utah’s high-priority recreation lakes and reservoirs are sampled monthly during the May-through- October recreation season. Other lakes, rivers, and streams are sampled on a targeted, six-year, rotating-basin schedule. While this six-year rotation schedule is helpful for assessment purposes, it does not provide ongoing protection for public health at less-frequented areas.
DWQ alerts local health departments if monthly sampling indicates elevated concentrations of E. coli in waters within their jurisdiction. Water-quality scientists take a second sample as soon as possible after the first sample, and if the test results exceed the numeric criteria established for that waterbody, the local health department and DWQ may jointly issue a health advisory. The site is then monitored on a regular basis during the advisory. The advisory remains in place until five consecutive samples are below the water-quality criteria for the site.
Risk of Exposure to E. coli
While most samples collected by DWQ don’t indicate a high risk of illness from exposure to E. coli, recreators should still assume all surface waters contain some E. coli or fecal contamination. People can protect themselves by not swallowing the water and washing their hands before touching their mouth or eyes. The single most important way to prevent person-to-person spread of E. coli is through thorough hand washing.
The E. coli O157:H7 strain responsible for serious illness is generally spread through contaminated meats and vegetables or direct contact with infected people and animals. However, this harmful strain may also be present in lakes and streams, and waterborne transmission is still possible through swimming and ingestion of contaminated water, so caution is advised.
Because fish are not warm-blooded, E. coli cannot live in the fillets, but the guts and water covering the fish could contain E. coli. Anglers should wash and cook the fish, and wash their hands after handling fish and lake water to reduce their risk.
If problems are discovered through routine testing, additional monitoring can help water-quality scientists identify the sources of the contamination. Since E. coli can come from many different points-of-origin and can be spread throughout a watershed, pinpointing the source(s) of contamination can be a difficult task. Once the sources are known, field investigations can assist scientists and managers in identifying problem areas and developing strategies to reduce pollution.
Regular testing helps identify areas with elevated levels of E. coli and protects the public from inadvertent exposure to high concentrations of disease-causing organisms. But monitoring alone isn’t the solution. Reducing or eliminating the sources of contamination will diminish the likelihood of E. coli and other pathogens making their way into Utah waters.
People should enjoy Utah’s beautiful lakes and streams but always be mindful of the possibility of E. coli in the water and take appropriate precautions.