Public Health’s role in protecting people from water contamination


Picture from Free Press Journal

Earlier in February, equipment failures and heavy rains caused King County’s West Point Treatment Plant to divert wastewater into Puget Sound. We sat down with Public Health’s Environmental Health Division staff to ask about potential health impacts and Public Health’s role during this event and others like it.

Why is Public Health involved in an event like this? As the local health agency, Public Health determines the potential risk to human health from sewage spills and events like the emergency bypass at West Point. Our role is to assess how likely people are to become exposed to contaminated water at public beaches, and then advise public beach property owners to inform the public of the risks. Typically, we will advise property owners to post signs warning the public to stay out of the water. Beaches potentially impacted by the West Point bypasses are owned by the City of Seattle. Beach “closure” updates for the current West Point event may be found at Seattle Parks and Recreation.

If the beach is posted does that mean people should stay off the beach?

The current closures advise people to stay out of the water, but walking on the beach is perfectly safe. SCUBA divers should also stay out of the water near a posted beach. Fishers should wash hands if they get water on their hands. The fish should be rinsed.

What is the risk of contamination to human health?

It’s important to avoid contact with contaminated water because of the bacteria, viruses and other organisms in human sewage. Public Health advises people to wash their hands after going to the bathroom for the very same reason – exposing yourself to feces can make you ill with gastrointestinal problems like upset stomach, diarrhea, and vomiting, skin problems like rashes or other conditions and illnesses.

Of course, the likelihood of getting sick may depend on how much sewage you’re exposed to. During the periods of bypass, the discharge has been 85-90 percent stormwater, and 10-15 percent untreated wastewater. Once it goes into the Puget Sound, this combined stormwater-wastewater mix is dramatically diluted further.

Nevertheless, out of an abundance of caution we will keep the beaches near West Point closed until we are certain there are no further impacts.

Read more about water-related illness at the U.S. Centers for Disease Control and Prevention.

What about pets – can they go in the water?

Animals should always be washed off after going in the water at a beach, stream, or lake.

If no signs are posted, does that mean people don’t need to worry about contamination?

It’s always important to wash your hands or take a shower after going into any body of water. Urban beaches are heavily used and potentially contaminated by dogs and wildlife.

What about shellfish harvesting?

No Puget Sound beach in mainland King County is safe for shellfish harvesting because of on-going pollution that has impacted our shorelines for decades. Some areas of Vashon Island are open. Before shellfish harvesting, always check the Shellfish Safety Information Page maintained by the Washington State Department of Health’s Shellfish Program. You will learn what locations are open for shellfish harvesting, as well as what species of shellfish are safe to harvest.

How does Public Health determine when to have property owners post signs?

If Public Health hears of a water contamination event, we will review the results of water tests. Since it can take a day or two to get water tests back from the lab, we frequently tell property owners to post signs before we know for sure whether the water is contaminated – out of an abundance of caution. Once we have the water tests back from the laboratory, we will advise the property owners to leave the signs in place or to remove them, depending on the results of the water tests.

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Originally posted on February 17, 2017