“Is it safe to swim in the river?” is one of the most common questions ShoreRivers hears from community members. Fecal bacteria and toxic algae in waterways pose threats to both water quality and public health. People who come in contact with bacteria- or toxin-laden water can contract eye, ear, and respiratory diseases, skin rashes, gastrointestinal issues, or brain or liver damage. To assess the health of our rivers and potential risks to human health, ShoreRivers regularly monitors bacteria pollution at 28 sites throughout the mid and upper Eastern Shore and works closely with government agencies to track toxic algal blooms.
The Swimmable ShoreRivers program tests all the rivers in the ShoreRivers region for bacteria at popular swimming locations, marinas, yacht clubs, and towns. ShoreRivers staff and volunteers conduct tests on a weekly or bi-weekly basis from Memorial Day through Labor Day. The program follows EPA’s standard protocols for collecting and analyzing samples and uses a pass/fail system to determine if bacteria levels are safe or unsafe for swimming. You can view the results from the sites at theswimguide.org and get updates during swim season by following #SwimmableShoreRivers on social media.
Additionally, the Swimmable ShoreRivers program works with government health agencies at the local and state levels to monitor toxic algal blooms and inform the public of serious potential health risks to humans and pets. Algal blooms occur naturally, but increased levels of nutrient pollution in our waterways from fertilizers, septic systems, and wastewater plants fuel larger, more toxic, and longer-lasting blooms.
In the ShoreRivers region, toxic blooms occur most frequently on the Sassafras River due to its lower salinity levels. This summer ShoreRivers dealt with a toxic algal bloom on the Sassafras that lasted for almost three months. This was the largest, longest lasting, and most toxic bloom ever recorded on the river, causing the Maryland Department of the Environment to issue a water contact advisory for the whole river.
The results from ShoreRivers’ monitoring in 2020 show that bacteria and algal conditions vary based on location, weather, and other factors, making systematic, scientific analysis vital. The majority of the bacteria monitoring sites passed more than 60% of the time. However, a few sites failed more than 40% of the time; meaning that in the majority of times sampled, the bacteria levels in the water exceeded EPA’s threshold for safe water contact. Specifically, these sites are located at Hambrooks Bay Beach, Crouse Park, Denton, Broad Cove Claiborne, Morgan Creek Landing, and Duck Neck.
“Bacteria pollution most commonly comes from leaking sewer lines and septic systems, stormwater runoff, domestic and wildlife droppings, and land application of manure and sewage,” says ShoreRivers Choptank Riverkeeper Matt Pluta. “Our results show that bacteria levels increase after rainfall, so after a wet summer like the one we just had, we expected bacteria levels to be high at many sites.”
Now that the program has baseline data showing which sites frequently have elevated levels of bacteria, ShoreRivers will focus on the next most frequent question from the public: “Where does bacteria pollution come from?” ShoreRivers is currently exploring partnerships and innovative technologies to help identify specific sources of bacteria pollution at specific testing locations.
“Once we know where the bacteria is coming from—whether it’s leaking sewer lines, failing septic systems, over-application of fertilizer, or people not picking up after their pets—we can start implementing real solutions,” Pluta says. “Monitoring techniques such as DNA sampling and bacteria source tracking are improving and becoming more reliable. It’s another tool in our Riverkeeper toolbelt to help improve water quality conditions so Eastern Shore waterways are always safe and swimmable.”
For more information, visit shoreriver.org/swim or email mpluta@shorerivers.org.
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ShoreRivers protects and restores Eastern Shore waterways through science-based advocacy, restoration, and education. shorerivers.org Contributed Image
